International Journal of Heavy Vehicle Systems (88 papers in press)
Dynamic modelling and design of tracked vehicle suspension system using magnetorheological valve
by Sung Hoon Ha, Min-Sang Seong, Juncheol Jeon, Seung-Bok Choi
Appraisal of numerical-based finite element method to synthesise the wheel-obstacle collision dynamics using a single-wheel tester
by Chongfeng Wei, Hamid Taghavifar, Aref Mardani
Abstract: As a very substantial aspect of vehicle dynamics and vibrational controlling, it is essential to ascertain the role of tyre-obstacle collision kinetics. Ride comfort assessments are pivotal in predicting the non-linear deformation, particularly when traversing large road obstacles. The present study focused on the assessment of a tyre travelling over obstacles at different heights using a well-equipped soil bin facility and a single-wheel tester. The vertically and longitudinally oriented load cells were used to measure the vertical and longitudinal force variations with the frequency of 30 Hz. Additionally, a FE tyre model was developed specifically for this purpose using explicit integration in ABAQUSTM. It was found that with the increase of height of road obstacle, the resonant amplitude of spindle force response as well as the tyre deformation becomes greater in both longitudinal and vertical directions. Furthermore, at greater load, the tyre overriding obstacle impact force increases significantly. It was revealed that the new proposed model can serve as a functional alternative to classical modelling tools for the prediction of nonlinear wheel dynamics.
Keywords: road obstacle; FE tyre model; single-wheel tester; vehicle dynamics.
Design of a truck cab torsion bar
by Luigi Solazzi
Abstract: This work describes the study developed and the design of a specific component called torsion bar, installed on commercial vehicles for the cab suspension, to both increase driver comfort and allow the cab to be rotated for maintenance work on the engine. Currently, the component is made from conventional structural steel: the central element is a single unit of considerable size, a significant factor especially in terms of the space required during shipping. The aim of this research is to design a structure using materials with greatly superior mechanical performance in order to reduce its weight and incorporate a number of design features to make it easier to ship, reducing its overall size and thus the costs involved. The solution developed achieves this aim, with a 25% weight reduction and easy dismantling and shipping. The technical features designed into the solution have reduced the sensitivity of the assembly procedure to operator-related variability.
Keywords: finite element method; cab suspension; torsion bar; truck; high-strength steels.
Non-linear control of vehicles rollover using sliding mode controller for new eight degrees of freedom suspension model
by Amir Hossein Kazemian, Majid Fooladi, Hossein Darijani
Abstract: The stability control system is a part of active safety systems in vehicles, which is designed to control the vehicles dynamic motion in emergency manoeuvres. In the present study, modelling and simulation of a four degrees of freedom passive suspension system (4DOFs) initially has been considered and then, in order to improve the efficiency of controlling system, a new suspension system is designed with 8DOFs by adding masses to sprung and unsprung parts of suspension system and using hybrid semi-active damper. To investigate the effect of DOF on the controller performance, a sliding mode controller (SMC) for models with 8DOFs is designed in Matlab and controller performances are studied. Also, numerical results from a typical vehicle that is simulated in Carsim are the input for the Matlab simulation. Investigations show that increasing degrees of freedom accompanied by applying a hybrid semi-active damper leads to better stability and good handling characteristics of vehicle.
Keywords: semi-active hybrid system; good handling; sliding mode control; stability control; suspension system; rollover; Lyapunov theory.
Experimental comparison of control methods for armoured personnel carriers with semiactive magneto-rheological suspension
by Sabri SaltÄ±k, Zafer Dülger
Abstract: In this study, the control methods of a semiactive MR (Magneto-Rheological) suspension system for an armoured military vehicle are compared. System modelling and testing procedures are described, and then control algorithms are tested and observed on a quarter-car test setup; this setup is modified from a passive to a semiactive system. For tests and simulations, a special offroad profile is formed. This profile is formed depending on the standard military test courses and terrains. During the observation, control ability and personel comfort are observed as the main subjects. Finally, depending on the test results, displacements, accelerations and their effects on subsystems are compared and construed as advantages and disadvantages.
Keywords: magneto-rheological; semiactive; armoured vehicle; hybrid control; clipped control.
Evaluation criteria of wheel/rail interaction measurement results by track-side control equipment
by Gintautas Bureika, Mikhail Levinzon, Stasys Dailydka, Stasys Steisunas, Rasa Zygiene
Abstract: Recently, the condition of wheelsets of running trains is controlled by trackside automated control equipment (TACE), which measures parameters of wheel/rail impact and signals possible damage to the wheels. Vertical forces result from wheel/rail interaction and determine all dynamic loads transferred to elements of both structures. Calculation of strength and lifetime of train running gear and roadbed of rail track should be based on values of these interaction forces. Railway companies using TACE face the major problems low reliability of TACE-measured impact force values and low repeatability of TACE readings. These problems occur because wheel/rail interaction is a completely stochastic phenomenon. The present level of technology does not allow developing a reliable system for measuring these vertical forces during operation, and it is necessary to control the indirect indicators by defining the studied interaction of wheels. One of these indicators is irregularity of the wheel running surface, whose magnitude is regulated and measured in train inspection stations. This paper evaluates a derived criterion the dynamic factor Kd, used for estimation of repeatability (reliability) of TACE readings - for Lithuanian Railways, and proposes a new system of criteria ensuring sufficient reliability of rail vehicle wheel damage measurement data.
Keywords: rail vehicle; wheel flat; wheel/rail interaction; wheel load impact detector; data repeatable; data reliability.
Firing-on-the-move stability system for armoured vehicle: design and optimisation of disturbance rejection control to reject recoil force
by Vimal Rau Aparow, Khisbullah Hudha, Zulkiffli Abd Kadir, Noor Hafizah Amer, Muhamad Murrad
Abstract: Recoil force creates unwanted yaw moment at the centre of gravity of armoured vehicles. This moment causes instability and diverts the armoured vehicle from its intended direction after firing. This research is focused in developing an active disturbance rejection control to overcome the effect of recoil force using inner and outer loop controls. The outer loop control is designed based on two feedback loops known as firing-on-the-move as the first feedback loop and active front wheel steering as the second feedback loop. The outer loops are designed to encounter the disturbance due to gun force and to improve the stability of the vehicle. An optimisation technique using the Taguchi method and a genetic algorithm are used to identify the most dominant outer loop control as well as to optimise the hybrid controller parameters, neuro-PI. The simulation results show that controller has improved the handling performance of the armoured vehicle after the firing impact.
Keywords: firing-on-the-move feedback; active front wheel steering feedback; armoured vehicle; genetic algorithm; Taguchi method; neuro-PI controller.
Hardware-in-the-loop simulation of trajectory-following control for a light armoured vehicle optimised with particle swarm optimisation
by Noor Hafizah Amer, Khisbullah Hudha, Hairi Zamzuri, Vimal Rau Aparow, Zulkiffli Abd Kadir
Abstract: Unmanned armoured vehicles are important in military missions and to minimise the casualties of military personnel. Steering control is one of the most important aspects in unmanned vehicles. Therefore, in this research, a trajectory following control from Stanley autonomous vehicle is employed and optimised for a Light Armoured Vehicle (LAV) to follow a pre-defined trajectory. The proposed controller is developed on a validated armoured vehicle model, which consists of a 7-degree-of-freedom handling model and other vehicle interactions. In order to study the controller
Keywords: armoured vehicle; trajectory tracking; trajectory following; path tracking; path following; HIL; Stanley.
Relative ride performance analysis of a torsio-elastic suspension applied to front, rear and both axles of an off-road vehicle
by Mu Chai, Subhash Rakheja, Wen-Bin Shangguan
Abstract: Relative ride performance potentials of a torsio-elastic suspension applied to front or rear or both axles of an off-road vehicle are investigated. A three-dimensional model of an articulated load-haul vehicle, incorporating kineto-dynamic model of a torsio-elastic suspension, is used to evaluate relative ride responses with front, rear and both suspended axles. The analyses are performed under random terrain excitations, synthesised considering low frequency coherence between elevations of the two terrain tracks. The model validity is demonstrated using the reported field-measured responses of a rear-suspended forestry vehicle. The optimal parameters of the three suspension configurations are identified by minimizing the vector sum of frequency-weighted rms accelerations av and frequency-weighted rotational vibration, while limiting roll deflection of the suspension link. Relative ride performance potentials of different axle suspensions are subsequently investigated for the loaded and unloaded vehicle in terms of frequency-weighted rms accelerations. The results show that the torsio-elastic suspension performance is relatively insensitive to variations in vehicle load. It is shown that the suspension applied to axle of the vehicle unit supporting driver cabin is more effective in limiting driver vibration with minimal sensitivity to load variations, while preserving effective roll stiffness. The fully-suspended vehicle, however, yields the most effective vibration attenuation.
Keywords: off-road vehicle ride; off-road terrain; torsio-elastic suspension; load sensitivity; suspension optimisation.
Estimation of vehicle sideslip angle scheme using time-finite convergence algorithm
by Peng Zhang, Feng Liu, Fei Sheng
Abstract: Since vehicle sideslip angle estimation scheme is a real-time application, in essence, the schemes convergence speed is an issue worth attention. This paper presents a new estimator scheme whose output is theoretically guaranteed to converge to real values in the desired interval, and this makes it possible to be a more reasonable solution for application such as electronic stabilisation control (ESC). To improve the accuracy and adaptive capability of this scheme, the unmodelled error compensating mechanism is adopted. Then experiment results based on veDYNA vehicle dynamic simulation environment validate the applicability of the method.
Keywords: vehicle sideslip angle; estimation; time-finite convergence.
Active vibration control of agriculture tractor suspension using optimised feedback controller
by Hassan Metered, Ahmed El-sawaf
Abstract: Nowadays, the development of an agriculture tractor suspension system is a vital research topic for the modern manufacturing industry. The ride comfort and tractor stability must be achieved using a suitable controlled suspension system. This paper concerns an investigation using the particle swarm optimization (PSO) algorithm to search for the optimum feedback controller gains for the active agriculture tractor suspension system, for the first time, to reduce the transmitted vibrations to the tractor body caused by road irregularities. A mathematical model and the equations of motion of an active quarter tractor suspension are derived and simulated using Matlab/Simulink software. The proposed PSO algorithm aims to minimise the dynamic tyre load generated by tractorterrain interaction as the objective function, with constraint of the actuator force. Suspension performance is assessed in time and frequency domains to prove the success of the proposed controller gains tuned using the PSO technique under different operating conditions. The simulation results reveal that the feedback controller gains tuned by the proposed PSO algorithm offer a significant improvement of the suspension performance, compared with both the conventional passive and the classical feedback gains tuned by the trial and error technique.
Keywords: agriculture tractor; particle swarm optimisation; active suspension controller; ride comfort; tractor stability.
