六自由度电动平台电动缸附加运动误差量化分析

Quantization Analysis of Passive Spiral Increment Motion Error of Cylinder of 6-DOF Electric Motion Platform

六自由度电动平台通过六个电动缸的协调伸缩和旋转运动,结合上下铰链的两自由度转动,实现上平台在三维空间的六自由度运动。由于电动缸通过螺旋副实现缸杆的直线运动,其直线运动与旋转运动之间存在螺旋关系,因此缸杆相对于缸筒的被动转动会引起缸杆的附加直线运动,从而对六自由度电动平台的位姿精度产生影响。针对六自由度电动平台进行了运动学分析。在此基础上进一步计算了电动缸在平台运动过程中产生的被动螺旋附加运动,并对该运动引起的误差进行了量化分析。仿真结果表明,在六自由度电动平台运动过程中产生的被动螺旋附加运动误差达到毫米数量级,将会对平台的位姿精度产生显著影响。对于高精度运动平台来说,必须研究补偿算法对其进行补偿。

6-DOF electric motion platform can realize motion of 6 degrees of freedom in 3 dimensional space through linear motion and rotation of 6 cylinders coordinated with 2 degrees of freedom rotation of upper joints and lower joints.As for cylinder accomplishes linear motion through spiral pair,there is spiral relationship between the linear motion and rotation of the cylinder.So a passive rotation of the rod relative to the cylinder can produce increment linear motion,which can induce pose error of the 6-DOF electric motion platform.Analysis of kinematics of the 6-DOF electric motion platform is implemented.On the basis,Computation and further quantization analysis of the passive spiral increment motion of the electric cylinder during the motion of the 6-DOF electric motion platform is carried out.Simulation results show that error produced by the passive spiral increment motion of the electric cylinder can reach millimeter magnitude,which will cause significant influence to the motion platform.To the 6-DOF electric motion platform with high precision specification,it has to study a compensation algorithm to compensate the error.