Vertical Hovering Control of Underwater Cleaning Robot for Ship Hull Self-fitting

With the increasing demand for large-scale ships in China in recent years, the demand for underwater cleaning robot becomes more and more urgent. In this paper, the problem of underwater cleaning robot's vertical hovering control is studied. Firstly, the kinematic and dynamic models of underwater cleaning robot are built. Because of the singularity of attitude angles in the motion process of underwater cleaning robot, the dual Euler method is used to calculate the attitude angles according to the range in kinematic modeling, which eliminates the error of the attitude angles in the near singular region. Secondly, in order to overcome the difficulty during hovering caused by the noncoincidence of barycenter and buoyancy center, the PID control strategy of angle and position is put forward to make the underwater cleaning robot reach the desired position and angle. At last, the external ocean current disturbance force is added, and MATLAB simulation is used to verify the effectiveness of the proposed method.