3-PPPS并联机翼调姿机构运动学标定

Kinematic calibration of 3-PPPS parallel wing posture adjustment mechanism

为解决一种3-PPPS并联机翼调姿机构因制造、装配过程中存在的误差因素所引起的调姿精度不高的问题,考虑了调姿系统结构误差因素对调姿机构位姿精度的影响。采用空间矢量链建立机翼部件调姿位移逆解方程,通过微分机构运动学方程,得到包含39项误差源的调姿机构位姿误差与几何误差之间的映射方程。利用激光跟踪仪测量调姿机构测量机翼参考点位置和定位器各轴的实际驱动量。通过最小二乘迭代法辨识出定位器结构误差,修正定位器反向驱动位移求解参数。经过运动学标定实验后,调姿平台的位置最大误差由2.68 mm降为0.82mm,角度最大误差由0.481°降为0.167°,从而验证了标定方法的有效性。

To solve the low precision of 3-PPPS parallel wing posture adjustment mechanism＇s pose due to the exist- ence of the error in the assembly and manufacturing process, the influence of posture adjustment system＇s structure error on pose accuracy was considered with parallel kinematics calibration method. The inverse solution equation of wing posture adjustment was established through space displacement vector chain. The mapping function between the geometric error and the posture error which contained 39 error sources was obtained with differential mechanism of kinematics equation. The laser tracker system was used to measure appearance frame measurement reference point position and actual displacements. The structure error was identified by iterative linear least squares, and the struc- tural parameters in inverse displacement equation were amended. After the kinematics calibration experiment, the maximum position error of parallel platform reduced from 2.68mm to 0.82mm, and the maximum angle error re- duced from 0. 481° to 0. 167°, thus the effectiveness was verified.