Research On The Evaluation Method Of Measurement Uncertainty For WMPS

workshop Measuring and Positioning System(wMPS)is a new type of non-orthogonal coordinate measuring system.It has been widely used in the field of large scale measurement.Its measurement range can be extended and the measurement accuracy is high,which can meet the requirements of large-scale industrial measurement.But the wMPS is a time scanning measurement system based on time-space transformation.So it cannot directly get geometric measurement information in the system.So the evaluation for the measurement accuracy of wMPS is very difficult and still do not have an effective evaluation method.In this paper,the evaluation method of the measurement uncertainty of wMPS is studied and the measurement uncertainty is evaluated from two aspects,the angle measurement and the coordinate measurement.The main research contents are as follows:Firstly,by derivation of angle measuring model of wMPS and analysis of error sources,a method for evaluating the accuracy of angle measurement is studied.And the methods for evaluating the accuracy of horizontal angle and vertical angle measurement is designed respectively.And the horizontal angle measurement accuracy evaluation experimental platform is built by using a multi tooth indexing table as the reference for the precision of angle.The experimental results show that the uncertainty of angle measurement can reach 1.7 "(k = 1),and wMPS has high measurement precision.Secondly,according to the accuracy evaluation experiment of horizontal angle measurement,the error from experiment adjustment process and the precision of experimental apparatus is studied.The error model is deduced and the calculation is carried out by MATLAB simulation.According to the existing error,the accuracy of the experimental platform is evaluated comprehensively.And the validity of the evaluation method of uncertainty of horizontal angle measurement is verified.Finally,the measuring point error evaluation experiment is designed to evaluate the measurement results of wMPS directly.According to the design of the experiment,the control field is established and a laser tracker is used as traceability benchmark to complete the evaluation of the measuring point uncertainty.The experimental results show that the error of the measuring result is 0.34 mm(the measurement range is 8 m×5 m×2 m).Based on the measurement principle of wMPS,the relationship between the evaluation method of the uncertainty of the angle measurement and the evaluation method of uncertainty of the measuring point is analyzed,and the consistency of the results obtained by the two methods is verified.