International Journal of Heavy Vehicle Systems (82 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
A real-time nonlinear vehicle preview model
by Bernard Linstrom, Schalk Els, Theunis Botha
Abstract: Motor vehicle accident statistics indicate that fatalities due to rollover of Sport Utility Vehicles (SUVs) are of high international concern. These vehicles are designed to be used on both smooth roads and rough off-road terrains. As a result of the typically softer suspension, as well higher centre of gravity (CG), compared with passenger vehicles, SUVs are more prone to rollover. Researchers have developed control strategies for prevention or mitigation of rollover based on the current state of the vehicle. Most of these strategies have the same drawback, being a delay in switching. Further delays are introduced by the controllers and actuators used to control vehicles dynamics (actuators, valves, etc.). This paper proposes a real-time nonlinear vehicle preview model capable of accurately predicting vehicle parameters a finite time step ahead based on the current state of the vehicle. The VPM is developed and experimentally validated on a Land Rover Defender 110 SUV fitted with a controllable hydro-pneumatic suspension system. Results indicate that several important vehicle parameters, including roll angle and lateral acceleration, can be accurately predicted up to more than 0.25 s into the future. Vehicle dynamics controllers can use the previewed parameters instead of the measured parameters to eliminate delays and make the strategies proactive instead of reactive.
Keywords: sport utility vehicle; rollover; vehicle preview; semi-active suspension.
Assessment of ground vehicle tankers interacting with liquid sloshing dynamics
by R.A. Ibrahim, Birkamjit Singh
Abstract: This article presents an assessment of the problems encountered with the design, dynamics and stability of road tankers. Generally, the research activities pertaining to these problems may be classified into three groups. These are liquid sloshing dynamics in moving containers, truck dynamics carrying solids, and dynamic coupling of liquid-vehicle systems. The most serious problem of road tankers is rollover accidents due to lateral acceleration during vehicle manoeuvres. For this reason, many countries have imposed regulations for the minimum threshold of vehicle lateral acceleration during its manoeuvres. This threshold value is usually estimated based on a quasi-dynamic approach, which assumes that the liquid free surface takes a position orthogonal to the total body forces due to gravity and lateral acceleration. The modal analysis of liquid free surface in common tank cross-section geometries, such as horizontal circular, elliptic and generic cross-section, is presented together with the corresponding equivalent mechanical models. In view of the popularity of horizontal elliptic cross-section tanks, the trammel equivalent pendulum has received extensive research activity and the main results are discussed. In order to minimise the problem of rollover, two approaches have received the attention of engineers. These are the design optimisation of the liquid container cross-section and the passive and active control of liquid sloshing. The most difficult problem of road tankers is the coupling dynamics of liquid and vehicle dynamics under different conditions, such as braking and lateral acceleration. In view of the complex nature of the dynamics of the coupled liquid-vehicle system, computer numerical simulations have been developed.
Keywords: rollover; liquid sloshing; equivalent mechanical models; directional stability; collision; hazard liquid.
Stability of long combination vehicles
by Gonzalo Guillermo Moreno Contreras, Lauro Cesar Nicolazzi, Daniel Martins
Abstract: In general, long combination vehicles (LCVs) show poor performance with regard to stability, and this has been the focus of many studies around the world. Some characteristics, such as the suspension topology, tyres, chassis and fifth wheel, have been analysed separately, to determine their influence on the vehicle stability calculation. Most vehicle stability models are developed in two dimensions, and they do not consider the longitudinal aspects of the vehicle and the road, such as the stiffness of the chassis, the location of the centre of gravity, and the longitudinal slope angle of the road. The use of three-dimensional models of vehicles allows a more rigorous analysis of the vehicle stability. In this context, the aim of this study was to develop a three-dimensional mechanism model to represent all of these characteristics. We propose an approach from the mechanisms domain using the Davies method, in order to combine these influences, which is closer to reality. The results suggest that some simplifications, such as the planar model of well-known static rollover threshold, show poor response in LCV stability study.
Keywords: long combination vehicles; stability; safety; Davies method.
Development of hybrid electric heavy-duty truck with self-propelled trailer
by Fereydoon Diba, Ebrahim Esmailzadeh
Abstract: A new architecture of hybrid drivetrain for tractor and semi-trailers is proposed. The goal is to use the maximum capability of the hybrid electric tractor and semi-trailers and to enhance the traction and fuel consumption efficiencies. This drivetrain architecture employs a self-propelled trailer so that the tractive effort is shared between the tractor and the semi-trailer. A comprehensive model of the vehicle, including the drivetrain model, is developed and a fuzzy logic controller is used to design the power management system (PMS). Simulation runs of the computer model were performed on two standard driving cycles to evaluate both the traction efficiency and fuel consumption of the proposed hybrid drivetrain architecture. The comprehensive results obtained indicate that the proposed self-propelled trailer drivetrain presents a superior advantage over the non-hybrid drivetrains and also the typical hybrid drivetrain for heavy vehicles.
Keywords: hybrid electric truck; tractor and semi-trailer; power management system; self-propelled trailer; fuzzy logic control.
Real-time estimation of pneumatic tyre hysteresis loss
by Haytham El-Zomor
Abstract: There are many types of loss that can be considered during vehicle motion. The rolling resistance of the pneumatic tyres plays an important role in the fuel consumption and the overall energy efficiency for on/off road vehicles. An experimental test-rig for a single tyre was constructed and built especially for this current work. Experimental investigation of radial and bias-ply tyre loading/unloading characteristics and contact area to estimate the hysteresis loss during vehicle motion has been carried out at different operating conditions. Accordingly, an empirical formula has been concluded to estimate the hysteresis loss function of tyre construction, inflation pressure, and the deformed volume. The proposed hysteresis loss equation accuracy lies within an average error of 10.6%. This equation is appropriate for a real-time vehicle system by adding tyre inflation pressure sensor and vertical deflection sensor.
Keywords: tyre dynamics; rolling resistance; tyre hysteresis loss; tyre deflection; tyre deformed volume; tyre contact area.
Appraisal of numerical-based finite element method to synthesise the wheel-obstacle collision dynamics using a single-wheel tester
by Chongfeng Wei, Hamid Taghavifar, Aref Mardani
Abstract: As a very substantial aspect of vehicle dynamics and vibrational controlling, it is essential to ascertain the role of tyre-obstacle collision kinetics. Ride comfort assessments are pivotal in predicting the non-linear deformation, particularly when traversing large road obstacles. The present study focused on the assessment of a tyre travelling over obstacles at different heights using a well-equipped soil bin facility and a single-wheel tester. The vertically and longitudinally oriented load cells were used to measure the vertical and longitudinal force variations with the frequency of 30 Hz. Additionally, a FE tyre model was developed specifically for this purpose using explicit integration in ABAQUSTM. It was found that with the increase of height of road obstacle, the resonant amplitude of spindle force response as well as the tyre deformation becomes greater in both longitudinal and vertical directions. Furthermore, at greater load, the tyre overriding obstacle impact force increases significantly. It was revealed that the new proposed model can serve as a functional alternative to classical modelling tools for the prediction of nonlinear wheel dynamics.
Keywords: road obstacle; FE tyre model; single-wheel tester; vehicle dynamics.
A study on design methods for condenser radiator fan module mounting system
by Xiao-Ang Liu
Abstract: The design requirements of the automotive condenser radiator fan module (CRFM) mounting system are proposed. A six Degrees of Freedom (DOFs)CRFM model is established. Calculation methods for determining the root mean square value of the mount reaction force in a CRFM mounting system under cooling fan excitation is developed. Design and calculation methods for displacement control of the CRFM under extreme load are discussed. Robustness analysis is presented through a design of experiment method. Atthe end of this paper, a calculation example is proposed to get the mount stiffness and tuning point based on the design requirements for mount reaction forces and CRFM C.G. displacement. The effects of mount stiffness at linear section on natural frequencies and energy distributions of the CRFM and on RMS value of mount reaction forces are validated by a generic example.
Keywords: condenser radiator fan module mounting system; design requirements; robustness analysis; calculation method.
Design of a truck cab torsion bar
by Luigi Solazzi
Abstract: This work describes the study developed and the design of a specific component called torsion bar, installed on commercial vehicles for the cab suspension, to both increase driver comfort and allow the cab to be rotated for maintenance work on the engine. Currently, the component is made from conventional structural steel: the central element is a single unit of considerable size, a significant factor especially in terms of the space required during shipping. The aim of this research is to design a structure using materials with greatly superior mechanical performance in order to reduce its weight and incorporate a number of design features to make it easier to ship, reducing its overall size and thus the costs involved. The solution developed achieves this aim, with a 25% weight reduction and easy dismantling and shipping. The technical features designed into the solution have reduced the sensitivity of the assembly procedure to operator-related variability.
Keywords: finite element method; cab suspension; torsion bar; truck; high-strength steels.
Including deformation in a model for engine block dynamics: measurement and prediction of vibration
by Pär Mikaelsson, Tommy Andersson, Mårten Olsson
Abstract: Internal combustion engines are sources of vibration in many applications. Engine mounted components need to be designed with respect to fatigue, to withstand these vibrations. In order to compute an estimate of the fatigue life of a component, the vibration load needs to be known. A methodology that is based on a seven degrees of freedom model to represent the engine block is proposed. By fitting measured accelerometer data to this model, acceleration levels in arbitrary positions and directions, related to the engine block, may be computed. Results presented for an engine vibration measurement show good agreement between measured and computed vibration levels. A measure to find erroneous accelerometer definitions is also proposed and exemplified through measurement results. The method also enables pointing out local dynamic phenomena at measurement points.
Keywords: engine; engine block vibrations; engine block twist; rigid body vibrations; vibration measurement; vibration estimation;.
Non-linear control of vehicles rollover using sliding mode controller for new eight degrees of freedom suspension model
by Amir Hossein Kazemian, Majid Fooladi, Hossein Darijani
Abstract: The stability control system is a part of active safety systems in vehicles, which is designed to control the vehicles dynamic motion in emergency manoeuvres. In the present study, modelling and simulation of a four degrees of freedom passive suspension system (4DOFs) initially has been considered and then, in order to improve the efficiency of controlling system, a new suspension system is designed with 8DOFs by adding masses to sprung and unsprung parts of suspension system and using hybrid semi-active damper. To investigate the effect of DOF on the controller performance, a sliding mode controller (SMC) for models with 8DOFs is designed in Matlab and controller performances are studied. Also, numerical results from a typical vehicle that is simulated in Carsim are the input for the Matlab simulation. Investigations show that increasing degrees of freedom accompanied by applying a hybrid semi-active damper leads to better stability and good handling characteristics of vehicle.
Keywords: semi-active hybrid system; good handling; sliding mode control; stability control; suspension system; rollover; Lyapunov theory.
