Development of an automatic balancing system for a small satellite attitude control simulator

The objective of this thesis is the calibration and balancing of a viable ground-based satellite simulator. The simulator uses an air bearing as the primary method for the emulation of the frictionless environment of space. Of particular concern for accurate simulation are sensor calibration, attitude determination, and system balancing. "Balancing" refers to the process of moving the center of mass of the simulator near to the center of rotation of the air bearing to reduce the interference of gravitational torques.; The attitude sensors were calibrated using a two degrees-of-freedom tilt table. This table allowed for accurate knowledge of system attitude while recording sensor data. Attitude determination was accomplished using the ZYX Euler angles, with pitch and roll being measured directly from the angular position sensor and yaw being estimated from magnetometer data.; This thesis developed an automatic balancing system for the simulator. This system calculates the system center of mass by analyzing the dynamic sensor data along with the integrated equations of motion. The algorithm uses the method of least squares to estimate the vector from the center of rotation to the center of mass. The center of mass of the simulator is then moved near to the center of rotation by means of movable masses that are adjusted to the correct location. The algorithm is able to move the center of mass to a location closer than two hundredths of a millimeter from the center of rotation. This adjustment increases the period of oscillation of the simulator to more than 60 seconds.