Tracking control of wheeled mobile robots with a single steering input - control using reference time-scaling

This paper presents a time-scaling based control strategy of the kinematic model of wheeled mobile robots with one input which is the steering angle. The longitudinal velocity of the mobile robot cannot be influenced by the controller but can be measured. Using an on-line time-scaling, driven by the longitudinal velocity of the robot and its time derivatives, one can achieve exponential tracking of any sufficiently smooth reference trajectory with non-vanishing velocity. The price to pay is the modification of the traveling time along the reference trajectory according to the time-scaling. The measurement of the time derivatives of the velocity is no longer necessary if the tracking controller is designed to the linearized tracking error dynamics.