Assessment of the vertical load applied to the pavement on pothole events by a commercial truck
by Pablo Kubo, Arthur Larocca, Joshua Dawson
Abstract: Given the importance of the road transportation and its correct maintenance, the assessment of the real loads applied to the pavement proved to be a relevant subject. Based on an experimental methodology and a statistical analysis, this work quantifies and evaluates the vertical loads applied to the pavement by the wheels of a commercial vehicle on pothole events. As a first experimental approach, the main objective of this study is to investigate the isolated influence of the vehicle
Keywords: roadway; commercial vehicle; truck; suspension; damage.
Computational modelling and simulation of commercial truck with road-tire interactions to evaluate ride comfort
by Ashish Gupta, Vikas Rastogi
Abstract: This paper deals with a bond graph model of road truck, which includes roll and pitch motions The vehicle system is comprised of cab, cargo, base frame, suspension system and pneumatic tires The dynamic behavior of the truck has also been presented, which incorporates the wheel/tires, axle/suspension and frame of the vehicle The potential usefulness of the integrated bond graph model of vehicle may be used for the evaluation of the ride comfort Another focus of the paper is the dynamic and thermal analysis of tire system, which demonstrates its behavior at different temperature conditions The simulation of the model is carried out to obtain the vertical accelerations of the cab, cargo and base frame at various operating speeds. The ride comfort of the cab is evaluated using the FFT analysis at various speeds and the analysis is corroborated with the standard ISO 2631.
Keywords: over the road truck; comfort evaluation; bond graph modelling; ride comfort.
Analysis of results obtained on vehicle technical inspection using fBRAKE in Spain and development of a new model for semi-trailers based on Regulation No. 13
by Álvaro Barba Nieto, José Luis San Román García, Vicente Díaz López, Susana Sanz Sánchez
Abstract: Determination of braking efficiency in heavy vehicles is not a trivial issue. Following the entry into force of Directive 2010/48/EU, and with this ISO-21069, the Spanish Periodic Technical Inspection sector has had to tackle difficulties. Developing procedures to inspect vehicles in fully laden condition, with methods of pressure measurement or with equivalent methods, has been the main difficulty. This paper explains briefly the methods proposed by ISO-21069 and the methods used in Spain. Then, Spanish inspection results on heavy vehicles are statistically analysed, including the autonomous community in which fBRAKE is in use, in order to compare results each other. This analysis takes into account the percentage of braking deficiencies detected in periodic technical inspections on each autonomous community. Finally, a new model for the fBRAKE alternative method is presented in order to obtain more accurate results during inspection using this method.
Keywords: braking efficiency determination; vehicle technical inspection; Directive 2012/48/EU; ISO-21069; Regulation No.13; heavy vehicles; braking system pressure; Spain; vehicle brakes; simulation; modelling.
Experimental comparison of control methods for armoured personnel carriers with semiactive magneto-rheological suspension
by Sabri SaltÄ±k, Zafer Dülger
Abstract: In this study, the control methods of a semiactive MR (Magneto-Rheological) suspension system for an armoured military vehicle are compared. System modelling and testing procedures are described, and then control algorithms are tested and observed on a quarter-car test setup; this setup is modified from a passive to a semiactive system. For tests and simulations, a special offroad profile is formed. This profile is formed depending on the standard military test courses and terrains. During the observation, control ability and personel comfort are observed as the main subjects. Finally, depending on the test results, displacements, accelerations and their effects on subsystems are compared and construed as advantages and disadvantages.
Keywords: magneto-rheological; semiactive; armoured vehicle; hybrid control; clipped control.
Determination of coefficient of restitution in impact of railway wagons
by Dragan Petrović, Milan Bizic
Abstract: Experimental testing of railway wagons' impact has shown that the same test conditions with different types of cargo gave different results. The theoretical model established in this paper enables determination of energy that is lost during the impact and the coefficient of restitution. If an inappropriate cargo is used, it is possible to register forces that are more than 50% less that the actual values. It is necessary to determine limit values of the coefficients of restitution for every type of wagon and cargo. The results of this paper may be important for improving the international regulations relating to the experimental testing of wagons.
Keywords: determination; coefficient of restitution; testing; impact; railway wagons.
Acoustical system modelling of the heavy truck air intake system
by Özgün Yakar, Haluk Erol
Abstract: In this paper, a statistical energy analysis method is applied to the heavy truck air intake system to predict the intake orifice noise, as well as the radiated noise. Because very few numbers of modes exist below 500 Hz for the intake system subjected to the analysis, the noise contribution of the system below 500 Hz has been considered. Below that frequency band, results have lower confidence levels because of the methods statistical characteristics. Radiated noise analysis has been performed to predict the noise radiation from the air intake system part surfaces. With this method, radiated noise directivity from the air intake system part surfaces can also be predicted. This information provides an idea of noise reduction. The effect of the material on the radiated noise has been studied. At higher frequencies, the confidence level regarding the dynamic response becomes higher, such that it leads us to predict high frequency problems.
Keywords: acoustical system modelling; heavy truck; air intake system.
Optimal design of passive suspension system of a 6
by Mahmoud Mohsen, Hisham Kamel, Alhossein Mostafa Sharaf, Samir Mohamed El-Demerdash
Abstract: This paper presents the optimal design of passive suspension system of a 6
Keywords: vehicle dynamics; ride comfort; genetic algorithm; suspension optimisation.
Dynamic characteristics of passive and semi-active cabin mounts for vibration control of a wheel loader
by Seung-Bok Choi, Soon-Yong Yang, Chulhee Han, Chul-Soo Shin, Jin-Young Jung, Sung-Jae Kim, In-Dong Kim
Abstract: In this study, the dynamic characteristics of passive mounts and a semi-active magneto-rheological (MR) mount for vibration attenuation of a wheel loader cabin are evaluated. First, the design procedures of the two different passive mounts are described, and the principal design parameters such as stiffness are determined from a simple but practically feasible dynamic model. Then, passive mounts with different material characteristics are manufactured and experimentally tested. Second, a semi-active MR mount is designed based on the field-dependent yield stress of the MR fluid. A prototype of the MR mount is then manufactured considering two flow paths an annular and a radial path. Finally, the dynamic characteristics of the three mounts such as the frequency-dependent stiffness and damping are evaluated, and their salient properties are discussed. In addition, it is shown through the transmissibility investigation that the semi-active cabin mount can effectively provide vibration isolation for a broad range of frequencies.
Keywords: magneto-rheological fluid; MR mount; heavy wheel loader; cabin mount; viscous mount; cabsus mount.
Evaluation criteria of wheel/rail interaction measurement results by track-side control equipment
by Gintautas Bureika, Mikhail Levinzon, Stasys Dailydka, Stasys Steisunas, Rasa Zygiene
Abstract: Recently, the condition of wheelsets of running trains is controlled by trackside automated control equipment (TACE), which measures parameters of wheel/rail impact and signals possible damage to the wheels. Vertical forces result from wheel/rail interaction and determine all dynamic loads transferred to elements of both structures. Calculation of strength and lifetime of train running gear and roadbed of rail track should be based on values of these interaction forces. Railway companies using TACE face the major problems low reliability of TACE-measured impact force values and low repeatability of TACE readings. These problems occur because wheel/rail interaction is a completely stochastic phenomenon. The present level of technology does not allow developing a reliable system for measuring these vertical forces during operation, and it is necessary to control the indirect indicators by defining the studied interaction of wheels. One of these indicators is irregularity of the wheel running surface, whose magnitude is regulated and measured in train inspection stations. This paper evaluates a derived criterion the dynamic factor Kd, used for estimation of repeatability (reliability) of TACE readings - for Lithuanian Railways, and proposes a new system of criteria ensuring sufficient reliability of rail vehicle wheel damage measurement data.
Keywords: rail vehicle; wheel flat; wheel/rail interaction; wheel load impact detector; data repeatable; data reliability.
On robust controllers for active steering systems of articulated heavy vehicles
by Shenjin Zhu, Yuping He, Jing Ren
Abstract: This paper examines the robustness of different controllers for active steering systems (ASSs) of articulated heavy vehicles (AHVs) in terms of the directional performance. Controllers based on the linear quadratic regulator (LQR) technique were designed for ASSs. The success of the LQR-based controllers is dependent on the accuracy of linear models for AHVs. When designing ASS controllers, linearisation of the AHV models is usually necessary; this results in model inaccuracy and un-modelled dynamics, and the robustness of the LQR-based controllers may be degraded. ASSs for AHVs are assessed in the time-domain, which may lead to an incomplete performance evaluation. This paper assesses the robustness of the ASS controllers designed with the techniques of sliding mode control (SMC), nonlinear sliding mode control (NSMC), and mu-synthesis (MS). The ASS controllers are evaluated using numerical simulation in terms of the trade-off between the manoeuvrability and the lateral stability at high speeds.
Keywords: AHVs: articulated heavy vehicles; ASSs: active steering systems; SMC: sliding mode control; NSMC: nonlinear sliding mode control; MS: mu-synthesis; GA: genetic algorithm; robustness index.
Firing-on-the-move stability system for armoured vehicle: design and optimisation of disturbance rejection control to reject recoil force
by Vimal Rau Aparow, Khisbullah Hudha, Zulkiffli Abd Kadir, Noor Hafizah Amer, Muhamad Murrad
Abstract: Recoil force creates unwanted yaw moment at the centre of gravity of armoured vehicles. This moment causes instability and diverts the armoured vehicle from its intended direction after firing. This research is focused in developing an active disturbance rejection control to overcome the effect of recoil force using inner and outer loop controls. The outer loop control is designed based on two feedback loops known as firing-on-the-move as the first feedback loop and active front wheel steering as the second feedback loop. The outer loops are designed to encounter the disturbance due to gun force and to improve the stability of the vehicle. An optimisation technique using the Taguchi method and a genetic algorithm are used to identify the most dominant outer loop control as well as to optimise the hybrid controller parameters, neuro-PI. The simulation results show that controller has improved the handling performance of the armoured vehicle after the firing impact.
Keywords: firing-on-the-move feedback; active front wheel steering feedback; armoured vehicle; genetic algorithm; Taguchi method; neuro-PI controller.
Hardware-in-the-loop simulation of trajectory-following control for a light armoured vehicle optimised with particle swarm optimisation
by Noor Hafizah Amer, Khisbullah Hudha, Hairi Zamzuri, Vimal Rau Aparow, Zulkiffli Abd Kadir
Abstract: Unmanned armoured vehicles are important in military missions and to minimise the casualties of military personnel. Steering control is one of the most important aspects in unmanned vehicles. Therefore, in this research, a trajectory following control from Stanley autonomous vehicle is employed and optimised for a Light Armoured Vehicle (LAV) to follow a pre-defined trajectory. The proposed controller is developed on a validated armoured vehicle model, which consists of a 7-degree-of-freedom handling model and other vehicle interactions. In order to study the controller
Keywords: armoured vehicle; trajectory tracking; trajectory following; path tracking; path following; HIL; Stanley.
