International Journal of Heavy Vehicle Systems (71 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
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.
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.
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.
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.
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;.
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.
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 kit 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.
Influence of shock absorbers damping rates on the fatigue of anti-roll bars of a commercial vehicle
by Arthur Larocca, Mina Youssef, Anne Gadbois, Dragos Zamfir, Pablo Kubo
Abstract: Within the framework of an integrated product development, the main objective of this study is to assess the influence of shock absorbers damping rates on the fatigue of anti-roll bars of a commercial vehicle. In this regard, force and displacement data have been collected in a durability test track with an instrumented bus on curb weight and gross axle weight rating. Based on the theory of fatigue damage accumulation, the durability of each anti-roll bar of a bus (front and rear suspension) was assessed for three different shock absorbers damping rates. Statistical significance between different shock absorbers has been identified for both bars on both loading conditions. The results pointed out that, in some cases, a softer damper could reduce by almost half the fatigue life of an anti-roll bar when compared to the same bar with stiffer dampers.
Keywords: anti-roll bar; stabilizer bar; shock absorber; damper; damping rate; damping coefficient; fatigue; damage; commercial vehicle; concurrent engineering; integrated product development.
Prediction and analysis of semi-low-floor bus driver seat vibrations by using the response surface methodology
by Medisetti Jaganmohan Rao, S.P. Sivapirakasam
Abstract: In India, Semi-Low-Floor (SLF) buses were used as shuttles within the city. The main objective of this paper is to develop a quadratic model for prediction of driver seat vibration and analysis of relationship between the seating parameters and driver seat vibrations. Response surface methodology was used to develop the regression model in SLF bus driver comfort. In the development of the predictive model, the seating parameters backrest inclination, horizontal distance from the ABC pedal, foam thickness and speed were considered as model variables, and seat vibration was considered as a response variable. The statistical analysis showed speed was the most significant process parameter to influence seat vibration. Other parameters were found to be insignificant but the interactions among them were found to be significant. Apart from objective analysis, the subjective assessment parameters comfort, visibility and confidence also studied for all the trials. At back-rest inclination 90
Keywords: semi-low-floor bus; DoE; process parameters; weighted acceleration; response surface method; regression model.
Numerical study on whole body vibration evaluation in wheeled and tracked armoured vehicles
by Leonardo Menna Barreto Martinelli, Mário Fedatto Neto, Herbert Martins Gomes
Abstract: The vibration felt by humans is a mechanical agent that can induce discomfort or even produce health damage, depending on its intensity as well as its frequency content. Armoured vehicles are examples of equipment that produce high vibration levels, especially in critical terrain situations, both for the robustness of the suspensions and for the weight and details in the design. There are few articles in the literature evaluating this situation for occupants of these vehicles. The numerical modelling of the vertical dynamics can result in an adequate tool for initial tests and prototypes as well as being able to evaluate vibration levels in terrain situations, speed, occupant positioning, stiffness, and suspension damping. In this work, three armoured vehicles are modelled and compared travelling on an irregular road with bump obstacles in order to evaluate potential high levels of acceleration. Comparisons with international standards are performed with the aim of situating these levels in terms of whole body vibration and impact vibration. Suspension modelling uses a nonlinear Newmark numerical integration method to account suspension nonlinearities present in the tracked vehicle. Discussions and comparisons between each of the vehicle models are presented, along with graphics related to ground reaction force signals and accelerations in the vehicles body and seats. Comfort and health risks graphs are presented and show that there is a gradation regarding comfort levels of the investigated vehicles, with the tracked vehicle indicating high probability of health risk for training routines.
Keywords: vehicle suspension; armoured vehicles; whole body vibration; tracked vehicles; comfort.
Dynamic analysis and design optimisation of a heavy military vehicle
by Burak Can Çiçek, Bülent Acar, S.Kemal İder
Abstract: This paper investigates the dynamic response of a heavy military vehicle that is subjected to a dynamic firing load while it is settled on its outriggers. This dynamic behaviour is one of the major design factors of a launching vehicle. Two different finite element (FE) models are created in ANSYS software to obtain the dynamic behaviour of the launching vehicle. The first model is a detailed finite element model and the second model is a simple and fewer degrees of freedom (DOF) parametric FE model, which is created with the ANSYS Parametric Design Language (APDL) in order to perform the design optimisation by swiftly changing the parameters such as clamp attachment positions on the chassis, outrigger deployment and outrigger case cross-section.
Keywords: heavy military vehicle; dynamic analysis; finite element; design optimisation; outrigger.
