[Kinematics analysis and scale optimization of four degree of freedom generalized spherical parallel mechanism for ankle joint rehabilitation].

By analyzing the physiological structure and motion characteristics of human ankle joint, a four degree of freedom generalized spherical parallel mechanism is proposed to meet the needs of ankle rehabilitation. Using the spiral theory to analyze the motion characteristics of the mechanism and based on the method of describing the position with spherical coordinates and the posture with Euler Angle, the inverse solution of the closed vector equation of mechanism position is established. The workspace of mechanism is analyzed according to the constraint conditions of inverse solution. The workspace of the moving spherical center of the mechanism is used to match the movement space of the tibiotalar joint, and the workspace of the dynamic platform is used to match the movement space of subtalar joint. Genetic algorithm is used to optimize the key scale parameters of the mechanism. The results show that the workspace of the generalized spherical parallel mechanism can satisfy the actual movement space of human ankle joint rehabilitation. The results of this paper can provide theoretical basis and experimental reference for the design of ankle joint rehabilitation robot with high matching degree. 剖析人体踝关节生理结构及运动特性，提出一种四自由度广义球面并联机构来满足踝关节康复运动需求。采用螺旋理论分析机构运动特性，基于球坐标描述位置、欧拉角描述姿态的方法，建立机构位置逆解封闭矢量方程。根据逆解约束条件分析机构工作空间，以机构动球心工作空间匹配踝部胫距关节运动空间、动平台工作空间匹配踝部距下关节运动空间为目标，采用遗传算法对机构关键尺度参数进行优化设计。研究结果表明，该广义球面并联机构工作空间能够满足人体踝关节康复实际运动空间。通过本文研究结果，可为高匹配度踝关节康复机器人本体设计提供理论依据和实验参考。.