并联构型装备几何参数可辨识性研究

INVESTIGATION INTO THE IDENTIFIABILITY OF GEOMETRICPARAMETERS OF PKM SYSTEMS USING A SUBSET OF POSE ERRORMEASUREMENTS

以6自由度并联构型装备为例,研究了基于误差子集检测信息的几何参数辨识问题。在数学上严格证明造成误差雅可比矩阵奇异的原因,并提出了一种基于最小误差子集检测信息的运动学标定方法。该方法仅需检测末端历经所有可能自由度时关于某一平面的平面度误差、在平动时关于该平面内任意直线的直线度误差以及在初始位形下的姿态误差便可辨识出系统的全部几何参数,具有经济、高效且适用于少自由度系统的特点。

The identifiability of geometric parameters of 6-DOF parallel kinematic machines is studied using a subset of pose error data. The vigorous mathematic proof is given to justify the deficiency of the identification matrix when the 'flatness' error data referenced to a single plane is only measured. The conclusions lead to a new approach for the identification of the entire set of geometric parameters using a minimum set of pose error measurements. This set includes the 'flatness' error of a fictitious plane generated by the endpoint sensor, the orientation error of the end-effector at the initial configuration, and the straightness and squareness errors along two orthogonal axes normal to the plane. This approach is so general and efficient that it can also be used for geometric parameter identification of the PKM systems with fewer than 6 degrees of freedom.