A new approach of a path-tracking system of a differential drive robot for an arbitrary set of waypoints using sliding mode control.

Autonomous differential-drive robots are typically controlled to follow a desired path. This path may be defined by a continuous curve or set of waypoints. Few studies have examined cases in which a path is defined by an arbitrary set of waypoints. This paper introduces a new approach to a path-tracking system for an arbitrary set of waypoints using a sliding mode control (SMC) system. This approach is based on a nonlinear kinematic model of the tracking error derived in this research for a differential-drive robot. Based on the derived error model, a sliding mode controller is introduced to drive the tracking error to zero. The stability of the system was also investigated. In addition, the effects of robot dynamics were incorporated into the proposed controller without prior knowledge of the exact parameters of the robot. Simulations were conducted to compare the proposed control system with a widely used approach to demonstrate the effectiveness of the proposed controller in tight maneuvers, particularly at directional discontinuity and/or sharp turns. The proposed technique was verified through real-time experimental tests using a differential drive robot.