International Journal of Vehicle Systems Modelling and Testing (18 papers in press)

Regular Issues

• Vehicle yaw stability control: literature review  
  by Mohamed Omar, Moustafa El-Gindy 
  Abstract: Vehicle dynamics control can be realised through controlling the vehicle in longitudinal, lateral and/or vertical motion. The focal point of this study is vehicle lateral dynamics control, where yaw stability control has a great influence on vehicle handling and stability performance. Vehicle dynamics control is experiencing an ongoing evolution to ensure vehicle safety and ride comfort. Consequently, several research studies have been proposed to improve vehicle lateral dynamics via yaw stability control. Based on these previous studies in the past three decades, this review paper aims to investigate the main fundamental elements of vehicle yaw stability control structure, in terms of the used vehicle models, control objectives, various control systems implemented for active chassis control and control allocation strategies.
  Keywords: active chassis control; vehicle dynamics control; direct yaw control; active steering control; integrated chassis control; torque vectoring; differential braking; active front steering; active rear steering.
  
  
• Feedback linearisation and disturbance observer based path following control for autonomous ground vehicle  
  by Pengpeng Feng, Jianwu Zhang, Tongli Lu 
  Abstract: In this paper, a feedback linearisation and nonlinear disturbance observer based controller is proposed for the path following of an autonomous ground vehicle. The path following is realised through the tracking of the designed yaw rate and lateral velocity generated by a upper layer controller according to the path information. A feedback linearisation controller is designed considering the nonlinearity in the vehicle model. Then the disturbance caused by external disturbance and tyre model error is estimated by a nonlinear disturbance observer, and the corresponding compensation is added into the control input to improve the performance of the controller in disturbance rejection. The stability of the comprehensive system is proved using Lyapunov method. Simulations and comparisons performed in a Carsim-Simulink joint platform verify the effectiveness of the present controller.
  Keywords: autonomous ground vehicle; path following; feedback linearisation; nonlinear disturbance observer; robust compensation.
  
  
• Variable transmission ratio and active steering control for steer-by-wire steering  
  by Bin Zhao, XiaoBin Fan, GengXin Qi 
  Abstract: Steering-by-wire is different from traditional mechanical steering. It cancels the mechanical connection between the steering wheel and the steering mechanism and can freely design the transmission ratio. This paper uses CarSim and Simulink co-simulation to establish a vehicle model with steer-by-wire based on the yaw angle gain. The ideal transmission ratio is designed with constant weight and constant lateral acceleration gain. The fuzzy control design is adopted at high speed, and the sliding mode control algorithm of active steering is designed based on the ideal transmission ratio. Finally, it is verified by simulation experiments that the vehicle stability and handling after variable transmission ratio are better than traditional mechanical steering, which effectively reduces the operating burden of the driver.
  Keywords: steer-by-wire; yaw angle gain constant; weighted design; ideal transmission ratio; fuzzy control; sliding mode control.
  
  
• Static analysis of the carcass geometry influence on an automotive radial tyre using finite element model  
  by Marcos Campolina, Cádmo Dias, Pedro Américo Jr, Jánes Landre Jr 
  Abstract: The use of finite element models has been a great ally in product development, especially in the automotive industry in order to predict and obtain product improvements, in the case of this paper focused on tyre development. This paper describes a finite element model, from the elaboration of the tyre computer-aided design model up to the tyre service conditions for a static analysis of the tyre and with special attention to the effect of changing the geometry of the carcass from mono-ply to bi-ply and the way that it affects directly the structure stiffness of the tyre. The model allows a greater number of analyses to be carried out in less time than the development and testing of one industrial prototype. Descriptions of the model structure and construction procedure is provided, including inflation and footprint analyses and lateral, longitudinal and vertical stiffness.
  Keywords: tyre model and forces; pneumatic tyres; finite element model; vehicle dynamics; virtual simulation.
  
  
• Improved models of vehicle differential mechanisms using various approaches  
  by Maxym Diachuk, Said Easa 
  Abstract: The mathematical modelling of the branched automotive drivetrain is mainly based on various configurations of the differential mechanisms (DM). This paper proposes variant mathematical methods for modelling DM's dynamics. The symmetric (open) DM is considered first. Two mathematical methods based on ODE and DEA problems are applied. The asymmetric self-locking inter-axle differential with proportional friction moments is then considered. Three variants of the mathematical models for this DM type are represented. The linearised model uses the shortest description based on a previous step solution. Two other nonlinear models are formed by mixing with ODE and DEA approaches. The Simulink blocks for implementing developments were composed. The models were validated by comparing the results under the same conditions to prove their mathematical coherence. The analysis of the proposed variants was carried out regarding structural complexity, usability, computational speed, and relative accuracy. Conclusions about their usability in drivetrain dynamics and active control were made.
  Keywords: symmetric differential; self-locking differential; friction clutch; differential efficiency.
  
