Spacecraft Line-of-Sight Control Using a Single Variable-Speed Control Moment Gyro

Abstract

Complete attitude control of a spacecraft is not possible with only one single-gimbal variable-speed control moment gyro due to the conservation of angular momentum. However, partial attitude control without violating the angular momentum conservation principle is still possible. In this paper feedback controllers using only one singlegimbal variable-speed control moment gyro are presented that drive all three components of the angular velocity of a rigid spacecraft to zero, while at the same time a spacecraft body-axis points along an arbitrary inertial direction. To solve this problem, we first introduce a pair of angles to parametrize all feasible final spacecraft orientations at rest without violating the angular momentum constraint. Based on this parametrization, an LQR control law is designed to locally achieve the control objective. Afterwards, a multistage control law is proposed to achieve the same control objective for large initial conditions.

Integrated Power and Attitude Control Design of Satellites Based on a Fuzzy Adaptive Disturbance Observer Using Variable-Speed Control Moment Gyros

“…where (5) and I is the identity matrix. Let h 1 = J and h 2 = A I Ω and assume that the term̈can be neglected.…”

“…Using a classical dynamics approach, the nonlinear equations for a VSCMG cluster in a rigid spacecraft have been derived for different kinematic descriptions of the spacecraft orientation. Tsiotras published a series of papers related to this problem [4,5], and Yoon and Tsiotras [4] extended their earlier IPAC developments to include actuation and energy storage with VSCMGs and designed a model-based controller to achieve exact attitude tracking with a perfect known spacecraft model. However, the mass moment of the inertia matrix must be precisely known, and many researchers simplify the model by assuming that the gimbals have zero inertia to facilitate the controller design [6].…”

Optimal Attitude Control for Spacecraft Using Two Variable-Speed Control Moment Gyros

“…[6][7][8][9][10][11] In the case of a single-gimbal variable-speed control moment gyro (SGVSCMG), spacecraft pointing is achieved using two degrees of freedom. 12,13) This paper discusses a rest-to-rest spacecraft maneuver using two SGVSCMGs. Time trajectories of angular momentums and gimbal angles are derived analytically and numerically with the goal of minimizing maneuvering time subject to a set of physical constraints.…”

Attitude Stabilization of a Spacecraft with Two Parallel Control Moment Gyroscopes

“…Following this, a number of results were reported on partial attitude control, such as angular velocity stabilization [3,4], spin-axis stabilization [5] or line-of-sight control [6][7][8], and full attitude stabilization [9][10][11][12][13][14] (i.e., stabilizing the complete attitude equations) of a rigid spacecraft by means of two torques. Various actuators ranging from thrusters [1][2][3]5,[9][10][11], reaction wheels/momentum wheels [12,13] to control moment gyroscopes (CMGs) [4,[6][7][8]14,15] were considered. The CMG system can be classified as a single-gimbal, double-gimbal, or variable-speed type.…”