﻿ 电液负载模拟器摩擦参数辨识及补偿
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Friction parameter identification and compensation for electro-hydraulic load simulator
Guo Yanqing, Fu Yongling, Zhang Peng, Chen Juan
School of Mechanical Engineering and Automation, Beijing University of Aeronautics and Astronautics, Beijing 100191, China
Abstract:Due to the interference of friction while controlling the electro-hydraulic load simulator, a new model with the consideration of friction was presented. In this model, the test sample was simplified as retractable rigid rods and LuGre model was used to describe the friction. The friction coefficients of LuGre model could be identified based on two specific working conditions and the accuracy of coefficients can be verified by virtue of the corresponding identification data. In order to validate the feasibility of proposed model, the friction compensation controller was deduced on the basic of structural invariance principle. Then a large number of experiments including displacement servo, torque servo, redundant force et al, were carried out. Experimental results show the friction acting on load simulator can be eliminated with the employment of LuGre model and friction compensation controller.
Key words: electro-hydraulic load simulator     LuGre model     friction parameter identification     friction compensation     structure unchangeable principle

 Ki—电流放大器增益;Mf—马达转子摩擦力;θm—马达轴角位移;Kf—马达侧力矩传感器扭转刚度; θi—惯量盘转动角度;R—被试件连接处距传动主轴中心的距离;Kd—弹性负载和阻尼负载侧力矩传感器的扭转刚度; Kt—角度传感器扭转刚度；Bm—负载等效阻尼系数;Yx—试件相对长度变化量;θd—弹性负载侧的角位移. 图 1 电液负载模拟器结构图 Fig. 1 Structure of electro-hydraulic load simulator

 图 2 系统结构图 Fig. 2 System structure
2 摩擦力的精确描述及参数辨识

2.1 静力摩擦系数辨识

 图 3 LuGre静力参数辨识 Fig. 3 Identification of LuGre static parameter
2.2 动力摩擦系数识别

 图 4 LuGre动力参数识别 Fig. 4 Identification of LuGre dynamic parameter

 参数 单位 值 DM m3/rad 2.5×10-4 βe N/m2 6.9×108 Ki A/V 0.004 Kc+CtM m5/(N·s) 2.5×10-9 Kq m2/s 0.04444 Vt m2 9.0×10-5 Ksv m/A 3.75 Ts s 0.0075
4 实验分析

 设备名称 型号 作用 采集控制板卡 研华PCI 1716L 力矩信号采集、伺服阀控制 计数卡 研华PCI 1784 角度传感器读数 角度传感器 雷尼绍RESM圆光栅 角度测量 扭矩传感器 长城计量TS3500 力矩测量 伺服阀 303所3Q-40 驱动摆动马达 伺服阀驱动器 609厂MKZ801F.14 伺服阀驱动电路

 图 5 位移伺服摩擦补偿前控制曲线 Fig. 5 Displacement servo without friction compensation
 图 6 位移伺服摩擦补偿后控制曲线 Fig. 6 Displacement servo with friction compensation
 图 7 摩擦补偿前后位移伺服误差对比 Fig. 7 Servo displacement error comparison of the system without and with friction compensation

 图 8 力矩伺服摩擦补偿前控制曲线 Fig. 8 Torque servo without friction compensation
 图 9 力矩伺服摩擦补偿后控制曲线 Fig. 9 Torque servo with friction compensation

 图 10 力矩伺服摩擦补偿前后误差对比 Fig. 10 Servo torque error comparison of the system without and with friction compensation

 图 11 摩擦补偿在多余力消除时的效果 Fig. 11 Effect of surplus force elimination by friction compensation
5 结 论

1) 依据LuGre模型的特点,对模型进行简化处理,可分别辨识出模型的静力参数和动力参数.有效解决了LuGre模型参数不容易辨识的问题.通过辨识曲线可以看出所得出的辨识参数具有较高的准确性;

2) 通过分析和建立包含摩擦的系统模型,可为设计摩擦补偿控制器提供清晰的思路.在此基础上,利用结构不变性原理,可获得摩擦补偿具体控制模型和补偿流程;

3) 依据负载模拟器的任务,较全面地对摩擦补偿进行了实验验证,通过实验曲线,证明了摩擦补偿的有效性,可为类似应用提供一定的参考.

#### 文章信息

Guo Yanqing, Fu Yongling, Zhang Peng, Chen Juan

Friction parameter identification and compensation for electro-hydraulic load simulator

Journal of Beijing University of Aeronautics and Astronsutics, 2014, 40(9): 1256-1262.
http://dx.doi.org/10.13700/j.bh.1001-5965.2013.0604