高精度光电稳定平台采用两轴四环架的结构形式扩展其跟踪范围,但增加了环架间的耦合和系统的复杂度。提高稳定精度是控制系统设计的核心指标。以平台系统的动力学方程为基础,导出状态空间模型。针对内、外环架间的耦合特性,提出将内、外环架分系统作为多入多出对象进行多变量控制设计。采用H∞控制设计方法,根据平台系统对稳定性能和随动性能的不同要求综合控制器。仿真结果显示,与内、外环架系统单独设计的频域控制器相比,在随动精度满足要求的基础上,稳定精度显著提升;多变量H∞控制方法能够有效改善系统性能。
To extend target tracking range,the two-axis,four-gimbal configuration was used for high precision electro-optical stabilizing platform,which may cause coupling among gimbals and increase complexity of the system.The core objective of control system design was to improve the performance of stabilization.Based on dynamic equations of the platform system,state space model was derived.According to the coupling characteristic of inner and outer gimbal subsystem,it was proposed to regard the inner/outer subsystem as a multi-input,multi-output object for multivariable control system design.With H∞ design method employed,the controller was synthesized according to the demands of the platform system to stabilization and position servo performance.Simulation results showed that:1) compared with the frequency domain controller with independent design of inner and outer subsystem,the proposed method can improve the stabilization precision greatly while satisfying the servo precision demand;and 2) multivariable H∞ control method can improve the system performance effectively.