New Model-Based Method to Improve the Moving Performance of the Planar Near-Field Scanning Frame

A new model-based method is proposed to improve the moving performance of the planar near-field scanning frame. First, the geometric error model of the planar near-field scanning frame is established based on homogeneous coordinate transformation and multi-body system theory. Then, 21 underdetermined parameters in the geometric error model are derived by using the laser interferometer measurement system with unique light path and configurations. Based on the established error model, online error compensation in combination with structural optimization are proposed to reduce geometric errors efficiently. Finally, the proposed method is utilized to derive a novel planar near-field scanning frame. Scanning planeness in XY plane with z = 10 mm is calculated by using the Monte Carlo simulation method, results show that the calculated scanning planeness satisfies demands for the planar near-filed scanning frame, which validates the effectiveness of the proposed method.