Relative ride performance analysis of a torsio-elastic suspension applied to front, rear and both axles of an off-road vehicle
by Mu Chai, Subhash Rakheja, Wen-Bin Shangguan
Abstract: Relative ride performance potentials of a torsio-elastic suspension applied to front or rear or both axles of an off-road vehicle are investigated. A three-dimensional model of an articulated load-haul vehicle, incorporating kineto-dynamic model of a torsio-elastic suspension, is used to evaluate relative ride responses with front, rear and both suspended axles. The analyses are performed under random terrain excitations, synthesised considering low frequency coherence between elevations of the two terrain tracks. The model validity is demonstrated using the reported field-measured responses of a rear-suspended forestry vehicle. The optimal parameters of the three suspension configurations are identified by minimizing the vector sum of frequency-weighted rms accelerations av and frequency-weighted rotational vibration, while limiting roll deflection of the suspension link. Relative ride performance potentials of different axle suspensions are subsequently investigated for the loaded and unloaded vehicle in terms of frequency-weighted rms accelerations. The results show that the torsio-elastic suspension performance is relatively insensitive to variations in vehicle load. It is shown that the suspension applied to axle of the vehicle unit supporting driver cabin is more effective in limiting driver vibration with minimal sensitivity to load variations, while preserving effective roll stiffness. The fully-suspended vehicle, however, yields the most effective vibration attenuation.
Keywords: off-road vehicle ride; off-road terrain; torsio-elastic suspension; load sensitivity; suspension optimisation.
Economic life cycle of a fleet bus: a case study
by Hugo Raposo, Jose Torres Farinha, Luis Ferreira, Filipe Didelet
Abstract: The purpose of the paper is to discuss the application of econometric models to Life Cycle Cost (LCC) of an urban fleet bus with emphasis on the maintenance costs. To strengthen the foregoing analysis, the precedent results are compared with theoretical data that represents a good maintenance and functioning management. It is also observed the importance and interest of inflation ratios, as well as the price of fuel, since they can change dramatically the time of withdrawal of urban passenger buses. The paper analyses if there is a variation at the time of the vehicle replacement, obtained from several methods namely the methods of income annual uniform and minimisation of average total cost with reduction to the present value. It also points to an eventual relation between the maintenance policy and the spare fleet. Also, the paper shows the relation between maintenance performance and time replacement of fleet bus. The paper examines some differences between the replacement simulations through theoretical econometric models, when they are applied to real data.
Keywords: equipment replacement; LCC; spare fleet; planned maintenance.
Estimation of vehicle sideslip angle scheme using time-finite convergence algorithm
by Peng Zhang, Feng Liu, Fei Sheng
Abstract: Since vehicle sideslip angle estimation scheme is a real-time application, in essence, the schemes convergence speed is an issue worth attention. This paper presents a new estimator scheme whose output is theoretically guaranteed to converge to real values in the desired interval, and this makes it possible to be a more reasonable solution for application such as electronic stabilisation control (ESC). To improve the accuracy and adaptive capability of this scheme, the unmodelled error compensating mechanism is adopted. Then experiment results based on veDYNA vehicle dynamic simulation environment validate the applicability of the method.
Keywords: vehicle sideslip angle; estimation; time-finite convergence.
Ride comfort performance of a nonlinear full-car using active suspension system with active disturbance rejection control and input decoupling transformation.
by Faried Hasbullah, Waleed F. Faris, Fadly Jashi Darsivan, Mohammed Abdelrahman
Abstract: In this article, Active Disturbance Rejection Control (ADRC) and a control method combining ADRC with Input Decoupling Transformation (ADRC-IDT) are proposed to improve ride comfort of a nonlinear full-car with active suspension system. Simulation of the model in frequency domain as well as time domain with three types of road profile speed hump, double bumps and random excitation, as the disturbance to the system is performed to evaluate the performance of the proposed ADRC-IDT in comparison with ADRC and the passive system. Through experimental simulation studies, the ability of the proposed controllers to cope with varying process is investigated.
Results show that ADRC-IDT was able to produce comparable performance to a typical ADRC control structure with fewer control parameters.
Keywords: active suspension; ride comfort; active disturbance rejection control; input decoupling transformation; nonlinear spring; nonlinear damper; full-car; ADRC; ADRC-IDT.
Active vibration control of agriculture tractor suspension using optimised feedback controller
by Hassan Metered, Ahmed El-sawaf
Abstract: Nowadays, the development of an agriculture tractor suspension system is a vital research topic for the modern manufacturing industry. The ride comfort and tractor stability must be achieved using a suitable controlled suspension system. This paper concerns an investigation using the particle swarm optimization (PSO) algorithm to search for the optimum feedback controller gains for the active agriculture tractor suspension system, for the first time, to reduce the transmitted vibrations to the tractor body caused by road irregularities. A mathematical model and the equations of motion of an active quarter tractor suspension are derived and simulated using Matlab/Simulink software. The proposed PSO algorithm aims to minimise the dynamic tyre load generated by tractorterrain interaction as the objective function, with constraint of the actuator force. Suspension performance is assessed in time and frequency domains to prove the success of the proposed controller gains tuned using the PSO technique under different operating conditions. The simulation results reveal that the feedback controller gains tuned by the proposed PSO algorithm offer a significant improvement of the suspension performance, compared with both the conventional passive and the classical feedback gains tuned by the trial and error technique.
Keywords: agriculture tractor; particle swarm optimisation; active suspension controller; ride comfort; tractor stability.
Performance and an optimisation control scheme of a heavy-duty diesel engine fuelled with LNG-diesel dual-fuel
by Jiantong Song, Jvbiao Yao, Jiangyi Lv
Abstract: Natural gas is one of the most promising alternative fuels owing to the abundant source, low price, environment friendliness and high octane number. Compared with CNG, LNG is more suitable for heavy-duty vehicles because of the high energy density. In order to study the performance and exhaust emissions of a LNG-diesel dual-fuel heavy-duty engine equipped with a common rail injection system, the BSFC, smoke density, HC, CO, CO2 and NOx emissions of the dual-fuel and diesel are compared and analysed based on bench tests of a diesel engine. Experimental results show that the BSFC, HC and CO emissions of dual-fuel increase sharply compared with diesel under light loads. In order to improve the performance and exhaust emissions under light loads, an optimisation control scheme, in which the dual-fuel engine runs in the original diesel mode under light loads and in dual-fuel mode under medium and heavy loads, is proposed and analysed.
Keywords: LNG-diesel dual-fuel; common rail; heavy-duty diesel engine; performance; exhaust emissions; optimisation control scheme.
Evaluation of advanced steel usage on seat construction to reduce bus weight in compliance with FMVSS and APTA regulations
by Mustafa Ozcanli, Gonca Dede
Abstract: In this study, advanced steel usage on seat construction was studied to obtain weight reduction, and structural analysis was done by using a finite-element analysis (FEA) method. Two different seat frames were used. Different loading conditions were applied. One of the seat frames were made of mild steel, which is a conventional seat frame material and used as a reference for comparison. The other was made of advanced steel to obtain a weight reduction by optimising thickness and improving the design. The results show that the maximum displacement and maximum stress are decreased for four tests when advanced steel is used. In addition, using advanced steel can provide significant weight reduction for seat frame. Thus, using advanced steel provides fuel efficiency over the vehicle's operating life and also can reduce CO2 emissions. Besides comparison of the structural safety and weight reduction, this study researches a lightweight seat concept for future electric/hybrid busses.
Keywords: advanced steel; automotive seat frame; finite element analysis; structural analysis; vehicle weight reduction.
Hunting stability and derailment analysis of the high speed railway vehicle moving on curved tracks
by Caglar Uyulan, Metin Gokasan, Seta Bogosyan
Abstract: This study aims to build an advanced and effective dynamic model, which is capable of examining both the hunting instability at the critical speed and wheel climb derailment occurrence evaluated with derailment quotients, in one integrated model implicitly. In terms of control subject, the proposed railway vehicle model is compatible with a variable structure model reference adaptive controller using state variables, robust adaptive or sliding mode controller, etc., to stabilise enormously lateral hunting oscillations, which cause system instability, and to perform real-time derailment avoidance. The mathematical dynamic model, which is composed of a vehicle body, two bogie frames and two wheelsets for each bogie frame, is modelled with 35-DOF (degrees of freedom) equations of motion. The railway vehicle is supported with lateral, longitudinal and vertical damping and stiffness related to primary and secondary suspensions. The states of this railway vehicle model are lateral, vertical displacements and velocities of the vehicle body, bogies, wheelsets and yaw, roll, and pitch angles and angular velocities of the vehicle body, bogies, and wheelsets. A heuristic nonlinear creep model supported by Kalkers theory and a flange-rail contact model are used to reveal the effects of the creep forces and moments, which are acting on wheel-rail contact. The nonlinear coupled differential equations of motion were solved to analyse the dynamic behaviour, which is represented by the time response of the railway vehicle moving on curved tracks using Matlab&Simulink software. The hunting behaviour was analysed by investigating the eigenvalues of the railway vehicle at the hunting speed by the assistance of the Gershgorin disc theorem. In addition, the influence of the railway vehicle speed on calculated derailment quotient of the left wheel in the front wheelset of the front bogie was investigated at sharp radius of the curved track. The safe speed of the railway vehicle moving on curved track was also estimated by using active derailment criteria from Nadal and Weinstock. The variation of the derailment coefficients at critical speeds with various radii of curved tracks was also examined by using these derailment criteria. The main superiority of the proposed model is that one can both predict incipient derailment actively and also determine nonlinear critical hunting speeds with higher precision.
Keywords: hunting analysis; derailment analysis; Lyapunov’s indirect method; full railway vehicle model.
Irregularity model of welded rail joint and wheel
by Kaiyun Wang
Abstract: Due to the irregularity excitation of welded rail joints (WRJs), the dynamic impacting force between the wheel and the rail would be obviously enhanced. According to measured irregularities of WRJs in heavy
Keywords: welded rail joint; heavyhaul railway; wheelrail interaction; irregularity; vehicletrack coupled dynamics.
