一种新型踝关节康复机器人的设计与控制

摘要

踝关节是人体下肢起关键作用的活动和负重关节,踝关节损伤的术后康复训练非常重要.本文设计了一种新型的基于3-RRR球面并联机构的踝关节辅助康复机器人,该装置的机构非常紧凑,具有球面转动特性,符合踝关节生理机构特性.本文完成了机器人机械结构设计,对机构进行了建模分析,推导了机构的运动学逆解.针对并联机构正运动学求解困难的问题,采用了迭代方法求得机构的正运动学数值解,并通过算例证明了算法的高效性.依据踝关节康复的不同阶段的需求,进一步探讨了机器人的不同控制模式,前期采用位置控制实现牵引运动训练,中后期则采用阻抗控制实现患者的肌肉力量训练,这种控制模式保证了机器人良好的柔顺性和交互安全性.%The human ankle plays an important role in maintaining motion functions and bearing large loads.The postoperative recovery is very vital for patients with ankle injuries.A novel ankle rehabilitation robot based on 3-RRR parallel mechanism is proposed in this paper.The mechanism is featured with spherical motion abilities,it is well compatible with the ankle structure.Mechanical design and system scenario is firstly discussed,then the 3-RRR spherical parallel mechanism is modeled.The inverse kinematics is studied using coordinate transformation matrices.An iterative algorithm is designed to solve the forward kinematics since that its analytical solution is difficult to acquire.Considering the different periods of ankle rehabilitation,two control modes are proposed.Position control scheme is applied to achieve motion training,while impedance control method is more effective in mid-late stages of rehabilitation for muscle strength recovery.The control system structure is well designed to guarantee good compliance and safety in human machine interaction.