Precision evaluation method for large-scale assembly tooling measurement field

Abstract

The present application belongs to the technical field of aircraft assembly, and particularly relates to a precision evaluation method for a large-scale assembly tooling measurement field. The method comprises: step S1, on the basis of a ranging precision parameter of a measurement device, calculating a ranging precision of a measured length at a station, and using the ranging precision as a ranging error; step S2, calculating an envelope coefficient on the basis of the ratio of the length of a through line of a measurement station envelope and the measured length at the station, and correcting the ranging error to obtain an envelope error; step S3, determining a continuity error on the basis of the maximum spacing between continuity reference points; step S4, determining a temperature change error on the basis of the maximum temperature difference in a measurement field and a material correction coefficient; step S5, determining a measurement error; and step S6, performing comparison with a given required tooling precision, and evaluating whether the measurement error meets a precision requirement for constructing the measurement field. The present application increases the precision of calculating an assembly tooling precision error in an aircraft assembly tooling measurement field.

Description

A large assembly tool measurement field accuracy evaluation method TECHNICAL FIELD

[0001] The application belongs to the technical field of aircraft assembly, and particularly relates to a large assembly tool measurement field accuracy evaluation method. BACKGROUND

[0002] The aircraft tooling is an important basis for aircraft product manufacturing, and according to the aviation manufacturing engineering manual, the national military standard, the aviation industry standard and the like, the tooling target accuracy is generally selected according to 1 / 3-1 / 5 of the aircraft product manufacturing accuracy, and the measurement field is a reference for the installation of the tooling positioning piece and the measurement of the aircraft product process, and the accuracy and stability design thereof is extremely important.

[0003] Since the 15 mu m+6ppm measurement accuracy of the laser tracker is the most precise and reliable among all large-size measurement devices, based on the matching of the device accuracy index and the tooling target accuracy, large-size tooling measurement mainly adopts the laser tracker. The large-size tooling measurement field design includes the processes of envelope design, continuity design, visibility design and stability design, wherein the proportion of the envelope design directly affecting the tooling measurement accuracy accounts for about 1 / 3, the continuity design affecting the tooling measurement accuracy accounts for about 1 / 7, and temperature, vibration, structure deformation and the like also have a great influence on the tooling measurement accuracy.

[0004] However, in the design process of the large assembly tooling, the measurement accuracy quantitative design has been in a fuzzy state, and the calculation process basically performs rough evaluation according to the factory ranging accuracy of the related measurement device, and the assembly tooling measurement field accuracy under the influence of multiple physical fields cannot be qualitatively and quantitatively explained, thereby causing the measurement field accuracy concept to be more and more fuzzy, and the related measurement system design software development is difficult to be carried out. SUMMARY

[0005] In order to solve the above technical problems, the application provides a large assembly tool measurement field accuracy evaluation method, mainly comprising:

[0006] Step S1, calculating the ranging accuracy under the station length measurement according to the ranging accuracy parameter of the measurement device, and taking it as the ranging error, wherein the station length measurement includes the global station length measurement and the local station length measurement, and correspondingly, the ranging error includes the global ranging error and the local ranging error;

[0007] Step S2, calculating the envelope coefficient according to the ratio relationship between the envelope body penetrating line length of the measurement station and the station length, and correcting the ranging error based on the envelope coefficient to obtain the envelope error, wherein the envelope coefficient includes the global envelope coefficient and the local envelope coefficient, and correspondingly, the envelope error includes the global envelope error and the local envelope error;

[0008] Step S3: Determine the continuity error based on the maximum spacing of the continuity reference points;

[0009] Step S4: Determine the temperature change error based on the maximum temperature difference in the measurement field and the material correction factor;

[0010] Step S5: Determine the measurement error based on the ranging error, envelope error, continuity error, and temperature change error. The measurement error includes global measurement error and local measurement error.

[0011] Step S6: Compare the measurement error with the given tooling accuracy requirements to assess whether the measurement error meets the accuracy requirements for the measurement field construction.

[0012] Preferably, in step S2, the maximum value of the line connecting the two boundary connection points within the envelope of the measurement station is selected as the length of the through line of the envelope of the measurement station.

