Adaptive Attitude Control and Closed-Loop Power Tracking for an Integrated Power and Attitude Control System Using Variable Speed Control Moment Gyroscopes

Abstract

The adaptive attitude control of a rigid spacecraft with a cluster of N variable speed control moment gyroscopes is considered from a perspective of passivity. The time-varying, spacecraft inertia matrix is considered to be unknown. The system dynamics are derived using a special form of Euler-Lagrange equations. The spacecraft tracking error dynamics are shown to be passive. When the inertia matrix is assumed to be known, a proportional controller is proposed based on passivity to make the system globally asymptotically stable. The controller is redesigned for the case with an unknown inertia matrix. The control law and parameter adaptation law are designed as an interconnection of two passive systems. Using passivity, the control design is conflgured to globally asymptotically stabilize the closed-loop system and develop an estimate of the unknown spacecraft inertia matrix. A null space solution is used to provide both open/closed-loop power tracking of the spacecraft to complete the integrated power and attitude control problem. Numerical simulations are provided for validation.