The positioning accuracy reliability analysis of calibrated robot considering the effect of measurement uncertain factors

The positioning accuracy reliability (PAR) of industrial robots significantly influences operational efficiency, production safety, and product quality. To understand the impact of various measurement factors on PAR, an MDH model is constructed, and a corresponding axis measurement method is proposed to obtain the robot's geometric parameters. The single-point and multi-point PAR of the calibrated robot are subsequently analysed, and relevant formulas are derived. Factors affecting the reliability of geometric parameter calibration are examined, and MCS Method is employed to assess the PAR of serial industrial robots. Under multiple uncertainty scenarios, the Staubli TX60 robot is measured and calibrated using a Leica AT960 laser tracker. Experimental results reveal when accuracy threshold is set at 0.3 mm, the positioning reliability across 50 points influenced by joint motion step reaches 0.9884, while the reliability affected by the joint motion range decreases to 0.5326. These findings indicate that measurement uncertainties significantly affect the positioning accuracy of calibrated robots. For applications with high-precision requirements, it is essential not only to perform calibration but also to select the most appropriate calibration strategy to minimize the influence of measurement uncertainty.