变刚度关节机构设计与变阻抗增益控制仿真研究

Simulation Study of Variable Stiffness Joint Mechanism Design and Variable Impedance Gain Control

摘要: 随着我国人口老龄化日益严重，脑卒中的发病人数也持续扩增，绝大部分幸存患者存在上肢运动功能障碍。传统的康复机器人采用刚性驱动，无法有效应对卒中患者康复训练过程中的痉挛与震颤，训练效果较差。本文针对康复机器人的康复训练的有效性与安全性，基于特殊曲面原理，采用凸轮–弹簧–滚子机构作为变刚度关节的刚度调节机构，并设计了一种双电机并联驱动的变刚度关节。其次，基于所设计关节的动力学模型研究其阻抗控制方法。然后基于人肘关节解剖学数据与Hill肌肉模型对肘关节主动力矩进行估计，并根据力矩估计值通过刚度调节电机对关节刚度进行预调节。最后，对变刚度关节的静态刚度特性进行实验验证，并在MATLAB中搭建了Simulink仿真模型，对其变刚度控制特性进行仿真实验。结果表明，研究设计的变刚度关节的变刚度特性良好，验证了变刚度控制器及运动阻抗控制器的有效性。

Abstract: With the increasingly serious aging population in China, the incidence of stroke continues to ex-pand, and most of the surviving patients have upper limb motor dysfunction. Traditional rehabili-tation robots with rigid drive cannot effectively deal with spasms and tremors during rehabilitation training of stroke patients, and the training effect is poor. Aiming at the effectiveness and safety of rehabilitation training of rehabilitation robot, this paper adopts cam-spring-roller mechanism as the stiffness adjusting mechanism of variable stiffness joint based on the principle of special curved surface, and designs a variable stiffness joint driven by double motors in parallel. Secondly, the im-pedance control method is studied based on the dynamic model of the designed joint. Then, the el-bow joint active torque was estimated based on the anatomical data of human elbow joint and the Hill muscle model, and the joint stiffness was pre-adjusted by the stiffness regulating motor ac-cording to the estimated torque. Finally, the static stiffness characteristics of the variable stiffness joint were verified by experiments, and a Simulink simulation model was built in MATLAB to simu-late the variable stiffness control characteristics. The results show that the variable stiffness of the joint designed in this study is good, and the effectiveness of the variable stiffness controller and the motion impedance controller is verified.