Introducing a revised model for determination of rollover threshold speed of buses
by Mohammadreza Sabouri, Arman Hamidi
Abstract: Rollover is critical for intercity bus vehicles, as they often carry a large number of passengers while having a relatively high centre of gravity. Using the same models for determining the Rollover Threshold Speed (RTS) of different types of vehicle may induce some errors, as most of the existing models do not consider several factors such as vehicle type and dimension, vehicle load, turning radius of the axles, and diversion angle of the curve. This study intends to propose a more accurate relationship for determining the rollover speed of the intercity bus vehicles considering the aforementioned factors. Using the revised model, it was shown that when both the radius of the horizontal curve and the diversion angle are small, the diversion angle plays an important role in determining the RTS. The results also suggest that under the assumptions of this study, the RTS for three-axle buses happens at lower speeds compared with two-axle buses.
Keywords: centre of gravity height; curve radius; diversion angle; heavy vehicles; intercity bus; payload; regression model; rollover collisions; RTS; rollover threshold speed; superelevation; traffic accidents; TruckSIM.
Study of tyre-terrain interaction of a military vehicle
by Lucas Sousa, Ricardo Costa Neto
Abstract: Wheeled military vehicles are often used on deformable terrains. In order to understand their performance, a tyre-terrain interaction model is required. The aim of this paper is to present the application of semi-empirical tyre models based on Wong-Reece models in order to investigate the drawbar pull, the resistive torques, the sinkage and the stress distributions beneath each tyre of a six-wheeled military vehicle. An accurate prediction of terrain forces is of interest to engineers and vehicle designers to understand the vehicle performance. Furthermore, a heavy military vehicle can be immobilised owing to particular tyre-terrain properties. In a combat situation, an immobilised vehicle can be dire. The military vehicle was simulated on compact sand and dry sand, when the tyre behaves like a rigid wheel in driven and towed conditions.
Keywords: military vehicles; wheel mechanics; deformable terrains; mobility prediction; Wong-Reece theory.
Experimental-theoretical modelling of the lateral sloshing in rail tankers
by Jose A. Romero Navarrete, Frank Otremba, Alejandro A. Lozano Guzmán
Abstract: The objective of this paper is to describe and to validate a simplified pendulum-analogy model to simulate the interaction of a liquid cargo with its carrying vehicle. For that purpose and scope, a scale-down testing rig is proposed to assess the effect of a sloshing cargo on the level of dynamic forces developed at the wheel-rail interface under a lateral perturbation. The resulting testing rig consists of a rectangular container, spring-supported on a two wheelset bogie having a scale down of 1/10 with respect to a full-size equipment. The chassis and cargo representing the sprung mass, and the wheelset representing the unsprung mass of the resulting mechanical system. The testing rig is used to validate a simple pendulum-based, simplified three degree of freedom mathematical model, of the response of a partially filled container to lateral accelerations. The model comprises a full analogy of the sloshing cargo with the simple pendulum, where the tension in the pendulum bar perturbates the sprung mass. The length of the pendulum is set according to validated methodologies. The resulting mathematical scheme reveals a high correlation with the experimental output, on the order of 99%, while some other performance measures, related to the peak forces and the range of variation of the wheel-rail forces, also show good concordance with the experimental results. Additional simplifications made on the model further suggest that the length of the pendulum, the position of its pivot, and the track width, are the most important parameters influencing
the magnitude of the wheel-rail forces.
Keywords: sloshing; rail tankers; pendulum analogy; experimental modelling; mechanical fatigue.
Bidirectional adaptive cruise control for intelligent vehicles
by Chentong Bian, Guodong Yin, Liwei Xu, Ning Zhang
Abstract: Most of the previously investigated adaptive cruise control methods focused on maintaining a safe front clearance of the host vehicle. Owing to fault or heat fading, the vehicle behind an intelligent vehicle may lose part of braking performance and collide with the intelligent vehicle. Thus the control system of an intelligent vehicle should simultaneously maintain the front and rear clearances on such a critical condition, which is seldom discussed before. In this study, a bidirectional adaptive cruise control algorithm is proposed to reduce such collisions. Simulations have been done to confirm the validity of the proposed algorithm. The simulation results show that the proposed algorithm can reduce the collisions caused by the following vehicle with low braking performance, which cannot be resolved by traditional adaptive cruise control. Thus, compared with the traditional adaptive cruise control, the proposed algorithm can improve the safety of intelligent vehicles in collision avoidance.