  
• Influence of road and rider characteristics on durability of motorcycles  
  by Aptin Haerian, Kemal Öztürk, Robert Liebich 
  Abstract: The present work deals with the virtualisation of motorcycle customer behaviour. First, a method was found to identify design-relevant customers based on collected onboard signals. For vertical excitations, the roughness of the road and ridden velocities were examined with multi-body simulations (MBS). A measurement of a real motorcycle equipped with wheel load transducers and data-logging devices on a test track was used for validation. Using a similar dataset, an approach is presented with which virtual tracks are created. A measured speed profile and scatter for the vertical excitation were considered to obtain precise loads via MBS. Besides the virtualisation of the road, a novel algorithm was developed to generate speed profiles based on rider characteristics. Different synthetic rider types from beginner to expert were defined and compared. The developed methods enable the identification of design-relevant customers and the simulation of load profiles resulting from real customer usage.
  Keywords: virtual environment; motorcycle; driver behaviour; durability; multi-body systems; driver-vehicle systems.
  
  
• Special and misuse events for motorcycles  
  by Aptin Haerian, Kemal Öztürk, Robert Liebich 
  Abstract: The present work deals with the topic of special and misuse events for motorcycles. First, a novel approach was found to define these events based on signal characteristics related to durability engineering. Furthermore, a multi-body simulation (MBS) model of a motorcycle was created to determine loads for special events. A suitable tyre model and relevant control systems were integrated for co-simulations. To validate the virtual model, wheel forces and selected onboard signals were compared with measurements of a real motorcycle ridden on a proving ground. The model showed sufficient agreement as the maximum wheel forces could be predicted with accuracies between 80% and over 99%. Afterwards, the loads were used to define representative special events. The kerb, sleeper, and bumper impacts were the most important events as they led to the highest forces. The gained perceptions enable a faster and more target-oriented definition of design loads while additionally saving costs.
  Keywords: special events; multi-body simulation; motorcycle; durability; misuse events; impact.
  
  
• Non-pneumatic tyre-road interaction using finite element analysis  
  by Charanpreet Singh Sidhu, Zeinab El-Sayegh, Moustafa El-Gindy 
  Abstract: The purpose of this research is to identify the important characteristics of the Non-Pneumatic (NP) tyre by relating the structural stiffness of the wheel to the contact conditions. Based on experimental and published data, the NP tyre model will be validated under different conditions. A successful outcome of this research would increase the efficiency of the tyre design, while providing a better understanding of NP tyre behaviour under different contact conditions. In this study, Finite Element Analysis (FEA) was used to develop a NP tyre-road interaction model. An analytical model of NP tyre was then validated in static and dynamic response using several virtual tests. The validated NP tyre model was then used to evaluate the tyre-road interaction characteristics using rolling resistance test under different operating conditions.
  Keywords: non-pneumatic tyre; rolling resistance; finite element analysis; drum cleat; PAM-Crash; first mode of vibration; contact area; shear beam.
  
  
• On rolling resistance of bicycle tyres with ambient temperature in focus  
  by Malte Rothhamel 
  Abstract: Two sets of bicycle tyres were tested with a one-degree-of-freedom two-wheeled pendulum, a portable rolling resistance test bed. The vertical load affected the rolling resistance coefficient only to a minor degree. The wider tyre showed an about 10% lower rolling resistance coefficient in comparison to a narrow tyre of the same type. Tyre inflation pressure and temperature are the major influencing factors for rolling resistance. Both of them affect by a factor of two to three in the relevant range. Based on the data about temperature and inflation pressure, a simple model is suggested.
  Keywords: rolling resistance; tyres; bicycle; ambient temperature; inflation pressure; tyre width; vertical load.
  
  
• INVESTIGATION OF ANTILOCK BRAKING SYSTEM PERFORMANCE UNDER TYRE-ROAD INTERACTION PARAMETERS USING CARSIM  
  by P. BASKAR, Sarthak Murarka, Rahul Jain, Dhananjay Poddar 
  Abstract: The performance of a braking system is affected by a variety of tyre-road characteristics like the tread pattern, the depth of the tread, road conditions, and tyre pressure; all these parameters will have a direct impact on braking distance. Aquaplaning can occur in severe rain with substantial water build-up on the road surface, even with relatively fresh tyres with minimal sipes. To reduce this risk, wet weather tyres contain unique rubber formulations and tread patterns. Vehicle accidents hold greater severity both in terms of damage to the vehicle and loss of life. Therefore, car manufacturers prioritise vehicle and occupant safety over other additional features. An investigation has been carried out to simulate the functioning of an anti-lock braking system and evaluate its performance under these various tyre-road interaction parameters. The results show that the performance of ABS was greatly influenced by tread patterns, tyre inflation, vehicle weight, and road conditions.
  Keywords: anti-lock braking system; regenerative braking system; braking distance; tyre inflation pressure; tyre tread pattern.
  
