Cross-Coupling Control for Slippage Minimization of a Four-Wheel-Steering Mobile Robot

Abstract

The paper presents a cross-coupling controller for a four-wheel steering mobile robot with independently actuated steering and driving of each wheel. The aim of the controller is to minimize slippage during transient states of the vehicle control. Linear approximation of the criterion for no slippage is adopted for the design of the LQR-based cross-coupling controller of steering actuators. Driving actuators are coupled with steering actuators in pairs corresponding to each wheel so that their transient errors are kept mutually proportional. The experiments performed on a dynamic model of the vehicle demonstrate significant reduction of slippage with moderate vehicle posture errors.