A visually guided spherical underwater robot

This paper proposes a visual servoing system for a spherical underwater robot. Based on the spherical robot design, the forces and moments acting on it are analyzed and the governing motion equations are derived. The system consists of an on-board bottom facing camera module which is color coded to extract the position information and then guide the robot to follow the reference pattern placed at the bottom of the test tank. The visual servoing system proposed here allows the spherical underwater robot to track and follow a given target underwater. The main features of the system are, to track the color coded pattern and simultaneously feedback the orientation command to the onboard controller. Experimental results with real time data feedback demonstrate that the proposed algorithm can track the color pattern well and a better control on the spherical underwater robot can be achieved, even under various dynamic operating conditions.