Large component butt joint skin milling edge method based on robot transfer station

Abstract

The application discloses a kind of big component closing skin milling edge method based on robot station change, belong to aircraft assembly technical field.First, establish coordinate system, position and measure A skin, then carry out first station by error compensation processing mode and deformation compensation processing mode and milling edge, utilize the same way to carry out station change positioning and milling edge, measure A skin milling edge after edge as B skin milling edge reference, remove A skin after positioning and measuring B skin, utilize the same way to carry out first station and station change milling edge to B skin, finally two skin closing.The application realizes the automatic processing of robot station change of skin closing large component closing skin by the application of system reference unique, theoretical position of assembly station position, deformation compensation processing, error compensation processing and other technologies.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of aircraft assembly, and relates to a large component butt joint skin milling method based on robot transfer station, in particular to a method for automatically milling the butt joint skin of a large aircraft component according to high-precision butt joint data of the large aircraft component by using a robot. BACKGROUND

[0002] With the rapid development of automatic equipment, automatic skin milling robots have been gradually introduced into the field of aircraft assembly to perform automatic processing of the skin edges. At present, the application modes of the automatic skin milling technology mainly include: direct processing by the robot according to data, and line searching processing by the robot using a visual assembly.

[0003] The direct processing by the robot according to data is suitable for small-size part-level processing. Due to the positioning error of the robot, the motion error of each joint of the robot, the deformation error of the tool and the skin, and other reasons, there is a large error between the wall plate edge position after the processing at the transfer station and the theoretically required processing position, which is not suitable for the skin milling of the large component butt joint part which needs to be positioned by the robot transfer station and the butt joint skin respectively and has strict tolerance requirements for the butt joint gap of the skin.

[0004] The line searching processing by the robot using a visual assembly needs to manually draw the cutting line position on the part first, and the robot cuts the part by searching for the line with vision, and the milling task is completed by removing the drawn line. However, due to the inaccuracy of the thickness of the drawn line trace, the accuracy of the drawn line position (the position tolerance of the manually drawn line is about 0.5 mm), and other reasons, there is a certain gap between the processed part and the expected part (the error after processing is about 0.6 mm to 0.7 mm). Due to the existence of manual line drawing, the part needs to be manually trial-assembled on the assembly first to determine the processing allowance and draw the allowance edge position, which leads to the fact that the allowance milling cannot realize true automation.

[0005] For the large component butt joint part which needs to be processed by the robot transfer station and needs to be positioned by the skin in several times and has strict tolerance requirements for the butt joint gap of the skin, the skin milling after using the above processing methods cannot achieve the control requirements of the butt joint value. In order to meet the control requirements, a processing allowance needs to be reserved, and the skin edge needs to be manually processed again during the large component butt joint. SUMMARY

[0006] In view of the deficiencies of the current robot automatic milling edge technology in robot station milling edge and gap tolerance requirement of the joint skin milling edge, the application provides a large part joint skin milling edge method based on robot station, which realizes automatic processing of the large part joint skin robot station by using the technology of building a unique coordinate system, assembling the theoretical position frame, deformation compensation processing and error compensation processing, etc. The application is suitable for automatic milling edge of other skins with joint relationship, high-precision processing of single skin edge position and high-precision milling of the frame.

[0007] In order to achieve the above purpose, the technical scheme of the application is as follows:

[0008] A large part joint skin milling edge method based on robot station, the milling edge method comprises the following steps:

[0009] Step 1, building a coordinate system

[0010] The A skin and the B skin with joint relationship are fixed on the frames of the A part and the B part respectively, and the measuring device takes the four coordinate system reference points distributed on the ground around the work station as the coordinate system reference to build a measuring coordinate system.

[0011] Step 2, positioning the A part

[0012] The tooling bearing the A part is moved to the work station, the position and attitude of the A part are adjusted to the theoretical position by the measuring device, and then the A part is fixed.

[0013] Step 3, measuring the A skin milling edge

[0014] The A skin milling edge is measured by the measuring device, and compared with the theoretical edge of the A skin to determine the milling value of the A skin.

[0015] Step 4, A skin robot first station positioning milling edge

[0016] According to the robot working parameters, the A skin cutting part is divided into multiple milling edge areas, the robot is moved to the work station of the first milling edge area, and the coordinate system of the robot is built with the same coordinate system reference as step 1.

