含冗余支链的二自由度微动平台运动学分析

Kinematic Analysis of A Two DOF Micro-positioning Platform with Redundant Loop

引入冗余支链设计微动平台,采用并联机构的构型原理分析了微动平台末端能够实现的输出运动特征,保证了引入冗余支链的同时不改变机构的运动学特性。在此基础上给出了中轴线对称布置和对角线对称布置的两种含冗余支链的微动平台结构形式,并采用矢量法分别建立了其运动学模型并给出了实例,分析结果表明对角线对称布置方案在两轴线方向上的驱动特性一致,而中轴线对称布置方案在两轴线方向上表现了非对称性,两种方案适用于不同的应用场合,结论为微动平台的实际选型和参数设计提供了理论基础。

Redundant sub-chains are introduced for micro-positioning platform design.In order to keep the kinematic characteristics unchanged while adopting redundant sub-chains,the end-effector kinematic characteristics of the micro-positioning platform are analyzed using parallel mechanism＇s type synthesis principle.Two typical types of the micro-positioning platforms,including the medial-axis-symmetry and diagonal-symmetry,are both presented based on the above analysis.Their kinematic models and numerical examples are also established using vector method.Results show that the motion characteristics are identical about x and y axes for the type of diagonal-symmetry,while for the type of medial-axis-symmetry the motion characteristics are different about x and y axes.These two types are fit for different application situations.These analytical results provide important foundations for actual type selection and parameter design of micro-positioning platform.