Robust Steering Control of an Advanced Mobility Unit Considering the Communication Time Delay

A vehicle chassis equipped with advanced mobility units exhibits high mechanical decoupling, rendering its steering control particularly vulnerable to communication delays and external disturbances. To address this issue, a disturbance-observer-based robust steering control method is proposed considering a communication time delay. First, a steering dynamics model of the advanced mobility unit is established about the kingpin axis, with the communication time delay modeled as a constant. Subsequently, a composite controller comprising model-based feedforward compensation, proportional-derivative (PD) feedback, and an outer-loop disturbance observer is designed. By employing a Lyapunov-Krasovskii functional, linear matrix inequalities incorporating both delay and disturbance terms are derived to synthesize the PD controller gains. Simulation results demonstrate that, under a 30 ms communication time delay and triangular torque disturbances of ±100 Nm, the steady-state tracking error for constant steering commands is limited within 1 deg, and the tracking error for sinusoidal steering commands is nearly negligible, while the system remains stable throughout. These results validate the effectiveness of the proposed method in suppressing the effects of communication time delay and disturbances while achieving high-precision steering angle tracking performance.