Hunting stability and derailment analysis of the high speed railway vehicle moving on curved tracks
by Caglar Uyulan, Metin Gokasan, Seta Bogosyan
Abstract: This study aims to build an advanced and effective dynamic model, which is capable of examining both the hunting instability at the critical speed and wheel climb derailment occurrence evaluated with derailment quotients, in one integrated model implicitly. In terms of control subject, the proposed railway vehicle model is compatible with a variable structure model reference adaptive controller using state variables, robust adaptive or sliding mode controller, etc., to stabilise enormously lateral hunting oscillations, which cause system instability, and to perform real-time derailment avoidance. The mathematical dynamic model, which is composed of a vehicle body, two bogie frames and two wheelsets for each bogie frame, is modelled with 35-DOF (degrees of freedom) equations of motion. The railway vehicle is supported with lateral, longitudinal and vertical damping and stiffness related to primary and secondary suspensions. The states of this railway vehicle model are lateral, vertical displacements and velocities of the vehicle body, bogies, wheelsets and yaw, roll, and pitch angles and angular velocities of the vehicle body, bogies, and wheelsets. A heuristic nonlinear creep model supported by Kalkers theory and a flange-rail contact model are used to reveal the effects of the creep forces and moments, which are acting on wheel-rail contact. The nonlinear coupled differential equations of motion were solved to analyse the dynamic behaviour, which is represented by the time response of the railway vehicle moving on curved tracks using Matlab&Simulink software. The hunting behaviour was analysed by investigating the eigenvalues of the railway vehicle at the hunting speed by the assistance of the Gershgorin disc theorem. In addition, the influence of the railway vehicle speed on calculated derailment quotient of the left wheel in the front wheelset of the front bogie was investigated at sharp radius of the curved track. The safe speed of the railway vehicle moving on curved track was also estimated by using active derailment criteria from Nadal and Weinstock. The variation of the derailment coefficients at critical speeds with various radii of curved tracks was also examined by using these derailment criteria. The main superiority of the proposed model is that one can both predict incipient derailment actively and also determine nonlinear critical hunting speeds with higher precision.
Keywords: hunting analysis; derailment analysis; Lyapunov’s indirect method; full railway vehicle model.
Irregularity model of welded rail joint and wheel
by Kaiyun Wang
Abstract: Due to the irregularity excitation of welded rail joints (WRJs), the dynamic impacting force between the wheel and the rail would be obviously enhanced. According to measured irregularities of WRJs in heavy
Keywords: welded rail joint; heavyhaul railway; wheelrail interaction; irregularity; vehicletrack coupled dynamics.
Irregularity model of welded rail joint and wheelrail dynamic responses in heavyhaul railway
by Kaiyun Wang, Zhiyong Shi, Shen Wang
Abstract: Plenty of welded rails are applied in the modern railway. Owing to the irregularity excitation of welded rail joints (WRJs), the dynamic impacting force between the wheel and the rail would be obviously enhanced. According to measured irregularities of WRJs in heavyhaul railway, the irregularity model and its wheelrail dynamic responses are investigated in this paper. A modified excitation model is put forward to simulate the irregularity of WRJ. Dynamic interactions excited by the irregularities of WRJs are analysed, including the measured irregularity, the theoretical irregularities obtained from a traditional model and a modified model. Effects of parameters of the modified excitation model on dynamic interaction are discussed. Results show that there is an obvious concave shape located on the weld point nearby, which can bring about the marked wheelrail interaction force within the frequency scope of 20300Hz, and has much effect on the vibration of the wheelsets and rail. The traditional excitation model of WRJ cannot represent the measured shape very well. There is a poor agreement in the wheelrail vertical force between the measured and traditional irregularities of WRJ. The modified excitation model of WRJ is formed by a convex wave and a concave wave, and has four parameters. From the point of view of the geometrical shape, the irregularity simulated by the modified model is highly similar to the measured irregularity. Furthermore, the dynamic performances excited by the modified irregularity are consistent with those owing to the excitation of the measured irregularity. As for the wavelength and depth of the short wave in the modified excitation model of WRJ, there are obvious influences on the wheelrail dynamic performance. With the growth of the depth, the wheelrail dynamic indices will increase linearly. However, they will decrease nonlinearly with the increase of the wavelength.
Keywords: welded rail joint; heavyhaul railway; wheelrail interaction; irregularity; vehicletrack coupled dynamics.
Dynamic modelling of a railway wheelset based on Kanes method
by Te Wen Tu
Abstract: This study applies Kanes method to generate the equations of motion for a railway wheelset moving on a tangent track at a constant speed. Since the wheel and rail close contact conditions are used to obtain two nonholonomic constraint equations, the lateral vibration of the wheelset can be proven as a nonholonomic system possessing two degrees of freedom. Moreover, using Kanes approach to derive the linearised equations, we can take advantage of bypassing the full nonlinear equations and to obtain two equations with dynamic decoupling. When the set of equations in this work is compared with those in the literature, we find that two gyroscopic effect terms exist and yaw gravitational stiffness disappears, so that the critical speeds calculated in this work are always lower than those in the literature for the same numerical cases. Finally, the contact conditions along with the creepages between wheels and rails can be directly expressed in terms of generalised speeds by using Kanes method. It shows that Kanes method focuses on motions rather than on configurations.
Keywords: Kane’s method; nonholonomic system; motion constraint; dynamic decoupling; gyroscopic effect.
Multi-objective optimisation of injector and diesel engine by genetic algorithm: Nu-SVR modelling
by Hadi Taghavifar, Simin Anvari
Abstract: The current study deals with application of evolutionary multi-objective genetic algorithm (MOGA) in a 1.8 L Ford diesel engine to enhance the power, fuel consumption, and air-fuel uniformity. To do so, four design parameters of engine geometry and injector parameters were defined and three sub-objectives are considered to get either maximised or minimised. On the sub-objectives, constraints are imposed to introduce the feasible solutions. The best solution is obtained at RunID66 from 70 design points. The results showed that increasing bowl radius after a certain point is not useful for enhancement of the mixture homogeneity. The second part of the study, support vector regression technique is applied on the input and output data to make a model to predict the engine power.
Keywords: diesel engine; diesel injector; Nu-SVR; MOGA; Pareto front.
A novel pneumatic-mechanical energy regenerative suspension for air brake trucks
by Jiang Liu, Xiaowei Li, Ye Zhang, Peng Chen
Abstract: A novel energy-regenerative suspension system was proposed to convert the vibration from the road unevenness into the pneumatic potential energy for the trucks air brake. A mathematical model for the new regenerative suspension is given. Using ADAMS and Easy5, pneumatic-mechanism co-simulations are performed. The regenerative ratios are calculated for typical cases and their efficiency factors are discussed. Then the dynamics K&C performances for this new suspension are analysed by comparing with the
traditional leaf spring suspension. The results indicate that the new design can
recycle the vibration energy efficiently and improve the ride comfort as well.
Keywords: energy-regenerative suspension; new mathematic model and co-simulations; air brake truck; dynamics K&C.
Introducing wheel-rail adhesion control into longitudinal train dynamics
by Qing Wu, Maksym Spiryagin, Colin Cole, Yan Sun
Abstract: Conventional Longitudinal Train Dynamics (LTD) simulations apply a number of assumptions regarding wheel-rail adhesion, and wheel-rail adhesion control has not previously been considered. This paper introduces locomotive wheel-rail adhesion control into LTD using co-simulation and parallel computing techniques. An in-house LTD simulator was connected to a commercial MBS dynamics simulator using the TCP/IP protocol. A heavy haul train with the configuration of three locomotives and 150 wagons was modelled. The wagons were modelled in the LTD simulator while the locomotives were modelled in the MBS simulator. The locomotive models were three-dimensional models that included wheel-rail contact models and adhesion control models. Simulations of locomotives were processed in parallel using three computer cores. Co-simulations with and without the consideration of curve lubrication were conducted and compared with a conventional LTD simulation. Computing times with and without parallel computing were also compared. The results show that, when compared with conventional LTD simulations, wheel-rail adhesion control generates evident differences for maximum traction forces, average train speeds, maximum in-train forces and force patterns. With three computer cores, parallel computing reduced the computing time by about 46% from about 3.7 hours to about 2.0 hours.
Keywords: longitudinal train dynamics; wheel-rail contact; adhesion control; traction modelling; parallel computing;co-simulation.
Optimal regenerative braking torque of permanent-magnet synchronous motor in electric vehicle
by Dongmei Wu, Yang Li, Jianwei Zhang, Changqing Du
Abstract: This study investigated a method to determine the optimal regenerative braking torque with maximum energy recovery at given speed, which is essential for the regenerative braking control of electric vehicles. The method is based on the loss modelling of a permanent-magnet synchronous motor (PMSM) system, which consists of an electric motor and an inverter. The system-loss model is established based on a PMSM mathematical model including iron loss, and is used to derive the optimal regenerative braking torque symbolic formula. In addition, the parameter sensitivity of the optimal regenerative braking torque is analysed, and a method for online parameter identification is used to obtain the actual parameter values in real time. Thus, the accuracy and adaptability of the optimal regenerative braking torque during the motor-operation process is improved. The analysis results are validated through simulation and bench tests.
Keywords: regenerative braking torque; permanent-magnet synchronous motor; loss model; parameter sensitivity; electric vehicle.
Component sizing optimisation of hybrid electric heavy duty truck using multi-objective genetic algorithm
by Fereydoon Diba, Ebrahim Esmailzadeh
Abstract: Component sizing optimisation of a novel architecture of hybrid drivetrain for line-haul truck has been considered. This drivetrain architecture employs a self-propeller trailer and the traction is shared between the tractor and trailer. The comprehensive model of the vehicle, including the hybrid electric drivetrain, is developed. The drivetrain components have been optimised using a multi-objective genetic algorithm to minimise three objective functions, namely, the acceleration time, the fuel consumption and the drivetrain price. The overall efficiency of the optimised hybrid drivetrain has been evaluated using computer model simulations. Engineering economic analysis is performed to demonstrate the ownership cost of the proposed drivetrain compared with the non-hybrid and the non-optimised hybrid drivetrain for heavy duty vehicles. The results show that the proposed drivetrain has a superior capability in reducing the fuel consumption and the ownership cost.
Keywords: hybrid electric truck; component sizing; self-propeller trailer; multi-objective optimisation; genetic algorithm.
Hydraulic retarder torque control for heavy duty vehicle longitudinal control
by Chaoxian Wu, Xuexun Guo, Bo Yang, Xiaofei Pei, Sijing Guo
Abstract: This paper studies the hydraulic retarder torque control strategies for heavy duty vehicle longitudinal control to reduce abrasion of the friction brake. A hydraulic retarder whose oil volume rate is controlled by a pneumatic system is modelled. A hierarchical controller is developed for longitudinal control. In the upper controller, the target total brake force is calculated and then distributed on the friction brake and the retarder. In the lower controller, two retarder torque control strategies, PID control and mixed PID and sliding mode control, are employed and compared. Simulations are conducted with varying vehicle mass and varying desired vehicle velocity. Results shows that the mixed PID and sliding mode controller has better speed tracking performance, robustness and torque control accuracy.
Keywords: hydraulic retarder; torque control; longitudinal control; heavy duty vehicle; sliding mode control.
CAE analysis and road load data acquisition on bogie bracket of heavy duty commercial vehicle
by P. Thangapazham, L.A. Kumaraswamidhas, D. Muruganandam, Dharanivendhan T
Abstract: The bogie bracket is a unit of the suspension system in automotive vehicles, such as heavy duty automotive commercial trucks, railways and other machinery, to carry shock and load. Bogie brackets are extensively employed in heavy vehicles to connect the chassis and wheels. This part has been identified as one of the most critical components in the suspension system of commercial vehicles. Computer Aided Engineering (CAE-PERMAS Version-14.0) simulation software has been used for stress analysis and to study the forces influencing the failure of bogie bracket due to stress concentration. Stress concentration factor has been found in every zone of the bracket and the weaker sections have been identified in three iterations. Two different road conditions were taken for the critical analysis: a) Rough Road (RR) condition; b) Mining Road (MR) condition. Road Load Data Acquisition (RLDA) tests were conducted to validate the CAE analysis. Six pairs of bogie brackets were tested on different road test tracks in RR and MR conditions. Maximum strain was measured through a strain gauge attachment. The maximum stress and strain induced in the brackets were observed in all tests. Hair crack failure in the bracket was detected at the weaker section. The eventual sudden crack failure of the bracket took place during the cobble-stone track test in RLDA. The failure rate and mode of failure were observed in six pairs of samples under RR and MR conditions. In RR condition the cobble-stone test was the influencing surface for failure, and in MR condition the kutcha road induced failure.