Irregularity model of welded rail joint and wheelrail dynamic responses in heavyhaul railway
by Kaiyun Wang, Zhiyong Shi, Shen Wang
Abstract: Plenty of welded rails are applied in the modern railway. Owing to the irregularity excitation of welded rail joints (WRJs), the dynamic impacting force between the wheel and the rail would be obviously enhanced. According to measured irregularities of WRJs in heavyhaul railway, the irregularity model and its wheelrail dynamic responses are investigated in this paper. A modified excitation model is put forward to simulate the irregularity of WRJ. Dynamic interactions excited by the irregularities of WRJs are analysed, including the measured irregularity, the theoretical irregularities obtained from a traditional model and a modified model. Effects of parameters of the modified excitation model on dynamic interaction are discussed. Results show that there is an obvious concave shape located on the weld point nearby, which can bring about the marked wheelrail interaction force within the frequency scope of 20300Hz, and has much effect on the vibration of the wheelsets and rail. The traditional excitation model of WRJ cannot represent the measured shape very well. There is a poor agreement in the wheelrail vertical force between the measured and traditional irregularities of WRJ. The modified excitation model of WRJ is formed by a convex wave and a concave wave, and has four parameters. From the point of view of the geometrical shape, the irregularity simulated by the modified model is highly similar to the measured irregularity. Furthermore, the dynamic performances excited by the modified irregularity are consistent with those owing to the excitation of the measured irregularity. As for the wavelength and depth of the short wave in the modified excitation model of WRJ, there are obvious influences on the wheelrail dynamic performance. With the growth of the depth, the wheelrail dynamic indices will increase linearly. However, they will decrease nonlinearly with the increase of the wavelength.
Keywords: welded rail joint; heavyhaul railway; wheelrail interaction; irregularity; vehicletrack coupled dynamics.
Dynamic modelling of a railway wheelset based on Kanes method
by Te Wen Tu
Abstract: This study applies Kanes method to generate the equations of motion for a railway wheelset moving on a tangent track at a constant speed. Since the wheel and rail close contact conditions are used to obtain two nonholonomic constraint equations, the lateral vibration of the wheelset can be proven as a nonholonomic system possessing two degrees of freedom. Moreover, using Kanes approach to derive the linearised equations, we can take advantage of bypassing the full nonlinear equations and to obtain two equations with dynamic decoupling. When the set of equations in this work is compared with those in the literature, we find that two gyroscopic effect terms exist and yaw gravitational stiffness disappears, so that the critical speeds calculated in this work are always lower than those in the literature for the same numerical cases. Finally, the contact conditions along with the creepages between wheels and rails can be directly expressed in terms of generalised speeds by using Kanes method. It shows that Kanes method focuses on motions rather than on configurations.
Keywords: Kane’s method; nonholonomic system; motion constraint; dynamic decoupling; gyroscopic effect.
Multi-objective optimisation of injector and diesel engine by genetic algorithm: Nu-SVR modelling
by Hadi Taghavifar, Simin Anvari
Abstract: The current study deals with application of evolutionary multi-objective genetic algorithm (MOGA) in a 1.8 L Ford diesel engine to enhance the power, fuel consumption, and air-fuel uniformity. To do so, four design parameters of engine geometry and injector parameters were defined and three sub-objectives are considered to get either maximised or minimised. On the sub-objectives, constraints are imposed to introduce the feasible solutions. The best solution is obtained at RunID66 from 70 design points. The results showed that increasing bowl radius after a certain point is not useful for enhancement of the mixture homogeneity. The second part of the study, support vector regression technique is applied on the input and output data to make a model to predict the engine power.
Keywords: diesel engine; diesel injector; Nu-SVR; MOGA; Pareto front.
Research on a rollover protective technique for a vibroseis truck based on reliability analysis
by Zhen Chen, Zhiqiang Huang, Dongyang Li, Shuang Jing, Zhifei Tao
Abstract: Owing to its environmental friendly performance and high-quality signal stimulation ability, vibroseis has become a key technology in oil and gas exploration. However, rollover accidents occur frequently in the process of vibroseis truck driving, which endangers the drivers and apparatus on the truck. We need to develop a technique for studying a rollover protective method for a vibroseis truck. Therefore, we first study the driving stability of vibroseis trucks to determine the limit state function of stable driving. Then, the stable driving reliability analysis of the vibroseis truck could be performed under complicated road stimulation. The analysis results show that the risk of rollover still exists, so it is necessary to install a rollover protective structure (ROPS) on the vibroseis truck. However, it is still unknown whether the rollover protective structure is able to protect the driver. Therefore, through the research on engineering vehicle safety regulations and standards, we have established a systematic and scientific evaluation index system of safety protection and performance. Then, based on the FEA (Finite Element Analysis) technology, we performed the dynamic simulation analysis of vibroseis truck rollover with and without the rollover protective structure, and the stress to strain, impact deformation, acceleration and energy absorption principles have been determined. The simulation results show that the rollover protective structure could absorb impact energy to continuously resist rollover, which plays a significant role in protecting the vibroseis truck. The research results will not only greatly enhance the security protection performance of the vibroseis truck in field operations, improving the quality and safety of oil and gas exploration, but this innovative method of improving the performance of energy absorption and avoiding continuous rolling will provide scientific and reliable guidance for the similar design of vehicle anti-rollover structure in the field.
Keywords: vibroseis truck; stable driving reliability; rollover protective structure; safety evaluation; dynamic simulation analysis.
A novel pneumatic-mechanical energy regenerative suspension for air brake trucks
by Jiang Liu, Xiaowei Li, Ye Zhang, Peng Chen
Abstract: A novel energy-regenerative suspension system was proposed to convert the vibration from the road unevenness into the pneumatic potential energy for the trucks air brake. A mathematical model for the new regenerative suspension is given. Using ADAMS and Easy5, pneumatic-mechanism co-simulations are performed. The regenerative ratios are calculated for typical cases and their efficiency factors are discussed. Then the dynamics K&C performances for this new suspension are analysed by comparing with the
traditional leaf spring suspension. The results indicate that the new design can
recycle the vibration energy efficiently and improve the ride comfort as well.
Keywords: energy-regenerative suspension; new mathematic model and co-simulations; air brake truck; dynamics K&C.
Analysis of longitudinal fluid sloshing in tank wagon
by Shahin Yousefi, Mahdi Naseri , Majid Shahravi
Abstract: In order to study the phenomenology of fluids dynamic performance in containers and assessment of fluids specification in closed containers, the longitudinal fluid sloshing has been studied and the mechanical parameters of sloshing in a horizontal cylindrical container have been extracted through image processing in the test. The test stand has been prepared and three different fluids, water, petrol and oil, have been tested in three filling percentages of 30%, 50% and 80%. The sloshing dominant frequency and the damping ratios of these fluids have been extracted according to experimental test. In the following, fluid sloshing has been simulated by using 2-D equivalent mechanical model, and the parameters of vibration that include mass, spring stiffness and damping coefficient have been calculated using an optimised equivalent mechanical model. Then the results of experimental tests has been compared with optimised equivalent mechanical model results.
Keywords: longitudinal sloshing; tank wagon sloshing; image processing; damping ratio; sloshing frequency; optimised mechanical model of sloshing; partially filled tanker.
Application of the Taguchi-based entropy-weighted TOPSIS method for optimisation of diesel engine performance and emission parameters
by Mohd Muqeem, Ahmad Faizan Sherwani, Mukhtar Ahmad, Zahid Akhtar Khan
Abstract: Diesel engines convert chemical energy into mechanical energy generally with low efficiency. However, if these engines are operated at optimum levels of input parameters, they can produce power more efficiently with minimum harmful exhaust emissions. The current research work is carried out with an aim to determine these optimum levels of the input parameters. Four input parameters were selected and their optimum combinations were determined using Taguchi-based TOPSIS coupled with entropy weight method. Taguchis L25 orthogonal array was adopted to perform the experiments. All the test runs were carried out in random manner with three replicates of each to improve the accuracy of the experiments. The preference values (relative closeness of the distinct alternative to the positive ideal solution) predicted by the Taguchi method and the values obtained by regression analysis, at optimum input parameter settings, were compared and a good relation was found between them.
Keywords: brake thermal efficiency; brake specific fuel consumption; exhaust emission; TOPSIS; entropy weight; Taguchi approach.
Introducing wheel-rail adhesion control into longitudinal train dynamics
by Qing Wu, Maksym Spiryagin, Colin Cole, Yan Sun
Abstract: Conventional Longitudinal Train Dynamics (LTD) simulations apply a number of assumptions regarding wheel-rail adhesion, and wheel-rail adhesion control has not previously been considered. This paper introduces locomotive wheel-rail adhesion control into LTD using co-simulation and parallel computing techniques. An in-house LTD simulator was connected to a commercial MBS dynamics simulator using the TCP/IP protocol. A heavy haul train with the configuration of three locomotives and 150 wagons was modelled. The wagons were modelled in the LTD simulator while the locomotives were modelled in the MBS simulator. The locomotive models were three-dimensional models that included wheel-rail contact models and adhesion control models. Simulations of locomotives were processed in parallel using three computer cores. Co-simulations with and without the consideration of curve lubrication were conducted and compared with a conventional LTD simulation. Computing times with and without parallel computing were also compared. The results show that, when compared with conventional LTD simulations, wheel-rail adhesion control generates evident differences for maximum traction forces, average train speeds, maximum in-train forces and force patterns. With three computer cores, parallel computing reduced the computing time by about 46% from about 3.7 hours to about 2.0 hours.
Keywords: longitudinal train dynamics; wheel-rail contact; adhesion control; traction modelling; parallel computing;co-simulation.
Optimal regenerative braking torque of permanent-magnet synchronous motor in electric vehicle
by Dongmei Wu, Yang Li, Jianwei Zhang, Changqing Du
Abstract: This study investigated a method to determine the optimal regenerative braking torque with maximum energy recovery at given speed, which is essential for the regenerative braking control of electric vehicles. The method is based on the loss modelling of a permanent-magnet synchronous motor (PMSM) system, which consists of an electric motor and an inverter. The system-loss model is established based on a PMSM mathematical model including iron loss, and is used to derive the optimal regenerative braking torque symbolic formula. In addition, the parameter sensitivity of the optimal regenerative braking torque is analysed, and a method for online parameter identification is used to obtain the actual parameter values in real time. Thus, the accuracy and adaptability of the optimal regenerative braking torque during the motor-operation process is improved. The analysis results are validated through simulation and bench tests.
Keywords: regenerative braking torque; permanent-magnet synchronous motor; loss model; parameter sensitivity; electric vehicle.
Component sizing optimisation of hybrid electric heavy duty truck using multi-objective genetic algorithm
by Fereydoon Diba, Ebrahim Esmailzadeh
Abstract: Component sizing optimisation of a novel architecture of hybrid drivetrain for line-haul truck has been considered. This drivetrain architecture employs a self-propeller trailer and the traction is shared between the tractor and trailer. The comprehensive model of the vehicle, including the hybrid electric drivetrain, is developed. The drivetrain components have been optimised using a multi-objective genetic algorithm to minimise three objective functions, namely, the acceleration time, the fuel consumption and the drivetrain price. The overall efficiency of the optimised hybrid drivetrain has been evaluated using computer model simulations. Engineering economic analysis is performed to demonstrate the ownership cost of the proposed drivetrain compared with the non-hybrid and the non-optimised hybrid drivetrain for heavy duty vehicles. The results show that the proposed drivetrain has a superior capability in reducing the fuel consumption and the ownership cost.
