A Sliding Mode Control Scheme for Steering Flexibility and Stability in All-wheel-steering Multi-axle Vehicles

Multi-axle vehicles that have important roles in transport systems require high load-carrying capacity, steering performance, and stability. Thanks to the multiple steering characteristics, the dynamic performance of multi-axle vehicles can be greatly improved, which also brings great challenges for the design of their steering controller. Therefore, this paper proposes a steering control scheme for an all-wheel-steering multi-axle vehicle with the goal of optimizing low-speed steering flexibility and high-speed vehicle stability. With the dynamic analyses, the vehicle's steady-state gains at different speeds are reshaped, which provide the closed-loop steering control system with good tracking performance. Correspondingly, a steering controller based on the sliding mode control approach is designed to control the steering angle of each wheel at different axles. The super-twisting control algorithm is also combined with a model-based observer to deal with disturbance while eliminating chattering effects of the control system. Simulation results based on a co-simulation platform verify the efficiency and disturbance rejection of the proposed control approach.