On robustness and precision of mobile robots missions

This paper proposes solutions for the robust achievement of displacement missions by a wheeled mobile robot. The considered disturbances are generated by the use of inaccurate configuration estimates as feedback information. Those errors are characterized in a bounded error context. We introduce a trajectory tracking controller whose stability is analysed by a Lyapunov function the time derivative of which is negative definite inside a large domain around the zero error. This property makes it possible to define a bounded attractive domain around the nominal trajectory, quantifying thus the guaranteed precision of the mission. The method is extended to a parking non-stationary controller and illustrated by a real experiment. (C) 2001 Elsevier Science Ltd. All rights reserved.