Keywords: hybrid electric truck; component sizing; self-propeller trailer; multi-objective optimisation; genetic algorithm.
Hydraulic retarder torque control for heavy duty vehicle longitudinal control
by Chaoxian Wu, Xuexun Guo, Bo Yang, Xiaofei Pei, Sijing Guo
Abstract: This paper studies the hydraulic retarder torque control strategies for heavy duty vehicle longitudinal control to reduce abrasion of the friction brake. A hydraulic retarder whose oil volume rate is controlled by a pneumatic system is modelled. A hierarchical controller is developed for longitudinal control. In the upper controller, the target total brake force is calculated and then distributed on the friction brake and the retarder. In the lower controller, two retarder torque control strategies, PID control and mixed PID and sliding mode control, are employed and compared. Simulations are conducted with varying vehicle mass and varying desired vehicle velocity. Results shows that the mixed PID and sliding mode controller has better speed tracking performance, robustness and torque control accuracy.
Keywords: hydraulic retarder; torque control; longitudinal control; heavy duty vehicle; sliding mode control.
CAE analysis and road load data acquisition on bogie bracket of heavy duty commercial vehicle
by P. Thangapazham, L.A. Kumaraswamidhas, D. Muruganandam, Dharanivendhan T
Abstract: The bogie bracket is a unit of the suspension system in automotive vehicles, such as heavy duty automotive commercial trucks, railways and other machinery, to carry shock and load. Bogie brackets are extensively employed in heavy vehicles to connect the chassis and wheels. This part has been identified as one of the most critical components in the suspension system of commercial vehicles. Computer Aided Engineering (CAE-PERMAS Version-14.0) simulation software has been used for stress analysis and to study the forces influencing the failure of bogie bracket due to stress concentration. Stress concentration factor has been found in every zone of the bracket and the weaker sections have been identified in three iterations. Two different road conditions were taken for the critical analysis: a) Rough Road (RR) condition; b) Mining Road (MR) condition. Road Load Data Acquisition (RLDA) tests were conducted to validate the CAE analysis. Six pairs of bogie brackets were tested on different road test tracks in RR and MR conditions. Maximum strain was measured through a strain gauge attachment. The maximum stress and strain induced in the brackets were observed in all tests. Hair crack failure in the bracket was detected at the weaker section. The eventual sudden crack failure of the bracket took place during the cobble-stone track test in RLDA. The failure rate and mode of failure were observed in six pairs of samples under RR and MR conditions. In RR condition the cobble-stone test was the influencing surface for failure, and in MR condition the kutcha road induced failure.
Keywords: rough road; mining road; computer aided engineering; road load data acquisition.
A comparison of test manoeuvres for determining rearward amplification of articulated heavy vehicles
by Yuping He
Abstract: Rearward amplification (RA) is an effective indicator of lateral stability for multi-trailer articulated heavy vehicles (MTAHVs). The International Organization for Standardization released the test manoeuvres, ISO-14791, for determining the indicator for MTAHVs. ISO-14791 recommends three methods, including two time-domain and one frequency-domain, to derive the RA measures. It was reported that the results from the three methods were not in good agreement. To explore this inconsistency among these methods, a multiple cycle sine-wave steering input (MCSSI) manoeuvre was simulated to obtain steady-state responses of MTAHVs. Furthermore, an automated frequency response method (AFRM) was used to derive the measures in the frequency domain. This paper presents simulation results based on an A-Train Double. Results demonstrate that the steady-state RA measures under a MCSSI manoeuvre are in excellent agreement with those from frequency-domain methods. It is revealed that drivers steering behaviours impose a non-negligible impact on the transient RA measures of MTAHVs.
Keywords: rearward amplification; test manoeuvres; ISO-14791; multi-trailer articulated heavy vehicles; lateral dynamic; numerical simulation.
Determination of the most efficient bus rollover computer simulation technique according ECE R66
by Petr Rogov, Lev Orlov
Abstract: A review of the existing methods of the bus rollover computer simulation is conducted in the article. In order to investigate the motion of the bus before collision with ditch surface, the mathematical model of the bus motion was developed. To confirm the reliability of this model a comparison between the results of mathematical modelling, FEM simulation and experimental rollover of a bus section is made. It is found that the friction coefficient between the bus and the tilting platform, as well as the bus centre of gravity height, affect the ratio between the bus kinetic energy of the impact and the potential energy of the bus at the beginning of the rollover. As a result, an experimentally confirmed theoretical foundation for the most accurate method of computer simulation of the bus rollover according to UNECE Regulation No. 66 is given.
Keywords: mathematical model; finite element method; passive safety; bus rollover; ECE R66; experiment; bus load conditions.
Controller structure for high response engine exhaust throttles
by Ádám Bárdos, Huba Nemeth, Barna Szimandl
Abstract: Exhaust throttles are widely used as cost effective endurance brakes on commercial vehicle diesel engines. To fulfill the requirements as endurance brakes exhaust flaps have only two states: fully opened and fully closed. However, there are several possible new applications, suggested by the authors, in which exhaust throttles could be utilized e.g. brake blending, automated manual transmission support, exhaust gas thermomanagement etc. To provide these functionalities a backpressure controller which can adjust the exhaust manifold pressure arbitrarily is needed. In this paper the design and performance evaluation of an exhaust pressure controller is described which satisfies the new requirements derived from the possible future functions of exhaust throttles. A first engineering principle based, mean-value, nonlinear model of the engine and the actuator is described and validated with test bench measurements. Based on the nonlinear model a feed forward term was obtained with model inversion. As feedback an LQ servo controller was designed. The controller performance and the compliance of requirements was evaluated in three different test cycles on a medium-duty diesel engine, simulating brake blending, thermomanagement, and EGR support operations.
Keywords: diesel engines; exhaust throttle; pressure control; nonlinear control systems; optimal control.
Taguchi-based grey relational analysis for multi-response optimisation of diesel engine performance and emission parameters
by Mohd Muqeem, Ahmad Faizan Sherwani, Mukhtar Ahmad, Zahid Akhtar Khan
Abstract: In order to achieve high performance and low emission of diesel engines, it is necessary to operate the engine at optimum condition. The aim of this paper is to optimise the input parameters of a diesel engine, which results in optimum performance and emission. Four input parameters, viz., compression ratio, fuel injection timing, air temperature and air pressure, each at five levels, were considered in this study. However, the main focus was on turbocharged air temperature and pressure. Four response variables, i.e., brake thermal efficiency, brake-specific fuel consumption, hydrocarbon emission and smoke opacity, under no load, half load and full load conditions, were measured. Twenty five experiments as per Taguchi L25 orthogonal array were performed, and experimental data was analysed using Grey Relational Analysis (GRA) to accomplish multi-response optimisation. Regression analysis was done to determine the experimental value of the Grey Relational Grade (GRG) at optimum setting of the input parameters. In order to validate the experimental results, the experimental value of the GRG was compared with that of the predicted value, and the comparison revealed a good relation between the predicted and experimental values of the GRG at optimum combination of the input parameters.
Keywords: brake-specific fuel consumption; brake thermal efficiency; Taguchi approach; grey relational analysis; hydrocarbon emission; smoke opacity.
Multi-axle vehicle dynamics with roll
by Daniel E. Williams
Abstract: The classic two-axle yaw-plane or bicycle model has long provided basic insight into vehicle handling. It has previously been augmented to allow sprung mass roll, and more recently to accommodate multiple axles, any of which could be steering. In this work these two extensions of the yaw-plane model are combined, to form a dynamic model of a vehicle with an arbitrary number of axles, any of which could be steered, and also with a suspension that allows sprung mass roll. As such this work introduces the most general yaw-plane model to date.
Keywords: vehicle dynamics; commercial vehicle dynamics; multi-axle vehicle dynamics; multi-axle steering; vehicle ride; vehicle handling.
Influences of roller diameter error on the mechanical properties and fatigue life for the main bearing of rotating drum in concrete mixing truck
by Jia-peng Yang, Qi An
Abstract: The rotating drum's supporting main bearing (RDSMB) of a concrete mixing truck is usually a double row spherical roller bearing (SRB). In manufacturing, the roller diameter inevitably has a certain error, and this error should have a great influence on the mechanical properties and fatigue life of the bearing. In this paper, the RDSMB of a certain type of concrete mixing truck is studied. The calculating equations are established to get the radial load and axial load acting on the main bearing. A mechanical model for SRB has been derived through the force analysis considering radial load, axial load, inner ring tilting angle and roller diameter error. The effects of single roller diameter error and random distribution errors of two row rollers on the axis orbit, roller maximum load, roller load experience and the fatigue life of RDSMB are studied. A series of influence relationship curves are obtained and analysed.
Keywords: concrete mixing truck; main bearing; rotating drum; mechanics analysis; mechanical properties; roller diameter error; random distribution errors; axis orbit; roller load; fatigue life.
An investigation of the effect of elastic membrane on liquid sloshing in partially filled tank vehicles
by Qiongyao Wang, Subhash Rakheja, Wen-Bin Shangguan
Abstract: Roll plane fluid slosh within a partly-filled tank with an elastic membrane restraining the free surface is investigated through development of a two-dimensional computational fluid dynamic and fluid-structure interaction (CFD-FSI) model. The air-membrane-liquid interaction analysis is performed to investigate the effect of the membrane on the liquid cargo movement, and peak and mean magnitudes of lateral slosh force and roll moment under 0.3g lateral acceleration excitation. Laboratory experiments were conducted on a 50%-filled scaled 0.536 m diameter tank with an elastic membrane-like restraint under harmonic lateral acceleration excitations. The validity of the CFD-FSI model is demonstrated on the basis of the laboratory-measured responses in terms of lateral slosh force and roll moment. The effectiveness of the membrane in limiting the fluid slosh is illustrated by comparing simulation results obtained for a 7.55 m long and 2.03 m circular tank with and without the membrane. It is shown that addition of the membrane could yield substantial reduction in the fluid cargo motion and thus roll moment attributed to fluid sloshing, while increasing the fundamental slosh frequency by more than 2 times that obtained for the cleanbore tank. The study is limited to a fixed location of the membrane in the tank, near the tank centre. Higher fill volumes thus resulted in greater membrane deformation, and increase in the wetted area and membrane pre-tension.
Keywords: tank trucks; fluid slosh; elastic membrane; fluid-membrane interaction.