  
• Research and optimum of the dynamic parameters of the QZSS embedded in the seat suspension system of vehicles  
  by Xiangjie Wang, Van Liem Nguyen, Shiming Li, Van Quynh Le 
  Abstract: A quasi-zero stiffness structure (QZSS) embedded to the seat suspension is proposed to improve the driver's ride quality. A dynamic model of the seat suspension added by the QZSS is established to analyse the effect of the QZSS's design parameters and geometrical ratios on the dimensionless restoring force and dimensionless dynamic stiffness of the system model. The QZSS's design parameters and geometrical ratios are then optimized via the genetic algorithm to obtain the quasi-zero stiffness and minimum values of the seat's displacement and acceleration. The results show that the dimensionless restoring force and dimensionless dynamic stiffness are remarkably affected by the QZSS's design parameters. By optimising the QZSS's design parameters, the driver's ride comfort with the QZSS are greatly reduced in comparison without the QZSS under the different simulation conditions. Therefore, the application of the QZSS optimized on the seat suspension can further improve the driver's ride quality.
  Keywords: seat suspension; quasi-zero stiffness structure; ride quality; multi-objective genetic algorithm; nonlinear dynamic model.
  
  
• Research on ABS control strategy of cornering braking of electric vehicle with four in-wheel motors  
  by Kun Yang, Jinzhao Xiao, Di Tan, Chao Ma, Zhaoqiao Gao, Jilei Wang 
  Abstract: To solve the problem of increased wheel inertia and significantly different wheel target slip rates during cornering braking of the electric vehicle with four-wheel-motors, the target slip rates were optimized by particle swarm algorithm, and a braking stability control strategy is proposed. The upper controller calculated the required compensating yaw moment and slip rate increment, the lower controller used a logic threshold value ABS control algorithm to control the wheel-braking force using three schemes: single-wheel control, single-side control, and no turn control applied, respectively. The control strategy was verified based on a condition with an initial speed of 90 km/h, a front wheel turning angle of 5.7
  Keywords: electric vehicle with four in-wheel motors; anti-lock braking system; cornering braking; logic threshold; orthogonal test; particle swarm optimization algorithm.
  
  
• Design and optimisation of double wishbone suspension for high performance vehicles  
  by Rishu Sharma 
  Abstract: Technology is an unpredictable friend, nudging us forward with one hand while demanding exorbitant tolls with the other. With the control on the parameters like camber angle, scrub radius, roll centre height etc, the careful design of double wish bone allows the motion control of wheel throughout the suspension process. The paper considers the high-performance vehicles and impinges the issues related to optimization of double wishbone suspension system. CAD and simulation is used as the method for carrying the analysis. The analysis will help the researchers and practitioners to frame the strategies to develop a system with reduced vibrations and noise.
  Keywords: camber; scrub radius; caster angle; bellcrank; A-arms; tyre data; suspension geometry.
  
  
• Comparison of methods for winter road friction estimation using systems implemented for floating car data  
  by Sofia Sollén, Johan Casselgren 
  Abstract: Winter road maintenance is important for preventing accidents and enabling mobility. If the road friction gets low, there is a higher risk of road accidents. Therefore, it is vital to have information about road friction levels. Traditionally this is done by dedicated vehicles; however, using friction information from floating car data (FCD) would be more beneficial, as the coverage both in time and space increases. In this investigation, road friction data from three FCD suppliers, using only one test vehicle each, has been compared with a continuous method of road friction measurement. The test has been conducted on proving grounds covered with ice and snow, and on public roads covered with water, ice, snow, and slush; thereby both high friction and low friction surfaces have been evaluated. The investigation shows that the FCD provides a continuous method of friction measurement and is closer to the reality of road friction experienced by road users.
  Keywords: road friction; friction estimation; winter road maintenance; vehicle data; optical sensor; floating car data; big data; experimental validation; vehicle testing.
  