[0017] According to the calculated cutting amount, the robot performs the sub-milling edge processing by the error compensation processing mode, the error compensation processing mode refers to the sub-milling cutting method adopted for the robot positioning error, measurement error and robot station processing generated tool engagement difference, etc., which causes the problem that the measured value of the gap after processing deviates from the theoretical value, and after each milling cutting is completed, the next processing is performed through measurement and calculation; in addition, due to the extrusion between the milling cutter and the skin during the milling edge process, the skin produces a small amount of elastic deformation, and the milling cutter appears to let the cutter phenomenon, therefore, during each milling cutting, the milling cutter needs to mill the skin along the reverse direction of the processing path to realize the deformation compensation processing of the deformation, and finally complete the A-skin milling edge in the current milling edge region.

[0018] Step 5, robot station positioning milling edge of A-skin

[0019] The robot is moved to the next milling edge region, and the coordinate system of the robot is established again based on the same system reference as in step 1. The robot performs sub-milling edge processing in the current milling edge region by the error compensation processing mode to solve the tool engagement difference problem and various errors, and deformation compensation processing is performed after each milling cutting.

[0020] The height difference h1 between the milling edge to be milled in the current milling region and the milled edge of the previous milling region is measured; the processing value H1 is calculated according to the actual situation of the processing site (the principle of equal extension of the joint edge and the minimum processing amount is used for calculation), the first milling edge is performed with the processing value H1, and deformation compensation processing is performed.

[0021] The height difference h2 between the milled edge after the first milling edge and the milled edge of the previous milling region is measured again, and the processing value H2 is calculated, the second milling edge is performed with the processing value H2, and deformation compensation processing is performed, and during the processing, the milling edge is implemented with the value of h2-(h1-H1) as the compensation value of the current milling edge.

[0022] The same method is used to perform multiple milling, until the A-skin in the current milling edge region is processed to the theoretical edge, the total number of milling i is determined according to the actual processing situation, i≥3; the height difference h n between the milled edge after the previous milling edge and the milled edge of the previous milling region is measured before each milling, and the processing value H n is calculated, the nth milling edge is performed with the processing value H n , and deformation compensation processing is performed, where n=1, 2, …, i; during each processing, the milling edge is implemented with the value of h n -(h n-1 -H n-1 ) as the compensation value of the nth milling edge.

[0023] Repeat step 5 until the A-skin completes the milling edge processing of all milling edge regions.

[0024] Step 6, Measure the edge position of the milled A skin

[0025] Establish the coordinate system of the measuring device with the same reference as in Step 1, and measure the edge position of the milled A skin.

[0026] Step 7, Move out the A part

[0027] Move the A part out of the work station position to make room for the robot to process the B part.

[0028] Step 8, Position and fix the B part

[0029] Move the tooling carrying the B part to the work station position, establish the coordinate system of the measuring device with the same reference as in Step 1, adjust the position and attitude of the B part to the theoretical position with the help of the measuring device, and fix it.

[0030] Step 9, Measure the milled edge of the B skin

[0031] Measure the milled edge of the B skin with the measuring device, compare it with the edge position of the milled A skin measured in Step 6, and determine the milling value of the B skin.

[0032] Step 10, Position and mill the edge of the B skin at the first station

[0033] According to the robot working parameters, divide the part to be cut of the B skin into multiple edge milling areas, move the robot to the work station position of the first edge milling area, and establish the coordinate system of the robot with the same reference as in Step 1. Process the first station edge milling of the B skin with the same error compensation processing method as in Step 5; for the first edge milling area, calculate the height difference and processing amount based on the milled edge of the A skin.

[0034] Step 11, Position and mill the edge of the B skin at the transfer station

[0035] Move the robot to the work station position of the next edge milling area, and establish the coordinate system of the robot with the same reference as in Step 1. Process the edge milling of each edge milling area in turn to the theoretical position with the same error compensation processing method as in Step 5, and perform deformation compensation processing for each milling.

[0036] Repeat Step 11 until the B skin completes all edge milling of the edge milling areas.

[0037] Step 12, Join the A and B parts

[0038] Move the robot out of the work station position, move the tooling carrying the A part to the work station position, establish the coordinate system of the measuring device with the same reference as in Step 1, adjust the position and attitude of the A part to the theoretical position with the help of the measuring device, and complete the joining of the A and B parts.

[0039] The beneficial effects of the present application are as follows:

[0040] The present application solves the following problems in the robot milling edge technology:

[0041] (1) The problem that the robot direct processing according to data is not applicable to the skin milling edge which requires robot transfer station, positioning of the skin respectively, and strict tolerance requirement of skin joint gap.

[0042] (2) The problem that the robot uses visual components to search for lines for processing, and the milling edge position is not accurate enough.

[0043] (3) The present application realizes high position precision milling edge of the skin in the case of robot transfer station, which saves the operation of manual secondary repair of the skin during part joint, and realizes the automatic processing of the robot to the joint skin in a true sense. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 It is a schematic diagram of the principle of the present application.