Adaptive sliding mode control of a four-wheel-steering autonomous vehicle with uncertainty using parallel orientation and position control
by Armin Norouzi, Hadi Adibi-Asl, Reza Kazemi, Parvin Fathi Hafshejani
Abstract: Control systems of autonomous vehicles or driver assistant control systems always face uncertainties due to the in-vehicle and environmental disturbances. In addition, the steering ability for rear tyres leads to more stability and more handling and manoeuvrability. In this paper the adaptive sliding mode control (ASME) strategy is employed to improve handling issues due to the roads friction, which plays a key role in handling dynamics. The proposed dynamic model used in this paper is a simple and useful two degrees of freedom model. Two parallel ASMCs are used: one for positioning error and the other for angular error. The simulation is executed for two different road conditions with consideration of the hypercritical condition. To verify the designed controller, the controller is applied to the nonlinear full vehicle model. The simulation results prove that the controller perfectly works for different road conditions. The controller is also robust against uncertainties such as road friction.
Keywords: autonomous vehicle; four-wheel-steering vehicle; vehicle lateral control; adaptive sliding mode control.
Effects analysis of suspension parameters, different wheel conicities and wheel nominal rolling radii on the derailment safety and ride comfort
by Yung-Chang Cheng, Po-Hsien Wu
Abstract: Using a modified heuristic nonlinear creep model with different wheel conicities and nominal rolling radii, a 31 degrees-of-freedom railway vehicle system with rail irregularities in the lateral and vertical directions is modelled and analysed. The effects of suspension system parameters, different wheel conicities and nominal rolling radius on the derailment quotient, the offload factor and the ride comfort index are illustrated and compared. Generally, the derailment risk is underestimated and ride comfort is overestimated when the linear creep model is used for dynamic analysis of a railway vehicle system. The derailment risk is increased and the ride comfort performance is decreased when a worn wheel that has a different wheel nominal rolling radius is used. Finally, for a softer primary and secondary suspension system, the derailment risk for a worn wheel is also increased.
Keywords: modified heuristic nonlinear creep model; derailment quotient; offload factor; ride comfort; wheel nominal rolling radius; suspension system parameters; wheel conicity.
Special Issue on: Recent Advances in Active Safety Control Systems for Commercial Vehicles
Rollover prevention for a heavy vehicle using optimised slide mode steering control
by Zhilin Jin, Chao Wang, Lei Zhang, Wanzhong Zhao, Amir Khajepour
Abstract: For a heavy vehicle, active steering can effectively prevent rollover, however, it also changes the operation of the vehicle away from the drivers intentions. To improve rollover stability and reduce tracking error, an optimised slide mode steering control strategy is proposed. A four degrees of freedom linear model is used, which includes lateral, yaw, and roll motions of the sprung mass and unsprung mass. This model is also validated to describe heavy vehicle rollover dynamics. From the model, slide mode control based roll angle and slide mode control based lateral displacement strategies are developed, respectively, and the optimised slide mode steering control strategy is presented to track the set routes and prevent vehicle rollover. Furthermore, some typical numerical cases are simulated to demonstrate the effectiveness of the control strategies. The results show that the optimised slide mode steering control strategy can effectively reduce vehicle rollover risk and significantly improve the performance of tracking the drivers intention for a heavy vehicle.
Keywords: heavy vehicle rollover; optimised slide mode control; active steering; rollover prevention.
Braking intention recognition algorithm based on electronic braking system in commercial vehicles
by Hongyu Zheng, Shenao Ma, Lingxiao Fang, Weiqiang Zhao, TianJun Zhu
Abstract: The aim of this research is to investigate the braking intention identification method adaptive to the Electronic Braking System (EBS) in commercial vehicles. Based on the neural network, a braking intention identification model is established that takes both emergency braking and general braking into account. Then, considering the complex transportation environment, a multi-condition identification model with respect to four typical braking conditions is developed using fuzzy logic. The experimental results of the two models demonstrate that the proposed strategy can make good use of driver braking intention. The proposed method provides theoretical guidelines on driver behaviour adaptation on the longitudinal active safety system, which promotes vehicle safety and braking performance.
Keywords: braking intention identification; neural network; fuzzy logic; electronic brake system; commercial vehicle.
Modelling, verification and analysis of articulated steer vehicles and a new way to eliminate jack-knife and snaking behaviour
by Yu Gao, Yanhua Shen, Yaodong Yang, Wenming Zhang, Levent Güvenç
Abstract: A nonlinear articulated steer vehicle (ASV) model coupled with a 12-DOF dynamic model and full-hydraulic steering system model is derived. Field tests of single-lane change at unloaded and loaded condition are made to verify the accuracy of the ASV model by comparison of velocity, articulation angle, yaw rate and oil pressure. Considering the effect of varying bulk modulus, the unstable area of ASV decided by oil pressure and air content is confirmed according to the critical speed analysis by 3-DOF linear model. To reveal the differences between the nonlinear vehicle model and the linear vehicle model, articulation angle responses of the two models are compared. Results show that the nonlinear vehicle model has a reduced unstable area compared with the linear model, which means the nonlinear model is less sensitive to disturbance than the linear model. As the torsional stiffness is influenced by the fluid pressure when the oil is entrapped with air, a new way to improve the stability of ASV by filling-oil pressure control is presented. Simulation results show that the jack-knife and snaking behaviour are eliminated and the appropriate filling-oil pressure for this ASV is confirmed at 1.0 MPa.
Keywords: modelling; verification; articulated steer vehicle; stability; bulk modulus; jack-knife and snaking behaviour; control.
Improving stability and comfort of an in-wheel motor drive electric vehicle via active suspensions
by Guo-dong Yin, Zhen Wang, Ning Zhang, Xian-jian Jin
Abstract: This paper presents a method of a controller design to improve the handling and stability of an in-wheel motor drive electric vehicle using active suspensions with considerations of parameter uncertainties and control saturation. The construction of the mathematical model of vehicle suspensions combines active suspensions with vehicle lateral stability together. Through the robust H∞ optimal control of active suspensions, the vehicle lateral stability has been improved and the vertical dynamic displacements of suspensions have decreased. The uncertain parameters include the vehicle body mass, suspension spring stiffness and suspension damping coefficient. The control saturation considered results from the physical limitations of actuators. Active suspensions are designed with linear matrix inequalities feedback control method to attenuate the effect of the lateral acceleration on the roll angle and the suspension stroke. Simulation results show that the designed controller can improve vehicle handling and stability and has good robustness.
Keywords: active suspension; robust H∞ optimal control; in-wheel motor; actuator saturation.
Dynamics integrated control for a four wheeled independent control electric vehicle
by Guoying Chen, Lei He, Buyang Zhang
Abstract: The four wheeled independent control electric vehicle (FWIC-EV) has each wheel with independent steering, driving and braking. Apart from conventional vehicles, all independent chassis actuators drive by wire allows vehicle dynamic improvement to assist the driver in enhancing handling and cornering stability. In this paper, a multilevel integrated control, including motion controller and control allocation, is introduced for the performance improvement. In the strategy, the motion controller based on model prediction control (MPC) optimises the vehicle control forces and moments within the actuators characteristics, and tracks the longitudinal and lateral references. According to the calculation of the MPC controller, the control allocation minimises the each wheels tyre workload, and distributes the wheels steering angles and driving/braking torques. In the processing of the allocation, the constraints divided into equality and inequality constraints are respectively introduced for simplification. Based on a FWIC-EV co-simulation vehicle model and an experimental platform, the performance of the multilevel integrated control is demonstrated.
Keywords: electric vehicle; integrated control; model prediction control; allocation; tyre workload.
Modelling and analysis of the influences of various liquid sloshing characteristics on tank truck dynamics
by Ying Wan, Weiqiang Zhao, Changfu Zong, Hongyu Zheng, Zhenyang Li
Abstract: This paper focuses on the degree of vehicle-liquid coupling and its influence on the whole vehicle in actual manoeuvres and the modelling theory of liquid sloshing in liquid tank trucks. A complicated two-way coupled dynamic model and three simplified models for tank trucks were developed. Based on the four models, the vehicle-liquid coupling dynamic characteristics and their influence on the whole vehicle are discussed from the aspects of lateral handling stability and longitudinal braking performance, with various actual manoeuvres of different emergency level.
Keywords: heavy vehicle systems; tank trucks; tanker; vehicle-liquid coupling dynamics; sloshing characteristics; two-way coupled model; simplified models; equivalent model; computation fluid dynamics; CFD; actual manoeuvre; handling stability; longitudinal braking performance.
Research on lane keeping control strategy for buses
by Xiaojian Han, Weiqiang Zhao, Hongyu Zheng, Lijiao Yu
Abstract: Owing to the frequent occurrence of commercial vehicle lane departure, a novel lane departure warning (LDW) system based on driver behaviour characteristics and a lane keeping assisted system (LKAS) based on an electrohydraulic steering system for buses are presented in this paper. Considering the differences between driver behaviour characteristics, a newly designed dynamic warning algorithm is proposed to predict the lane departure risk. Then for the LKAS control, a simulation model of the electro-hydraulic steering system for buses is introduced for the active steering assisted control, and a multi-mode active control algorithm is designed for the lane keeping. In order to verify the effectiveness of the proposed control strategy, the co-simulation softwares of TruckSim, AMESim and MATLAB/Simulink are employed for the experiment validation. After extended simulation, it is found that the proposed LDW algorithm demonstrates an effective lane departure detection, and when the imminent lane departure is detected, the multi-mode active control algorithm can rapidly make adjustments to avoid the bus departing from the original lane.
Keywords: driver assistance systems; bus; warning system; driver types; dynamic warning line; steering system model; active steering control; piecewise PID controller.
A new driving condition identification method for heavy duty vehicles based on HHMM model
by Tianjun Zhu, Bin Li, Changfu Zong
Abstract: Aiming to improve the active safety of heavy duty vehicles, a new dynamic driving condition identification method is developed in this paper through incorporating Hierarchical hidden Markov models (HHMM) into the rollover warning system for heavy duty vehicles to assist the driver to be aware of the driving conditions. The corresponding data under typical driving conditions are first collected and then put into test with Student's t-test method and Grubbs test method (T-G test method). The outliers filtered by T-G test from the data are detected and eliminated. K-Means algorithm, used to set up the rollover threshold value, and Baum-Welch algorithm for optimising the proposed rollover warning model, are discussed in detail. Computer simulations under different driving conditions are carried out to verify the optimised HHMM model. The simulation results demonstrate that the proposed driving condition identification method can effectively identify the driving status with a high accuracy under a variety of driving conditions and could be used for real-time rollover warning control.
Keywords: hierarchical hidden Markov model; heavy duty vehicles; driving condition identification; rollover warning system.
