Research On Calibration Method Of AACMM Based On Multi-functional Calibration Parts

Articulated arm coordinate measuring machine(AACMM)is widely used in the field of 3D measurement due to their large measurement space,easy on-site measurement,and simple operation.But limited by its serial open-chain structure,the error is amplified step by step,thus affecting the measurement accuracy of the measuring machine.Scholars at home and abroad have designed a variety of calibration parts to improve the measurement accuracy,and put forward different calibration methods based on the calibration parts.However,different calibration methods use different calibration parts,so it is impossible to compare the calibration methods to judge their pros and cons.In view of the above problems,this paper designs a new type of calibration part,conducts in-depth research on various calibration methods,improves and optimizes various calibration methods,and proposes a related calibration strategy based on the new calibration part,aiming to improve the calibration accuracy and accuracy of the measuring machine.Calibration efficiency.The main research contents of this paper include :(1)Aiming at the problem that the existing calibration methods cannot be compared,a multifunctional calibration part is designed in this paper.Firstly,the kinematics model of AACMM is constructed,and the structural parameters to be calibrated are analyzed.Then,according to the measuring space of the measuring machine,the structural size of the multi-function calibration piece is determined.Finally,the mechanical properties of the multi-functional calibration component are simulated and analyzed to prove its feasibility.(2)The feasibility of the multifunctional calibration device is verified by simulation and experiment.According to the sampling strategies of the traditional multi-point calibration method,length calibration method,virtual circle center calibration method and virtual circle center distance calibration method,the sampling strategies of different calibration methods based on multi-function calibration parts are obtained,and the traditional calibration method is optimized by the control variable method.,analyze the characteristics of different calibration methods,and get the applicable occasions of different calibration methods.(3)The calibration method is deeply studied through simulation and experiment.Firstly,the traditional calibration method is optimized,and the MU(Maximize Utilization)calibration method is proposed.By improving the objective function,the collection number of calibration points is reduced.Then,in view of the problem that the algorithm cannot be identified in the MU calibration method,the HMU(Hybrid Maximize Utilization)calibration method is proposed,which combines multiple calibration methods to reduce the requirements of the multi-functional calibration component for the calibration environment.Finally,the validity of the HMU calibration method is verified by experiments,and the calibration accuracy and calibration efficiency are improved.