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半闭环双边控制系统研究

Research on Half Closed Loop Bilateral Control System

【作者】 李锋

【导师】 韦庆;

【作者基本信息】 国防科学技术大学 , 控制科学与工程, 2009, 硕士

【摘要】 随着空间探索的深入,遥操作技术的应用将会越来越广泛。双边控制是一种很重要的遥操作方式,它能应用于非结构化且未知的从端环境。在时延力反馈双边控制系统中,根据主端操作者获取反馈力的方式的不同,将双边控制区分为全闭环方式和半闭环方式。本文针对空间在轨监测任务需求,采用半闭环方式构建力反馈双边控制系统。在前人的研究中,时延力反馈双边控制系统的性能指标被概括为稳定性、透明性和跟踪性。由于透明性和跟踪性是借用电路理论中的阻抗概念定义的,缺乏直观性,定量度量也比较困难,因此提出一种新的性能指标——相位差指标,其特点是容易理解,简单实用。通过仿真实验,验证了相位差指标的实用性。在新的性能指标的框架下,对时延力反馈双边控制系统进行研究。建立了半闭环力反馈双边控制系统模型,基于Lyapunov稳定性得到保证系统稳定的参数约束方程,设计了双边控制器,分别在单边时延0.5、1.5、3、5秒时进行了仿真实验,运用相位差指标分析了实验结果,得到系统时延对系统性能的影响规律,为大时延情况下的双边控制器设计提供了指导。在保证系统稳定的基础上进一步研究系统的操作性能。分析了系统输入频率、系统时延以及相位差之间的相互关系。研究了系统输入频率对系统性能的影响规律,找出了合理的输入频率限定,用来指导操作员的操作;研究了系统时延对系统性能的影响规律,由此就可以在系统时延未知的情况下,通过相位差推导出当前的系统时延;研究了系统时延与输入频率的相互关系,在系统时延增大的情况下,输入频率必须降低,才能保证相位差指标良好,系统操作性能良好。搭建了半实物仿真实验系统,分别在系统单边时延为1、3、5秒的情况下进行实验,验证了所设计的双边PD控制器的稳定性。通过分析不同时延下的实验曲线,验证了系统时延变化对相位差指标的影响规律。针对工程实践中遇到的时延跳变情况,由程序模拟时延跳变过程,实验结果表明在时延由1秒跳变为3秒时,双边控制系统保持稳定,操作性能良好。

【Abstract】 With the development of space exploration, teleoperation technology will be used more and more widely. Bilateral control, which can apply in non-structure, unknown environment, is a very important method of teleoperation. In the system of bilateral control with force feedback and time delay, according to the difference of obtaining feedback force by operator, the bilateral control method can be divided into half closed loop and closed loop mode. In this paper, aiming at the mission requirements of space-orbit monitoring, we construct the system of bilateral control with force feedback adopting half closed loop method.Based on previous research, the performance index of the system of bilateral control with force feedback and time delay can be summarized as stability, transparency and tracking. Due to using the impedance of circuit theory to define transparency and tracking, it lacks of intuition and is difficult to measure, thus we propose a new kind of performance index - phase difference, which is easy to comprehend and simple to use. The practicability of the phase difference was validated by simulation experiment.Under the frame of the new performance index, we research on the system of bilateral control with force feedback and time delay.A model of bilateral control system of half closed loop is built up. The parameter constraint equations are obtained based on Lyapunov stability. Bilateral controllers are designed for simulation experiment with time delay of 0.5, 1.5, 3 and 5 seconds. The result of the experiment is analyzed with the index of phase difference, finds the rule by which the time delay affects the system performance, and provides guidelines for design of bilateral control system with large time delay.More study of the manipulation performance of the system is made with the assurance of stability of the system. The connection between the input frequency of the system and the index of phase difference is analyzed. As well as the connection between the time delay of the system and the index of phase difference. The rule by which the input frequency affects the system performance is analyzed. And a limitation of input frequency is obtained for directing the manipulator’s movement. The rule by which the time delay affects the system performance is analyzed, and based on the rule the unknown time delay of the system can be deduced from the phase difference. The connection between the time delay and the input frequency is studied, and find that the input frequency of the system must be decreased when the time delay of the system is increasing. Otherwise, the index of phase difference will be increasing, and the system performance of manipulation will be getting bad.We build a semi-simulation semi-practicality experiment system, do the experiment with 1, 3, 5 seconds unilateral delay respectively, validate the stability of the bilateral PD controller that we designed. By the analysis of the experiment curves under different time delay, validate the impact rule of the phase difference along with the variational time delay. For the variable time delay in engineering practice, simulating the time delay jump by the program, experiment results show that while the time delay from 1 second jump to 3 seconds, the bilateral control system is stable, in good working order.

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