Single joint module angle error analysis and modelling of self-driving articulated arm coordinate measuring machine

Abstract

The self-driving articulated arm coordinate measuring machine (AACMM) is a new type of flexible coordinate measuring equipment. The integrated joint module is introduced to the AACMM joint for self-driving control and measurement. The error source of the joint angle of the self-driving AACMM is analysed based on the internal components of the joint module, and single and comprehensive models of the single-joint module angle error are established. Numerical simulation and calibration experiment of torsion deformation angle error model of the single joint module are carried out. Results show that the angle error of each joint module includes the joint torsion deformation error, the angle error of the harmonic reducer, the angle measurement error of the magnetic encoder, and the error of the servo motor control system. The simulation error of the joint rotation angle shows a cosine variation trend under different loads, and the error fluctuation range is positively correlated with the load. The joint rotation angle calibration error shows a periodic variation, and the overall error fluctuation range is [-80.7 arcsec, 61.31arcsec]. The analysis and modelling calibration of the angle error of the AACMM single joint module offer an important theoretical foundation for the further research of the AACMM joint angle error compensation to improve the positioning and measurement accuracy of the measuring machine.