Abstract: The in-situ machining operation of mobile milling robot is an effective way to solve the high-efficiency and high-precision manufacturing of large and complex components. Its positioning accuracy is an important technical indicator and has great significance for the final manufacturing quality. In order to solve the problems such as the limitation of multi data communication, the difficulty of compensation method and the lack of NC code function caused by the lack of openness and integration of the existing mobile robot controller, a method for improving the accuracy of NC-driven mobile milling robot was proposed. The NC-driven mobile milling robot system is researched, and the bus communication architecture is constructed to realize the control of 840Dsl NC-driven mobile robot. The closed-loop control principle of the robot joint grating and the grating pitch compensation method are proposed to realize the compensation of the self-weight and the external load of the mobile robot. A method of robot kinematic parameter identification based on geometric constraints and two-step error is proposed, which solves the alignment of the coordinate system and avoids the angular error from being drowned by the distance error. A high-precision positioning method for mobile robot based on spatial grid segmentation is proposed to achieve non-geometric error compensation. Through experimental design, comparison, and verification, the accuracy improvement method of the NC-driven mobile milling robot improves the positioning accuracy from millimetre level to 0.11 mm, which proves the validity and correctness of the above method and lays the foundation for the widespread application of mobile milling robots.

Key words: NC-driven, parameter identification, accuracy improvement, mobile milling robot, large and complex components