Keywords: rough road; mining road; computer aided engineering; road load data acquisition.
A comparison of test manoeuvres for determining rearward amplification of articulated heavy vehicles
by Zhituo Ni, Shenjin Zhu, Yuping He
Abstract: Rearward amplification (RA) is an effective indicator of lateral stability for multi-trailer articulated heavy vehicles (MTAHVs). The International Organization for Standardization released the test manoeuvres, ISO-14791, for determining the indicator for MTAHVs. ISO-14791 recommends three methods, including two time-domain and one frequency-domain, to derive the RA measures. It was reported that the results from the three methods were not in good agreement. To explore this inconsistency among these methods, a multiple cycle sine-wave steering input (MCSSI) manoeuvre was simulated to obtain steady-state responses of MTAHVs. Furthermore, an automated frequency response method (AFRM) was used to derive the measures in the frequency domain. This paper presents simulation results based on an A-Train Double. Results demonstrate that the steady-state RA measures under a MCSSI manoeuvre are in excellent agreement with those from frequency-domain methods. It is revealed that drivers steering behaviours impose a non-negligible impact on the transient RA measures of MTAHVs.
Keywords: rearward amplification; test manoeuvres; ISO-14791; multi-trailer articulated heavy vehicles; lateral dynamic; numerical simulation.
Determination of the most efficient bus rollover computer simulation technique according ECE R66
by Petr Rogov, Lev Orlov
Abstract: A review of the existing methods of the bus rollover computer simulation is conducted in the article. In order to investigate the motion of the bus before collision with ditch surface, the mathematical model of the bus motion was developed. To confirm the reliability of this model a comparison between the results of mathematical modelling, FEM simulation and experimental rollover of a bus section is made. It is found that the friction coefficient between the bus and the tilting platform, as well as the bus centre of gravity height, affect the ratio between the bus kinetic energy of the impact and the potential energy of the bus at the beginning of the rollover. As a result, an experimentally confirmed theoretical foundation for the most accurate method of computer simulation of the bus rollover according to UNECE Regulation No. 66 is given.
Keywords: mathematical model; finite element method; passive safety; bus rollover; ECE R66; experiment; bus load conditions.
Controller structure for high response engine exhaust throttles
by Ádám Bárdos, Huba Nemeth, Barna Szimandl
Abstract: Exhaust throttles are widely used as cost effective endurance brakes on commercial vehicle diesel engines. To fulfill the requirements as endurance brakes exhaust flaps have only two states: fully opened and fully closed. However, there are several possible new applications, suggested by the authors, in which exhaust throttles could be utilized e.g. brake blending, automated manual transmission support, exhaust gas thermomanagement etc. To provide these functionalities a backpressure controller which can adjust the exhaust manifold pressure arbitrarily is needed. In this paper the design and performance evaluation of an exhaust pressure controller is described which satisfies the new requirements derived from the possible future functions of exhaust throttles. A first engineering principle based, mean-value, nonlinear model of the engine and the actuator is described and validated with test bench measurements. Based on the nonlinear model a feed forward term was obtained with model inversion. As feedback an LQ servo controller was designed. The controller performance and the compliance of requirements was evaluated in three different test cycles on a medium-duty diesel engine, simulating brake blending, thermomanagement, and EGR support operations.
Keywords: diesel engines; exhaust throttle; pressure control; nonlinear control systems; optimal control.
Taguchi-based grey relational analysis for multi-response optimisation of diesel engine performance and emission parameters
by Mohd Muqeem, Ahmad Faizan Sherwani, Mukhtar Ahmad, Zahid Akhtar Khan
Abstract: In order to achieve high performance and low emission of diesel engines, it is necessary to operate the engine at optimum condition. The aim of this paper is to optimise the input parameters of a diesel engine, which results in optimum performance and emission. Four input parameters, viz., compression ratio, fuel injection timing, air temperature and air pressure, each at five levels, were considered in this study. However, the main focus was on turbocharged air temperature and pressure. Four response variables, i.e., brake thermal efficiency, brake-specific fuel consumption, hydrocarbon emission and smoke opacity, under no load, half load and full load conditions, were measured. Twenty five experiments as per Taguchi L25 orthogonal array were performed, and experimental data was analysed using Grey Relational Analysis (GRA) to accomplish multi-response optimisation. Regression analysis was done to determine the experimental value of the Grey Relational Grade (GRG) at optimum setting of the input parameters. In order to validate the experimental results, the experimental value of the GRG was compared with that of the predicted value, and the comparison revealed a good relation between the predicted and experimental values of the GRG at optimum combination of the input parameters.
Keywords: brake-specific fuel consumption; brake thermal efficiency; Taguchi approach; grey relational analysis; hydrocarbon emission; smoke opacity.
Multi-axle vehicle dynamics with roll
by Daniel E. Williams
Abstract: The classic two-axle yaw-plane or bicycle model has long provided basic insight into vehicle handling. It has previously been augmented to allow sprung mass roll, and more recently to accommodate multiple axles, any of which could be steering. In this work these two extensions of the yaw-plane model are combined, to form a dynamic model of a vehicle with an arbitrary number of axles, any of which could be steered, and also with a suspension that allows sprung mass roll. As such this work introduces the most general yaw-plane model to date.
Keywords: vehicle dynamics; commercial vehicle dynamics; multi-axle vehicle dynamics; multi-axle steering; vehicle ride; vehicle handling.
Influences of roller diameter error on the mechanical properties and fatigue life for the main bearing of rotating drum in concrete mixing truck
by Jia-peng Yang, Qi An
Abstract: The rotating drum's supporting main bearing (RDSMB) of a concrete mixing truck is usually a double row spherical roller bearing (SRB). In manufacturing, the roller diameter inevitably has a certain error, and this error should have a great influence on the mechanical properties and fatigue life of the bearing. In this paper, the RDSMB of a certain type of concrete mixing truck is studied. The calculating equations are established to get the radial load and axial load acting on the main bearing. A mechanical model for SRB has been derived through the force analysis considering radial load, axial load, inner ring tilting angle and roller diameter error. The effects of single roller diameter error and random distribution errors of two row rollers on the axis orbit, roller maximum load, roller load experience and the fatigue life of RDSMB are studied. A series of influence relationship curves are obtained and analysed.
Keywords: concrete mixing truck; main bearing; rotating drum; mechanics analysis; mechanical properties; roller diameter error; random distribution errors; axis orbit; roller load; fatigue life.
An investigation of the effect of elastic membrane on liquid sloshing in partially filled tank vehicles
by Qiongyao Wang, Subhash Rakheja, Wen-Bin Shangguan
Abstract: Roll plane fluid slosh within a partly-filled tank with an elastic membrane restraining the free surface is investigated through development of a two-dimensional computational fluid dynamic and fluid-structure interaction (CFD-FSI) model. The air-membrane-liquid interaction analysis is performed to investigate the effect of the membrane on the liquid cargo movement, and peak and mean magnitudes of lateral slosh force and roll moment under 0.3g lateral acceleration excitation. Laboratory experiments were conducted on a 50%-filled scaled 0.536 m diameter tank with an elastic membrane-like restraint under harmonic lateral acceleration excitations. The validity of the CFD-FSI model is demonstrated on the basis of the laboratory-measured responses in terms of lateral slosh force and roll moment. The effectiveness of the membrane in limiting the fluid slosh is illustrated by comparing simulation results obtained for a 7.55 m long and 2.03 m circular tank with and without the membrane. It is shown that addition of the membrane could yield substantial reduction in the fluid cargo motion and thus roll moment attributed to fluid sloshing, while increasing the fundamental slosh frequency by more than 2 times that obtained for the cleanbore tank. The study is limited to a fixed location of the membrane in the tank, near the tank centre. Higher fill volumes thus resulted in greater membrane deformation, and increase in the wetted area and membrane pre-tension.
Keywords: tank trucks; fluid slosh; elastic membrane; fluid-membrane interaction.
Adaptive sliding mode control of a four-wheel-steering autonomous vehicle with uncertainty using parallel orientation and position control
by Armin Norouzi, Hadi Adibi-Asl, Reza Kazemi, Parvin Fathi Hafshejani
Abstract: Control systems of autonomous vehicles or driver assistant control systems always face uncertainties due to the in-vehicle and environmental disturbances. In addition, the steering ability for rear tyres leads to more stability and more handling and manoeuvrability. In this paper the adaptive sliding mode control (ASME) strategy is employed to improve handling issues due to the roads friction, which plays a key role in handling dynamics. The proposed dynamic model used in this paper is a simple and useful two degrees of freedom model. Two parallel ASMCs are used: one for positioning error and the other for angular error. The simulation is executed for two different road conditions with consideration of the hypercritical condition. To verify the designed controller, the controller is applied to the nonlinear full vehicle model. The simulation results prove that the controller perfectly works for different road conditions. The controller is also robust against uncertainties such as road friction.
Keywords: autonomous vehicle; four-wheel-steering vehicle; vehicle lateral control; adaptive sliding mode control.
Effects analysis of suspension parameters, different wheel conicities and wheel nominal rolling radii on the derailment safety and ride comfort
by Yung-Chang Cheng, Po-Hsien Wu
Abstract: Using a modified heuristic nonlinear creep model with different wheel conicities and nominal rolling radii, a 31 degrees-of-freedom railway vehicle system with rail irregularities in the lateral and vertical directions is modelled and analysed. The effects of suspension system parameters, different wheel conicities and nominal rolling radius on the derailment quotient, the offload factor and the ride comfort index are illustrated and compared. Generally, the derailment risk is underestimated and ride comfort is overestimated when the linear creep model is used for dynamic analysis of a railway vehicle system. The derailment risk is increased and the ride comfort performance is decreased when a worn wheel that has a different wheel nominal rolling radius is used. Finally, for a softer primary and secondary suspension system, the derailment risk for a worn wheel is also increased.
Keywords: modified heuristic nonlinear creep model; derailment quotient; offload factor; ride comfort; wheel nominal rolling radius; suspension system parameters; wheel conicity.
Measurements and simulations of sliding wear, leakage and acoustic isolation of engine rubber gaskets
by Fredrik Birgersson, Par Mikaelsson, Tommy Andersson, Marten Olsson
Abstract: Design and verification of gasket elements between engine-mounted components requires computation and physical tests, with respect to wear. Wear is a common problem in engines and mainly comes from engine vibrations and thermal loading. The vibrations are due to inertial loads as well as reaction forces to gas pressure in the cylinders. For existing engine types, measured vibrations are commonly used as input to calculations and shaker test rigs. The translation, rotation and twisting of the complete engine block can be simulated by fitting the measured acceleration signals at four or more positions of the engine block. Here, a new method to correctly simulate the measured wear rate of an oil pan rubber gasket is described. Much work exists on investigations of gasket sealings between cylinder head and block, where the thermal loading becomes very important. The method described herein focuses instead on other types of gasket on the engine, where the main failure mode is due to sliding wear caused by the engine block and component vibrations. In order to correctly reproduce wear and leakage of rubber, both the dynamic and static properties of the rubber need to be accurately described. A comparison between measured and simulated wear of an engine oil pan gasket showed good agreement and a discussion on how to improve the gasket condition is included.
Keywords: sliding wear; leakage; engine rubber gaskets; engine vibrations; oil pan.
