电液伺服摩擦加载技术的研究

发布时间：2018-04-03 08:43

  本文选题：摩擦加载　切入点：摩擦系数波动　出处：《哈尔滨工业大学》2016年硕士论文

【摘要】：本文所研究的电液伺服摩擦加载技术可以用在电液伺服负载力波形模拟以及碰撞加速度波形模拟等研究领域,具体比如航天返回舱的碰撞模拟,负载模拟器、台车碰撞模拟器等等。传统液压或电动负载模拟器是用驱动装置通过刚性连接直接给承载装置施加负载力,由于位置和力的耦合而产生多余力,多余力得不到完全消除导致其很难提高频宽和加载精度;传统意义上的碰撞模拟器,也就是对加速度波形的模拟,由于有需要超大流量阀和频宽低等问题,也很难达到理想的波形复现。本文所研究的摩擦力加载,中间环节用摩擦副代替了刚性连接,没有了力和位置的耦合,也因此没有了多余力问题,理论上可以拥有更优的加载性能。电液伺服摩擦加载技术是一个新的技术,这种技术也有只能进行与运动方向相反的力加载以及摩擦系数波动较大等缺点。本文首先对摩擦环节进行仿真研究,然后进行摩擦力加载系统线性、非线性模型数学建模,从而可以对系统关键参数展开线性分析,并据此综合液压系统伺服阀流量和机械系统的支撑架刚度进行综合交互设计。根据本文所设计的加载原理结合理论分析,进一步对摩擦力加载系统试验台进行设计与搭建。搭建好试验台,首先对摩擦力加载系统的子系统——夹紧力系统的控制特性展开研究。针对相位滞后的问题,分别提出用反馈——前馈综合控制器和提高机械刚度的软、硬件解决方法,并在实验中对相位滞后问题得到一定程度的改善。结合理论研究,进行实验验证和分析。首先对本系统的摩擦特性展开实验研究,分析各种摩擦材料的摩擦特性,并根据实验结果选择进一步实验所采用的摩擦材料。从夹紧力系统开始研究,初步掌握加载系统控制特性,最后对摩擦加载系统展开实验分析。摩擦系数的波动在摩擦力控制时体现出来,普通控制器,比如PID控制器很难适应这种波动。这是一种系统不确定性,据此设计了鲁棒控制器,分别用μ综合鲁棒控制器和H∞鲁棒控制器对系统进行控制分析,最后对实际系统进行系统辨识,根据辨识出来的传递函数设计鲁棒控制器,并进行了相关的实验分析。
[Abstract]:The electro-hydraulic servo friction loading technology studied in this paper can be used in the research fields of electro-hydraulic servo load waveform simulation and impact acceleration waveform simulation, such as the impact simulation of space return cabin, load simulator, etc.Car collision simulator and so on.The traditional hydraulic or electric load simulator uses the driving device to directly apply load force to the bearing device through rigid connection, which produces multiple Yu Li due to the coupling of position and force.It is very difficult to improve the bandwidth and loading accuracy due to the failure of eliminating the multiple Yu Li completely. The traditional impact simulator, that is, the simulation of acceleration waveforms, has some problems such as the need for super-large flow valves and low bandwidth.It is also difficult to achieve ideal waveform reproduction.In this paper friction loading is studied in which the friction pair is used to replace the rigid connection and there is no coupling between the force and the position. Therefore there is no more Yu Li problem and the better loading performance can be obtained theoretically.The electro-hydraulic servo friction loading technique is a new technique, which can only carry out force loading opposite to the direction of motion, and the friction coefficient fluctuates greatly.In this paper, first of all, the friction link is simulated, and then the linear and nonlinear models of friction loading system are established, so that the key parameters of the system can be analyzed linearly.According to this, the hydraulic servo valve flow and the support frame stiffness of the mechanical system are integrated and interactively designed.According to the loading principle designed in this paper and theoretical analysis, the friction loading system test-bed is further designed and built.The control characteristics of the clamping force system, the subsystem of the friction loading system, are studied in this paper.Aiming at the problem of phase lag, the software and hardware solutions to improve the mechanical stiffness by using feedback feedforward integrated controller are put forward, and the phase lag problem is improved to a certain extent in the experiment.Combined with theoretical research, experimental verification and analysis are carried out.Firstly, the friction characteristics of the system are studied experimentally, the friction characteristics of various friction materials are analyzed, and the friction materials used in further experiments are selected according to the experimental results.Starting with the study of clamping force system, the control characteristics of the loading system are preliminarily grasped. Finally, the experimental analysis of the friction loading system is carried out.The fluctuation of friction coefficient is reflected in friction force control, and it is difficult for ordinary controller, such as PID controller, to adapt to the fluctuation.This is a kind of system uncertainty. According to this, a robust controller is designed, and the control analysis of the system is carried out by using 渭 synthesis robust controller and H 鈭，

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