绳索驱动踝关节康复机器人的变刚度特性

Research on Variable Stiffness of a Cable-Driven Ankle Rehabilitation Robot

人口老龄化和心脑血管疾病年轻化导致踝关节运动功能障碍患者人数日益增多,给社会和家庭带来了沉重压力。为了减轻康复理疗师的工作强度,提高康复效率,文中提出一种新型绳索驱动踝关节康复机器人,辅助理疗师对患者进行康复训练,它具有人机结构匹配度高,刚度可变,安全柔顺等特点。基于指数积公.式与封闭向量环方法,对踝关节康复机器人的执行机构进行了运动学分析,建立了绳索长度与末端执行器位姿之间的关系,以及绳索收放速度与末端执行器运动速度之间的关系。同时,文中对踝关节康复机器人进行了机构整体刚度建模与分析,在绳索驱动系统中加入了变刚度装置,并对变刚度装置进行了设计与优化,以提高踝关节康复机器人的刚度变化范围。最后,文中通过多组数值仿真实验分别对机器人运动学和刚度进行了仿真模拟,检验机器人的运动性能与变刚度特性。

As the aging of the population and the cardio-cerebrovascular diseases deepen,patients with ankle dyskinesia increase,which brings heavy burden on society and family.In order to reduce the workload of physical therapists,a novel cable-driven ankle rehabilitation robot is designed in this paper to assist physical therapists in rehabilitation training for the patients,with the characteristics of human-robot matching structure,variable stiffness,safety and flexibility.Based on the product of exponential formula and closing-vector-circle method,the kinematics analysis of the end effector of the ankle rehabilitation robot is carried out.The relationship between the cable length and the pose of the end effector,and the relationship between the cable retracting speed and the speed of the end effector are studied.Meanwhile,the sifness of the ankle rehabiltation robot is modeled and analyzed.In order to improve the stiffness variation range of the ankle rehabilitation robot,a variable-stiffness device is designed and added into the cable-driven system.Typical simulation examples are presented to examine the results of kinematics and stiffness modeling and analysis.