On-Orbit Robust Control Experiment of Flexible Spacecraft ETS-VI

An on-orbit attitude and vibration control experiment has been performed as a part of experiments of the ETS-VI, which was launched by the H-II rocket in August 1994. The purpose is to develop precise attitude control technology for future large spacecraft or large space structures. To this end, we have designed three types of controllers in linear quadratic Gaussian and H 1 frameworks to achieve the robust stability against residual modes and modal parameter errors. The experiments were done at the beginning of 1995, and their feasibility has been proved. The  ight experiment results and the modeling and the controller synthesis methods are reported. Based on the on-orbit results, the capabilities of controllers are compared and discussed.