Biased Random Walk For Controlling a Mobile Robot

Some bacteria like Escherichia Coli present a movement that can be modeled as a biased random walk. Biased random walk can be used for artifi- cial creatures as a very simple and robust control policy for tasks like goal reaching. In this paper we show how a very simple control law is able to guide a simulated mobile robot equipped with an omni-directional camera toward a target without any knowledge of the actuators or of the camera. Ex- periments to validate the robustness of the approach show that the robot is able to reach the target having sustained several damages, namely the reduction of the size or uncontrollability of one wheel, rotation of the axle of one wheel and obscuration of 20% of the camera image. We then show experimentally that the best behavior is obtained using a bias which is roughly proportional to the random walk step, with a coefficient dependent on the physical structure of the robot, on its actuators and on and its sensors after the damage.