新型完全各向同性3T并联机构及其特性分析

Analysis of a Novel Fully-isotropy 3T Parallel Mechanism

针对并联机构耦合带来运动学分析与控制困难的问题,提出了一种新型完全各向同性的三维移动并联机构,该并联机构动平台和静平台之间由3条支链连接,3条支链的第一个移动副在空间中呈正交分布,使得该机构的动平台具有3个移动自由度,且输入输出一一对应。这种机构最突出的优点是运动副简单,三维移动解耦,运动学分析简单,便于该机构运动控制设计。采用螺旋理论分析了该机构的自由度及性质,确定了机构的主动副,给出了机构的位置和速度正反解,分析了机构工作空间及运动性能。根据机构输入输出关系,求得机构雅可比矩阵,验证了机构具有完全各向同性。研究结果对该机构的进一步应用具有理论指导意义。

To avoid the difficulties in the kinematics analysis and control brought by the existence of coupling in a PM,a novel kind of fully isotropic PM with three translational degrees of freedom was presented.This PM was connected by three limb chains between the moving platform and the fixed base.The first prismatic pairs of three limb chains were in orthogonal distribution,which made the moving platform of the mechanism have three translational degrees of freedom,and there existed a one-to-one correspondence between the input and output displacements.The mechanism＇s most prominent advantages are simple kinematic pairs,three translations decoupled,simple kinematics analysis and to facilitate the mechanism motion control design.Using screw theory the degree of freedom and properties were analyzed and the active pair of the mechanism was determined.It also gave out the mechanism＇s forward and inverse position and velocity analysis,workspace and movement performance.According to the relationship of input and output,Jacobi matrix was solved and fully isotropic of mechanism was verified.Thus it provides a theoretical guidance to the further applications,and also has good application prospects.