Research on loaded brake performance test of trucks
by Wanyou Huang, Yanyan Fan, Mingjin Yu
Abstract: As regulated by the truck inspection specification in the China National Standard GB21861-2014 that, from the 1st March of 2017 a new detection program should be added to test the loaded braking performance for trucks that have more than three (including three) axles. And it is specified that the trucks should be lift loaded by brake test platform. In this article, the axle load model of a three-axle truck upon lift loading is built, and the calculation model of vehicle centroid position is created as well. The effectiveness of the axle load model is verified by real vehicle test with a three-axle heavy duty van. The maximum relative error between model calculation results and real test values is 3.17%, which indicates that the axle load model is valid. Based on the axle load model, analysis is conducted to get impact laws of lifted height, wheelbase, centroid position and composite stiffness on the lift loaded axle load, which provides a basis for the vehicle braking performance test. According to the results of real vehicle tests, the maximum braking force of the first, second and third axles is increased by 30.6%, 73.3% and 5% after the respective axle is lift loaded. The growth of both axle load and braking force reach a maximum when lift loading is applied on the second axle. Therefore, it is feasible to do loaded brake tests on the second axle using the test method of lift loading. On the other hand, as the growth of braking force is not obvious when the third axle is lift loaded, so it is inadvisable to do lift loaded brake tests on the third axle.
Keywords: truck; braking performance; load test; anti-force brake test platform; axle-load models.
Study of a steering model for four-axle 8x8 off-road vehicles
by Yun-Jui Chung, Chung-Hsien Chuang, Yung-Chi Chang, Tyng Liu
Abstract: The purpose of this study is to establish a steering model for a four-axle 8x8 vehicle, which provides the design of the assisted steering system. To obtain the best steering performance, this system aims to minimise the turning radius. In this study, the steady-state mathematical steering model of this vehicle is established and the actual physical parameters are added to this model. By actually driving the vehicle, the model is verified and the results show that the model can accurately predict the steering behaviour of the vehicle. After correction, the model is added to assist the steering of the fourth axle and find the optimal steering mode. To evaluate the design, this model inputs the functions of time and steering wheel angle and outputs the tracks of driving this vehicle. We verify the steering assistance design of this vehicle by comparing the driving tracks with and without it.
Keywords: four-axle vehicles; turning radius; mathematical model; steering assistance.
Relative navigation control of articulated vehicles based on LTV-MPC
by Guoxing Bai, Yu Meng, Qing Gu, Weidong Luo, Li Liu
Abstract: The automation of articulated vehicles is an important trend of the intelligent transportation system in the mining industry. The relative navigation is a key technology in automatic vehicles. One of the challenges in the relative navigation of the articulated vehicle is that the system constraints may cause the actuator saturation and other problems. In order to solve these problems, this paper presents a relative navigation control method based on Linear Time Varying Model Predictive Control (LTV-MPC). This control method can explicitly take the system constraints into account. The performance of the controller is verified by simulation and experiment. The results show that the articulated vehicle with the LTV-MPC controller can track the target heading direction, and the steady-state error is less than 0.3 rad. The relative navigation controller based on LTV-MPC can be used to improve the automatic driving performance of the articulated vehicle.
Keywords: articulated vehicle; relative navigation; motion control; LTV-MPC; nonlinear systems.
Estimation of friction surface temperature of a dry clutch
by Tolga Cakmak, Muhsin Kilic
Abstract: This paper presents an approach to estimate the temperature on the friction surface of a dry clutch. The study comprises both experimental measurements and transient thermal numerical analysis of heavy duty truck clutches for the successive engagements on a sloping road. Compared with previous mathematical models in the literature, pressure plate surface convection coefficient, energy dissipation, engagement duration and variation of the clutch housing air temperature were obtained on the basis of experimental data and have been applied as input in the 3D clutch transient thermal finite element analysis. Simulation results show that the design of the clutch plate has a significant effect on the temperature rise at the friction surface.
Keywords: dry clutch; energy dissipation; engagement duration; finite element analysis; transient thermal simulation.
Modelling, parametrisation and validation of a truck steering system to predict the steering-wheel torque
by Jan Loof, Igo Besselink, Henk Nijmeijer
Abstract: The prediction of the steering-wheel torque in a steering system is a challenging subject. The steering system of a truck consists of many components, including a hydraulic power-steering system. A model is developed that includes the most important components. A Wheatstone bridge is used to model the hydraulic valve system. A flexible supply hose and compressible fluid in the cylinder chamber are taken into account. The model is parametrised using test-bench measurements. The model is validated by means of additional measurements on the same test-bench. The model is verified for quasi-static conditions and up to a frequency higher than a driver will ever use. The predictions of the steering-wheel torque, steering-wheel angle and pressures in the system are accurate for high torque amplitude inputs. For small inputs the model is still able to predict the steering-wheel torque with an error smaller than 10%.
Keywords: commercial vehicle; hydraulic power-steering; Wheatstone bridge; steering system; steering-wheel torque prediction; parametrisation.
Ground-watching navigation for trailer-steering control
by Qiheng Miao, David Cebon
Abstract: This paper discusses two ground-watching navigation strategies for path-following control of a steered trailer at low speeds. Such systems provide navigation information by processing the features of the road surface in successive images. Theoretical performance of the systems was initially investigated in simulation. Field testing was conducted for three manoeuvres: a straight line, a lane change and a 90
Keywords: heavy goods vehicles; active trailer steering; ground-watching navigation; off-highway;.
Analysing human effect on the reliability of mining equipment
by Burak Ozdemir, Mustafa Kumral
Abstract: In the mineral industries, heavy equipment is widely used, and the operator performance is a significant factor for fulfilling intended functions of this equipment. This study aims to analyse and interpret the effect of the human factor on the reliability of the equipment used in the mining industry. In doing so, a combined approach based on the reliability analysis, statistical inference and a machine learning technique is proposed. A case study was conducted on haul trucks in a mining operation. The case study showed that the reliability drops of haul trucks vary in the range of 0.84% and 2.45% in a shift. It was also calculated that 16.9% of these reliability drops were associated with operator habits. A trucks condition at the beginning of a shift and the initial reliability contribute to 36.3% and 31.1% of the reliability drops, respectively. The findings can be used in scheduling training programs, short-term mine planning, and simulation of material handling systems.
Keywords: human factor; equipment reliability; scoring; machine learning.
Development for generalised multi-axle steering vehicle handling
by Xiang Chen, Kong-hui Guo
Abstract: This paper devotes its main effort to develop the generalised multi-axle steering vehicle handling for more comprehensive analysis with the factors of vehicle body roll, multi-axle, unsprung mass, steering centre distance, steering ratio coefficient and steering delay. A linear vehicle dynamic model is established first. Then,the multi-axle steering vehicle handling is analysed from the two aspects of steady-state and transient-state. For the steady-state, the expressions of equivalent wheelbase and steady factor are derived from the generalised vehicle dynamic equations, and some special conditions are discussed in detail. For the transient-state, the expressions of frequency characteristics and root locus are deduced and the influences of steering delay and steering ratio coefficient to multi-axle steering vehicle handling are analysed in depth. The corresponding results derived from the generalized dynamic model can be used for analysing the various influences on multi-axle steering vehicle handling.
Keywords: multi-axle steering vehicle handling; vehicle dynamic model; steady-state characteristics; transient-state characteristics.
Active fault tolerance control for active suspension with control input time-delay and actuator gain variation fault
by Hongbo Wang
Abstract: An active suspension system subject to control input time-delay and actuator gain fault is considered in this paper. System dynamics models with time-delay and gain fault are built. A sliding-mode controller is designed to maintain the stability for the time-delay system. By employing a robust observer and residue errors, the gain fault is detected and diagnosed. The control law reconfiguration is adopted to realise the active fault tolerance control. The act-and-wait control is applied for the active suspension nonlinear system. Comparative simulation results for a quarter-car active suspension system are presented to show the effectiveness of the adopted control scheme.
Keywords: active suspension; time delay; gain fault; fault tolerance control.
New method to predict truck-semitrailer jackknifing effect
by Roberto Spinola Barbosa
Abstract: A new method based on two articulated bodies with internal inertial force, similar to the structural buckling effect, is proposed to describe the unstable yaw relative angular movement between truck and semitrailer, known as jackknifing. An analytic expression is derived from the proposed linear model, allowing the prediction of the deceleration limit prior to the yaw instability phenomenon. The influences of the relevant contributing factors, such as vehicle mass, brake distribution, height of center of mass, vertical load transfer and lateral tyre stiffness, are considered. A detailed non-linear model with 19 degrees of freedom is developed and used as a simulation tool to verify dynamic performance. The analytical results of the jackknife effect were validated by comparison with the instability tendency simulated with a complete vehicle dynamic model. The results show good agreement between the proposed analytical expression and the numerical simulation. The proposed analytic expression is independent of the vehicle speed and does not require a stability analysis or an integration process, as other techniques available in the literature.
Keywords: jackknifing; truck; dynamic; safety; instability.
Building a novel dynamics rollover model for critical instability state analysis of articulated multibody vehicles
by Qingyuan Zhu, Chaoping Yang, Huosheng Hu, Xiongfeng Wu
Abstract: Articulated wheel loaders in the construction industry have poor lateral stability and a high rate of accidents owing to their multibody structure and uneven working fields. In order to realise early rollover warning and active control, it is necessary to explore the mechanism of instability and the change rules of dynamics parameters. This paper proposes a novel dynamics rollover model with six degrees of freedom for modelling the instability process of an articulated wheel loader. The proposed rollover model is compared with a virtual prototype and a 1:5 scale-down physical prototype under four typical working conditions to verify its reliability, and its accuracy is investigated via a rotation motion under a constant steering angle under the critical state of rollover. Finally, the dynamics rollover model is used to investigate the influence of different kinematic parameters on lateral stability of an articulated wheel loader with steady-state margin angle as stability index.
Keywords: articulated wheel loader; dynamics model; lateral stability.
Analysis and practical validation on a multi-linkage scissor platforms drive system for the satellite test facilities
by Nor Mohd Haziq Norsahperi, Salmiah Ahmad, Siti Fauziah Toha, Iskandar Al-Thani Mahmood
Abstract: This paper evaluates a new method for measuring the reaction forces on the multi-linkages scissor mechanism driven by a ball-screw system. Unlike the previous approach introduced by Spackman, the overall detailed structures were not considered. In this paper, the proposed method took into account all reaction forces on the designed linkages to evaluate accurate actuators sizing. The fusion of the structural-virtual work (SV) analysis overcomes the problems associated with the previous conventional technique, whereby the reaction forces on each linkage where measured to avoid the over-sizing of driving system, and also to sustain the system performance with cost reduction. The idea was proven in three ways: analytical analysis, simulation analysis and experimental analysis based on the developed prototype. In addition, to ensure the results are acceptable to the practitioners in this field, a dynamic study was conducted to observe the effect of speed variations on the driving system. From the simulation performance analysis, it was discovered that the estimated torque was reduced by 29% as compared to the conventional approach. The 12% error between the result from simulation and the ones from the experiment has suggested that the SV method is superior to the conventional analysis, where the error between the conventional analysis and the hardware is 60%. The successful method proposed in this paper can be further implemented for all multi-linkages systems in a heavy vehicle used in industry that requires accurate actuators sizing.
Keywords: scissor mechanism; motion study; static analysis; dynamic analysis; drive system; satellite facilities.
Improving curving performance of a straddle-type monorail vehicle by using semi-active devices
by Ali Suat Yıldız, Selim Sivrioğlu
Abstract: This paper is concerned with improving the curving performance of monorail vehicles, which are one of the modern mass transport systems, by using semi-active magnetorheological (MR) dampers. Controlling the curving dynamic of the monorail vehicles with semi-active devices is a new research area. The considered monorail vehicle has one segment supported by two bogies. As a secondary suspension, lateral and vertical MR dampers are taken into consideration in addition to air suspensions. Control performances of the robust Hinf and adaptive control are investigated and compared with a passive case along a designed road profile. Parametric uncertainties in running tyres and vehicle mass are taken into consideration in the control simulations. Simulation results show that the designed controllers improved the roll, yaw and vertical motions of the monorail vehicle when compared with uncontrolled and passive cases. These improvements provide better comfort and safer conditions, and a small turning radius can be achieved by monorail vehicles equipped with the semi-active suspension system.
