Optimized underwater manipulator path planning to minimize the disturbance on robot

The movement of the underwater manipulator during floating tasks introduces large perturbations to the robot body state. We presents an online path finding and trajectory generation method for an underwater manipulator in such a scenario. The goal of the path planning in this paper is to cause the smallest possible variation in disturbance moments to the robot body during the movement of the robotic arm. Initially, disturbance graphs are obtained for different combinations of robot arm joint angles. A graph search algorithm is then used to find the initial trajectory. In order to make the trajectory smoother and to match the dynamics of the robot, polynomials are used to optimise the trajectory and information on the derivatives of the polynomials is further utilised to constrain the trajectory. To illustrate the effectiveness of this approach, the algorithm proposed in this paper is compared with conventional motion planning methods performing the same task in a simulated environment, and the results show that our approach brings the least variation in disturbance moments.