基于液压浮动支撑的全天时复杂工况下大口径主镜位置自稳定技术研究

Because of the large stiffness and damping property, hydraulic floating support technology is becoming the perfect choice for supporting primary mirror of large telescope. But there are still some preambles in practical application. For example, complex disturber, like pitching motion of telescope and wind load on mirror. And there is also a very hard problem to solve that the temperature-varying character of the hydraulic floating support system. These are the key problems that influent the position control effect of large mirror. In this study, the classification and distinguish method is used to relies the self stabilization control of primary mirror. The disturber is classified and studied. Different control method was formulated to deal with different class disturber. And the time-varying parameters of support system are identified. Using the temperature range partition with same character method is using to design the vary-parameter controller. The primary mirror of large telescope will be control always keep at the perfect position by using these methods. And the imaging quality of telescope will be well in all day along.

液压浮动支撑技术因为具有大刚度、高阻尼等优点成为大型望远镜主镜位置控制的优选支撑方法，但在实施中还面临一些技术挑战。例如：望远镜的俯仰运动和风载对主镜造成的复杂干扰，温度改变引起的系统参数变化等。这些问题是影响主镜位置控制效果的关键所在。本项目采用分类分别控制的策略实现主镜的自稳定控制。通过对干扰进行分类和特性研究来制定针对不同干扰的控制策略，达到消除主要干扰影响的效果。通过划分等特性温度区间，对系统时变参数进行辨识，并以此为基础设计了变参数的反馈控制器，来保证望远镜全天时的成像质量。

为了满足大口径望远镜镜面成像对主镜位置的高精度需求，课题开展期间针对大口径主镜液压支撑系统的自稳定控制方法的研究，内容包括理论和黑箱两种建模方法，单缸和多缸循序渐进的建模思路，以及基于线性扩张观测器和一阶动态滑模的控制方法，主镜位置控制器的设计和最终对该控制系统的仿真和试验验证。研证结果显示：在俯仰轴以1°/s的速度匀速运动情况下，每个支撑区域的跟踪误差最大值小于0.5 μm；在俯仰轴正弦引导情况下，跟踪误差最大值为1 μm，明显优于传统的比例积分控制的13 μm跟踪误差，满足大型望远镜主镜位置控制系统的设计要求，为大口径望远镜主镜位置控制系统设计提供了一定参考。