[0013] Preferably, in step S2, the envelope coefficient ρ is calculated using the following formula. 包络 :

[0014] When L 贯穿线 ≥2L 站位 At that time, ρ 包络 =0;

[0015] When L 贯穿线 <2L 站位 At that time, ρ 包络 =(2L) 站位 -L 贯穿线 ) / (2L 站位 );

[0016] Among them, L 贯穿线 L is the length of the through line. 站位 Length measurement for the station.

[0017] Preferably, in step S3, the continuity error σ is calculated using the following formula. c σ c =0.0235*L e ;

[0018] Among them, L e This represents the maximum spacing between adjacent continuous reference points.

[0019] Preferably, in step S4, the temperature change error σ is calculated using the following formula. T σ T =(1-ρ3)*(T) max -T min )*α*L4 / 2;

[0020] Wherein, p3 is the material correction coefficient, a is the thermal expansion coefficient of the tool body structure material of the measurement field, L4 is the maximum value of the distance between any two tool measurement object points on the process equipment in the measurement field along the direction of the through line parallel to or perpendicular to the envelope, T max and T min are the maximum and minimum temperatures in each temperature measurement point of the measurement field, respectively.

[0021] Preferably, in step S4, the measurement field is arranged with four temperature measurement points at least at the four corners of the foundation.

[0022] Preferably, step S5 further comprises:

[0023] Step S51, determine the measurement accuracy coefficient p 测量精度 :

[0024] When σ 测距 ≥ σ 需求精度 , p 测量精度 = 0;

[0025] When σ 需求精度 > σ 测距 ≥ σ 需求精度 / 3, p 测量精度 = 3(σ 需求精度 - σ 测距 ) / (2σ 需求精度 );

[0026] When σ 测距 < σ 需求精度 / 3, p 测量精度 = 1;

[0027] Wherein, σ 需求精度 is the given tool requirement accuracy, and σ 测距 is the distance measurement error calculated in step S1;

[0028] Step S52, determine the global measurement positioning error σ a according to the following formula: σ a = (σ L 2 + σ t 2 + σ e1 2 + σ c 2 + σ T 2 + A 2 ) 1 / 2 + ((σ L + σ t + σ e1 + σ c + σ T + A) - (σL 2 +σ t 2 +σ e1 2 +σ c 2 +σ T 2 +A 2 ) 1 / 2 )*ρ 测量精度 ;

[0029] wherein, σ L is the global ranging error, σ t is the measuring device station transfer error, σ e1 is the global enveloping error, σ c is the continuity error, σ T is the temperature variation error, and A is the maximum amplitude of the external vibration source of the measuring field at the position of the workpiece in the measuring field;

[0030] The global measurement repeated positioning error σ a1 is determined according to the following formula: σ a1 = (σ L 2 +σ e1 2 +σ c 2 ) 1 / 2 +((σ L +σ e1 +σ c )-(σ L 2 +σ e1 2 +σ c 2 ) 1 / 2 )*ρ 测量精度 ;

[0031] The local measurement positioning error σ b is determined according to the following formula: σ b = (σ L1 2 +σ e2 2 +σ c 2 +σ T 2 ) 1 / 2 +((σ L1 +σ e2 +σ c +σ T )-(σ L1 2 +σ e22 +σ c 2 +σ T 2 ) 1 / 2 )*ρ 测量精度 ;

[0032] wherein, σ L1 is the local measurement error, σ e2 is the local enveloping error;

[0033] The local measurement repeatability error σ b1 is determined according to the following formula: b1 σ L1 2 +σ c 2 ) 1 / 2 +((σ L1 +σ c )-(σ L1 2 +σ c 2 ) 1 / 2 )*ρ 测量精度 .

[0034] Preferably, the step S52 further comprises:

[0035] When the length of the through line of the global measurement station position envelope is less than 5m, the measurement reference of A is the global coordinate system of the tooling, otherwise, the measurement reference of A is the main body skeleton structure closest to the tooling positioning point.

[0036] Preferably, the step S6 further comprises:

[0037] When the global measurement repeatability error σ a1 is less than or equal to the global required accuracy σ of the tooling, and when the local measurement repeatability error σ b1 is less than or equal to the local required accuracy σ0 of the tooling, the measurement error meets the measurement field construction accuracy requirement.

