Simultaneous thrust vector control and vibration isolation of satellites using steerable smart platforms

Abstract

This paper presents an innovative concept, control strategies and experimental verification of simultaneous thrust vector control and vibration isolation of satellites. First, the innovative concept is introduced by employing a smart platform as an active structural interface between the main thruster of a satellite and the satellite structure. Second, the inverse kinematics and singularity analysis of the smart platform are performed. Third, thrust vector control model of satellites with smart platforms is deduced. Fourth, a multiple loop control strategy is proposed. It includes three cascaded feedback loops for nonlinear compensation of actuators, smart platform control and trust vector control, respectively, and a combined feedback-feedforward control scheme for vibration isolation. Finally, experiments are carried out and experimental results are illustrated and discussed. The cascaded multiple feedback loops compensate the hysteresis (for piezoelectric stacks inside the three linear actuators that individually have simultaneous precision positioning and vibration suppression), dead-zone, back-lash, and friction nonlinearities very well, and provide precision and quick smart platform control and satisfactory thrust vector control capability. The experimental results demonstrate that the simultaneous thrust vector control and vibration suppression is achieved with satisfactory performance.