Accuracy traceability method based on precision coordinate control network for workshop measurement positioning system
First Claim
1. An accuracy traceability method based on precision coordinate control network for wMPS(workshop Measurement Positioning System), comprising the following steps:
- Step 1;
providing N SMR nests and M stations in the measurement space and arranging a laser tracker (201) in station 1;
Step 2;
arranging an SMR (202) on SMR nest 1 to form a global control point 1, measuring 3-d coordinates of global control point 1, and by the same manner, moving the SMR(202) to SMR 2, SMR 3 . . . until SMR N−
1 and SMR N respectively to measure the 3-d coordinates of global control point 2, global control point 3 . . . until global control point N−
1 and global control point N;
Step 3;
arranging the laser tracker (201) on station 2, station 3 . . . until station M−
1 and station M in sequence, and repeating the step 2 after each time the laser tracker (201) is moved, thus obtaining measurements for all the global control points via all the stations and in the step 2 and step 3, the laser tracker (201) must measure at least 3 global control points at each station;
Step 4;
calculating the positions (locations and orientations) of stations according to the 3-d coordinates of all global control points at all stations, thus obtaining initial iteration values of 3-d coordinates of all the stations and global control points;
Step 5;
using the range value from station to global control point measured by the laser tracker (201) as a constraint to establish optimization goal equation for adjustment calculation;
by using the dynamic weighting method, tracing the measurement accuracy of 3-d coordinates of global control points to that of the interferometer range measurement of the laser tracker (201), thus establishing the precision coordinate control network;
wherein the detailed steps of establishing the precision coordinate control network comprise;
Step 5-1;
according to the 3-d coordinates of global control points in individual station coordinates, calculating the range value rij of the laser tracker;
wherein, i represents the ith station, i=1,2, . . . , M;
j represents the jth global control point, j=1,2, . . . , N;
Step 5-2;
taking the coordinates of station 1 as the global coordinates to calibrate each stations, and calculating the 3-d coordinates of global control points (xj0 yj0 zj0) and station (xi0 yi0 zi0) of the laser tracker in global coordinates, which are taken as the initial values during the optimization process;
Establishing redundant range equations in global coordinates, the formula is expressed as follows;
lij=√
{square root over ((xj−
Xi)2+(yi−
Yi)2+(zj−
Zi)2)}
(1)Wherein, lij is range value, formula (1) is expanded by (xj0 yj0 zj0) and (Xi0 Yi0 Zi0) via first order Taylorseries expansion to obtain;
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Abstract
The present invention relates to an accuracy traceability method based on precision coordinates control network for workshop Measurement Positioning System, which includes the steps: setting a plurality of SMR (Spherically Mounted Retroreflector) nests and stations in the measurement space; forming a global control point by using SMR; measuring all the 3-d coordinates of global control points in all the laser tracker stations; using the range value measured by the laser tracker as constraints to calculate the 3-d coordinates of global control points by using the dynamic weighting method; arranging a plurality of transmitters and calibrating the transmitters in combination with precision coordinate control network; measuring all global control points and measured points simultaneously by using wMPS, and using the 3-d coordinates of global control points as the constraints for adjustment calculation to obtain the 3-d coordinates of the measured points. The present invention takes advantages of accurate range measurement of laser tracker as a constraint to achieve the followings: obtaining high accuracy 3-d coordinates of global control points, constructing precision coordinate control network and using it as the measurement standards of wMPS, achieving on-site accuracy traceability, and thus improving the measurement accuracy of wMPS.
11 Citations
3 Claims
-
1. An accuracy traceability method based on precision coordinate control network for wMPS(workshop Measurement Positioning System), comprising the following steps:
-
Step 1;
providing N SMR nests and M stations in the measurement space and arranging a laser tracker (201) in station 1;Step 2;
arranging an SMR (202) on SMR nest 1 to form a global control point 1, measuring 3-d coordinates of global control point 1, and by the same manner, moving the SMR(202) to SMR 2, SMR 3 . . . until SMR N−
1 and SMR N respectively to measure the 3-d coordinates of global control point 2, global control point 3 . . . until global control point N−
1 and global control point N;Step 3;
arranging the laser tracker (201) on station 2, station 3 . . . until station M−
1 and station M in sequence, and repeating the step 2 after each time the laser tracker (201) is moved, thus obtaining measurements for all the global control points via all the stations and in the step 2 and step 3, the laser tracker (201) must measure at least 3 global control points at each station;Step 4;
calculating the positions (locations and orientations) of stations according to the 3-d coordinates of all global control points at all stations, thus obtaining initial iteration values of 3-d coordinates of all the stations and global control points;Step 5;
using the range value from station to global control point measured by the laser tracker (201) as a constraint to establish optimization goal equation for adjustment calculation;
by using the dynamic weighting method, tracing the measurement accuracy of 3-d coordinates of global control points to that of the interferometer range measurement of the laser tracker (201), thus establishing the precision coordinate control network;
wherein the detailed steps of establishing the precision coordinate control network comprise;Step 5-1;
according to the 3-d coordinates of global control points in individual station coordinates, calculating the range value rij of the laser tracker;
wherein, i represents the ith station, i=1,2, . . . , M;
j represents the jth global control point, j=1,2, . . . , N;Step 5-2;
taking the coordinates of station 1 as the global coordinates to calibrate each stations, and calculating the 3-d coordinates of global control points (xj0 yj0 zj0) and station (xi0 yi0 zi0) of the laser tracker in global coordinates, which are taken as the initial values during the optimization process;Establishing redundant range equations in global coordinates, the formula is expressed as follows;
lij=√
{square root over ((xj−
Xi)2+(yi−
Yi)2+(zj−
Zi)2)}
(1)Wherein, lij is range value, formula (1) is expanded by (xj0 yj0 zj0) and (Xi0 Yi0 Zi0) via first order Taylorseries expansion to obtain; - View Dependent Claims (2, 3)
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Specification