[0038] Preferably, the step S5 further comprises:

[0039] The step S53, determining the global maximum error σ a2 is: σ a2 = max(σ a1 , σ d , σ s );

[0040] The local maximum error σ b2 is determined as: σ b2 = max(σ b1 , σ d , A);

[0041] wherein σ d is the deformation of the foundation structure, σ s is the deformation of the tooling structure caused by non-load.

[0042] The application constructs an assembly tool precision error calculation method under the influence of multiple physical fields, distinguishes precision evaluation of global large-scale measurement and local small-scale measurement, and improves the calculation precision of the assembly tool precision error of the aircraft assembly tool measurement field. BRIEF DESCRIPTION OF DRAWINGS

[0043] Fig. 1 is a schematic diagram of the arrangement of each measurement point of a preferred embodiment of the large assembly tool measurement field precision evaluation method of the application.

[0044] wherein 1-process equipment; 2-enlarged reference point; 3-continuity reference point; 4-global measurement station; 5-local measurement station; 6-foundation; 7-tooling measurement object point; 8-temperature measurement point; 9-global measurement station envelope; 10-local measurement station envelope. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical scheme and advantages of the application clearer, the technical scheme in the embodiment of the application will be described in more detail below in combination with the drawings in the embodiment of the application. In the drawings, the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The described embodiments are part of the embodiments of the application, not all embodiments. The embodiments described below by reference to the drawings are exemplary and are intended to explain the application, and cannot be understood as limiting the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the application. The embodiments of the application will be described in detail below in combination with the drawings.

[0046] The application provides a large assembly tool measurement field precision evaluation method, which is suitable for the calculation and evaluation of the design precision of a large-size assembly tool high-precision measurement system exceeding 5m.

[0047] Referring to Fig. 1 firstly, the process equipment 1 is dispersed or integrally arranged on the foundation 6, the extended reference points 2 and the continuity reference points 3 are arranged on the foundation 6 or the process equipment 1 according to the measurement system enveloping and continuity principle, the global measurement station 4 is arranged above the ground according to the global measurement requirement related to the system measurement or integral measurement, the local measurement station 5 is arranged above the ground according to the local measurement requirement of the engine, landing gear and the like, the tool measurement object point 7 is arranged on the positioning structure of the process equipment 1, and the temperature measurement point 8 is arranged on the protruding position of the maximum planar four corners or the three-dimensional eight corner position of the process equipment 1 or the foundation 6. In Fig. 1, the four temperature measurement points T1-T4 are arranged outside the process equipment and are located at the four corner tip positions of the foundation 6.

[0048] The maximum outer contour is obtained according to all the extended reference points 2, the continuity reference points 3 and the tool measurement object points 7 associated with the global measurement station 4 in the measurement field, and the global measurement station envelope 9 is formed, and the maximum outer contour is obtained according to all the extended reference points 2, the continuity reference points 3 and the tool measurement object points 7 associated with the local measurement station 5, and the local measurement station envelope 10 is formed.

[0049] The large assembly tool measurement field precision evaluation method provided in the application mainly includes the following steps:

[0050] In step S1, the ranging accuracy under the station length is calculated according to the ranging accuracy parameter of the measurement equipment, and the ranging accuracy is taken as the ranging error, wherein the station length includes the global station length and the local station length, and correspondingly, the ranging error includes the global ranging error and the local ranging error.

[0051] In this step, the ranging accuracy parameter includes the ranging constant and the ranging coefficient, and the ranging accuracy formula is usually expressed as: ranging accuracy = ranging constant + ranging coefficient * ranging. Taking a certain type of laser tracker as an example, the ranging constant is 15 μm, the ranging coefficient is 6 μm, the global station length L = 14.4 m, and the local station length L1 = 5.9 m are taken as the ranging, the ranging accuracy calculated by the above formula is taken as the ranging error, and thus the global ranging error σ L = 15 μm + 6 μm * 14.4 = 0.101 mm, and the local ranging error σ L1 = 15 μm + 6 μm * 5.9 = 0.05 mm.

[0052] It should be noted that the unit of the global station length and the local station length is m, and the unit is not taken in the calculation, but only the value is taken under the unit.

