System Identification and Automatic Mass Balancing of Ground-Based Three-Axis Spacecraft Simulator

Abstract

The ground-based spacecraft simulator is a useful tool to develop and verify new control laws required by modern spacecraft applications. In order to simulate the space environment with the ground-based spacecraft simulator, the effects of gravity should be minimized. In this paper, a three-axis rotational rigid spacecraft simulator on a spherical air-bearing system is considered. The method of estimating the inertial properties of a spacecraft as well as the location of the center of mass is presented with the batch least-square estimation. The identified center of mass location is used to actuate the automatic mass balancing system to compensate for the center of mass offset. Adaptive control of the automatic mass balancing system is also presented when the balancing masses are actuated in real-time to eliminate the center of mass offset from the center of rotation. The proposed technique is implemented on the Three Axis Simulator 2 (TAS2) which is a ground-based experimental testbed for the Bifocal Relay Mirror Spacecraft (BRMS).