高精度高刚度六自由度调整机构的设计及分析

设计一种基于Stewart构型的具有高精度和高刚度的六自由度精密调整机构。首先,对调整机构进行构型设计并作了运动学分析;接着,建立了误差模型并对构型进行了精度分析,包括精度分配及模特卡洛模拟法验证;之后,根据理论分析结果,对调整机构进行结构设计,主要包括单足位移促动器的设计和偏置铰链的设计;最后,对调整机构进行了刚度分析。本文的分析结果为此六自由度调整机构的重复定位精度为X、Y向±2μm,Z向±0.54μm,R_x,R_y,R_z方向±6.13μrad,横向振动基频为104.3 Hz,轴向刚度为61.3 N/μm。分析结果显示此六自由度精密调整机构满足设计要求,验证了调整机构结构设计的合理性。

DESIGN AND THE ANALYSIS OF SIX-DEGREE-OF-FREEDOM ADJUSTING MECHANISM WITH HIGH ACCURACY AND STIFFNESS

A precision adjusting mechanism of six-degree-of-freedom(SDOF)based on Stewart structure with high accuracy and high stiffness is designed in this paper.Firstly,the configuration of adjusting mechanism was designed and the kinematics analysis was conducted;Then,the error model was established and the precision of the configuration of parallel platform was analyzed.After that,the structure of adjusting mechanism was designed according to the theoretical analysis results,including the single displacement actuator and the offset hinge;Finally,the stiffness of the adjusting mechanism was analyzed.This article obtaining the analysis results that the repeatability of the SDOF adjusting mechanism were ±2 m in X and Y direction,±0.54 m in Z direction,±6.13 rad in Rx,Ry,Rz direction,and the fundamental frequency of the transverse vibration was 104.3 Hz and the axial stiffness was 61.3 N/μm.The analysis results showed that the SDOF precision adjusting mechanism fulfilled the design requirements,and the rationality for structure design of adjustment mechanism was verified.