[0053] For the global station length L and the local station length L1, as shown in FIG. 1, the global station length L is obtained according to the maximum distance value of all the extended reference points 2, continuity reference points 3 and tool measurement object points 7 in the global measurement station 4 and the global measurement station envelope 9, and the local station length L1 is obtained according to the maximum distance value of the extended reference points 2, continuity reference points 3 and tool measurement object points 7 in the local measurement station 5 and the local measurement station envelope 10. In this embodiment, the extended reference points 2, continuity reference points 3 and tool measurement object points 7 in the global measurement station 4 and the global measurement station envelope 9 are respectively connected, and the distance between the left one of the extended reference points 2 and the global measurement station 4 is the largest, which is taken as the global station length L, and the measurement result is L = 14.4 m. At the same time, the extended reference points 2, continuity reference points 3 and tool measurement object points 7 in the local measurement station 5 and the local measurement station envelope 10 are respectively connected, and the distance between the lower left corner of the tool measurement object point 7 and the local measurement station 5 is the largest, which is taken as the local station length L1, and the measurement result is L1 = 5.9 m.

[0054] In step S2, the envelope coefficient is calculated according to the ratio relationship between the through line length of the measurement station envelope and the station length, and the ranging error is corrected based on the envelope coefficient to obtain the envelope error. The envelope coefficient includes the global envelope coefficient and the local envelope coefficient, and correspondingly, the envelope error includes the global envelope error and the local envelope error.

[0055] In some optional embodiments, in step S2, the maximum value in the line connecting two boundary connection points in the measurement station envelope is selected as the through line length of the measurement station envelope. As shown in FIG. 1, the through line length L2 in the global measurement station envelope 9 is 29.3 m, and the through line length L3 in the local measurement station envelope 10 is 8.3 m.

[0056] In some optional embodiments, in step S2, the envelope coefficient ρ is calculated by the following formula 包络 :

[0057] When L 贯穿线 ≥ 2L 站位 , ρ 包络 = 0;

[0058] When L 贯穿线 < 2L 站位 , ρ 包络 = (2L 站位 -L 贯穿线 ) / (2L 站位 );

[0059] Wherein, L 贯穿线 is the through line length, and L站位 Length measurement at the station.

[0060] In this embodiment, the envelope coefficient ρ 包络 Including the global envelope coefficient ρ 全局包络 and local envelope coefficient ρ 局部包络 The corresponding calculated envelope error includes the global envelope error σ. e1 and local envelope error σ e2 Global envelope coefficient ρ 全局包络 The through-line used in the calculation is the through-line within the global measurement station envelope 9, with a length L2 = 29.3m. The station measurement length used is the global station measurement length L = 14.4m. Since L2 > 2L, the global envelope coefficient ρ 全局包络 If the value is 0, calculate the global envelope error σ. e1 =ρ 全局包络 *σ L =0 * 0.101 mm = 0. Correspondingly, the local envelope coefficient ρ 局部包络 The through-line used in the calculation is the through-line within the envelope 10 of the local measurement station, with a length L3 = 8.3m. The station measurement used is the local station measurement length L1 = 5.9m. Since L3 < 2L1, the local envelope coefficient ρ 局部包络 =(2L1-L3) / (2L1)=(2*5.9-8.3) / (2*5.9)=0.29, from which the local envelope error σ is calculated. e2 =ρ 局部包络 *σ L1 =0.29*0.05mm=0.0145mm.

[0061] Step S3: Determine the continuity error based on the maximum spacing of the continuity reference points.

[0062] This step is used to calculate the continuity error. In some optional embodiments, in step S3, the continuity error σ is calculated using the following formula. c σ c =0.0235*L e ;

[0063] Among them, L e This represents the maximum spacing between adjacent continuous reference points.

[0064] In this embodiment, as shown in Figure 1, the maximum spacing L in the continuity reference point 3 e =1.5m, therefore, σ c =0.0235*L e =0.0235×1.5=0.035mm.

[0065] Step S4: Determine the temperature change error based on the maximum temperature difference of the measurement field and the material correction coefficient.