Keywords: semi-active suspension; MR damper; adaptive controller; monorail vehicle; Hinf control.
On the dynamics of a four-axle railway vehicle with dry friction yaw damping
by Hans True, Anders H. Christiansen, Susanne E. Knutz, Lene B. Rasmussen
Abstract: The dynamics of a railway vehicle with four wheel sets and dry friction yaw damping is investigated. The stick/slip mechanism is considered. The speed of the vehicle is the control parameter. The first bifurcation points are found. The results demonstrate the influence of the stick/slip on the dynamics of the vehicle. For speeds above the critical speed the symmetry of the dynamical problem is broken and may result in asymmetric periodic or erratic - possibly chaotic - motions. Three different numerical integrators are applied and their effectiveness is compared. Dry friction damping is still used in almost all freight wagons in the world owing to the low costs of the elements.
Keywords: non-smooth dynamics; railway vehicle dynamics; bifurcations.
Optimum operational conditions of mining trucks based on the vibrational health risk of the driver
by Mohammad Javad Rahimdel, Mehdi Mirzaei
Abstract: This paper aims to propose the optimum payload and speed limit and load geometry for a heavy duty 60-ton truck in Sungun Copper Mine of Iran as a case study to keep the vibrational health risk at the lowest possible level while maintaining the production rate at the planned level. These trucks need special consideration because of their specific hydro-pneumatic suspension system, large size, and payload capacity. There is limited evidence considering the effect of speed, payload and load geometry on the vibrational health risk of mining trucks. Also, there is not much research to suggest the practical conditions helping to drive the trucks in safe conditions, along with keeping the production rate at the planned level. The Root Mean Square (RMS) of vibrations at different operational conditions was obtained. Then, an optimization problem was developed to propose the optimum payload and truck speeds at various conditions. The optimum payload was 65 tons. The optimum speed of loaded truck was obtained in the range of 30 to 35 km/h at good roads and 15 km/h at poor roads. Also, the optimum speed range of empty truck was in the range of 15 to 20 km/h. Operational conditions have a significant effect on the RMS values. Uniform payloads and materials accumulated on the left side can have the lowest and highest effects on the vibrational health risk, respectively. This paper addresses the mine managers to propose practical solutions for reducing the vibrational health risk of mining trucks, as well as keeping the production rate at the planned level.
Keywords: mining truck; whole body vibration; optimisation; regression analysis.
Adaptive online estimation of centre of gravity height for commercial vehicles
by Zhi-Jun Fu, Bin Li
Abstract: A novel parameter error-driven robust estimation method is proposed for online estimation of centre of gravity (CG) height of a tour bus vehicle. Unlike the commonly used recursive least squares (RLS) method, a parameter error-driven updating law is synthesised to ensure improved performance in terms of steady-state error and robust convergence. The stability of the proposed estimation method is illustrated using the Lyapunov approach. The proposed CG estimation method is based on directly measurable lateral acceleration and relative roll angle of the sprung mass, while the high order signals are eliminated using the filtering approach. The validity of the proposed estimation method is illustrated through implementations in TruckSim platform. Simulation results show that the proposed estimation method can yield accurate online estimation of the CG height, together with effective suspension roll stiffness and damping properties.
Keywords: centre of gravity height; commercial vehicles; parameter estimations; roll dynamics; adaptive estimation.
Comparative study of dynamic programming and Pontryagins minimum principle for autonomous multi-wheeled combat vehicle path planning
by Amr Mohamed, Jing Ren, Xishi Huang, A.N. Ouda, G.M. Abdo
Abstract: This paper presents a comparative study of two path planning algorithms using optimal control theory for the autonomous multi-wheeled combat vehicle. The developed optimal path planning algorithms use Pontryagin's Minimum Principle (PMP) and Dynamic Programming (DP) approaches. PMP and DP are two major branches of the optimal control theory. Up to now, little work has been done to compare their performance in the application of navigating autonomous vehicles. In this paper, a simplified two DOF vehicle model is used to derive the differential equations of the vehicle. The cost function associated with the path generation is to be minimized with the vehicle dynamics equations. A comparative study and performance analysis of generated optimal paths using the proposed algorithms was carried out for various scenarios. The simulation results demonstrate that the generated optimal solution using PMP is very close to the DP solution, which is the guaranteed global optimum. In addition, the initial and final condition parameters and the vehicle dynamics are satisfied. However, the PMP computation time is significantly less than the DP.
Keywords: path planning; dynamic programming; autonomous vehicle; Pontryagin’s minimum principle.
Low speed performance based standards for Nordic countries
by Fredrik Bruzelius, Sogol Kharrazi
Abstract: Performance Based Standards (PBS) is an effective regulator policy that can address variation complexity in vehicle combinations. This paper investigates aspects of using computer simulation and mathematical models to assess the performance of vehicle combinations in low speed manoeuvring, in particular on roundabouts. A set of 22 vehicle combinations, including existing conventional heavy vehicles as well as prospective high capacity vehicles, is used to study the effects of turn angle and road surface conditions on the friction demand and swept path measures. Simulation results suggest that the friction demand measure is dependent on the available grip. This makes it hard to interpret and may not be suitable in the PBS framework. The swept path measure is relatively unaffected by friction levels, and can hence be calculated with simple and robust expressions not considering the road interaction. However, turn angle affects the swept path measure considerably, and should be addressed when designing the PBS scheme implementation into the legislations.
Keywords: low speed performance based standards; high capacity transport vehicles; friction demand; swept path; vehicle performance assessment.
A new numerical method for analysing the interaction of a bridge structure and travelling cars due to multiple high-speed trains
by Mehmet Akif Koc, Ismail Esen, Mustafa Eroglu, Yusuf Cay
Abstract: Dynamic interaction between a 10-DOF high-speed train model and a simply supported bridge beam is studied. The second-order coupled equations of the bridge beam and train are derived using the Lagrange method. The proposed method provides considerable advantage by taking 0.5% of the time needed in analysing of the train-bridge interaction (TBI) previously given in the literature using the finite element method (FEM). The presented modelling, which includes the dynamic forces on the train components from the interaction, is created in a manner that it may concern both train and bridge engineers. It is shown that, while moving on the bridge, the dynamic forces on the train body, front and rear bogies, and wheels, as well as the bridge, are significantly affected by the speed and mass of the train, along with the flexibility of the bridge. Effects of multiple cars are included in the modelling.
Keywords: high-speed train; bridges; dynamic interaction; dynamic forces; successive loading.
Research on partially filled characteristics of vehicular hydrodynamic retarders
by Lingxing Kong, Wei Wei, Hongbin Mu, Qingdong Yan
Abstract: Hydrodynamic retarders are widely used on heavy vehicles as auxiliary braking components. Figuring out the partially filled characteristics is of practical significance for the design and control of retarders. In this paper, torque characteristics under variable filling rate of a dual-torus hydrodynamic retarder are studied by theoretical deduction as well as CFD simulation, and the results are verified with experimental data. 1D flow theory was implemented to calculate the circulating flow-rate and brake torque on the basis of energy balance equation. 3D CFD simulation was conducted using commercial code CFX, and VOF model was adopted to simulate air-oil two-phase flow when the chamber is partially filled. The results showed that, unlike the common assumption that brake torque is in direct proportion to the filling ratio of the chamber, the torque presents a non-linear relationship versus filling ratio. This is mainly caused by the non-linear distribution pattern of the circulating flow-rate. In the bench test, the filling ratio is derived by monitoring the flow-rate into and out from the chamber, and the experimental results validated the non-linear relationship between brake torque and filling ratio.
Keywords: brake torque characteristics; CFD; filling ratio; vehicular hydrodynamic retarder; two-phase flow.
Review on NOX emissions from using biodiesel blends in diesel engines
by Mahmoud Sayed, Mohamed Elhemaly
Abstract: Environmental pollution is a major problem in all countries around the world. ICE The Internal Combustion Engine (ICE) is considered one of the main sources of emissions, thus most countries are interested in using biodiesel as an alternative fuel. Scientists, researchers, and manufacturers are facing the challenge of reducing fuel burning emissions and at the same time achieving the main technological requirements, such as increasing the vehicle performance, decreasing the fuel consumption, etc. Some of recent studies indicate that many vehicles and movable equipment accept the use of biodiesel blends (Bb). Mainly, the new engines can be operated with Bb of 20%, 30% and B100 (pure biodiesel). Nitrogen oxides (NOx) represent one of the exhaust gases that have a great impact on environmental conditions. This work presents an analytical study of NOx emissions, summarising the practical solutions to reduce NOx emitted from diesel engines burning Bb.
Keywords: biodiesel fuels; biodiesel blends; NOx emissions; diesel engine; internal combustion engine.
Integrated application of network traffic and IDM models in the test laboratory analysis of autonomous vehicles and electric vehicles
by Tamás Péter, Ferenc Szauter, Zoltán Rózsás, István Lakatos
Abstract: The aim of the research is to develop a laboratory model-based diagnostic procedure that performs tests of the motion processes of autonomous electric vehicles in a particular city, on a transport network or track. The test consists of a laboratory based generation of the corresponding speed and steering angle signals, corresponding to real driving and traffic conditions, which are also used in the test procedure. The procedure takes into account the real trajectory tracking process as well (P
Keywords: autonomous electric vehicles; laboratory model-based diagnostic procedure; corresponding speed and steering angle signals; laboratory based generation; real traffic environment.
Listening to the voice of the customer using an immersive combine simulator: innovative techniques for product development
by Greg Luecke, Don Kieu, Stephen Gilbert, Brian Gilmore, Chanse Meusel, Timothy Hunt, Noreen Kelly
Abstract: This work describes a combine harvester simulator and virtual environment (VE). This interactive and realistic simulator is a novel and unique apparatus used for development and testing of human-machine systems during the design of agricultural vehicles and systems. The combine simulator and VE are being used to develop and evaluate new technologies and automated systems. The simulator provides an innovative testing platform in which to conduct active harvesting experiments that would otherwise be difficult or impossible to perform. The successes of two studies, Auger Spout Aiming and Combine Implement Adjust are described, including experimental results. The novel approach used with this simulator to acquire the voice of the customer can be generalised to the development of other products with a human interface, and applications in other domains are considered.
Keywords: computer graphics; human computer interaction; product development; simulation; systems simulation; user-centred design; user interfaces; virtual reality.
A new approach to modelling the hitch joint of a tractor semi-trailer using virtual Pacejka tyre model
by Mohamad Hafiz Harun, Khisbullah Hudha, Pakharuddin Mohd Samin, Saiful Anuar Abu Bakar, Zulkiffli Abd Kadir
Abstract: In this study, a new approach to modelling of the hitch joint of a tractor semi-trailer is proposed by adopting the virtual Pacejka tyre model. The virtual Pacejka tyre model is connected with a 16 DOF tractor semi-trailer combination in Matlab-Simulink software and verified using validated software known as TruckSim. Two sets of simulations are conducted in the verification process, which involves a double lane change (DLC) and steep steer cornering (SSC) test. It is observed from the results that by modelling the hitch joint as a virtual Pacejka tyre model, the behaviour of the developed model closely follows the behaviour of the validated TruckSim model.
