【作者】 孔德杰；

【导师】 戴明；

【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， 2013， 博士

【摘要】 机载光电平台是一种光、机、电高度集成的精密侦察设备，在火力控制、导航、侦察系统中有着广泛的应用。伺服系统作为光电精密跟踪技术中的一项核心技术，是机载光电平台保持较高视轴稳定精度的重要保证。伺服系统对扰动力矩的抑制能力是衡量机载光电平台伺服系统性能的重要标志，也是机载光电平台伺服系统研究的主要课题之一。本文主要研究内容是提高机载光电平台伺服系统的扰动力矩抑制能力，从而改善机载光电平台低速性能，达到提高机载光电平台视轴稳定精度的目的。本文以某型两轴四框架机载光电平台为研究对象，对两轴四框架机载光电平台各框架耦合进行了分析研究，指出平台各框架间的运动耦合和转动惯量耦合是由机载光电平台机械结构带来的，由运动耦合和转动惯量耦合产生的扰动力矩会对机载光电平台伺服系统性能产生影响，而转动惯量耦合还对控制对象的准确建模造成影响。机载光电平台正常工作时，处于频繁地起动、制动状态中，尤其是在长焦距跟踪目标时，一般工作于低速模式下，且受摩擦、风阻、载体晃动、线扰等所带来的扰动力矩影响，工作环境较为恶劣，对伺服系统动态性能要求很高，这就要求机载光电平台的伺服系统具有较强的动态抗扰性能。传统的机载光电平台伺服系统一般作为经典的单输入单输出系统（SISO），采用的是带有位置环、速度环、电流环的传统三闭环控制模式，控制律一般采用PI控制律。这就造成了伺服系统对扰动力矩抑制能力较弱，难以有效克服扰动力矩这一关键影响因素。这在机载光电平台工作在低速段时尤为明显，具体表现为机载光电平台视轴晃动量比较大，导致成像质量下降，甚至造成跟踪失败。在设计机载光电平台伺服系统时，需要把扰动转矩也看作输入，则伺服系统可以看作双输入（脱靶量和扰动力矩）单输出（脱靶量）系统（DISO）。充分考虑这一性质，本文设计机载光电平台伺服系统时，在伺服系统中引入了加速度反馈环节来提高机载光电平台的扰动力矩抑制能力，并改善机载光电平台的低速性能，进而提高机载光电平台视轴稳定精度。针对两轴四框架机载光电平台控制对象难以准确建模的问题，提出了对框架轴角加速度直接测量的方法,使加速度反馈闭环的实现不基于控制对象模型，从而避免了机载光电平台控制对象模型难以准确建立的问题。本文对机载光电平台伺服系统引入加速度反馈环节进行了原理性分析与研究，分析与研究结果表明在机载光电平台伺服系统中引入加速度反馈环节后增强了伺服系统的动态力矩刚度，提高了对扰动力矩的抑制能力，并改善了机载光电平台的低速性能。以某型两轴四框架机载光电平台为实验平台，对其伺服系统中引入加速度反馈环节进行了实验。实验结果表明，在机载光电平台伺服系统的经典PI控制律中引入加速度反馈环节后，机载光电平台低速性能得以明显改善；其伺服系统对0.3N·m突加扰动力矩抑制能力提高了约5dB；在载机仿真转台θ=sin4πt位置正弦运动时，其对运动耦合带来的周期性力矩扰动抑制能力提高了约14dB；在载机仿真转台做θ=sin2πt位置正弦运动时，其视轴稳定精度由48.39μrad提高到28.75μrad。更多还原

【Abstract】 Airborne Electro-Optical Platform (AEOP) is precision reconnaissanceequipment with highly integrated optical, mechanical and electrical, which has beenwidely used in the firepower control, navigation and reconnaissance system. As a coretechnology in the photoelectric precision tracking technology, servo system is theimportant guarantee of high precision optical axis stability to the airborneoptoelectronic platform. The ability of resisting disturbance torques is an importantsymbol to measure the performance of AEOP servo system, and is one of the maintopics of AEOP servo system. The main research contents of this paper is how toimprove the ability of AEOP servo system in resisting disturbance torque, in order toimprove the low speed performance of airborne photoelectric platform, to improvethe line of sight (LOS) stabilization accuracy of AEOP.In this paper, the object is AEOP with a two axis four framework, and eachframe of AEOP coupling were analyzed. This paper pointed out that the movementcoupling and inertia coupling between different frames are caused by mechanicalstructure of AEOP, are the cause of disturbance torques that affected the servo systemperformance of AEOP. And the inertia coupling also affects the accuracy of thecontrol object model. AEOP always is operated in frequent starting and braking state,especially tracked the target in the long focal length, generally work in low-speedmode, working environment is very bad because of the influence of friction,disturbance resistance, carrier sloshing and line disturbance brings, so high dynamicperformance is required,which requires AEOP servo system has strong dynamic anti- disturbance performance. Traditional servo system of AEOP as a classic Single-inputSingle-output system (SISO), is used with traditional three closed-loop control modethat includes position loop, velocity loop, current loop, and control law generally usethe Proportional Integral (PI) controller. This has resulted in ability of resistingdisturbance torques of servo control system is weak, difficult to effectively overcomedisturbance torques. It is particularly, such as LOS stabilization accuracy of AEOP isbad, degrade image quality and even cause tracking failure, when AEOP is operatedunder low speed,.In the design of AEOP servo system, the disturbance torque is seen as the input,the servo system is a Dual-input (Miss Distance and Disturbance Torques) Single-output (Miss Distance) system (DISO). So designing of AEOP servo system in thispaper, the acceleration feedback is introduced in the servo system to improve the lowspeed performance and the ability of resisting disturbance torques, and then improvethe AEOP stabilization accuracy. Because the control object model of AEOP with twoaxes and four frame is established difficultly, a method of direct measurement of shaftangular acceleration was adopted in this paper. So the acceleration feedback loop isnot based on the control object model, and the problem that the control object modelof the AEOP is difficult to establish was avoided.In this paper, the acceleration feedback introduced in the servo system of theAEOP is analyzed and researched, and analysis results show that the accelerationfeedback loop enhances dynamic stiffness of the servo system, improves the ability tosuppress disturbance moment in the servo system of the AEOP. The accelerationfeedback was put to test in the servo system of AEOP with two axis four framework.Experimental results show that, when the acceleration feedback loop was introducedin the classical PI control system, rejection disturbance torques ability of the servosystem raised about5dB on0.3N·m sudden disturbance torque; raised about14dB onposition sinusoidal motion at θ=sin4πtwith aircraft simulation turntable; and LOSstabilization accuracy was raised from48.39μrad to28.75μrad on position sinusoidalmotion at θ=sin2πtwith aircraft simulation turntable.更多还原