Backward and forward path following control of a wheeled robot

A wheeled mobile robot is one of the most important types of mobile robots. A subcategory of these robots is wheeled robots towing trailer(s). Motion control problem, especially in backward motion is one of the challenging research topics in this field. In this article, a control algorithm for path-following problem of a tractor-trailer system is provided, which at the same time provides the ability to control the backward and forward motions of the tractor-trailer robot. To this end, first the kinematic equations of a wheeled robot with a trailer is extracted and then reference paths for the robot are defined. Path following equations, in addition to the robot mathematical equations, also represent the robot movement with respect to the reference path. Then, by using transformations the system equations are expressed in a new space and subsequently a control algorithm is proposed for the system. The investigated control law make the system asymptotically stable around the reference path. Finally, obtained results have been presented which guarantee the designed controller.