Utilizing Redundancy of Orientation-Control Wheels for Lowering Energy-Consumption of Space Robot Systems that Regenerate Electricity.

Abstract

Lowering energy consumption of space robot systems has triple fold reasoning : lighter-weight systems, longer life-time, easier heat-control. In this paper, we have studied this problem from control point of view. It has been proposed to regenerate electricity and store it when a space robot decelerate its motion. Even when we regenerate electricity, there still is energy loss due to various physical reasons such as heat loss by electric resistance of motors and mechanical friction, recharging loss of battery, and so on. The recharging efficiency is known to be 75-80% and the rest is the recharging loss. We aim at totally eliminating this loss by motion control. The main idea is to control the motion of a space robot system with the artificial constraint of kinetic energy conservation. This makes recharging unnecessary and recharging-loss zero. We utilize the redundancy of control momentum wheels to meet the scalar constraint. The simulation result shows that a three-second motion with the proposed control can save approximately 40-84 (J) .