[0066] This step is used to calculate the temperature variation error. In some optional embodiments, the temperature variation error σ is calculated in step S4 by the following formula T : σ T = (1 - p3) * (T max - T min ) * a * L4 / 2;

[0067] wherein p3 is a material correction coefficient, a is the thermal expansion coefficient of the tool body structure material of the measurement field, L4 is the maximum distance between any two tool measurement object points on the process equipment in the measurement field along the direction parallel or perpendicular to the through line of the envelope, T max and T min are the maximum and minimum temperatures of the temperature measurement points of the measurement field, respectively.

[0068] In some optional embodiments, the measurement field is provided with at least four temperature measurement points at the four corners of the foundation in step S4.

[0069] In this embodiment, the maximum envelope point temperature in the envelope range of the overall structure of the process equipment 1 and the foundation 6 in the same measurement period is measured and obtained, i.e. the temperatures T1 = 25.2℃, T2 = 25.8℃, T3 = 26.1℃, and T4 = 24.6℃ of the four corner temperature measurement points 8 of the detected tool in FIG. 1, so that T max - T min = 1.5℃. Before this, the thermal expansion coefficient of the tool body structure material can be obtained, and it is assumed that a = 1 x 10 -5 / ℃. The maximum distance L4 between the tool measurement object points is shown in FIG. 1, and the measurement result is L4 = 24.6m, and the unit needs to be converted to mm during calculation. The purpose of introducing the material correction coefficient p3 is mainly to adjust the interval specific value of the temperature variation error σ T according to the consistency of the tool structure, material and the assembled product. When the tool structure, material and the assembled product are completely consistent, the material correction coefficient p3 = 1, and the temperature variation error σ T is 0. Conversely, when the tool structure, material and the assembled product are completely inconsistent, p3 = 0. In this embodiment, it is assumed that the consistency of the tool structure, material and the assembled product estimated by the tool designer is about 80%, so that σ T = (1 - p3) * (T max - T min ) * a * L4 / 2 = (1 - 80%) * 1.5℃ * 1 x 10 -5 / ℃ * 24.6 * 10 3 / 2 = 0.036mm.

[0070] Step S5, determining the measurement error according to the ranging error, the enveloping error, the continuity error and the temperature change error, the measurement error including a global measurement error and a local measurement error.

[0071] This step S5 is used for synthetically calculating the measurement error including the global measurement error and the local measurement error according to the multiple parameters calculated above, the global measurement error being calculated using the global parameters including the global measurement precision coefficient, the global ranging error, the global enveloping error, etc., and the local measurement error being calculated using the local parameters including the local measurement precision coefficient, the local ranging error, the local enveloping error, etc.

[0072] In some optional embodiments, the step S5 further includes:

[0073] Step S51, determining the measurement precision coefficient ρ 测量精度 :

[0074] When σ 测距 ≥ σ 需求精度 , ρ 测量精度 = 0;

[0075] When σ 需求精度 > σ 测距 ≥ σ 需求精度 / 3, ρ 测量精度 = 3(σ 需求精度 - σ 测距 ) / (2σ 需求精度 );

[0076] When σ 测距 < σ 需求精度 / 3, ρ 测量精度 = 1;

[0077] Wherein, σ 需求精度 is the given tooling requirement precision, and σ 测距 is the ranging error calculated in step S1.

[0078] In this embodiment, in order to calculate the measurement error, the measurement precision coefficient ρ 测量精 度 As mentioned above, since the measurement error includes the global measurement error and the local measurement error, the measurement precision coefficient ρ 测量精度 here includes the global measurement precision coefficient ρ1 and the local measurement precision coefficient ρ2. The σ 测距 used for calculating the global measurement precision coefficient ρ1 is the global ranging error σ L , such as σ L = 0.101 mm given in step S1, and the σ 需求精度 is the tooling global requirement precision σ, which is assumed to be σ = 0.2 mm; the σ 测距The local ranging error σ L1 σ, as given in step S1 L1 =0.05mm, tooling required accuracy σ 需求精度 For the required local accuracy σ0 of the tooling, assume σ0 = 0.1mm. Substituting this into the formula in step S5, we can see that:

[0079] For the global measurement accuracy coefficient ρ1, since σ > σ L If ρ > σ / 3, then ρ1 = 3(σ - σ L ) / (2σ)=3*(0.2-0.101) / (2*0.2)=0.7425.

