基于扩张状态观测器的快速步进/凝视成像机构控制

提出一种基于扩张状态观测器并引入加速度补偿策略的控制器设计方案,以实现快速步进/凝视成像机构对控制性能的高要求。首先,阐述了扩张状态观测器理论,对其特性进行了详细分析,并设计了以成像机构为被控对象的三阶线性扩张状态观测器。通过将观测器置于速度内环反馈通道,设计了基于扩张状态观测器的位置和速度双回路控制器。在此基础上,利用观测器输出的加速度估计值,提出加速度补偿策略,并设计了补偿环节。实验结果表明,与无加速度补偿环节相比,引入加速度补偿后,成像机构每次步进调节时间由76ms减小到33ms,凝视期间的角位置精度由约0.07°减小到0.01°以内,速度波动减小约2~3倍,成像机构的控制性能明显改善。控制器设计简单,需整定参数少,对于提高同类控制系统性能具有较高的实用价值。

Extended state observer based control of fast step/stare imaging mechanisms

An extended state observer (ESO) based controller with acceleration compensation strategy was proposed to satisfy the high requirements for control performance of fast step/stare imaging mechanisms. First, the theory of ESO was described and its characteristics were expatiated. Then, the third-order linear extended state observer (LESO) was designed with an imaging mechanism as the controlled object. By placing the observer in the feedback channel of the speed loop, a double loop controller of position and speed based on an ESO was designed. On this basis, an acceleration compensation strategy was proposed, and the compensating link was described using the estimated acceleration output by the observer. The experiment results showed that the settling time of the imaging mechanism was reduced at every step from 76 ms to 33 ms and the accuracy of the angular position during the period of stare decreased approximately 0.07°to 0.01°. In addition, the speed fluctuation was reduced by approximately two to three times compared with that without acceleration compensation. The control performance of the mechanism was significantly improved to meet high-performance requirements. The design process of the controller was simple and the adjusted parameters were less than that of traditional designs, which is of high practical value in terms of improving the performance of similar control systems.