Control of independent rear wheel drive vehicle

Abstract

The problem of the wheel torque control for independent rear wheel drive vehicle is considered. This problem is especially relevant in a view of the modern trends to integrating the antilock braking systems (ABS) and antislip control systems (ACS) in the car. The plant model is presented by fifth order differential system including three degree of freedom single mass flat model of the car and second order model of wheel dynamics. It is shown by simple considerations that order of the plant can be reduced to the second one. The single track vehicle model is shown to be used not only at a constant riding speed but at the high velocities with limited variations as well. The reference inputs are defined for torque controlled vehicle to be like four wheel steering (FWS) one with high maneuverability at a low speed and high stability at a high speed. So FWS system is discussed to be redundant in the car with ABS and ACS. The sliding mode technique is applied for control design. Naturality of the use of sliding modes is caused by discontinuous mode of the actuators of ABS (ACS). A comparison between controlled and conventional cars is provided by computer simulations under various driving conditions such as lateral disturbance, lane change, turn at a low speed and variations of mass distribution.