基于音圈式Stewart平台的零刚度卫星复合姿态控制研究

Complex Attitude Control Study of a Zero Stiffness Satellite Based on Voice Coil Stewart Platform

针对扰动及卫星本体振动传递对高精度载荷姿态控制的影响,研究了基于音圈式Stewart隔振平台的零刚度超静卫星及其姿态控制问题。利用音圈作动器在电磁作用原理下存在结构间隙的特点,实现卫星载荷舱与本体舱结构非接触,理论上完全隔离振动。围绕该零刚度卫星两舱非接触引发的姿态控制难题,综合滑模控制强抗干扰能力和动态逆控制形式简明的特点,提出了鲁棒复合控制律,可弥补滑模控制律等效控制过于繁琐和动态逆控制器鲁棒性的不足,并证明了在该控制器作用下不确定动态系统的闭环稳定性。建立了载荷舱和本体舱的动力学与运动学模型,基于两舱相对动力学和运动学关系的分析,设计了载荷舱高精度高稳姿态控制和本体舱精确跟踪姿态控制律,证明了复合控制律的有效性。仿真结果表明:该零刚度卫星能实现较高的姿态控制精度,验证了所提算法的可行性及潜在的应用价值。

A zero stiffness ultra-quiet satellite based on voice-coil Stewart vibration isolation platform and its attitude control problem were studied to deal with the disturbance and vibration transformation from the satellite body platform to the high accuracy payload in this paper. Utilizing the characteristic of the structure gap of the voic^coil actuctor induced by the electromagnetism force, the payload module and body mudule of the satellite were mechanismly urrconnected and the vibrations could be theoreticaly complete isolated. Aiming at the attitude control problems caused by the mechanismly urrconnection of the two mudules of the zero stiffness satellite？ the robust complex control algorithm was proposed, which synthesized the disturbance rejection performance of sliding mode control and the simple controller form of dynamic inverse control and compsenated the disadvantages of too frequent equivalent control of sliding mode law and robustness lacknees of dynamic inversion control. The stability of the closed-loop system of uncetain dynamic system was proved under this controller. The dynamic and kinematic models of the payload module and body mudule were established. Based on the analysis of relative of dynamic and kinematic relationship between the two modules, the attitude control law of payload module with high accuracy and stability and the attitude tracking law of body module with high accuracy were designed. The effectiveness of the complex control law was demonstrated based on Lyapunov theory. The simulation results showed that high accuracy attitute control of the zero stiffness satellite was achieved, and the feasibility and potential application value of the proposedscheme was illustrated.