Control and obstacle avoidance of a WMR, based on sliding-mode, ultrasounds and laser

Abstract

In this paper is presented an algorithm for trajectory-tracking and obstacle avoidance for wheeled mobile robots (WMR). The proposed 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 and laser 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. Quantic equations are used to generate the paths used by the robot and calculating the velocity, acceleration, angular velocity and angular acceleration needed by the discrete-time sliding-mode controller to avoid the obstacles Realistic simulations and experimental results are performed to test the validity and performance of the proposed obstacle avoidance algorithm and the trajectory tracking controller.