ACTIVE SHARE AND VIBRATION CONTROL OF FLEXIBLE SPACE STRUCTURES

1. 对柔性结构主动形状控制的形状测量、估计和控制方法进行了基础研究。主动形状控制的主要问题是通过多点空间分布的结构挠度测量来估计柔性结构的变形形状，并确定产生最小综合恢复误差的最优静态控制力。估计和控制设计基于无限维方法，在解决估计问题后引入必要的有限元截断和近似。所提出的估计和控制设计方法已应用于悬臂梁的筋形控制系统。数值模拟结果表明，恢复误差的大小在很大程度上取决于可用作动器的数量及其位置。研制了一种用于静态形状测量的光学遥感装置样机。光学传感系统的主要组成部分包括激光扫描仪和安装在实验结构上的后向反射器（角立方）。测量系统确定指向目标角立方的瞄准线矢量。由于激光在每个旋转周期内对所有角立方进行顺序扫描，因此该方法适合于短时间内的多点测量。在实验室中建立了原型激光扫描仪，并进行了测试，用于测量模拟结构偏转的目标角立方的位置平移。针对柔性空间结构的振动控制问题，提出了一种鲁棒特征结构赋值方法。该方法生成具有吸引力的增益矩阵，降低H^*范数，以实现对植物扰动和残差模式的鲁棒稳定性。通过数值模拟验证了所提设计方法的有效性。

1. Fundamental studies have been done for developing methods of shape measurement, estimation and control for active shape control of flexible structure. The major subjects of the active shape control consists of estimating the deformed shape of a flexible structure from multi-point spatially distributed measurement of the structural deflections and determining the optimal static control force that yields the minimum integrated restoration errors. The estimation and control designs are based on an infinite-dimensional approach that introduces the necessary finite element truncation and approximation after solving the estimation problem. The proposed estimation and control design methods have been applied to a tendon shape control system for a cantilevered beam. The results of numerical simulation show that the magnitude of the restoration errors largely depends on the number of available actuators and their locations.2. A prototype remote optical sensing device has been developed for the static shape measurement. The main component of the optical sensing system consists of a laser scanner and retro-reflectors (corner cubes) mounted to the experiment structure. The measurement system determines the line of sight vector pointing the target corner cube. Since the laser beams scan all the corner cubes sequentially in each rotation cycle, the proposed method is fitted to the multi-point measurement in short time. The prototype laser scanner has been built in the laboratory and tested for measuring the position translation of the target corner cubes that simulates the structural deflections.3. A method of robust eigenstructure assignment has been developed for the vibration control of flexible space structures. The proposed method generates attractive gain matrices which reduce the H^* norm to achieve the robust stability for plant perturbations and residual modes. The usefulness of the proposed design approach was validated through numerical simulations.