Trajectory-tracking and discrete-time sliding-mode control of wheeled mobile robots

In this paper a discrete-time sliding mode control for the trajectory tracking problem of wheeled mobile robots is presented. The wheeled mobile robot (WMR) taken into account was PowerBot. PowerBot is a mobile platform with two differential driving wheels (2DW) and two balancing caster wheels. It is an automated guided vehicle specially designed and equipped for autonomous, intelligent delivery and handling of large payloads. PowerBot is a member of MobileRobots´ Pioneer family of mobile robots, which are research and development platforms that share a common architecture, foundation software and employ intelligence-based client-server robotics controls. Due to its size and high load carrying capacity PowerBot is an ideal robot for both, indoor and outdoor transportation. The algorithm has been designed in discrete-time domain in order to avoid problems caused by the discretization of continuous-time controllers. The simulation results and real time results prove the effectiveness of the proposed controller.