Research On Error Analysis And Self-calibration Method Of Articulated Arm Coordinate Measuring Machine

The Articulated Arm Coordinate Measuring Machine(AACMM)has the advantages of being portable,simple in operation,low in manufacturing cost and easy on-site use,has wide application in the field of geometric quantity detection.However,Subject to its series open chain structure,the accuracy of the AACMM is lower than that of the conventional orthogonal coordinate measuring machine.Kinematic calibration is an effective means of improving its accuracy.The thesis focuses on the calibration of the AACMM.The main research contents are as follows:Firstly,The mathematical model of the AACMM was established.The kinematics model of the AACMM was established,and the model was verified by the graphical simulation method.The AACMM error source was analyzed,and the relationship between various error sources and kinematic parameters was clearly defined.The analytical error model and position error model were established,and the equivalence between the analytical error model and the position error model was verified by numerical simulation.The correctness of the position error model was clarified.Secondly,The influence law of the kinematic parameter error of the AACMM on its measurement error is analyzed.The inverse kinematics solution of the AACMM under single-point measurement is solved by Newton's method.The scatter plot of the measurement error caused by the single kinematic parameter error is constructed,and the influence law of the kinematic parameter error on the measurement error of the measuring machine is analyzed.The distribution characteristics of the AACMM measurement space are analyzed and the position of the measuring point is planned.The distribution law and characteristics of the probe error are analyzed in the case of multiple measurement points,and the measurement area and the measurement configuration are preferably used to guide the operational use of the articulated coordinate measuring machine.Thirdly,The AACMM self-calibration method was studied.In order to solve the contradiction between search ability and convergence speed in Differential Evolution algorithm,a multi-point self-calibration method based on Differential Evolution-Simplex Method algorithm is proposed.In the process of differential evolution algorithm search,the simplex operator and the premature judgment link are added to achieve the convergence speed and search ability.The Observability index is introduced to evaluate the measurement configuration.The influence of the number of configuration and the number of measurement points on the calibration effect is studied by calibration simulation.Lastly,Self-calibration method experiment was carried out.A comparison experiment was performed between single point self-calibration method and multi-point self-calibration method.The experimental results show that the proposed multi-point self-calibration method is more advantageous.The feasibility is proved by experiments that the Observability index is used to evaluate the measurement configuration and then guide the AACMM calibration.