Positioning accuracy improvement of a large parallel pose alignment mechanism based on comprehensive error analysis

PurposeThis study aims to improve the positioning accuracy of a large-scale parallel pose alignment mechanism by calibration and error compensation.Design/methodology/approachThe dynamic modelling of the parallel pose alignment mechanism is achieved using the Newton Euler method. Combined with a deformation compatibility analysis, the support force at the spherical hinge and the friction of the follow-up prismatic pair are calculated. The deformation of the moving platform in multi-pose space is analysed by the integral method, and a corresponding deformation model is established. Based on the calculated support force, friction and deformation, the deformation error is analysed. Combined with the calculated deformation error, kinematics calibration and positioning error compensation are carried out.FindingsThe simulation results show that the deviation of structural error identification is decreased from 3.03 x 10-1 mm to 6.8 x 10-2 mm. The experimental results show that the maximum pose errors after compensation are reduced from 2.77 mm to 6.5 x 10-1 degrees to 3.9 x 10-1 mm and 3.7 x 10-1 degrees, which verifies the effectiveness of the proposed method.Originality/valueThis method can be used in the field of aircraft assembly for the calibration and error compensation of a large-scale parallel pose alignment mechanism based on positioners.