Semi-Optimal Control Using Shooting Method for Real Time Minimum-Time Maneuver of Satellite with VSCMG

Abstract

This study explores the minimum-time attitude maneuver of satellites using Control Moment Gyros (CMG). The CMG system is able to generate high torque and run for longer term than other actuators. However, it is known that the singular input that cannot generate effective torque appears in the optimal control for the minimum-time maneuver of a rigid spacecraft with a pyramid type SGCMG system. In previous studies, a new system equipped with variable speed CMG (VSCMG) to the CMG where the singular input appeared has been proposed. It is shown that the new system can rotate faster than the normal pyramid type SGCMG system in the simulation based on the optimal control law. However, for applications in actual satellites, numerical optimization cannot be used due to the high calculation cost. The objective of this study is to make the new semi-optimal control law for the minimum time attitude maneuver of the satellite equipped with the VSCMG. The new control law is designed using a rule-based feedforward control combined with feedback control. The result by numerical simulation has shown that the proposed control law enables the satellite to achieve faster maneuver without iterative calculations.