液压伺服柔驱机构设计及其刚度连续可调分析

Design and stiffness continuously adjustable analysis of hydraulic servo flexible drive mechanism

为满足液压机械臂工作时输出高刚度,碰撞时变刚度实现柔顺性,让机器人在不同工作条件和场景下具有相应的柔顺性,设计了一种兼具阀控泄漏量和浮动位的液压伺服柔驱机构。首先,介绍该关节结构和变刚度原理;其次,利用Amesim建立其动态仿真模型,确定阀控泄漏量和浮动位半径范围;然后,利用MATLAB/Simulink建立其刚度仿真模型,分析单个因素与关节变刚度的关系;最后,基于MATLAB拟合关节刚度多元非线性回归方程,并通过程序实现刚度初始散点和拟合四维曲线对比图。仿真结果表明:在保证较好的动态特性时,该柔驱机构刚度能在较宽范围内连续可调。

In order that the hydraulic manipulator outputs high stiffness while working,and changes stiffness to realize compliance while collision,the robot has corresponding flexibility under different working conditions and scenarios.A hydraulic servo flexible drive mechanism with both valve-controlled leakage and floating position was designed.Stiffness was reduced by internal and external unloading,so the robot could improve the safety of man-machine physical contact.Firstly,the joint structure and the principle of variable stiffness were introduced.Then,the dynamic simulation model was established by AMESim.The ranges of the valve controlled leakage and the radius of floating leakage were determined,when the following characteristics and motion characteristics of the mechanism were good.Next,the stiffness simulation model was established by MATLAB/Simulink,stiffness scatter values under different working conditions were obtained by simulation.Then the relationship between the single factor and the variable stiffness of the joint was analyzed.Finally,the multivariate nonlinear regression equation of joint stiffness,about floating position,valve control leakage and volume,was fitted based on MATLAB.And the comparison diagram of the initial stiffness scatters and the fitting four-dimensional curve was realized by the program.The results show that the stiffness of the flexible drive mechanism can be adjusted continuously in a wide range while ensuring good dynamic characteristics.