Research On The Parameter Calibration Of The Articulated Arm Coordinate Measuring Machine

The accuracy of the measuring equipment affects the whole industrial production process directly.So it is very important to improve the measurement accuracy of the measuring instruments.The parameter calibration of the articulated arm coordinate measuring machine can effectively improve the measurement accuracy.At present,the traditional calibration method has the disadvantages of large amount of calculation,complex calibration process,special standard device and high cost.In view of the above problems,this paper presents a method of the two points symmetry for measuring the parameters of articulated arm coordinate measuring machine.The calibration method can simplify the calibration process and reduce the computation.This paper analyzed the measuring principle of the articulated arm coordinate measuring machine.The mathematical model was established and derived the kinematics equation.The working space was studied by the Monte Carlo method.The work space points were plotted,and the boundary points were extracted by using the method of local quadrant distribution.The parameters of the articulated arm coordinate measuring machine were calibrated by the two points symmetry method.A set of mechanical fixture was designed and the accuracy of the calibration results was verified.Through the calibration experiment of the articulated arm coordinate measuring machine,the parameters of arm length,bias and perpendicularity error are acquired.The kinematic model is modified by using these parameters.The relative error of measuring standard ball diameter is increased from 0.384% to 0.225% after the correction.So the measurement accuracy of the joint arm coordinate measuring machine is improved by calibration.