[0080] For the local measurement accuracy coefficient ρ2, since σ0>σ L1 If ρ > σ0 / 3, then ρ1 = 3(σ0 - σ L1 ) / (2σ0)=3*(0.1-0.05) / (2*0.1)=0.75.

[0081] Step S52: Determine the global measurement and positioning error σ according to the following formula. a σ a =(σ L 2 +σ t 2 +σ e1 2 +σ c 2 +σ T 2 +A 2 ) 1 / 2 +((σ L +σ t +σ e1 +σ c + σ T +A)-(σ L 2 +σ t 2 +σ e1 2 +σ c 2 +σ T 2 +A 2 ) 1 / 2 )*ρ 测量精度 ;

[0082] Where, σ L For the global ranging error, σ t For the measurement equipment transfer error, σ e1 For the global envelope error, σ c For continuous error, σ TA is the maximum amplitude of the vibration source outside the measurement field at the tool position in the measurement field.

[0083] In some optional embodiments, step S52 further comprises:

[0084] When the length of the through line of the global measurement station position envelope body is less than 5m, the measurement reference of A is the tool global coordinate system, otherwise, the measurement reference of A is the main body framework structure near the tool positioning point. In this embodiment, the length L2 of the through line of the global measurement station position envelope body is 29.3m>5m, so the measurement reference of the amplitude A is the main body framework structure near the tool positioning point.

[0085] In the formula, ρ 测量精度 Using the global measurement accuracy coefficient ρ1=0.7425, the amplitude A is measured as 0.06mm, and the values of other parameters have been given before, substituting the formula gives: σ a = (0.101 2 +0.02 2 +0 2 +0.035 2 +0.036 2 +0.06 2 ) 1 / 2 +((0.101+0.02+0+0.035+0.036+0.06)-(0.101 2 +0.02 2 +0 2 +0.035 2 +0.036 2 +0.06 2 ) 1 / 2 )*0.7425=0.22mm.

[0086] The global measurement repeatability error σ a1 is determined according to the following formula: σ a1 =(σ L 2 +σ e1 2 +σ c 2 ) 1 / 2 +((σ L +σ e1 +σ c )-(σ L 2 +σ e1 2 +σ c 2 ) 1 / 2 )*ρ 测量精度 .

[0087] In this formula, ρ 测量精度 Using the global measurement accuracy coefficient ρ1 = 0.7425, and with other parameter values ​​already given, substituting them into the formula yields: σ a1 =(0.101) 2 +0 2 +0.035 2 ) 1 / 2 +((0.101+0+0.035)-(0.101 2 +0 2 + 0.035 2 ) 1 / 2 )*0.7425=0.128mm.

[0088] The local measurement positioning error σ is determined according to the following formula. b σ b =(σ L1 2 +σ e2 2 +σ c 2 +σ T 2 ) 1 / 2 +((σ L1 +σ e2 +σ c +σ T )-(σ L1 2 +σ e2 2 +σ c 2 +σ T 2 ) 1 / 2 )*ρ 测量精度 ;

[0089] Where, σ L1 For local ranging error, σ e2 This is a local envelope error.

[0090] In this formula, ρ 测量精度 Using a local measurement accuracy coefficient ρ2 = 0.75, and with other parameter values ​​already given, substituting them into the formula yields: σ b =(0.05) 2 +0.0145 2 +0.035 2 +0.036 2 ) 1 / 2 +((0.05+0.0145+0.035+ 0.036)-(0.05 2 +0.0145 2 +0.035 2+0.036 2 ) 1 / 2 )*0.75=0.119mm.

[0091] The local measurement repeatability error σ is determined according to the following formula b1 : σ b1 =(σ L1 2 +σ c 2 ) 1 / 2 +((σ L1 +σ c )-(σ L1 2 +σ c 2 ) 1 / 2 )*ρ 测量精度 .

[0092] In the formula, ρ 测量精度 The local measurement repeatability error σ is determined according to the following formula b1 =(0.075 2 +0.035 2 ) 1 / 2 +((0.05+0.035)-(0.075 2 + 0.035 2 ) 1 / 2 )*0.75=0.078mm.

