Adaptive sliding mode control of a four-wheel-steering autonomous vehicle with uncertainty using parallel orientation and position control

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 road's friction, which plays a key role in handling dynamics. The proposed dynamic model used in this paper is a simple and useful two-degree of freedom model. Two parallel ASMCs are used: one for positioning error and the other for angular error. The simulations are executed for two different road conditions with considering the hypercritical condition. To verify the designed controller, the controller is applied to the non-linear 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.