Research On On-site Calibration Method Of Articulated Arm Coordinate Measuring Machine Based On High Precision Machine Tool

Articulated arm coordinate measuring machine(AACMM)is a kind of instrument which is widely used in the inspection and measurement of parts in the industrial field.In structure,it is composed of multiple rotating joints and connecting rods in series.It looks like an Industrial mechanical arm,and has the characteristics of portable,simple operation and low manufacturing cost.In the process of industrial measurement,the measurement accuracy of AACMM depends on the on-site conditions to a certain extent.If the AACMM has problems in the detection,it is necessary to carry out the on-site calibration to ensure the measurement accuracy.Therefore,this paper studies the on-site calibration of AACMM and designs a set of on-site calibration of AACMM based on high precision machine tool.By using the high-precision positioning ability of on-site machine tools,various geometric reference quantities are provided for the calibration of articulated arm coordinate measuring,and the on-site application scope of the calibration method of measuring machine is expanded.The main research contents include:(1)Establishing kinematic model of AACMM.Based on the D-H matrix method,the kinematic model of AACMM was established,the error source of AACMM was analyzed,and the purpose and function of the structure parameter calibration were clarified.(2)Theoretical analysis of on-site calibration method of AACMM based on highprecision machine tool.Taking full advantage of the industrial on-site conditions,the high-precision machine tool is used as the high-precision positioning platform.Based on the Hammersley sequence method,a set of AACMM on-site calibration scheme is designed respectively for CNC horizontal lathe and CNC vertical milling machine.(3)Analysis of the influence of machine tool’s parameters on the calibration of AACMM.Based on the principle of the length calibration of AACMM,an objective function based on the length is established,and an IPDE calibration algorithm is proposed.On this basis,the influence of each axis stroke and positioning error on the calibration effect of AACMM was analyzed,and the applicability and feasibility of the calibration method were preliminarily determined by simulation.(4)On-site calibration experiment of AACMM based on high-precision machine tool.According to the simulation results,the model of the machine tool was selected,and the corresponding experimental scheme was designed.The length measurement accuracy of AACMM before and after calibration was compared based on ISO 10360-12 international standard,and the feasibility and effectiveness of the method studied in this paper were verified.This new idea could provide for the calibration of joint coordinate measuring machine in industrial on-site conditions.