An Error Compensation Method for Parallel Coordinate Measuring Machines Based on Kinematic Model and Kriging Interpolation

In precision manufacturing and automated inspection, the demand for online measurement of workpieces is continuously increasing in aerospace and equipment manufacturing industries. Because of the high speed and low accumulated error characteristics of parallel mechanisms, this paper proposes a 4-PUU parallel coordinate measuring machine (CMM) for in-line part measurement, and provides its error compensation methods. The position errors are classified into geometric and non-geometric errors. For geometric errors, an error model for geometric error identification is established, and an iterative method is employed for parameter identification. For non-geometric errors, a Kriging model is used for compensation based on the spatial similarity of errors. By combining geometric error modeling with spatial interpolation, an error compensation method for the 4-PUU parallel mechanism is proposed. After compensation, the positional accuracy of the mechanism is significantly improved. The robot’s average absolute positional error is reduced from 3.6905 mm to 0.0810 mm, a decrease of 97.81%. The experimental results show that the proposed method can improve the positional accuracy of the parallel CMM.