Keywords: tractor semi-trailer; hitch joint; double lane change; step steer cornering.
Investigation of diesel oilLPG content fuel use in heavy duty diesel engines with common rail system
by Máté Zöldy
Abstract: After the diesel scandal, the replacement of diesel fuel in heavy duty segments is an up-do-date issue to investigate. Liquified petrolum gas (LPG) could be one of the alternatives. In our research, we investigated different LPG-diesel blends and measured engine CO, CO2, NOx and particulate emissions, fuel consumption and torque, and also investigated combustion characteristics. Results show that, based on its very different chemical composition, LPG is not an optimal substitute for diesel fuels.
Keywords: diesel substitutes; emission reduction; LPG.
Impact of a modified braking valve for static and dynamic characteristics of pneumatic braking systems of agricultural trailers
by Zbigniew Kaminski, Krzysztof Kulikowski
Abstract: The pneumatic braking systems of agricultural trailers contain brake valves with adjustable predominance of the output pressure relative to the control pressure. The goals of our study were to improve the static and dynamic properties of agricultural trailer pneumatic braking systems by modification of brake valve construction with implementing a throttle valve to the predominance device. The proposed correction device makes the intensity of the predominance effect depends on the rate of pressure rise in control chamber of the braking valve. Initial testing of three braking systems of agricultural trailers has confirmed the effect of modifying relay emergency valve to shortening the response time of their braking systems, concomitantly maintaining a follow-up action under steady state conditions.
Keywords: braking dynamics; vehicle braking systems; road safety; air brake systems; agricultural trailers; relay emergency valve.
A virtual test platform for railway draft gear designs
by Qing Wu, Colin Cole, Maksym Spiryagin, Weihua Ma, Shihui Luo
Abstract: Draft gears are important shock absorbers in railway vehicle operations. Draft gear design and assessment processes commonly use results from physical drop-hammer tests, vehicle impact tests and laboratory rig tests, which all use quite different impact velocity ranges and impact severities from each other. Owing to the velocity-dependent characteristics of friction and viscous damping, draft gears can be better designed and assessed by using comprehensive draft gear test simulations. This paper developed a multipurpose virtual test platform for draft gear designs; the virtual platform can conduct drop-hammer test simulations, vehicle impact test simulations and laboratory rig test simulations for different types of draft gear using different draft gear models. The development for the virtual platform has used a versatile draft gear model that can simulate a number of different draft gear designs by using one model template; it has also used a multipurpose simulation strategy that can simulate different draft gear tests using the same dynamics model. Three virtual test examples are also presented in this paper.
Keywords: draft gear design; virtual platform; drop-hammer; vehicle impact; laboratory rig.
Integrated active steering control strategy for autonomous articulated vehicles
by Bo Wang, Hongshan Zha, Qin Li, Xiaobo Wang
Abstract: An integrated active steering control strategy for tractor and trailer unit of articulated vehicles is presented in order to achieve both autonomous and safe motion. Without drivers supervision or input, the tractor and trailer controllers are designed to preview and follow the demanded path automatically and safely. The system is implemented by integrated active steering control based on model predictive control (MPC). A driver preview model, used to preview and store the lateral position of the road path with time progressing, is introduced to provide information regarding the demanded path for the controller. Based on the MPC theory, the integrated active steering controller of the tractor and trailer is designed to minimise path-tracking deviation while taking lateral stability into account. The path-tracking deviation is measured by the distance between the CoG (centre of gravity) of tractor and trailer with respect to the demanded path, while lateral stability considers lateral acceleration and side-slip angle. The above index can be addressed via coordinated optimisation on the performance index according to different vehicle conditions. Finally, manoeuvrability and stability of the articulated vehicle under the proposed control strategy are studied and verified by simulations at low speed and high speed based on TruckSim-Simulink. The results confirm that the proposed integrated active steering system, as desired, is capable of keeping the articulated vehicle automatically following the demanded path with high stability. The lateral stability and path-tracking of both tractor and trailer are significantly improved.
Keywords: autonomous articulated vehicle; integrated active steering; lateral stability; model predictive control.
Simulation and design of a it for the electrification of a light tricycle truck
by Luca Pugi, Matteo Giglioli, Lorenzo Berzi, Edoardo Locorotondo, Alessandro Pretto
Abstract: The light tricycle truck represents a typology of commercial vehicles widely diffused especially in large urban areas of the emerging, fast-growing economies of Asia, Africa and South America. The tricycle offers a cheap and agile solution for the transportation of goods in congested urban areas. Despite its large diffusion around the world, electrification of this kind of vehicle has been neglected by large industrial groups because this process involves a relatively low margin of profit with respect to the wide population of vehicles that have to be upgraded. However, considering the enormous number of circulating tricycles, their electrification should be of fundamental importance for the sustainable growth of vast regions of the world. In this work, the authors propose the study of a very simple and cheap electrification kit that can be easily applied to upgrade a large part of existing conventional tricycles with relatively modest cost and technologies using small-sized plants diffused in both rural and urban areas. The kit is developed and applied to an APE Piaggio, a vehicle widely used worldwide that has historically influenced the development of many different light tricycle vehicles. The investigation is performed starting from the modelling phase of the dynamics of the vehicle in order to estimate its performance and to optimise various aspects related to the installation, e.g. the weight distribution. Particular attention is paid to the optimisation of regenerative braking and its blending with mechanical braking not only to maximise autonomy but in order to preserve vehicle stability with different curved track and vehicle loading conditions.
Keywords: electrification of light tricycle trucks; optimal blending of regenerative braking; stability; experimental identification of vehicle properties; vehicle second life.
Torsional vibrations in heavy-duty truck powertrains with dual mass flywheels
by Lina Wramner
Abstract: Many of the measures taken to improve combustion engine efficiency lead to higher torsional vibrations. For heavy-duty commercial vehicles it is foreseen that the conventional flywheel and clutch will not be able to sufficiently reduce those increased engine torsional vibrations to the driveline. In this paper, the steady-state torsional vibrations in a heavy-duty truck powertrain are studied. The focus is engine excited vibrations at high load within operating speed range. Vibration phenomena in a conventional heavy-duty powertrain and in powertrains equipped with dual mass flywheels are studied. It is shown how the use of a dual mass flywheel can enable down-speeding and increased engine torque with maintained or reduced levels of torsional vibrations.
Keywords: torsional vibrations; powertrain; driveline; heavy-duty truck; dual mass flywheel; DMF; resonances; simulation.
On the control strategies for vehicle stability enhancement
by Amro Elhefnawy, Hossam Ragheb, Al-Hossein Sharaf, Shawky Hegazy
Abstract: Currently, vehicle stability enhancement is the main objective of automotive suppliers to enhance the vehicle overall performance and handling. In this paper, different active vehicle chassis control systems and all the available techniques of integration will be discussed. At the beginning, a description of the main techniques used will be presented, then the necessity for combination of these active chassis control systems is studied, followed by a comprehensive review about the state-of-the-art approaches. The purpose of this study is to support automotive manufacturers and suppliers to reach an integrated vehicle chassis control architecture for flexible designs.
Keywords: vehicle stability; handling; ABS; AFS; DYC; ARC; coordination; control; integrated vehicle dynamics; lateral acceleration.
An innovative straddle monorail track switch design for the personal rapid transit
by Chih-Hung Li, Zong Jun Lu
Abstract: An innovative track switch design is proposed for a straddle monorail system that may serve as a personal rapid transit (PRT) system. Previously, a PRT system using the monorail design was thought impossible. Here we introduce onboard guide wheels on the monorail vehicles to be the only movable parts that direct the cars to different paths. Each vehicle activates its own switching mechanism and does not need to wait for the movement of the heavy track beams anymore. Guideways and ground rails accommodated by a switch platform are designed to replace the monorail track beams. To verify the system performance, a model monorail loop and a vehicle were built for testing. Test results and analyses show that the monorail vehicles have enough momentum to traverse the switch area without power, and the required headway for the proposed system is much less than the target of 10 seconds.
Keywords: monorail; PRT; personal rapid transit; track switch; headway.
Special Issue on: Recent Advances in Active Safety Control Systems for Commercial Vehicles
Rollover prevention for a heavy vehicle using optimised slide mode steering control
by Zhilin Jin, Chao Wang, Lei Zhang, Wanzhong Zhao, Amir Khajepour
Abstract: For a heavy vehicle, active steering can effectively prevent rollover, however, it also changes the operation of the vehicle away from the drivers intentions. To improve rollover stability and reduce tracking error, an optimised slide mode steering control strategy is proposed. A four degrees of freedom linear model is used, which includes lateral, yaw, and roll motions of the sprung mass and unsprung mass. This model is also validated to describe heavy vehicle rollover dynamics. From the model, slide mode control based roll angle and slide mode control based lateral displacement strategies are developed, respectively, and the optimised slide mode steering control strategy is presented to track the set routes and prevent vehicle rollover. Furthermore, some typical numerical cases are simulated to demonstrate the effectiveness of the control strategies. The results show that the optimised slide mode steering control strategy can effectively reduce vehicle rollover risk and significantly improve the performance of tracking the drivers intention for a heavy vehicle.
Keywords: heavy vehicle rollover; optimised slide mode control; active steering; rollover prevention.
Braking intention recognition algorithm based on electronic braking system in commercial vehicles
by Hongyu Zheng, Shenao Ma, Lingxiao Fang, Weiqiang Zhao, TianJun Zhu
Abstract: The aim of this research is to investigate the braking intention identification method adaptive to the Electronic Braking System (EBS) in commercial vehicles. Based on the neural network, a braking intention identification model is established that takes both emergency braking and general braking into account. Then, considering the complex transportation environment, a multi-condition identification model with respect to four typical braking conditions is developed using fuzzy logic. The experimental results of the two models demonstrate that the proposed strategy can make good use of driver braking intention. The proposed method provides theoretical guidelines on driver behaviour adaptation on the longitudinal active safety system, which promotes vehicle safety and braking performance.
Keywords: braking intention identification; neural network; fuzzy logic; electronic brake system; commercial vehicle.
Modelling, verification and analysis of articulated steer vehicles and a new way to eliminate jack-knife and snaking behaviour
by Yu Gao, Yanhua Shen, Yaodong Yang, Wenming Zhang, Levent Güvenç
Abstract: A nonlinear articulated steer vehicle (ASV) model coupled with a 12-DOF dynamic model and full-hydraulic steering system model is derived. Field tests of single-lane change at unloaded and loaded condition are made to verify the accuracy of the ASV model by comparison of velocity, articulation angle, yaw rate and oil pressure. Considering the effect of varying bulk modulus, the unstable area of ASV decided by oil pressure and air content is confirmed according to the critical speed analysis by 3-DOF linear model. To reveal the differences between the nonlinear vehicle model and the linear vehicle model, articulation angle responses of the two models are compared. Results show that the nonlinear vehicle model has a reduced unstable area compared with the linear model, which means the nonlinear model is less sensitive to disturbance than the linear model. As the torsional stiffness is influenced by the fluid pressure when the oil is entrapped with air, a new way to improve the stability of ASV by filling-oil pressure control is presented. Simulation results show that the jack-knife and snaking behaviour are eliminated and the appropriate filling-oil pressure for this ASV is confirmed at 1.0 MPa.
Keywords: modelling; verification; articulated steer vehicle; stability; bulk modulus; jack-knife and snaking behaviour; control.