Investigating the active suspension performance using 2/ robust controller combined with particle swarm optimisation
by Hamid Taghavifar, Leyla Tagahvifar, Aref Mardani
Abstract: A robust controller design technique for vehicle active suspension systems is investigated, which takes into consideration the road disturbance as the uncertainty of system parameters. The design of the robust controller is considered as a dynamic optimisation problem, and two artificial intelligence approaches of genetic algorithm and particle swarm optimization are adopted to find the optimum amounts of weighted mixture of H∞/H2. The cost function of the robust controller is designed based on the norms of the weighted mixture of H∞/H2 for a plant with a definite feedback gain and coefficient of norm of infinity that varies in the range between 0 and 1 representing absolute H2 and H∞, respectively. Particle swarm optimisation showed a competitive convergence to the global minimum of 127 in the shortest time and was selected as the best performing technique. The adopted system improved the system response in terms of sprung mass acceleration, suspension deflection and unsprung mass displacement. The obtained results from the simulations further confirm the superiority of the proposed system relative to the classical passive suspension, and signify the robustness of the active controller design.
Keywords: active suspension; robust control; suspension deflection; particle swarm optimisation.
Path-tracking errors for active trailer steering off-highway: a simulation study
by Qiheng Miao, David Cebon
Abstract: This paper discusses the tracking performance of a path-following steering system when operating off-highway. Simulation studies were conducted on three types of vehicle model: tractor-semitrailer, B-double and A-triple. The vehicles were simulated for a straight-line and a 450 roundabout with various road cambers, grades and adhesions. Results indicated that the path-following steering system was unable to provide good tracking performance under those conditions owing to longitudinal and lateral wheel slip interfering with its estimation of trailer location and orientation.
Keywords: simulation study; path-following control; active steering; off-highway.
Path planning and tracking for autonomous mining articulated vehicles
by Fengqian Dou, Yanjun Huang, Li Liu, Hong Wang, Yu Meng, Lianqiang Zhao
Abstract: This paper presents a path planning and tracking framework for autonomous mining articulated vehicles (AVs). The relation space method (RSM) is proposed for path planning. In this method, a self-organising, competitive neural network is adopted to identify the space around the vehicle. Then the vehicles optimal driving direction is determined by using the spatial geometric relationships of the identified space. A PID controller is used to control the vehicle speed, whereas a model predictive controller (MPC) is designed for steering control, where the path tracking error model is used for MPC development. In addition, the AVs dynamics model is built in Adams. The effect and sensitivity of the path-tracking controller are validated through the Matlab-Adams co-simulation. The test results show satisfactory path-tracking performance.
Keywords: articulated vehicle; relation space method; path planning and tracking; MPC.
Integrated control strategy for articulated heavy vehicles based on a linear model with real-time parameters
by Zhigen Nie, Jin Gao, Kun Zhang
Abstract: A control strategy for lateral performance improvement of articulated heavy vehicles (AHVs) by integrating active trailer steering and differential braking is presented. A linear model with real-time parameters is adopted in the strategy to achieve precise control for AHVs under the real-time vehicle states and conditions. The strategy is divided into a path-follow control mode and rollover control mode. A mode switching method is employed by the strategy to achieve good path following and yaw stability under normal working conditions and to avoid vehicle rollover under the limit conditions. Moreover, in order to obtain the optimal control effects for different control objectives and achieve fusion and coordination of multiple subsystems, the genetic particle swarm optimisation algorithm is used to obtain the optimal weight coefficients of the strategy. Experimental verification results indicate that the presented strategy achieves good control for AHVs across a wide range of different operating conditions.
Keywords: articulated heavy vehicles; integrated control; vehicle dynamics and control; parameter identification; optimal control.
Special Issue on: Heavy Vehicle Systems in Real-Time Applications
An investigation on the fatigue performance of austempered ductile iron steering knuckle
by Sivaraj Madhusudhanan, I. Rajendran
Abstract: The steering knuckle is one of the important components that connect the wheel in a car to the steering system; it is subject to time-varying load during its life, leading to fatigue failure. This study reports on the fatigue performance of the ADI material. SG iron is made up of three compositions, without alloying elements (X), SG +0.22% of nickel (X1) and SG+ 0.34% of nickel (X2). Three set of knuckles were heat treated and specimens were cut from the steering arm and converted into test sample (tensile and fatigue) form. The tensile test and fatigue test were done using 250 KN UTM machine and axial fatigue machine at constant load condition for different loads, respectively. The corresponding cycle stresses were recorded up to breakage and S-N curves drawn. The same composition of steering knuckle was used for component level fatigue test at a load of
Keywords: steering knuckle; austempering; ADI; SG iron; fatigue.
Parametric analysis of axial flux HUB motor for electric vehicles in rural areas
by Jency Joseph, Albert Victoire T. Aruldoss, F.T. Josh
Abstract: Heavy vehicle transportation in rural areas decreases the load factor and the transportation efficiency because of the size of the vehicle. Transportation efficiency in rural areas can be improved by reducing the size of the propulsion system in electric vehicles. A pancake-shaped axial flux permanent magnet brushless DC motor is proposed here which has compact size. The FEM and the Matlab/Simulink models have been developed to analyse its performance. A 2.75 kW motor has been designed using ANSYS Maxwell to extract the machine parameters, such as armature resistance, armature inductance, the weights of the stator and rotor, and the density. The torque-speed characteristics of the motor have been analysed by varying the motor parameters, snubber parameters and load. Optimum performance of the AFPM motor has been obtained at the value of 2.4 Ω of armature resistance and the moment of inertia of 20.8e-3 kg-m2
Keywords: axial flux permanent magnet motor; armature inductance; snubber resistance; electric vehicle.
Automated multimodal background detection and shadow removal process using robust principal fuzzy gradient partial equation methods in intelligent transportation systems
by Mohamed Shakeel, N. Arunkumar, Enas Abdulhay
Abstract: The continuous developments of computer technologies in the Intelligent Transportation Systems (ITS) place an important role on the various applications such as vehicle detection, traffic control detection and so on. Among these, the vehicle detection process plays a major role in providing effective solutions for congested roads, as well as the some other traffic control issues. During the vehicle detection process various techniques are introduced, but still some issues such as detecting a multimodal background subtraction, cast shadow removal, and illumination changes need to be improved. In this paper, the robust principal fuzzy subtraction method and gradient partial equation method (RPFGPE) are used to investigate the multi-modal background detection-subtraction with illumination changes and cast shadow removal method to effectively recognise the vehicle from the video footage. These methods analyse each pixel present in the video frame images while analysing the background as well as the cast shadow. The effectiveness of the proposed system is evaluated with the help of experimental results, and compared with the other methods for background subtraction, cast shadow removal with different illumination changes.
Keywords: intelligent transportation system; multimodal background subtraction; cast shadow removal; illumination changes; robust principal fuzzy subtraction method; gradient partial equation method.
Evaluation of outliers detection algorithms for traffic congestion assessment in smart city traffic data from vehicle sensors
by Ramona Ruiz-Blazquez, Mario Munoz-Organero, Luis Sanchez-Fernández
Abstract: On-board sensors in vehicles are able to capture real-time data representations of variables conditioning the traffic flow. Extracting knowledge by combining data from different vehicles, together with machine learning algorithms, will help both to optimise transportation systems and to maximise the drivers and passengers comfort. This paper analyses the information from several sensors while driving for the particular application of the detection and prediction of abnormal traffic conditions. The study is based on the combination of outlier detection mechanisms together with data classification methods. This study provides first a summary of the most common multivariate outlier detection methods and applies them to sensor data captured from sensor vehicles. Outliers detection represents an important task in discovering useful and valuable information, as has been proven in numerous researches. The aim of outlier detection will be to find and identify different abnormal driving conditions such as traffic jams. The output of the outlier detection phase will then be fed into several classifiers, which have been implemented to assess whether or not the multivariate outliers correspond to traffic congestion situations.
Keywords: multivariate outliers; traffic jams; outliers detection methods; vehicle telemetry; machine learning.
Robust detection and recognition of traffic signs on road panels
by S. Gokul, Kumar S. Suresh, S. Giriprasad
Abstract: Traffic panels provides vital information on roads with the aid of iconic symbols and text strings. Recognising these signs accurately at the right time is crucial for car drivers to ensure a safe journey. The automatic visual recognition and classification of the information contained in the panel could be very useful for driver assistance application. This paper proposes a method to identify and recognise the information contained in the traffic panels, as an application using colour space conversion for image acquisition then the colour decomposition and shape model generation using an active appearance model. The traffic panel detection uses a character descriptor based on adaptive fuzzy clustering. Multi-frame detection strategy is a simple way of using precision and recall. Finally the prediction accuracy is computed by using massive training artificial neural network.
Keywords: traffic panel; iconic symbols; active appearance model; adaptive fuzzy clustering; massive training artificial neural network.
Location optimisation for roadside unit deployment and maximising communication probability in multi-lane highway
by Naskath Jahangeer, B. Paramasivan
Abstract: Quick advances in wireless and mobile communications have led to a change of outlook in human lifestyles. Vehicular Ad hoc Network (VANET) is an emerging and challenging technology in mobile communication. Vehicle to infrastructure communication is a cornerstone for providing a wide plethora of VANET. To provide an acceptable quality of service, we need to place roadside units appropriately for better communication. In this paper, we propose to provide the desired geometry-based coverage strategy using a Voronoi sweep line algorithm and genetic approach. The simulation results illustrate that our coverage protocol performs well in highway vehicular networks.
Keywords: vehicular ad hoc network; deployment; roadside unit; Voronoi sweep line algorithm; genetic algorithm; smart PC.
Mapping the structure and evolution of heavy vehicle research: a scientometric analysis and visualization
by V. Venkatraman, N. Arunkumar, Angela Chantre Astaiza, Ana Isabel Muñoz Mazón, Laura Fuentes Moraleda, Mohammed Shahriar Khan
Abstract: In the last decades the research of heavy vehicles has taken great importance for the development of multiple industries at a commercial level and from the scientific point of view, which has led to the need for various studies in this field. This paper analyses the field of heavy vehicles from 1912 to the first quarter of 2017 identifying the patterns from the publications, including the most important authors and institutions; high-frequency categories and keywords; journal and author contributions; most important research topics and evolution of the field based on cluster analysis. A scientometric approach based on bibliometric analysis is employed. Records from WOS and Scopus have been gathered using two bibliometric tools CiteSpace and SciMAT.
Keywords: heavy vehicles; Web of Science; Scopus; co-citation; CiteSpace; SciMAT; visualisation research; research trends; bibliometric analysis.