Keywords: intelligent vehicle; bidirectional adaptive cruise control; collision avoidance; adaptive cruise control.
Experimental and numerical studies on improvement of drag force of a bus model using different spoiler models
by Cihan Bayindirli, Yahya Erkan Akansu, Mehmet Celik
Abstract: The purpose of this paper is to reduce of drag force of a bus model by using four different spoiler models. The tests were carried out at six different Reynolds numbers in the range from 3.8 x 105 to 7.9 x 105. The drag coefficient (CD) of the bus model was determined as 0.633 experimenatally in a wind tunnel and 0.645 numericaly in Fluent
Keywords: bus model; drag coefficient; wind tunnel; CFD; aerodynamic; spoiler.
Using a mobile app to estimate whole-body vibration and seat isolation performance in surface mining
by Alan G. Mayton, Brian Y. Kim
Abstract: The study objectives were twofold: 1) determine whether the whole-body vibration application (WBV app) may effectively serve as a simple tool for monitoring whole-body vibration exposure; 2) assess when the vehicle seat may need adjustment, repair, or replacement. Data were collected on 17 mobile mining vehicles and equipment at six surface operations. Comparing the WBV app to the Siemens/LMS reference system showed excellent correlation (r = 0.998 and 0.987, respectively), for frequency-weighted-root-mean-square acceleration (aw) and vibration dose value (VDV) normalised to an 8-hr shift. Seat performance, using the mobile app, showed greater variation, yet high positive correlations (r = 0.896 and 0.936) for the aw and VDV computational methods, respectively. Hence, the WBV app demonstrates potential as a low-cost instrument to measure WBV exposures for mobile equipment operators and the capability to estimate seat performance or seat effective amplitude transmissibility (SEAT) when used on two iPod Touch devices.
Keywords: whole-body vibration; mobile iPod app; surface mining; haul trucks; loaders; dozers.
Performance comparison of MD523 and SF400 bogie when passing through different turnouts
by Mahdi Naseritaheri, Shahin Yousefi, Majid Shahravi
Abstract: In recent years, the study of the dynamic behaviour of the high speed train has been taken into account when passing through the turnout. Some of these studies include examining wheel and rail dynamics when crossing the turnout nose and extracting the wheel's contact forces. The dynamical behaviour of passenger high-speed bogies during passage through the turnout is one of the most important factors in the safety of the vehicle. By increasing the speed of wagons when passing through the turnout, safety parameter and wheelset forces should be considered. The statistics have shown that 40% of derailment has taken place due to the inside of the turnout or the defect of the turnout. The purpose of this paper is to study and analyse the dynamics parameters of passenger wagon and safety of a bogie, such as the derailment and the forces of the wheelset when passing through the turnout with different turnout rail profiles, because the type of turnout rail profile and geometry of turnout affect dynamic performance of bogie. In order to investigate this, the simulation of a wagon in a multi-mass dynamic (MBS) UM software has been used on turnouts with different rail profiles and radius of turnout. As the results show, the geometric features of the turnout, such as its radius and turnout rail profile, have greatly influenced the dynamics of the wagon.
Keywords: turnout; derailment coefficient; high speed bogie; dynamic forces; turnout geometrical specification.
Investigating the effects of off-road vehicles on soil compaction using FEA-SPH simulation
by Fatemeh Gheshlaghi, Aref Mardani, Arash Mohebbi
Abstract: The study of terrain-tire interaction using simulation methods allows for accurate prediction of parameters such as soil density and rut depth which are either time-consuming and expensive or inaccessible with experimental methods. This research focuses to predict and evaluate the soil compaction after off-road tire traffic in different vertical loads on the tire. Soil-tire interaction is simulated using the Smoothed-Particle Hydrodynamics-Finite Element Analysis (SPH-FEA) techniques in Pam-crash software. In order to evaluate the simulation model, tests were conducted using a single-wheel tester in soil storage with different numbers of the pass and various loads. Soil density and rut depth were measured and compared with the simulation data. The results indicate that the tests and simulation data are in a good agreement with the coefficient of determination of 0.94. The tire with higher pass number makes greater rut depth and consequent soil density. The intensity of soil compaction due to vehicle weight is discussed in the results.
Keywords: Tire-soil interaction modeling; Rut depth; Soil density; Finite element analysis; Smoothed-particle hydrodynamics; Tester
Special Issue on: Recent Advances in Active Safety Control Systems for Commercial Vehicles
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.
Special Issue on: Heavy Vehicle Systems in Real-Time Applications
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.