并联式下肢康复外骨骼运动学及工作空间分析

Kinematics and Workspace Analysis of Parallel Lower Limb Rehabilitation Exoskeleton

针对下肢瘫痪病人,设计一种新型的平面三自由度并联式下肢外骨骼机构进行研究,运用指数积公式对该机构的位置正反解进行研究分析,同时对该机构的雅可比矩阵和运动奇异性进行分析。以工作空间最大为目标函数,分析影响并联机构工作空间的主要因素,如连杆长度、运动副转角、人体关节角度等对工作空间的约束。采用边界搜索法确定工作空间边界,计算出相应形状的工作空间面积,分析各机构参数对工作空间的影响。在运动学分析的基础上,以满足人体正常行走时髋关节和膝关节运动范围要求,以提高机构运动学性能为目标,进行结构参数优化设计。初步分析结果表明,对机构参数进行优化,能提高运动学性能指标,该机构能够用于下肢瘫痪病人进行康复训练,为进一步并联机构的设计研究奠定了基础。

In view of the lower paralysis patients,a new type of 3-DOF parallel lower limb exoskeleton mechanism is designed as the foundation for research,the forward and inverse position solution of the mechanism are analyzed with product of exponentials（POE）formulation,in the meanwhile,the Jacobian matrix and motion singularity of mechanism are also analyzed.Taking the maximum workspace as the objective function,the chief factors influencing the workspace of the parallel mechanism such as the workspace restriction of the length of linkage,the angle of motion pair and the human body＇s joint angle have been taken into account.The boundary of workspace is determined with the help of boundary search method,and the area of workspace is calculated.The influence of various parameters of the mechanism on the workspace is analyzed.On the basis of kinematics analysis,in order to satisfy the demand of hip＇s angle and knee＇s angle range of motion of normal human walking,to improve the mechanism kinematic performance as the goal,optimize the value of structural parameters.Preliminary analysis shows that the kinematical performance can been improved with optimizing the value of the structural parameters.The mechanism can be used to lower limb paralysis patients in rehabilitation training.The study paves the way for the design and analysis of the parallel mechanisms.