[0045] Figure 2 It is the first station positioning milling edge of the robot to the A skin.

[0046] Figure 3 It is the transfer station positioning milling edge of the robot to the A skin.

[0047] Figure 4 It is a schematic diagram of error compensation processing principle, wherein h1 is the height difference between the edge to be milled and the milled edge of the previous milling area, h2 is the height difference between the edge after the first milling and the milled edge of the previous milling area, h3 is the height difference between the edge after the second milling and the milled edge of the previous milling area; H1 and H2 are the processing amounts of the first and second times respectively.

[0048] Figure 5 It is the first station positioning milling edge of the robot to the B skin.

[0049] Figure 6 It is the transfer station positioning milling edge of the robot to the B skin.

[0050] In the figure: 1-A skin; 2-B skin; 3-System reference point; 4-Robot; DETAILED DESCRIPTION

[0051] In order to make the purpose, technical scheme and advantages of the present application more clear and explicit, the technical scheme will be described in detail below.

[0052] The present embodiment provides a large part joint skin milling edge method based on robot transfer station, and the principle is as shown in Figure 1 The milling edge method comprises the following steps:

[0053] Step 1, establishing coordinate system

[0054] Fix A skin 1 and B skin 2 of the docking relationship on the framework of A component and B component respectively, and establish the measurement coordinate system with the measurement equipment taking the four system reference points 3 distributed on the ground around the workstation position as the system reference.

[0055] Step 2, positioning and fixing A component

[0056] Move the tooling bearing A component to the workstation position, adjust the position and posture of A component to the theoretical position by means of the measurement equipment, and fix it.

[0057] Step 3, measuring the milled edge of A skin 1

[0058] Measure the milled edge of A skin 1 by means of the measurement equipment, and compare it with the theoretical edge of A skin 1 to determine the milling value of A skin 1.

[0059] Step 4, A skin robot first station positioning and milling

[0060] As shown in Figure 2 , according to the working parameters of robot 4 such as arm length, divide the to-be-cut part of A skin 1 into two milling areas, move robot 4 to the workstation position of the first milling area, and establish the coordinate system of robot 4 with the same system reference as step 1.

[0061] According to the calculated cutting amount, robot 4 performs multiple milling processing by means of error compensation processing, which is a method of multiple milling to solve the problem that the actual value of the gap after processing deviates from the theoretical value due to positioning error of robot 4, measurement error, and tool engagement difference caused by robot 4 station transfer processing. After each milling, the processing is performed again through measurement and calculation. In addition, due to the extrusion between the milling cutter and the skin during the milling process, the skin will produce a small amount of elastic deformation, and the milling cutter will appear to let go. Therefore, during each milling, the milling cutter needs to mill the skin in the reverse direction along the processing path to realize deformation compensation processing of the deformation, and finally complete the milling of A skin 1 in the first milling area.

[0062] Step 5, A skin robot station transfer positioning and milling

[0063] As shown in Figure 3 , move robot 4 to the second milling area, and again establish the coordinate system of robot 4 with the same system reference as step 1. Robot 4 performs multiple milling processing in this milling area by means of error compensation processing to solve the tool engagement difference and various errors caused by station transfer, and each milling is performed with deformation compensation processing, as shown in Figure 4 , in detail:

[0064] The height difference h1 between the edge to be milled at the current milling area and the edge after milling of the previous milling area is measured; the processing value H1 is calculated according to the actual situation of the processing site (the principle is to make the overhanging amount of the abutting edge equal and the processing amount of this time minimum), the first edge milling is performed with the processing value H1, and deformation compensation processing is performed.

[0065] The height difference h2 between the edge after the first edge milling and the edge after milling of the previous milling area is measured again, and the processing value H2 is calculated, the second edge milling is performed with the processing value H2, and deformation compensation processing is performed, and during the processing, the value of h2-(h1-H1) is used as the compensation value of the current edge milling to perform the edge milling processing.

[0066] The same way is used to perform multiple milling until the A skin 1 in the current edge milling area is processed to the theoretical edge, and the total number of milling i is determined according to the actual processing situation, i≥3; the height difference h n between the edge after the previous edge milling and the edge after milling of the previous milling area is measured before each milling, and the processing value H n is calculated, the nth edge milling is performed with the processing value H n , and deformation compensation processing is performed, where n=1, 2, …, i; during each processing, the value of h n -(h n-1 -H n-1 ) is used as the compensation value of the nth edge milling to perform the edge milling processing. In this embodiment, the milling is performed for three times.