[0093] It should be noted that the calculation range of the local measurement repeatability error σ b1 Generally only includes the local group joint positioning related areas of the engine, landing gear, hatch, section docking, etc.

[0094] Step S6, compare the measurement error with the given tooling requirement accuracy to evaluate whether the measurement error meets the measurement field construction accuracy requirement.

[0095] In some optional embodiments, step S6 further comprises:

[0096] When the global measurement repeatability error σ a1 is less than or equal to the tooling global requirement accuracy σ, and when the local measurement repeatability error σ b1 is less than or equal to the tooling local requirement accuracy σ0, the measurement error meets the measurement field construction accuracy requirement.

[0097] In this embodiment, the global station length L is 14.4m, and the local station length L1 is 5.9m, which belongs to large size measurement. As calculated before, σ a1 =0.128mm, σ =0.2mm, and σ b1= 0.078 mm, σ0= 0.1 mm, since σ a1 <σ, and σ b1 <σ0, therefore, the measurement error meets the measurement field construction accuracy requirement.

[0098] In some optional embodiments, step S5 is further followed by:

[0099] Step S53, determining the global maximum error σ a2 = max(σ a2 , σ a1 , σ d , σ s );

[0100] Determine the local maximum error σ b2 = max(σ b2 , σ b1 , σ d , A);

[0101] Wherein, σ d is the deformation of the foundation structure, σ s is the deformation of the tooling structure caused by non-load, and it is assumed that the deformation of the foundation structure σ d = 0.08 mm, and the deformation of the tooling structure caused by non-load σ s = 0.15 mm. Substituting the above parameters into the formula, the global maximum error σ a2 = max(0.128, 0.08, 0.15) = 0.15 mm, and the local maximum error σ b2 = max(0.078, 0.08, 0.06) = 0.08 mm.

[0102] According to the basic principle of laser tracker measurement, combined with the structural mechanics and thermodynamic transfer mode of large-scale aviation process equipment, the application constructs a calculation method for errors including envelope, continuity, ranging, heat, vibration, etc. The global and local ranging errors, envelope errors, continuity errors, temperature change errors, global measurement errors, local measurement errors, and maximum errors are calculated in turn. The compliance evaluation is carried out according to the comparison and analysis of the measurement error and the required accuracy. The value relationship, range, etc. of various calculation links are mathematically defined, the calculation method of the measurement field accuracy in complex environment is clarified, the global and local measurement accuracy is evaluated and distinguished, the qualitative and quantitative design of the whole process of the aircraft assembly tooling measurement field has important guiding significance, and the measurement field construction of large-size tooling has universal applicability.

[0103] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A large assembly tool measurement field accuracy evaluation method, characterized by, The method comprises the following steps: Step S1, calculating the ranging accuracy under station length measurement according to the ranging accuracy parameter of the measuring device, and taking it as the ranging error, wherein the station length measurement comprises global station length measurement and local station length measurement, and the ranging error comprises global ranging error and local ranging error; Step S2, calculating the envelope coefficient according to the ratio relationship between the through line length of the measuring station envelope body and the station length, and correcting the ranging error based on the envelope coefficient to obtain the envelope error, wherein the envelope coefficient comprises global envelope coefficient and local envelope coefficient, and the envelope error comprises global envelope error and local envelope error; Step S3, determining the continuity error according to the maximum distance of the continuity reference point; Step S4, determining the temperature change error according to the maximum temperature difference of the measuring field and the material correction coefficient; Step S5, determining the measurement error according to the ranging error, the envelope error, the continuity error and the temperature change error, wherein the measurement error comprises global measurement error and local measurement error; Step S6, comparing the measurement error with the given tooling requirement accuracy to evaluate whether the measurement error meets the measurement field construction accuracy requirement.

2. The method of claim 1, wherein, In step S2, the maximum value in the connecting line of two boundary connecting points in the measuring station envelope body is selected as the through line length of the measuring station envelope body.

3. The method of claim 2, wherein the method further comprises: In step S2, the envelope coefficient p is calculated by the following equation 包络 : When L 贯穿线 ≥ 2L 站位 , p 包络 = 0; When L 贯穿线 <2L 站位 At that time, ρ 包络 =(2L) 站位 -L 贯穿线 ) / (2L 站位 ); Wherein, L 贯穿线 is the length of the through line, L 站位 is the station length.

