Robust Lateral Motion Control of Electric Ground Vehicles With Random Network-Induced Delays

This paper presents a lateral motion control strategy for four-wheel independently actuated (FWIA) electric ground vehicles that use the controller area network as a communication medium. The proposed controller design aims to guarantee vehicle stability while tracking the desired yaw rate, in spite of random network-induced delays that exist in both the feedback and forward channels. By modeling the random network-induced delays in both channels as two homogenous Markov chains, statistic information of these delays is incorporated in the mode-dependent tracking controller design. The control law consists of state feedback control and integral control. To fully compensate for the network-induced delays, a delay-free stochastic closed-loop system is first obtained in a discrete-time framework by using a system augmentation technique. Then, a robust linear quadratic regulator-based H_∞ controller is developed to achieve the tradeoff between the tracking error and the control input while also attenuating the effect of external disturbance. Considering the physical limitation of in-wheel motors, the eigenvalue positions of the state matrix are constrained in a predefined area to further balance the control inputs and transient responses by using pole placement. Finally, an iterative linear matrix inequality algorithm is adopted to obtain the delay-dependent feedback control gains. Simulation results based on a high-fidelity, CarSim, full-vehicle model show the effectiveness of the proposed lateral motion control approach.