Pointing, control, and stabilization of solar dynamic systems on a space station

This paper presents the design and analysis of a drive system to soft couple the solar dynamic power systems from interaction with the structure of a single-keel space station. The drive system features a low-bandwidth controller that attenuates the dominant transverse boom torsional mode. In addition, minimizing the effects of induced force disturbances on pointing is essential in achieving desired pointing accuracy. An integral loop is included to attenuate low-frequency disturbances. In addition to the integration of the two controllers, the viable concept presented in this paper utilizes sun sensors mounted outboard of the alpha joint on the left and right transverse booms. Tracking error is minimized by using the pointing error from the sun in the control logic for alpha-drive slewing. The system is capable of achieving good stability robustness, performance, and acceptable disturbance rejection. Also presented are some preliminary results.