Adaptive mobility-based intelligent decision-making system for driver behaviour prediction with motion nanosensor in VANET
by S. Cloudin, P. Mohan Kumar
Abstract: VANET offers a dedicated short range wireless communication among vehicles on the road and to roadside units. This technology primarily aims to ensure road safety by disseminating safety information to nearby vehicles to alert drivers or control vehicles to avoid road accidents. The alertness of the driver influences the safety on the road. This paper contributes towards an intelligent decision-making system based on the driver behaviour under normal, reckless, fatigue and drunken conditions, and develops a mobility model to adapt these Support Vector Machine (SVM) classifier behaviours. Attributes such as speed, accelerometer, alcohol and eye blink values are fed to the Mega Trend Diffusion (MTD) function and the attributes are merged and classified. The basic decisions are made by a Fuzzy Interference System (FIS), which is used to find the driver behaviour and an appropriate decision will be taken for SVM classification. According to the behaviour of the driver, the speed and direction of the vehicle will be affected and it will be reflected in the mobility pattern of other vehicles. In this work, we use a motion nanosensor for control of the driver behaviour.
Keywords: VANET; driver behaviour; SVM; mega trend diffusion; fuzzy interference system; motion nanosensor.
IEEE 802.11p MAC with spectrum sensing scheme reliable for VANET using intelligent transportation system
by S. Karthikeyini, S. Shankar
Abstract: IEEE 802.11 standard supports Intelligent Transportation Systems (ITS) which access the vehicle based on WiFi technology. IEEE 802.11p, which supports data exchange between high-speed vehicle to vehicle communication through licensed frequency band 5.8GHz or 5.9GHz (5.85-5.925 GHz), support ITS application in Wireless Access in Vehicular Enviroment (WAVE) protocol stacks. The IEEE 802.11p standard provides multiple channel access to improve of traffic safety and traffic efficiency. In a congested area it needs enough spectrum for a commute of safety and non-safety messages. The proposed method, IEEE802.11p MAC, accesses the channel in a distributed fashion to avoid collisions and uses the cyclic autocorrelation function to detect the energy for broadcast signal and measured along the vehicle level. All information is aggregated for making a decision for data delivery in vehicular environments. The spectrum sensing method is employed to sense broadcast signals for finding out the occupancy status of the spectrum and availability of the licensed frequency bands. Thus the cognitive radio approach dynamically allocates the bandwidth for insufficient area, which mitigates the spectrum scarcity. The performance of the spectrum sensing technique is judged at a congested city-state of affairs using an ns2 simulator. The results establish the available licensed free channels and avoid collision by the dynamic TDMA method. The proposed approach represents an effective and warranted conversation over VANET measured through the high reliability and reduced delay and overhead of packet constraints.
Keywords: IEEE 802.11p; MAC protocol; CAF; CFD; dynamic TDMA.
Corrosion, adhesion and erosion study of MZ and ML system using thermal plasma
by B. Shreeram, I. Rajendran
Abstract: Mullite processed through Transferred Arc Plasma (TAP) is the most promising material in the ceramics industry for protective barrier coatings. The addition of impurities such as ZrO2 shows a significance improvement in the fracture toughness property. This present research compares the performance of La2O3 as a material equivalent to ZrO2. Mullite is mixed in different weight proportions varying from 10 to 20% with ZrO2 and La2O3 and ball-milled to obtain a homogeneous mixture. The compositions are processed using TAP and sprayed onto steel substrates. The substrates are tested for the microstructure and characterisation using SEM and XRD. Coating thickness, roughness, adhesion test and tribological properties are studied for erosion wear and sliding wear. The study reveals that La2O3 can be an excellent alternative and cost effective material for coatings.
Keywords: mullite; thermal barrier coatings; plasma spraying.
Evaluation of mechanical performance of friction-welded AISI304L grade stainless steel joints
by K. Umanath, K. Palanikumar
Abstract: In the welding of austenitic stainless steel (ASS) rods of an AISI304L grade, the significant issues are hot breaking and loss of erosion resistance. To resolve these problems, the solid state friction welding is the best method, and testing is required for the process. In this research work, friction-welded AISI304L rods of 10 mm diameter have used for conducting the experimental testing of tensile strength, fatigue strength, hardness strength and temperature transformation during the friction welding. The results show that the maximum tensile strength of the friction-welded joint is 532 MPa, which is equivalent to 94.16% of the base metals' tensile strength. The fatigue strength of the notched specimens is lower than that of un-notched specimens owing to the high crack propagation in the notched specimens.
Keywords: AISI304L alloys; friction welding; temperature analysis; fatigue strength; stainless steel.
Research on vehicle location-distribution problem based on uncertain demand and low carbon emission
by Pei Wang, Xiaodong Zhang, Han Boling, Lang Maoxiang
Abstract: Global warming is a major problem and challenge faced by mankind in the 21st century, and CO2 produced by anthropogenic activities is the main reason for exacerbating the greenhouse effect. Logistics and supply chain are important parts of today's economic activities and the main sources of air pollution and carbon emission. However, reasonable location of manufacturing plants and distribution centres can improve operation efficiency, shorten distribution distance and reduce carbon emission. Therefore, we take the location-distribution problem as a research object in this paper. This problem should combine with uncertain demand and carbon emission to conform to reality. In this paper, a bi-objective mathematical model, including the objectives of minimum cost and carbon emission, is established. Methods for measuring carbon emission quantitatively from plants and distribution are proposed. Constraints of the model take uncertain demand into account, and the scenario analysis method is used to deal with uncertain demands. Finally, the validity of the model is verified by an example. The results show that the greater the uncertainty of demand is, the more cost an enterprise should pay for resources to meet with customers needs, resulting in more carbon emission. Also, three stages existing in the relationship between cost and carbon emission are put forward, and some suggestions about location and distribution for each stage are given.
Keywords: location-distribution problem; bi-objective model; uncertain demand; carbon emission; scenario analysis.
Secure and compact implementation of optimised Montgomery multiplier based elliptic curve cryptography on FPGA with road vehicular traffic collecting protocol for VANET application
by S. Baskar, V.R. Sarma Dhulipala
Abstract: Nowadays, vehicular communication has a crucial role in vehicular adhoc networks (VANET) because it helps to gather several details such as traffic, accidents, vehicle identification, etc. Among the various details, traffic information helps to improve people's lifestyle without making any delay. This paper introduces the Road Vehicular Traffic Collecting (RVTC) protocol for collecting traffic information on roadside units. The collected information is transmitted to the users via a message including congestion details and own query related velocity (which helps to improve their travelling), but the main factor is security, which leads to reducing the entire vehicular communication process but also leads to longer delay and greater energy use. For overcoming these issues, optimised Montgomery multiplier based Elliptic Curve Cryptography (ECC) is used for maintaining the security. During the information transmission, the message is encrypted by adding the carry select adder (CSLA) based modular operation process in the Montgomery multiplier, which reduces the entire architecture design area and also maintains the information confidentiality with high security by consuming low energy while transmitting the information. In addition to this, the traffic collecting routing protocol maintains the information quality from a particular area to a destination location. The efficiency of the traffic information system is evaluated with the help of simulation results and targeted on Altera DE-2 FPGA (field programmable gate array).
Keywords: vehicular adhoc networks; road vehicular traffic collecting protocol; optimised Montgomery multiplier based elliptic curve cryptography; carry select adder.
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.
Investigation of mechanical, morphological studies and electrochemical micro-holing process parameters on Al6061-SiC-Gr hybrid metal matrix composites
by P. Satishkumar, N. Natarajan, S. Dharmalingam, S. Pitchandi
Abstract: In recent years, the aluminium alloy based (or) combined metal matrix composites (MMC) have played an important role in aerospace and automobile applications. They have good finer mechanical properties than conventional alloys, which increase their mechanical and chemical properties. This paper investigates a methodology for the optimisation of the electrochemical machining parameters on micro-holing of Al6061 + (6 Wt% SiC + 4 Wt% Gr) hybrid composites. The analysis of variance and Taguchi methodology (L27 orthogonal array) are used to study the influence of electrochemical micromachining parameters such as frequency, machining voltage, and electrolyte concentration on the material removal rate and overcut. In this present work, Al6061 has been taken as main matrix material combined with silicon carbide and graphite of size 15 to 30μm. Composite materials Al6061 + 6 Wt% SiC, Al6061 + 4 Wt% Gr and hybrid composite material Al6061 + (6 Wt% SiC + 4 Wt% Gr) are formed by a stir casting method, at a temperature of 540
Keywords: Al6061; graphite; silicon carbide; stir casting; electrochemical micromachining; mechanical properties; material removal rate; overcut; Taguchi methodology.
Anomalies detection from video surveillance using support vector trained deep neural network classifier
by S. Giriprasad, S. Mohan, S. Gokul
Abstract: Intelligent video surveillance plays a crucial role in various applications for detecting abnormal activities. The surveillance system uses many significant technologies for detecting the anomalies in the different applications but it fails to manage the accuracy while detecting the anomalies from huge crowd. This paper introduces an effective image processing technology based classifier for recognising and detecting the abnormality from the crowd in an effective manner. Initially the videos are captured with the help of the surveillance camera, and the background has been subtracted using the robust background principal analysis method. After extracting the background from the image, the different principal bow sifts descriptors are extracted. From the extracted descriptors, the similar descriptors are grouped using the bee based collaborative filtering approach. Finally the anomaly classification is done by support vector machine training based deep neural networks. Then the excellence of the system is evaluated with the help of the implementation results which use the highway traffic database and PV parked vehicle surveillance database and the obtained results are compared with the traditional classifiers
Keywords: Intelligent video surveillance; robust background principal analysis; principal bow sift descriptors; bee based collaborative filtering approach; support vector machine training based deep neural network.
Investigation of energy availability for vapour absorption refrigeration system from engine exhaust
by A. Balasubramanian, J. Venkatesan, G. Nagarajan, B. Gautham
Abstract: Today, automobiles use the technology of a vapour compression system to run the air conditioning system that is required to cool the occupants and keep them in an optimal temperature range. However, the rising fuel cost and the load limit on the combustion engines are disadvantages. The thermal efficiency of the internal combustion engine is only about 30-40%, and the exhaust gases carry a significant amount of heat as waste. Approximately 15% of all the electricity produced in the whole world is employed in refrigeration and air conditioning systems. If the heat carried away by the exhaust gases is trapped and converted into usable energy, the overall efficiency of an engine can be improved. The percentage of heat energy rejected to the environment through the exhaust is approximately 25-35% of the energy supplied by the fuel and varies with engine load and speed. The present work is aimed at recovering the waste heat that is used for running the automotive air conditioner working on the Vapour Absorption Refrigeration (VAR) system, replacing the vapour compression system. The generator of VAR is made to work on heat carried away by engine exhaust, which will improve the overall efficiency of the internal combustion engine. The exhaust gases from most passenger cars carry 2.5 kW to 10 kW of heat energy at different operating conditions.
Keywords: waste heat; generator; VAR; triple fluid; exhaust gas.