Robust guaranteed cost state-delayed control of yaw stability for four-wheel-independent-drive electric vehicles with active front steering system

A robust guaranteed cost state-delayed control design for four-wheel-independent-drive electric vehicles with active front steering system is presented in this paper. The main control objective is to deal with the time delay problem and improve yaw stability and handling performance of vehicle. To address the challenge of time delay problem, the time delay of steering system is assumed to be concentrated in vehicle state. In terms of the feasibility of a sequence of linear matrix inequalities (LMIs) derived from the selected Lyapunov-Krakovskii functional, the guaranteed cost memoryless state-delayed controller is designed, which ensures the corresponding closed-loop system is asymptotically stable with a guaranteed cost performance. Simulations for various operating manoeuvres are carried out using the platform of Matlab/Simulink-Carsim®. It is found from the simulation results that the proposed controller can effectively attenuate the delayed effect of steering system and preserve vehicle yaw stability.