并联2-UPS/RRR踝关节康复机构及运动性能分析

Parallel 2-UPS/RRR Ankle Rehabilitation Mechanism and Kinematic Performance Analysis

为了帮助患者恢复踝关节运动能力,在分析现有踝关节康复机器人机构的基础上,提出了一种简单、实用的3自由度2-UPS/RRR并联机构.该机构约束支链与动平台的设计,保证了机构的旋转中心与不同患者的踝关节旋转中心重合.计算了自由度,并应用解析法给出了机构的运动学逆解,建立了速度雅可比矩阵,通过对驱动参数的限定,求解了满足训练要求的机构工作空间.最后基于雅可比矩阵,仿真分析了机构的运动学性能,结果表明在规定的工作空间内机构具有良好的可操作性、运动灵活性和刚度特性.而且机构采用非冗余电动机驱动,结构简单,有效避免了支链间不必要的干涉,减小了整个机构的占用体积,相比当前的踝关节康复机构更具优势.

In order to recover the motion ability of the patient’s ankle joint, a practical 3DoF （degree of freedom） 2-UPS/RRR parallel mechanism with simple structure is presented, based on the analysis on the mechanisms of existing robots for ankle rehabilitation. The mechanism center of rotation matches accurately with the center of rotation of each patient’s ankle, owing to the design of constraint branches and the moving platform in this paper. Inverse kinematics of the mechanism is solved using the analytical method by calculating the freedom of the mechanism, and thereby the velocity Jacobian matrix is established. Then, the workspace of the mechanism, which should meet all the training requirements, is solved by demarcating the driving parameters. Lastly, the kinematics performance of the mechanism is analyzed in simulation based on the Jacobian matrix. The results show that the mechanism is of favourable operability, flexibility and stiffness characteristics within the specified workspace. Moreover, the non-redundant electric motor is in simple structure, unnecessary interferences between the branches are effectively avoided, and the occupancy volume of the entire unit is distinctly reduced, which are superior to some existing ankle rehabilitation robots.