【作者】 王强；

【导师】 冯建鑫；

【作者基本信息】 南京航空航天大学 ， 导航、制导与控制， 2022， 硕士

【摘要】 基于超声电机驱动双光楔的激光通信系统由于具有低功耗、轻量化和紧凑型的优势,是低轨小卫星星座激光通信组网的理想选择。然而,由于目前传统双光楔反解算法的局限性和超声电机很强的非线性、时变性,使得双光楔系统应用于激光通信仍面临着指向精度不够高、定向角度范围较小、响应速度较慢等诸多难题,因此需要在高性能的工程应用上做进一步优化。本课题分别从光束指向模型、双光楔反解算法、超声电机高精度伺服控制系统三个领域进行研究,建立一套较为完备的基于双光楔装置的激光通信小型化系统。本课题的主要完成工作如下:首先,采用了一种基于等效矢量模型的双光楔反解算法,用于将目标点坐标解算成双光楔旋转角度。本文通过研究光楔折射特性建立光楔等效矢量模型,把单个旋转光楔简化成一个运动矢量,然后运用矢量叠加分析方法来解算出射光线的矢量坐标,并利用正演迭代的思想求解双光楔的转动角度,使得扫描点与目标点的误差不断缩小,达到提高精度、简化计算目的。仿真结果表明,等效矢量迭代反解算法能有效提高计算精度、降低计算时间,在高精度光束指向领域具有广泛的应用前景。其次,建立了基于模糊自整定PID控制器的超声电机伺服控制系统,用于驱动双光楔使其旋转到理论角度。本文利用系统辨识法得到超声电机传递函数模型,并针对其很强的非线性和时变性,设计了模糊自整定PID控制器,以此建立超声电机伺服控制系统。仿真结果表明,该控制器大幅减少了稳态误差,但依然存在动态性能不足、参数难以调节的问题。然后,针对模糊自整定PID控制器相关参数难以整定的问题,引入量子遗传算法对该控制器参数进行智能整定。本文选取4种函数进行测试,验证了量子遗传算法相较于经典算法而言在收敛速率与收敛精度上的优势,并针对传统量子遗传算法的局限性对其进行了五个方面的改进。在此基础上,利用该算法整定模糊自整定PID控制器的参数,达到进一步改善控制效果的目的。仿真结果表明,基于量子遗传算法的超声电机模糊自整定PID控制系统进一步降低了稳态误差、缩短了调节时间,满足激光通信高精度、实时性的要求。最后,设计并搭建了一套基于双光楔装置的激光通信小型化仿真系统,在此基础上完成了激光通信高精度跟瞄的仿真实验,验证了改进后模糊自整定PID控制器的控制性能,实现了扫描点对目标点的跟踪功能,证明了该仿真系统符合激光通信的性能指标要求。更多还原

【Abstract】 The laser communication system based on ultrasonic motor driven Risley Prime has the advantages of low power consumption,lightweight and compact,so it is an ideal choice for laser communication networking of LEO small satellite constellation.However,due to the limitations of the traditional inverse algorithm of Risley Prime and the strong nonlinearity and time-varying of ultrasonic motor,the application of Risley Prime system in laser communication still faces many problems,such as insufficient pointing accuracy,small orientation angle range,slow response speed and so on.Therefore,it is necessary to make further optimization in high-performance engineering applications.In this study,the beam pointing model,Risley Prime inverse solution algorithm and high precision servo control system of ultrasonic motor were studied,and a relatively complete miniaturized laser communication system based on Risley Prime device was established.The main work of this study was as follows:Firstly,an inverse algorithm of double wedge based on equivalent vector model was proposed,which was used to solve the target point coordinates into the rotation angle of Risley Prime.the equivalent vector model of optical wedge was established by studying the refraction characteristics of optical Risley Prime.A single rotating wedge was simplified as a motion vector,and then vector superposition analysis was used to calculate the vector coordinates of the outgoing light.The forward iteration method was used to solve the rotation angle of the Risley Prime,so that the error between the scanning point and the target point was reduced continuously,and the purpose of improving the accuracy and simplifying the calculation was achieved.Simulation results showed that the equivalent vector iterative inverse solution algorithm can effectively improve the calculation accuracy and reduce the calculation time.It has a wide application prospect in the field of high-precision beam pointing.Secondly,a servo control system of ultrasonic motor based on fuzzy self-tuning PID controller was established,which was used to drive the Risley Prime to rotate to the theoretical angle.the transfer function model of ultrasonic motor was obtained by system identification method,and a fuzzy self-tuning PID controller was designed for its strong nonlinearity and time-varying,so as to establish the servo control system of ultrasonic motor.Simulation results showed that the controller greatly reduces the steady-state error,but there are still some problems such as insufficient dynamic performance and difficult to adjust parameters.Then,in order to solve the problem that the parameters of fuzzy self-tuning PID controller are difficult to tune,quantum genetic algorithm is introduced to tune the parameters of the controller intelligently.four kinds of functions are selected for testing,and the advantages of quantum genetic algorithm in convergence rate and convergence accuracy were verified compared with classical algorithms.In view of the limitations of traditional quantum genetic algorithm,five improvements were made.On this basis,the algorithm was used to tune the parameters of fuzzy self-tuning PID controller to further improve the control effect.The simulation results showed that the fuzzy self-tuning PID control system of ultrasonic motor based on quantum genetic algorithm can further reduce the steady-state error and shorten the adjustment time,and meet the requirements of high precision and real-time in laser communication.Finally,a miniaturized simulation system of laser communication based on Risley Prime device was designed and built.On this basis,the simulation experiment of laser communication with high precision tracking and aiming was completed,which verified the control performance of the improved fuzzy self-tuning PID controller,realized the tracking function of scanning point to target point,and proved that the simulation system meets the performance requirements of laser communication.更多还原