Sliding-mode control and sonnar based bubble rebound obstacle avoidance for a WMR

In this paper an algorithm for trajectory-tracking and obstacle avoidance for wheeled mobile robots (WMR) is presented. The algorithm creates a trajectory composed of a global trajectory generated off-line and local obstacle avoidance trajectories that are created when an obstacle is detected by the sonar sensors. Only one discrete-time sliding-mode controller is required to track the resulting trajectory and it does not require separate controllers for following the intended trajectory and avoiding the obstacle. The local avoidance trajectories are generated using Quintic equations to generate a path for the robot and assigning calculating the velocity, acceleration, angular velocity and angular acceleration needed by the discrete-time sliding-mode controller.