Posture control of mobile robot by hand-eye system considering nonholonomic constraints

We discuss a vision based control approach applied to a mobile robot with a hand-eye system. Car-like mobile robots require switchback motion to change the posture. However, a camera mounted on the robot may lose sight of the target object because of this motion. In this paper, we propose a control method for nonholonomic wheeled mobile robots without changing the camera view point in a hand-eye system. First, the camera is fixed at an initial position for a target object by visual servoing. Then, the cart switchbacks within reach of the hand-eye system. As a result, the cart posture can be controlled without influencing the camera view point. Using the proposed method, visual servoing techniques can be directly applied to position control of mobile robots by changing the cart posture not to be influenced by nonholonomic constraints. Moreover, it is possible to control the cart position from any initial postures. The validity of the proposed method is evaluated by simulations.