  
• Real consumption protocol for driving range determination in electric vehicles: application to urban routes  
  by Carlos Armenta-Deu, Hernán Cortés 
  Abstract: This paper is focused on the development of a customised protocol to determine the real driving range of electric vehicles under variable driving conditions. The method is based on the WLTP protocol but allows the user specific customisation instead of using a standard protocol. The protocol uses standard dynamic equations to develop the mathematical model, taking into account not only the energy consumption but also the energy recovery from regenerative braking. The methodology has been applied to specific urban routes combining downtown and peripheral paths, and the results have been compared to those obtained from the application of the WLTP protocol to the same driving conditions; the comparison has shown a very close agreement between the customised protocol and the WLTP within 97% accuracy. On the other hand, the proposed protocol has the advantage of using algorithms that are specifically adapted to the way of driving and type and characteristics of a route, thus being more realistic and more accurate than the standard WLTP protocol. The method can be applied to any type of electric vehicle, urban route, and way of driving and variable conditions, which makes it a very useful model to predict EV driving range.
  Keywords: electric vehicle; driving range; customisation; driving protocol; dynamic conditions.
  
  
• Integrated Brake Based Torque Vectoring Control of Vehicle Yaw Rate and Side-Slip Angle with Rollover-Prevention  
  by Karthik Poovendran, Theunis Botha, Schalk Els 
  Abstract: Torque vectoring is used on vehicles to improve stability and improve vehicle directional control. These systems are developed on sports vehicles and implemented on sport utility vehicles with a high centre of gravity. This may result in an increase in roll propensity of the vehicles. This paper develops and experimentally evaluates a Model Predictive Control (MPC) based torque vectoring system with yaw rate and slip-angle control while incorporating a rollover limit based on the zero moment point rollover index. The developed MPC is compared to a baseline LQR based yaw rate controller in simulation. The final controller is evaluated experimentally sport utility vehicle. The proposed controller was found to improve vehicle handling while reducing rollover propensity.
  Keywords: torque vectoring; direct yaw moment control; traction control; stability control; rollover prevention; zero moment point roll index.
  
  
• Analysis of low frequency response characteristics of multi-inertia channel hydraulic mounts  
  by Lin Zhihong 
  Abstract: To investigate the effects of the number and length of inertia channels and different cross-sectional areas on the low-frequency characteristics of hydraulic mounts. Firstly, analysis of the isolation of low frequency-large amplitude excitation hydraulic mounts relying mainly on inertial channels. Secondly, nine different structures of inertia channels are proposed and the mathematical model of hydraulic mounts is obtained using an equivalent mechanical method. Meanwhile, the influence of the number and length of inertia channels and the variation of a cross-sectional area on the low-frequency dynamic characteristics of hydraulic mounts are analyzed. Finally, the hydraulic mounts system model of the 1/4 vehicle model is built to analyse the effect of different inertia channels on the mounts' vibration isolation performance under road excitation. It has been shown that changing the number of inertia channels as well as the cross-sectional area can regulate the peak and peak frequency of the dynamic stiffness and loss angle of the hydraulic mounts; At the same time, it directly affects the vibration isolation performance of the mounts system.
  Keywords: hydraulic mounts; inertia channel; dynamic stiffness; loss angle.
  
  
• Development of a rolling truck tyre model using an automatic model regeneration algorithm
  by Shahram Shokouhfar, Subhash Rakheja, Moustafa El-Gindy 
  Abstract: A three-dimensional finite element model of a rolling radial-ply truck tyre is developed to predict its vertical and cornering properties at relatively high speeds. The model includes a detailed representation of the tyre complex geometry and multi-layered composite structure including the carcass and belt plies, bead fillers and tread. LS-DYNA, a nonlinear finite element code, is used as the simulation tool. An algorithm is developed for efficient formulation of the model for parametric analyses. The validity of the proposed tyre model is demonstrated by comparing the predicted load-deflection, cornering and free vertical vibration characteristics with the reported experimental data. The simulation results revealed robust behaviour of the tyre model up to rolling speeds of 100 km/h. The verified tyre model is subsequently employed to study the influences of various operating parameters, namely, the inflation pressure, vertical load, rolling speed and road friction on the tyre vertical and cornering properties.
  Keywords: rolling truck tyre models; multi-layered tyre structure; vertical tyre properties; cornering properties; parametric studies; finite element method; FEM; LS-DYNA; automatic model regeneration; truck tyres; tyre modelling; radial-ply tyres; carcass plies; belt plies; bead fillers; tyre tread; simulation; rolling speed; load deflection; free vertical vibration; tyre inflation pressure; vertical load; road friction; radial tyres.
  DOI: 10.1504/IJVSMT.2016.10000460