Analysis of 3-UPS/S Parallel Platform Vibration Responses under Hydraulic Servo Drives

Abstract

Abstract: Considering the vibration problems of parallel stabilized platforms in heavy loading, a 3-UPS/S parallel stabilized platform driven by hydraulic servo was studied. Based on the principles of virtual work, the dynamics model of the stabilized platform was established. Considering the actual working conditions, the dynamics model was simplified to obtain the vibration model of the stable platform. In order to improve the reliability of the calculation, experiments were carried out to obtain the actual stiffness of a single branch. Based on this, the stabilized platform modal tests were carried out by using pulse excitation method, the correctness of the vibration model was verified by comparing the measured values and theoretical values of natural frequencies. Finally, the influences of hydraulic cylinder vibrations on the movement of the moving platform and vibration responses of moving platform were analyzed under no-load and load. According to the analyses and calculations, the poor stability of the mechanisms is mainly caused by the vibrations of the hydraulic cylinders and the forced vibrations of the moving platforms under heavy loads.

Key words: parallel mechanism, hydraulic drive, vibration, stiffness

摘要： 考虑到并联稳定平台在重载情况下的振动问题，以液压伺服驱动3-UPS/S并联稳定平台为研究对象，基于虚功原理建立了稳定平台的动力学模型，并考虑实际工况，对动力学模型进行简化处理，得到了稳定平台的振动模型；为提高振动模型计算的可靠性，通过实验获得了机构的单分支实际刚度；在此基础上，采用脉冲激振法进行了稳定平台模态实验，对比固有频率实测值与理论计算值，验证了振动模型的正确性；最后分析了液压缸抖动对稳定平台运动的影响，以及空载和负载下稳定平台的振动响应，通过分析计算可知，机构的平稳性变差主要是由液压缸的抖动以及重载情况下稳定平台的受迫振动引起的。

关键词: 并联机构, 液压驱动, 振动, 刚度

CLC Number:

TH112

LI Yukun1,2;LI Yongquan1,2;WAN Yixin1,2;QIANG Hongbin2,3;ZHANG Lijie2,3. Analysis of 3-UPS/S Parallel Platform Vibration Responses under Hydraulic Servo Drives[J]. China Mechanical Engineering.

李玉昆1,2;李永泉1,2;万一心1,2;强红宾2,3;张立杰2,3. 液压伺服驱动3-UPS/S并联稳定平台振动响应分析[J]. 中国机械工程.

References

[1]ZHANG Lijie, GUO Fei, LI Yongquan, et al. Global Dynamic Modeling of Electro-Hydraulic 3-UPS/S Parallel Stabilized Platform by Bond Graph[J].Chinese Journal of Mechanical Engineering,2016,29(6):1176-1185.
[2]赵强,李洪人. 六自由度运动平台的振动分析与测试[J]. 机械强度,2006(增刊1):17-21.
ZHAO Qiang, LI Hongren. Vibration Analysis and Testing of 6-DOF Platform[J].Mechanical Strength, 2006(S1):17-21.
[3]李忠杰. 并联三自由度振动台优化设计与动态特性研究[D].秦皇岛：燕山大学,2015.
LI Zhongjie. Optimization Design and Dynamic Characteristics of 3-DOF Parallel Shaking Table[D]. Qinhuangdao: Yanshan University, 2015.
[4]BONEVI A, RYU J. A New Approach to Orientation Workspace Analysis of 6DOF Parallel Manipu-lators [J]. Mechanism & Machine Theory, 2001, 36(1):15-28.
[5]黄真.高等空间机构学[M]. 北京：高等教育出版社,2014：187-204.
HUANG Zhen. Advanced Spatial Mechanism[M]. Beijing：Higher Education Press, 2014：187-204.
[6]陈修龙,冯伟明,赵永生. 五自由度并联机器人机构动力学模型[J]. 农业机械学报,2013,44(1):236-243.
CHEN Xiulong，FENG Weiming，ZHAO Yongsheng. Dynamics Model of 5-DOF Parallel Robot Mechanism[J]. Journal of Agricultural Machiner,2013,44(1):236-243.
[7]马亚磊. 3-UPS/S样机性能分析及运动规划研究[D].秦皇岛：燕山大学, 2015.
MA Yalei. Performance Analysis and Motion Planning Research of 3-UPS/S Prototype [D]. Qinhuangdao: Yanshan University, 2015.
[8]殷祥超. 振动理论与测试技术[M]. 徐州：中国矿业大学出版社, 2007.
YIN Xiangchao. Vibration Theory and Testing Technology[M]. Xuzhou:China Mining University Press, 2007.
[9]彭启琮.数字信号处理[M]. 北京：高等教育出版社, 2017.
PENG Qicong. Digital Signal Processing[M]. Beijing：Higher Education Press, 2017.
[10]吕帮俊,彭利坤,杨国志. Gough-Stewart并联机构谐振频率特性实验研究[J]. 噪声与振动控制,2013(1):27-30.
LYU Bangjun, PENG Likun, YANG Guozhi. Experiment Study on Resonant Frequency Characteristics of Gough-Stewart Parallel Mechanism[J]. Noise and Vibration Control, 2013(1):27-30.

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