Output Constraint Control on Path Following of Four-Wheel Independently Actuated Autonomous Ground Vehicles

The path-following problem for four-wheel independently actuated autonomous ground vehicles is investigated in this paper. A novel output constraint controller is proposed to deal with the lateral offset control in path following and maintain the vehicle lateral stability in the presence of tire sliding effects. The innovations of this work lie in the following two aspects: 1) A novel output constraint control strategy, namely, the hyperbolic projection method, is proposed to strictly bound the lateral offset to prevent the vehicle from transgressing the safety bound in path following; 2) an adaptive and robust linear quadratic regulator controller is adopted to obtain the optimal active front-wheel steering and direct yaw-moment control inputs with vehicle lateral stability consideration and to eliminate the effect of parameter uncertainties. CarSim-Simulink joint simulation results indicate that the proposed controller can compactly bound the lateral offset to avoid transgressing the safe boundary during path following, particularly in extreme driving conditions, in the presence of tire sliding effects and system uncertainties.