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基于臂式机构的空间望远镜稳像控制研究
Research on Image Stabilization Control for the Space Telescope Based on the Arm Mechanism
【作者】 杨维帆;
【导师】 徐抒岩;
【作者基本信息】 中国科学院研究生院(长春光学精密机械与物理研究所) , 光学工程, 2014, 博士
【摘要】 空间望远镜在轨对目标凝视成像的过程中,平台或载体的轨道运动与姿态变化、其它外部扰动以及系统的控制偏差,都将导致望远镜的光轴指向与成像目标之间产生相对运动,即指向偏差和抖动,从而引起目标像的模糊,导致成像质量的下降。稳像控制的作用就是控制望远镜光轴指向,抑制各种因素对指向的干扰,实现望远镜对期望目标的精确指向和跟踪。借鉴目前国际上空间望远镜项目中以类似机械臂的机构作为望远镜一级稳像控制的新构想,本文以永磁同步电机(PMSM)直驱的臂式机构作为空间望远镜的稳像控制,围绕空间望远镜的高精度稳像控制技术,分析了影响稳像系统控制精度的主要因素,对基于臂式机构的稳像系统的运动学特性与稳定机理、单轴系统的动力学特性、抗干扰能力强的控制算法和控制策略等进行了深入的分析和探讨。对空间望远镜受平台或载体轨道运动与姿态变化的影响进行分析,给出了望远镜光轴的稳定方程。定义了在进行空间运动的分析时所涉及到的坐标系,分析了臂式机构在补偿外部干扰时的运动特性,建立了臂式机构逆运动学的数学模型,进行了相应的数学仿真分析;针对稳像控制系统惯性稳定的特点,进行了稳像系统的稳定机理分析,推导了基于陀螺稳定的稳像系统数学模型。以频域分析方法为基础,推导了单轴稳像控制系统的动力学方程,建立了单轴稳像控制系统的动力学模型。以此理论为基础,建立了稳像控制系统的角速度跟踪数学模型,在MATLAB/SIMULINK中搭建基于PI控制的稳像控制系统的速度跟踪仿真模型,得出了干扰项对控制系统性能的影响。针对系统轴系摩擦、电机齿槽力矩波动等控制系统内部扰动,在传统频域分析的基础上,提出了基于参考模型扰动观测器的扰动补偿控制方法和基于扩张状态观测器的控制方法,克服了系统内部摩擦和扰动力矩,提高了系统的控制精度。针对驱动电机在实际运行中的内部参数摄动问题,提出了基于自适应反步控制的速度跟踪策略,能够实现系统内部参数完全解耦,有效抑制了参数变化对系统动、静态的影响,实现了快速无超调响应,系统稳态精度高、速度响应平稳光滑,并具有很强的鲁棒性。在空间指向跟踪系统的原理样机中,分别对传统频率分析法中滞后校正、积分+超前校正、基于参考模型扰动观测器的积分+超前校正,以及基于扩张状态观测器的线性比例控制等控制方法进行了实验验证,对比几种控制方法的实验结果,对每个控制方法的控制性能进行了评价。
【Abstract】 During the staring and imaging process of Space Telescope, relative motionbetween imaging system’s optical axis and the objective target, caused by orbit’smotions and attitude’s change of the platform or carrier, external disturbance, anddeviation of control system, namely optical axis declination and jitter, caused theimage of the target blurred, leads to imaging quality declination. The role of imagingstabilization control is controlling the pointing of the telescope’s optical axis,depressing various disturbances to optical axis, realizing precise pointing andtracking to the expected target.Refer to the new idea which is using a similar mechanism like the robotic armas the image stabilization control of the telescope in the project of the internationalspace telescope at present, this dissertation using the arm mechanism which is driveddirectly by the permanent magnet synchronous motor (PMSM), focuses on the highaccuracy of the control technology, the main factors which imply control accuracy ofstabilizing system are analysed, the motive characteristic and the stable characteristicof the imaging stabilization system, the dynamic of the single-axis system and thecontrol algorithm and strategy which have the strong ability of anti disturbance areanalyzed and discussed.The factors impacting the control of image stabilization control system is analyzed, the motor characteristics (inverse model) of arm agency compensating forthe disturbance which is bring in by spacecraft attitude stabilization system isanalyzed, the mathematical model is established, and the mathematical simulationanalysis is implied. Meanwhile, for the image stabilization control system inertia andstability characteristics, stable mechanism of image analysis system is carried out,the image stabilization system mathematical model base on gyro-stabilized isdeduced, and the gyro installation under this condition is given.The kinetics model of single-axis image stabilization control system isestablished, and the kinetics equation is deduced, then the impact of the disturbancesof spacecraft on optic axis of telescope is obtained. Mathematical model of thewhole single-axis stable image control system is investigated, and its angular speedtracking model is attained. The model for speed tracking of stable image controlsystem with PI control is studied in MATLAB/SIMULINK, and the impact ofdisturbances on the performance of control system is analysed.On the reference model of the disturbance compensation control method and thecontrol method based on extended state observer, better to overcome the systeminternal friction and disturbing moment, improve the control precision of the system.In view of the drive motor internal parameter perturbation problem in actualoperation, put forward the step of adaptive steppingback control speed trackingstrategy, can realize completely decoupled internal system parameters, andeffectively restrain the influence of parameter change on the system dynamic andstatic, has realized the fast response, no overshoot high steady precision, speedsteady and smooth, make the system have strong robustness.Based on the principle prototype to tracking system of space optical imagingsystem, respectively, to the traditional frequency analysis method in lead correctionwith integral, lag correction, disturbance observer based on the reference model oflead correction with integral, and based on the extended state observation of linearcontrol methods, such as proportional control experimental verification, and theseveral control methods of the experimental results are analyzed, the control performance of each control method is evaluated.
【Key words】 Space Telescope; Image Stabilization Control; Dynamical Model; Disturbance Compensation; Observer; Adaptive Steppingback Control;
- 【网络出版投稿人】 中国科学院研究生院(长春光学精密机械与物理研究所) 【网络出版年期】2014年 09期
- 【分类号】TH743
- 【下载频次】238
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