Trajectory Tracking in a Mobile Robot without Using Velocity Measurements for Control of Wheels

In this paper we present a solution for the trajectory tracking problem in a newt mobile robot. We exploit the differential flatness property of the robot kinematic model to propose an input-output linearization controller which allows both the position and the orientation to track a desired trajectory. An important assumption is that robot has to be initially placed at a point on such a desired trajectory. This controller provides the velocity profiles that the robot wheels have to track and a second controller has to be designed in order to ensure the latter. This is accomplished by means of another differential flatness based control scheme which does not require measurements of any mechanical variables, i.e. velocities, to control the DC motors used as actuators at the wheels. We verify our findings through numerical simulations.