Lateral Tyre Force Distribution for Four-Wheel Steer-by-Wire Vehicles
- PDF / 928,105 Bytes
- 10 Pages / 595.276 x 790.866 pts Page_size
- 1 Downloads / 152 Views
ORIGINAL CONTRIBUTION
Lateral Tyre Force Distribution for Four-Wheel Steer-by-Wire Vehicles Saaransh Pandoh1 • Anirban Guha1 • Pasumarthy Seshu1
Received: 27 September 2018 / Accepted: 13 May 2020 Ó The Institution of Engineers (India) 2020
Abstract In a four-wheel independent steering vehicle, all the tyres have the capability of being steered independently. The traditional steering assemblies are mechanically limited because their inner and outer wheel’s steering angles are interrelated which makes it difficult to extract the maximum possible traction from the ground. Such steering systems are unable to take the advantage of the load transfer which occurs during the cornering. This work proposes a novel method of lateral tyre force distribution between the inner and outer wheels by making use of load transfer during the cornering of the vehicle. The distribution is obtained by using a function which maps the lateral acceleration of the vehicle to the distribution of the forces between the wheels. The function can be tailored according to the requirements of the driving. The control strategy involves simple equations to allow for an easy hardware implementation. The simulations performed through numerical solution of vehicle dynamics model using the computer program in MATLAB/Simulink show an improvement in the cornering performance of the vehicle and a significant reduction in workload of tyres. Keywords Four-wheel steering Vehicle dynamics Steer-by-wire Lateral force distribution List of Symbols z Displacement of sprung mass in vertical direction zi Displacement of ith un-sprung mass in vertical direction & Saaransh Pandoh [email protected] 1
Mechanical Engineering Department, IIT Bombay, Mumbai, India
h / x kf=r Cf=r zroll zpitch m mf=r Ix=y=z di ktf=tr
Pitch angle Roll angle Yaw velocity Spring constants of front/rear Damping constants of front/rear Height of roll centre of the vehicle Height of pitch centre of the vehicle Mass of the vehicle Mass of the front/rear un-sprung mass Moment of inertia in x/y/z direction Steering wheel angle at the ith wheel Spring constants of front/rear tyre
Introduction Performance and effectiveness are very important for the vehicles which move at higher speeds. The traditional twowheel steering systems have mechanical limitations which prevent them from making maximum use of the traction available from the ground. The paper by Rao et al. [1] analyses the skidding in the two-wheel ackermann steering. Skidding in ackermann steering reduces the performance as well as the life of the tyres. The four-wheel steering systems are able to control traction from both front and rear wheels. Thus, the performance of four-wheel steering is better compared to the conventional two-wheel steering systems. But they are also mechanically limited and are unable to extract the maximum forces from the ground. The direct yaw moment control and optimum tyre force distribution are some of the strategies proposed to improve the performance of the vehicles. These strategies require s
Data Loading...