Improving stability and comfort of an in-wheel motor drive electric vehicle via active suspensions
by Guo-dong Yin, Zhen Wang, Ning Zhang, Xian-jian Jin
Abstract: This paper presents a method of a controller design to improve the handling and stability of an in-wheel motor drive electric vehicle using active suspensions with considerations of parameter uncertainties and control saturation. The construction of the mathematical model of vehicle suspensions combines active suspensions with vehicle lateral stability together. Through the robust H∞ optimal control of active suspensions, the vehicle lateral stability has been improved and the vertical dynamic displacements of suspensions have decreased. The uncertain parameters include the vehicle body mass, suspension spring stiffness and suspension damping coefficient. The control saturation considered results from the physical limitations of actuators. Active suspensions are designed with linear matrix inequalities feedback control method to attenuate the effect of the lateral acceleration on the roll angle and the suspension stroke. Simulation results show that the designed controller can improve vehicle handling and stability and has good robustness.
Keywords: active suspension; robust H∞ optimal control; in-wheel motor; actuator saturation.
Dynamics integrated control for a four wheeled independent control electric vehicle
by Guoying Chen, Lei He, Buyang Zhang
Abstract: The four wheeled independent control electric vehicle (FWIC-EV) has each wheel with independent steering, driving and braking. Apart from conventional vehicles, all independent chassis actuators drive by wire allows vehicle dynamic improvement to assist the driver in enhancing handling and cornering stability. In this paper, a multilevel integrated control, including motion controller and control allocation, is introduced for the performance improvement. In the strategy, the motion controller based on model prediction control (MPC) optimises the vehicle control forces and moments within the actuators characteristics, and tracks the longitudinal and lateral references. According to the calculation of the MPC controller, the control allocation minimises the each wheels tyre workload, and distributes the wheels steering angles and driving/braking torques. In the processing of the allocation, the constraints divided into equality and inequality constraints are respectively introduced for simplification. Based on a FWIC-EV co-simulation vehicle model and an experimental platform, the performance of the multilevel integrated control is demonstrated.
Keywords: electric vehicle; integrated control; model prediction control; allocation; tyre workload.
Modelling and analysis of the influences of various liquid sloshing characteristics on tank truck dynamics
by Ying Wan, Weiqiang Zhao, Changfu Zong, Hongyu Zheng, Zhenyang Li
Abstract: This paper focuses on the degree of vehicle-liquid coupling and its influence on the whole vehicle in actual manoeuvres and the modelling theory of liquid sloshing in liquid tank trucks. A complicated two-way coupled dynamic model and three simplified models for tank trucks were developed. Based on the four models, the vehicle-liquid coupling dynamic characteristics and their influence on the whole vehicle are discussed from the aspects of lateral handling stability and longitudinal braking performance, with various actual manoeuvres of different emergency level.
Keywords: heavy vehicle systems; tank trucks; tanker; vehicle-liquid coupling dynamics; sloshing characteristics; two-way coupled model; simplified models; equivalent model; computation fluid dynamics; CFD; actual manoeuvre; handling stability; longitudinal braking performance.
Research on lane keeping control strategy for buses
by Xiaojian Han, Weiqiang Zhao, Hongyu Zheng, Lijiao Yu
Abstract: Owing to the frequent occurrence of commercial vehicle lane departure, a novel lane departure warning (LDW) system based on driver behaviour characteristics and a lane keeping assisted system (LKAS) based on an electrohydraulic steering system for buses are presented in this paper. Considering the differences between driver behaviour characteristics, a newly designed dynamic warning algorithm is proposed to predict the lane departure risk. Then for the LKAS control, a simulation model of the electro-hydraulic steering system for buses is introduced for the active steering assisted control, and a multi-mode active control algorithm is designed for the lane keeping. In order to verify the effectiveness of the proposed control strategy, the co-simulation softwares of TruckSim, AMESim and MATLAB/Simulink are employed for the experiment validation. After extended simulation, it is found that the proposed LDW algorithm demonstrates an effective lane departure detection, and when the imminent lane departure is detected, the multi-mode active control algorithm can rapidly make adjustments to avoid the bus departing from the original lane.
Keywords: driver assistance systems; bus; warning system; driver types; dynamic warning line; steering system model; active steering control; piecewise PID controller.
A new driving condition identification method for heavy duty vehicles based on HHMM model
by Tianjun Zhu, Bin Li, Changfu Zong
Abstract: Aiming to improve the active safety of heavy duty vehicles, a new dynamic driving condition identification method is developed in this paper through incorporating Hierarchical hidden Markov models (HHMM) into the rollover warning system for heavy duty vehicles to assist the driver to be aware of the driving conditions. The corresponding data under typical driving conditions are first collected and then put into test with Student's t-test method and Grubbs test method (T-G test method). The outliers filtered by T-G test from the data are detected and eliminated. K-Means algorithm, used to set up the rollover threshold value, and Baum-Welch algorithm for optimising the proposed rollover warning model, are discussed in detail. Computer simulations under different driving conditions are carried out to verify the optimised HHMM model. The simulation results demonstrate that the proposed driving condition identification method can effectively identify the driving status with a high accuracy under a variety of driving conditions and could be used for real-time rollover warning control.
Keywords: hierarchical hidden Markov model; heavy duty vehicles; driving condition identification; rollover warning system.
Investigating the active suspension performance using 2/ robust controller combined with particle swarm optimisation
by Hamid Taghavifar, Leyla Tagahvifar, Aref Mardani
Abstract: A robust controller design technique for vehicle active suspension systems is investigated, which takes into consideration the road disturbance as the uncertainty of system parameters. The design of the robust controller is considered as a dynamic optimisation problem, and two artificial intelligence approaches of genetic algorithm and particle swarm optimization are adopted to find the optimum amounts of weighted mixture of H∞/H2. The cost function of the robust controller is designed based on the norms of the weighted mixture of H∞/H2 for a plant with a definite feedback gain and coefficient of norm of infinity that varies in the range between 0 and 1 representing absolute H2 and H∞, respectively. Particle swarm optimisation showed a competitive convergence to the global minimum of 127 in the shortest time and was selected as the best performing technique. The adopted system improved the system response in terms of sprung mass acceleration, suspension deflection and unsprung mass displacement. The obtained results from the simulations further confirm the superiority of the proposed system relative to the classical passive suspension, and signify the robustness of the active controller design.
Keywords: active suspension; robust control; suspension deflection; particle swarm optimisation.
Path-tracking errors for active trailer steering off-highway: a simulation study
by Qiheng Miao, David Cebon
Abstract: This paper discusses the tracking performance of a path-following steering system when operating off-highway. Simulation studies were conducted on three types of vehicle model: tractor-semitrailer, B-double and A-triple. The vehicles were simulated for a straight-line and a 450 roundabout with various road cambers, grades and adhesions. Results indicated that the path-following steering system was unable to provide good tracking performance under those conditions owing to longitudinal and lateral wheel slip interfering with its estimation of trailer location and orientation.
Keywords: simulation study; path-following control; active steering; off-highway.
Path planning and tracking for autonomous mining articulated vehicles
by Fengqian Dou, Yanjun Huang, Li Liu, Hong Wang, Yu Meng, Lianqiang Zhao
Abstract: This paper presents a path planning and tracking framework for autonomous mining articulated vehicles (AVs). The relation space method (RSM) is proposed for path planning. In this method, a self-organising, competitive neural network is adopted to identify the space around the vehicle. Then the vehicles optimal driving direction is determined by using the spatial geometric relationships of the identified space. A PID controller is used to control the vehicle speed, whereas a model predictive controller (MPC) is designed for steering control, where the path tracking error model is used for MPC development. In addition, the AVs dynamics model is built in Adams. The effect and sensitivity of the path-tracking controller are validated through the Matlab-Adams co-simulation. The test results show satisfactory path-tracking performance.
Keywords: articulated vehicle; relation space method; path planning and tracking; MPC.
Integrated control strategy for articulated heavy vehicles based on a linear model with real-time parameters
by Zhigen Nie, Jin Gao, Kun Zhang
Abstract: A control strategy for lateral performance improvement of articulated heavy vehicles (AHVs) by integrating active trailer steering and differential braking is presented. A linear model with real-time parameters is adopted in the strategy to achieve precise control for AHVs under the real-time vehicle states and conditions. The strategy is divided into a path-follow control mode and rollover control mode. A mode switching method is employed by the strategy to achieve good path following and yaw stability under normal working conditions and to avoid vehicle rollover under the limit conditions. Moreover, in order to obtain the optimal control effects for different control objectives and achieve fusion and coordination of multiple subsystems, the genetic particle swarm optimisation algorithm is used to obtain the optimal weight coefficients of the strategy. Experimental verification results indicate that the presented strategy achieves good control for AHVs across a wide range of different operating conditions.
Keywords: articulated heavy vehicles; integrated control; vehicle dynamics and control; parameter identification; optimal control.
Special Issue on: Heavy Vehicle Systems in Real-Time Applications
IEEE 802.11p MAC with spectrum sensing scheme reliable for VANET using intelligent transportation system
by S. Karthikeyini, S. Shankar
Abstract: IEEE 802.11 standard supports Intelligent Transportation Systems (ITS) which access the vehicle based on WiFi technology. IEEE 802.11p, which supports data exchange between high-speed vehicle to vehicle communication through licensed frequency band 5.8GHz or 5.9GHz (5.85-5.925 GHz), support ITS application in Wireless Access in Vehicular Enviroment (WAVE) protocol stacks. The IEEE 802.11p standard provides multiple channel access to improve of traffic safety and traffic efficiency. In a congested area it needs enough spectrum for a commute of safety and non-safety messages. The proposed method, IEEE802.11p MAC, accesses the channel in a distributed fashion to avoid collisions and uses the cyclic autocorrelation function to detect the energy for broadcast signal and measured along the vehicle level. All information is aggregated for making a decision for data delivery in vehicular environments. The spectrum sensing method is employed to sense broadcast signals for finding out the occupancy status of the spectrum and availability of the licensed frequency bands. Thus the cognitive radio approach dynamically allocates the bandwidth for insufficient area, which mitigates the spectrum scarcity. The performance of the spectrum sensing technique is judged at a congested city-state of affairs using an ns2 simulator. The results establish the available licensed free channels and avoid collision by the dynamic TDMA method. The proposed approach represents an effective and warranted conversation over VANET measured through the high reliability and reduced delay and overhead of packet constraints.
Keywords: IEEE 802.11p; MAC protocol; CAF; CFD; dynamic TDMA.
Design and SAM analysis of reconfigurable four-legged mechanism using single degree of freedom
by A. Krishnaraju, Abdul Zubar
Abstract: A number of examples of walking equipment integrated with heavy vehicle systems and robots have been conceived, measured and built in the last 25 years to occupy modern fields of application. Compared with wheeled equipment, legged and walking machines show the advantage that they can act in highly unstructured terrain without having to prepare this terrain in advance by streets or rails. Legged robots cross obstacles more easily and depend upon the environmental situations. In this paper, a proposed kinematic four-legged model design is made by linkages using a single degree of freedom (DOF), then the paper performs the modelling and kinematic analysis of a reconfigurable four-legged walking mechanism driven by manual or a single actuator using SAM analyser software. A four-bar walking mechanism can be observed by different link lengths in path movements, velocity, and acceleration. In particular, a suitable model of the leg design and also kinematic analysis has been analysed. One of the most important concepts of this research is the desired simplicity of the four-legged walking mechanism.
Keywords: degrees of freedom; integrated system; heavy vehicle system; path trajectory; SAM analyser; simulation; walking equipment; stability.
