低密频太阳能帆板动力学参数在轨辨识和振动控制

太阳能帆板是典型的柔性空间结构,其固有频率低且密集,阻尼很小。为了抑制其振动,建立了基于动力学参数辨识的振动控制方法。该方法利用特征系统实现算法及其扩展算法如ERA/DC或OKID辨识结构的动力学参数,然后利用最优控制理论设计控制器。根据辨识和控制的方法以及适用的情况,提出了三种在轨辨识和控制集成方案,即ERA(ERA/DC)和LQR或LQG,OKID和LQG。对一具有低密频大型柔性空间站结构的数值仿真表明,上述在轨辨识和控制集成方案具有辨识速度快,辨识精度高,控制效果好等优点,适于柔性空间结构的在轨辨识和控制。

ON-ORBIT IDENTIFICATION AND VIBRATION CONTROL FOR SOLAR ARRAYS WITH LOW AND CLOSE FREQUENCIES

Solar arrays are typical flexible space structure with low and closely spaced natural frequencies and light damping. In this paper, a method of vibration control based on dynamic parameter identification is established to suppress vibrations of space structures. The dynamic parameters are identified by Eigensystem Realization Algorithm (ERA) or its extentions such as ERA/DC and OKID algorithm. Then they are used to design the optimal controller for suppressing vibrations. In light of the requirements and the applicability of the identifying methods and the control laws, three integrated on-orbit identification and vibration control schemes, i.e. LQR, LQG integrated with ERA(ERA/DC) and LQG integrated with OKID, are proposed. Numerical simulations show that the dynamic parameters of a flexible spacecraft with low and closely spaced frequencies can be obtained in a short time with a high precision by using the ERA, ERA/DC or OKID algorithm, and both the optimal control laws LQR and LQG based on the identifying parameter model are very effective for suppressing vibrations of flexible solar arrays. Therefore, it can be tentatively concluded that the identification and vibration control integrated schemes are the appropriate method for on-orbit applications.