Energy Optimization of an Underwater Swimming Manipulator with Rotary Thrusters and Rolling Joints

Abstract

The underwater swimming manipulator (USM) is a novel slender snake robot with several thrusters providing thrust in fixed directions. However, more thrusters mean much energy consumption. In order to save energy by reducing the number of thrusters, in this paper, the rotary thrusters and rolling joints are applied to the USM, so that a rotary thruster can provide thrust to the USM in all directions through the rotation of itself and the rolling joint. Besides, an energy optimization algorithm is designed to enable the thrusters to provide the minimum thrust in the optimal position with different body deformations. Moreover, a cost function is designed to limit the energy consumption, which is solved by sequential quadratic programming algorithm to find the optimal angles for rolling joints. Finally, simulations verify the effectiveness of rotary thrusters, rolling joints, and the energy-saving effect of the proposed energy optimization algorithm.