大型天文光学望远镜机架驱动高阶滑模控制仿真

Higher Order Sliding Mode Simulation for Mount Driving of Large Optical Astronomical Telescopes

针对当代大型天文光学望远镜机架伺服系统动力学要求,提出高阶滑模控制的方法。在建立机架伺服系统状态空间模型的基础上,将传统滑模变结构控制中的滑模面拓展为高维(三维及以上)微分流形,使系统动态的不连续性仅存在于最高阶,从而有效地抑制传统滑模控制中易产生高频振动的现象。根据大型天文望远镜机架通常运行在角秒级超低速的特性,提出变参数切换律,进一步地提高机架系统的低速跟踪性能。仿真结果表明,用该方法设计的驱动伺服系统具有良好的抑制内外部干扰和跟踪给定信号的效果。满足当代大型望远镜机架伺服系统超低速位置跟踪的要求。

For the dynamic requirement of the mount driving servo system of the contemporary large optical astronomical telescopes, a control method of higher order sliding mode （HOSM） was suggested. By establishing a state space model for the mount driving servo system, the manifold in the conventional sliding mode control to the differential manifold with higher dimensions （greater than 3-D） was extended. This method holds the dynamic discontinuity of the system only in the highest order, which effectively inhibit the behaviour of chattering in high frequency that existed in the conventional sliding mode controls. Additionally, according to the characteristics that the mount driving in large telescope should work at an ultra-lower velocity, a kind of switching law with variable parameters was proposed to improve the trace ability of the mount under an extremely low velocity. The simulation results show that such driving servo system can effectively resist inside and outside disturbance signals and track input signals, which satisfies the requirements for the mount driving servo system in large astronomical telescopes that hizh orecision and ultra-lower velocity is badly needed.