Special Issue on: Intelligent Transportation Techniques for Vehicle Tracking and Accident Identification Systems
Design and implementation of a 31 level asymmetrical cascaded MLI with DC-DC flyback converter for photovoltaic system using P&O technique for electric traction application
by Gowri Shankar, Belwin Edward
Abstract: This paper proposes a design and implementation of 31-level MLI (Multi-Level Inverter) supplied from a single solar panel with multi-output flyback converter for transformer-less railway traction drive. Four different kinds of DC voltage are made from the converter. The converter provides isolation for the circuit and also produces four different kinds of supply voltage based on the transformer turns ratio. Both symmetrical and asymmetrical MLI are used in this method. In the case of the symmetrical MLI, the magnitudes of the DC source are equal i.e., 60 Vdc, 60 Vdc,60 Vdc and 60 Vdc, whereas in asymmetrical MLI the DC source magnitudes are unequal and designed with a binary form of voltage, such as 15 Vdc,30 Vdc, 60 Vdc and 120 Vdc. Relating both the MLI, the asymmetrical MLI produces the same number of output voltage levels and power semiconductor switches. The phase Disposition Pulse Width Modulation (PD-PWM) technique is used for controlling the power semiconductor switches in MLI. In this proposed technique, we are using a single solar panel and single flyback converter, from which four DC output voltages are obtained in the ratio of 1:2:4:8. Our proposed technique requires fewer switches, i.e. seven switches for more levels, i.e. 31 levels, and it also gives less total harmonic distortion (THD). These are the main advantages of this proposed technique. The results are verified in MATLAB, PROTEUS and real-time system. This eliminates the need for a transformer in the railway traction drives and also results in a reduction in the THD of the voltage to be supplied to the traction motors.
Keywords: traction; PV system; MLI; DC-DC converter.
Research on intelligent transportation system based on internet of things
by Maozhu Jin, Qian Zhang, Hua Wang, Yuan Yuan
Abstract: Intelligent energy-saving systems and intelligent transportation systems are indispensable applications in ordinary people's lives. Therefore, it is particularly important to apply the internet of things technology to these two typical scenarios. The key technologies are fully investigated in this paper, and a intelligent energy-saving prototype system has been designed. At the same time, this paper focuses on the two core issues of traffic, and studies the two core technologies in intelligent transportation. Firstly, this paper introduces the research background of this topic, and then presents an overview of the internet of things, intelligent energy-saving system and intelligent transportation system. Next, this paper introduces the core technology and prototype system design of intelligent energy-saving system in the internet of things from four aspects, including system structure, hardware design, software design and test results.
Keywords: internet of things; intelligent transportation system.
Research on application of artificial intelligence model in automobile machinery control system
by Xiuyu Chen
Abstract: In order to improve the kinematics and ride comfort of the vehicle suspension system, this paper combines the ADAMS software with the artificial intelligence optimisation algorithm to simulate and optimise the suspension system of a certain type of off-road vehicle. The front suspension 1/2 virtual prototype model is established in ADAMS/View, and the kinematics analysis of the prototype model is made. In order to improve the kinematics characteristics of the front suspension, the genetic algorithm and the immune algorithm are used to optimise the positioning parameters of the front suspension based on the kinematics analysis of the suspension. The dynamic model of the whole vehicle is established in ADAMS/View, and the vehicle ride comfort is simulated and calculated. The spring stiffness and shock absorber damping of the rear suspension are optimised by using the immune algorithm, and the purpose of improving the ride comfort of the vehicle is realised.
Keywords: artificial intelligence; automobile; mechanical control system.
RMF-based target position estimation and collision probability forecasting technique in freeway junctions
by Pappan Sathiya, P. Anandhakumar
Abstract: Collisions between vehicles and pedestrians lead to brutal loss of life and assets on Indian roads. Accidents happen due to individuals' negligence and misjudgment of the speed of vehicles at freeway junctions. In this paper, a novel feature extraction technique is used for estimating the target position and to update the trajectory information. A vision-based technique is incorporated to acquire the target information in a simple and cost-effective method to examine the targets current position. Moreover, a distribution-based evaluation method is introduced to calculate the degree of conflict and to avoid crashes by alerting the target. The experimental results of the proposed technique reveal an improved performance of 9% in detection rate for public datasets over the existing GMM method. The proposed probabilistic collision avoidance system could be implemented on highways to reduce the accidents to a greater extent.
Keywords: probability distribution; RMF feature vector; target interaction; time of collision; virtual line.
A high strength and wear-resisting AA5083 alloy for armoured vehicle applications: structure property correlation
by T. Venugopal, P. Chandramohan
Abstract: Presently AA-5083 aluminum alloy is commonly applied in army land systems as it has demonstrated a record of protection from corrosion and great welding qualities. An alloy with high strength is constantly desired without increasing the weight to enhance the performance of armoured vehicles. In this study, an ultrafine-grained (UFG) structure is developed using equal channel angular pressing (ECAP), and its effects under route RA on the microstructural evolution, hardness, compression and wear behaviour of the AA-5083 alloy are studied. The ECAPed AA-5083 alloy exhibits the microstructural refinement of the base alloy. The grain size of the starting (as received) material is 56μm whereas the ECAPed AA-5083 exhibits the UFG sizes of ~4μm along the extrusion direction (ED) and ~5μm along the transverse direction (TD). The influence of microstructural refinement is corroborated with the hardness, compression and wear behaviour of the base AA-5083 alloy. The ECAPed AA-5083 alloy exhibits higher compressive strength (ED-351MPa and TD-339MPa) than the base alloy (144MPa). However, the ductility of the TD is low compared with the ED owing to the influence of compounds present in the microstructures. The strain hardening rate of the compressive stress-strain have been analysed and confirms the existence of stage-III and stage-IV. The wear studies have been performed to understand the influence of grain size on the wear behaviour. The Taguchi L9 orthogonal array was employed to perform the wear studies. Interestingly, the wear resistance of ECAPed (ED) alloy is superior to those of the TD and the base alloy. It is attributed to the finer grain size and distribution of finer particles along the grain boundary, which restricts the wear of the material. The as-processed alloys were further analysed using microhardness test. The maximum hardness of the ECAPed(ED) alloy is 138
Keywords: AA-5083; ECAP; wear; compression and hardness; armoured vehicles; ultrafine grain.
Automotive industry application of aluminium-based hybrid metal matrix composite
by P. Ramesh, M. Nataraj
Abstract: Monolithic materials cannot fulfill the demands for the advanced industrial requirements. Therefore, composite materials that possess the combined properties of different constituents are developed. The composites give a combination of desired properties, such as ductility, toughness, high strength and high modulus, so it is necessary to develop a material that will have low volume loss, increased service life, and less wear rate, for its use where there is a relative motion between components such as reciprocating or rotary elements found in machinery and automotive components. The basic requirements in the engine industry, which are major driving forces for developing and implementing new materials, are reduction of fuel consumption and vehicle emissions. Aluminium and other light metals have lower density compared with the standard materials used in the engine industry (grey cast iron and steel). Their use reduces mass, and increases the efficiency, and thus satisfies the basic requirements on fuel economy and vehicle emissions. Unfortunately their tribological properties are not satisfactory, which limits their application in manufacturing the tribo mechanical components. One of the possible solutions for this problem is use of Aluminium Metal Matrix Composites (Al MMCs). In this experimental work, Aluminium 6061 was used as matrix and Al2O3, SiC and E glass short fibres were used as the reinforcement material. The stir casting technique was used to fabricate the composites for reducing the porosity and minimising the casting defects. The samples were then tested for tribological properties using pin-on-disc tester at different sliding speeds, loads and sliding distance. Experimental result shows that the wear rate was decreased when increasing the reinforcements. This investigation concluded that the load and sliding speed are expanded to increase the wear rate but by developing the sliding distance the wear rate is decreased. The least wear rate is obtained with the composition of 70% weight proportion of Al 6061, 15% weight fraction of Al2O3, 9% weight fraction of SiC, and 6% weight fraction of E glass short fibre.
Keywords: MMCs; Al2O3; SiC; E glass fibre; stir casting.
Failure analysis of leaf spring suspension system for heavy load truck vehicle
by M. Nataraj, S. Thillikkani
Abstract: The failure of the leaf spring suspension system used in heavy load truck vehicle TATA LPT 1613TCIC model was investigated. In order to analyse this failure, the variations in the chemical compositional and micro-structural analysis along with material specification have been studied. The leaf spring fractured part was analysed by using a visual inspection technique and scanning electron microscope (SEM) analysis. Based on the fractography study, it was deduced that the failure of the fractured part was due to the cyclic load. Such loads lead to fatigue growth on the leaf spring model of TATA LPT 1613TCIC truck vehicle. Then finite element analysis of the leaf spring was carried out to find out the root cause of the failure of the leaf spring suspension system. The failure parameters were also optimised for the model of the TATA LPT 1613TCIC truck vehicle on the road drive safe operation. The fatigue life of the modified leaf spring has increased in comparison with the existing leaf spring lifecycles.
Keywords: leaf spring; finite element analysis; scanning electron microscope; fatigue life.
Response surface methodology based on polyamide incorporated with biolubricant for optimisation of operating parameters in heavy vehicles
by J. Narendran, T. Karthikeyan
Abstract: In this paper, the coefficient of friction and wear of pure and filled polyamide incorporated with and without biolubrication prediction models based on response surface methodology (RSM) are exhibited. The models were developed based on three-level design of experiments conducted on pure polyamides, such as Polyamide6, Polyamide66 and filled polyamides such as Polyamide66 filled with Glass Fiber 30 and Polyamide66 filled with molybdenum disulphide. The load, speed and sliding distance are considered as process parameters. Numerical models of second order RSM clearly show that the prediction capabilities of RSM models are more desirable. This implementation is leading to the identification of insignificant main factors and contact factors or insignificant quadratic expressions in the model, and in this manner can diminish the complication of the problem.
Keywords: polyamides; RSM; soybean oil; rice bran oil.
Test research on the adhesive and tractive performance of a wheeled tractor
by Zhen Zhu, Long Chen, Changgao Xia, Yingfeng Cai
Abstract: In order to improve the adhesive and tractive performance of a wheeled tractor, the test scheme for the research on the influencing factors of the adhesive performance is designed. The mechanical performance of the tested soil can be got according to the test data obtained by the soil shear apparatus. The relation between the tyre maximum driving force and the normal load, and the relation between the tyre deformation displacement and the tyre driving force, can be got according to the test data obtained by the test device. The test scheme for the test study on the tractive performance of a wheeled tractor should be divided into two types: the tractor operates with the ploughing unit on a soil road and the tractor operates with the loading vehicle on an asphalt road. The researches on the soil road mainly discuss the relations among ploughing resistance and resistance moment, vibration and vibration frequency, slip coefficient and ploughing depth. The researches on the asphalt road mainly discuss the relations among tractive efficiency, translational velocity of tractor and slip coefficient.
Keywords: test research; adhesive and tractive performance; wheeled tractor.
Study on vehicle driving state and parameters estimation based on triple cubature Kalman filter
by Gang Li, Dongsheng Fan, Ye Wang, Ruichun Xie
Abstract: For the problem of vehicle driving state and parameter estimation in the process of vehicle driving, the vehicle state and parameter estimation algorithms are studied based on the triple cubature Kalman filter. The nonlinear three degrees of freedom model with Dugoff tyre model is established. The vehicle driving state estimator, road adhesion coefficient estimator and vehicle parameter estimator are designed based on the theory of triple cubature Kalman filter. In order to estimate the driving state and parameters accurately, the three estimators connect to each other in the process of the estimation and form a closed-loop feedback in real time. The estimation algorithms are verified based on the driving simulator. The serpentine docking road conditions with changes speed are selected to verify the estimation algorithms based on the driving simulator in-loop simulation test. The experiments' results show that the vehicle driving state and parameters are estimated accurately by the estimation algorithms.
Keywords: Dugoff tyre; driving simulator in-loop simulation experiment; road friction coefficient; triple cubature Kalman filter; vehicle driving state; vehicle parameters.