Improving Path Tracking Performance of 4WIS Vehicles via Constraint-Oriented Consistent Coordinated Steering

Abstract Research has shown that when vehicles follow the Ackerman steering principle (ASP), the tire wear can be reduced and the path tracking performance can be improved. However, in the case of four-wheel independent steering (4WIS) vehicles, the steering systems of the four wheels are relatively independent, and there are differences and uncertainties in individual steering dynamics, which lead to challenges for all four wheels in simultaneously satisfying the ASP and may deteriorate the vehicle path tracking performance. In response to this problem, this paper introduces a four-wheel consistent coordinated steering control for 4WIS vehicles. The algorithm innovatively reconfigures the Ackerman steering relationships as coupling constraints among the wheels, and utilizes the constraint-following method to design controller. The controller achieves uniform boundedness (UB) and uniform ultimate boundedness (UUB) of ASP constraint error. The Carsim/Simulink joint simulation results demonstrate that the algorithm guarantees the approximate satisfaction of ASP in both the transient and steady-state of the vehicle path tracking. Also, it significantly improves the path tracking performance.