Mobile Robot Circumnavigating an Unknown Target Using Only Range Rate Measurement

This brief proposes a bounded continuous control law to steer a mobile robot to approach and maintain a predefined distance from an unknown stationary target in a GPS-denied environment where the positions of the robot and the target are not available. The control algorithm utilizes only the derivative of the distance between the mobile robot and the target, that is, range rate measurement. We demonstrate that the controller can achieve global convergence regardless of the initial states of the mobile robot. Compared with the existing works, the proposed control algorithm is the simplest form (derivative-type controller) and easy to implement. Numerical simulations and real-time experiments are both performed to confirm the effectiveness of the proposed control scheme.