Research On Error Analysis Of The Non-orthogonal Coordinate Measurement System

With the development of the advanced manufacturing that involves aerospace engineering,railway industry,large-scale mechanization and communication systems,the demand of large-volume metrology rockets.The measurement systems based on theodolite,total station and laser tracker are still prevalent.The common property of these systems is the three-axis orthogonal structure.Three axes are supposed to be perpendicular to each other and intersect with each other at one point.This strict requirement ensuring the measurement accuracy leads to the high cost of system design,manufacture,and maintaining.To feed the increasing demand of large-volume metrology,our group proposed a novel kind of coordinate measurement system named non-orthogonal coordinate measurement system whose sensor unit does not reply on the orthogonal structure to perform measurement.The cost of the system decreases in this case,but a problem also arises.The principles of traditional instruments and their error analysis models are no longer valid to the new one.Therefore,based on the previous researches on the non-orthogonal measurement system,this paper focuses on the system error analyses and uncertainty evaluation which is a key to the system developing process.The main contributions of this paper include:1.Estimated the main error sources of the sensor unit.The rotating angle error and the error of structure parameters are two main sources.The former one can be determined with polygonal prism and photoelectric autocollimator,and the later can be estimated using Monte Carlo method.2.Estimated the uncertainties of 200 simulated points in the non-orthogonal theodolite system simulation platform established by SolidWorks and MATLAB using Monte Carlo method.Given the result,the measurement uncertainty of the system could be estimated and the best working area can be determined.3.Analyzed the measurement error of the non-orthogonal total station system.The uncertainty of laser range finder is evaluated using GUM method,and the system measurement uncertainty is composed according to the measurement principle.4.Proposed a dynamical choosing method for the non-orthogonal total station system to choose system parameters dynamically during the measurement process.The effectiveness of this method is validated by a comparing experiment.