Path Tracking of a Bi-steerable Mobile Robot: An Adaptive Off-road Multi-control Law Strategy

Abstract : This paper proposes a path tracking control algorithm dedicated to off-road mobile robots equipped with two steering axles. Four wheel steering mobile robot allows to enhanced motion capability with respect to classical car-like mobile robot, while reducing the friction induced by the skid-steered architecture. In particular, such a kinematic structure makes it possible to independently control the robot heading and its position, or to increase turning capabilities. In this paper, a strategy is developed in order to reduce the space required when achieving manoeuvres around a desired trajectory. Contrarily to classical point of view, expressing a relationship between the front and rear wheels, the control laws here proposed aim at following the same path for the front and the rear centre of the axle. The robot is then split into two subsystems, regulating two lateral deviations with respect to a desired trajectory.