4. The method of claim 1, wherein, In step S3, the continuity error σ is calculated by the following equation c : σ c = 0.0235 * L e ; wherein L e is the maximum distance between adjacent continuity reference points.

5. The method of claim 1, wherein, In step S4, the temperature change error σ is calculated by the following equation T : σ T = (1 - p3) * (T max - T min ) * a * L4 / 2; Wherein, p3 is a material correction coefficient, a is a thermal expansion coefficient of a tool body structure material of the measurement field, L4 is a maximum value of a distance between any two tool measurement object points on the process equipment in the measurement field along a direction parallel to or perpendicular to a through line of the envelope, T max and T min are a maximum value and a minimum value of temperature in each temperature measurement point of the measurement field, respectively.

6. The method of claim 5, wherein the method further comprises: In step S4, the measuring field is arranged with at least four temperature measuring points at the four corners of the foundation.

7. The method of claim 5, wherein the method further comprises: Step S5 further comprises: Step S51, determining the measurement precision coefficient p 测量精度 : When σ 测距 ≥ σ 需求精度 , ρ 测量精度 = 0; When σ 需求精度 > σ 测距 ≥ σ 需求精度 / 3, ρ 测量精度 = 3(σ 需求精度 - σ 测距 ) / (2σ 需求精度 ); When σ 测距 < σ 需求精度 / 3, p 测量精度 = 1; where σ 需求精度 is the given tooling requirement accuracy, σ 测距 is the ranging error calculated in step S1. Step S52, determine the global measurement positioning error σ according to the following formula a : σ a = (σ L 2 + σ t 2 + σ e1 2 + σ c 2 + σ T 2 + A 2 ) 1 / 2 + ((σ L + σ t + σ e1 + σ c + σ T + A) - (σ L 2 + σ t 2 + σ e1 2 + σ c 2 + σ T 2 + A 2 ) 1 / 2 )* p 测量精度 ; wherein σ L is the global ranging error, σ t is the measuring device transfer station error, σ e1 is the global enveloping error, σ c is the continuity error, σ T is the temperature variation error, A is the maximum amplitude of the external vibration source of the measuring field at the position of the tool in the measuring field. The global measurement repeatability error σ is determined according to the following formula a1 : σ a1 = (σ L 2 + σ e1 2 + σ c 2 ) 1 / 2 + ((σ L + σ e1 + σ c ) - (σ L 2 + σ e1 2 + σ c 2 ) 1 / 2 )* p 测量精度 ; The local measurement positioning error σ is determined according to the following formula b : σ b = (σ L1 2 + σ e2 2 + σ c 2 + σ T 2 ) 1 / 2 + ((σ L1 + σ e2 + σ c + σ T ) - (σ L1 2 +σ e2 2 +σ c 2 +σ T 2 ) 1 / 2 )*ρ 测量精度 ; where σ L1 is the local ranging error, σ e2 is the local envelope error; The local measurement repeatability error σ is determined according to the following formula b1 : σ b1 = (σ L1 + σ 2 ) - (σ c + σ 2 ) 1 / 2 + ((σ L1 + σ c ) - (σ L1 2 + σ c 2 ) 1 / 2 ) * p 测量精度 .

8. The method of claim 7, wherein the method further comprises: Step S52 further comprises: When the through line length of the global measuring station envelope body is less than 5m, the measurement reference of A is the tooling global coordinate system, otherwise, the measurement reference of A is the main body skeleton structure close to the tooling positioning point.

9. The method of claim 7, wherein the method further comprises: Step S6 further comprises: When the global measurement repeatability error σ a1 is less than or equal to the global tooling requirement accuracy σ0, and when the local measurement repeatability error σ b1 is less than or equal to the local tooling requirement accuracy σ0, the measurement error meets the measurement field construction accuracy requirement.

10. The method of claim 7, wherein the method further comprises: Step S5 further comprises: Step S53, determining the global maximum error σ a2 is: σ a2 = max(σ a1 , σ d , σ s ); determining the local maximum error σ b2 is: σ b2 = max(σ b1 , σ d , A); where σ d is the ground structure deformation, σ s is the tooling structure non-load induced deformation.

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