A Switched-System Approach to Shared Robust Control and Obstacle Avoidance for Mobile Robots

Abstract

We propose a shared control structure for nonholonomic mobile robots, in which a human operator can command motions that override autonomous operation, and the robot overrides either the teleoperation or autonomous controller if it encounters an obstacle. We divide the whole configuration, including orientation, space into an obstacle avoidance and an obstacle-free region. This enables a switched-system approach to switch between autonomous and teleoperation mode, or the obstacle avoidance and the obstacle-free region. To reject disturbances or noise present in the error dynamics, two different robust control laws are proposed using a high gain and a variable structure approach. Lyapunov-based stability analysis is provided. To rigorously test the approach under different circumstances, experiments have been conducted by two different research groups. The results from two groups show that the shared control approach works effectively both in the teleoperation mode and autonomous mode with different system settings and environments.