[0067] Step 6, measuring the edge position after the edge milling of the A component

[0068] The coordinate system of the measuring device is established with the same built-in reference as in step 1, and the edge position after the edge milling of the A skin 1 is measured.

[0069] Step 7, moving out the A component

[0070] The A component is moved out of the working station to make space for the robot 4 to process the B component.

[0071] Step 8, positioning and fixing the B component

[0072] The tooling carrying the B component is moved to the working station, the coordinate system of the measuring device is established with the same built-in reference as in step 1, the position and attitude of the B component are adjusted to the theoretical position with the help of the measuring device, and then fixed.

[0073] Step 9, measuring the edge milling position of the B skin 2

[0074] The edge milling position of the B skin 2 is measured by the measuring device, and compared with the edge position after the edge milling of the A skin 1 measured in step 6 to determine the milling value of the B skin 2.

[0075] Step 10, positioning and edge milling of the B skin robot first station

[0076] As shown in Figure 5 According to the working parameters of the robot 4, the to-be-cut part of the B skin 2 is divided into two edge milling areas, the robot 4 is moved to the working station position of the first edge milling area, and the coordinate system of the robot 4 is established with the same establishment reference as step 1. The first station edge milling of the B skin 2 is carried out in the same error compensation processing mode as step 5; wherein, for the first edge milling area, the height difference and the processing amount are calculated based on the milled edge of the A skin 1.

[0077] Step 11, B skin robot station positioning edge milling

[0078] As shown in Figure 6 The robot 4 is moved to the working station position of the next edge milling area, and the coordinate system of the robot 4 is established with the same establishment reference as step 1. The edge milling of each edge milling area is carried out in turn to the theoretical position in the same error compensation processing mode as step 5, and deformation compensation processing is carried out for each edge milling.

[0079] Step 11 is repeatedly executed until the B skin 2 completes the edge milling of all edge milling areas.

[0080] Step 12, A and B parts are matched

[0081] The robot 4 is moved out of the working station position, the tooling carrying the A part is moved to the working station position, the coordinate system of the measuring device is established with the same establishment reference as step 1, and the position and attitude of the A part are adjusted to the theoretical position by means of the measuring device, and the matching of the A and B parts is completed.

[0082] The innovation of the present application is:

[0083] (1) The establishment reference is unique

[0084] The same establishment reference (the aircraft coordinate system) on the assembly station is used for the establishment of the measuring device and the establishment of the robot.

[0085] (2) Theoretical position of the assembly station is processed on the rack

[0086] Both parts are processed at the working station, and both are processed on the rack in the matching attitude. One part is processed, and the other part is moved away by a proper distance to provide a working space. The state of the first part after processing serves as the reference for the processing of the other part.

[0087] (3) Deformation compensation processing

[0088] During edge milling, the skin produces a small amount of elastic deformation due to the extrusion between the milling cutter and the skin, and the milling cutter appears to be let go. The deformation compensation processing is realized by milling the skin in the reverse direction along the processing path.

[0089] (4) Error compensation processing

[0090] Due to the occurrence of various errors such as robot positioning error and measurement error, the robot station processing produces the problem of tool joint difference; after adopting deformation compensation processing, the gap value between the joint skins still deviates from the theoretical requirements. In view of the two problems, the error compensation processing method of measurement, calculation and processing in batches is adopted to solve.

Claims

1. A method of robot station based large part coining skin edge milling, characterized in that, Firstly, the coordinate system is established, the A component is positioned and fixed, the A skin (1) milling edge is measured, the robot (4) is used to position and mill the edge of the A skin (1) at the first station and the transfer station, the edge position of the A skin (1) after milling is measured, the B component is positioned and fixed, the B skin (2) milling edge is measured, the robot (4) is used to position and mill the edge of the B skin (2) at the first station and the transfer station, and finally the A component and the B component are closed; The milling edge method comprises the following steps: Step 1, establishing a coordinate system The A skin (1) and the B skin (2) in the butt joint relationship are fixed on the skeletons of the A component and the B component respectively, and a measuring device is used to establish a measuring coordinate system with four system reference points (3) distributed on the ground around the work station as the system reference; Step 2, positioning and fixing the A component The tooling bearing the A component is moved to the work station, the position and attitude of the A component are adjusted to the theoretical position by means of the measuring device, and then the A component is fixed; Step 3, measuring the A skin (1) milling edge The measuring device is used to measure the A skin (1) milling edge, and the milling value of the A skin (1) is determined by comparing with the theoretical edge of the A skin (1); Step 4, A skin (1) robot (4) first station positioning and milling edge The part to be cut of the A skin (1) is divided into multiple milling edge areas, the robot (4) is moved to the work station of the first milling edge area, and the coordinate system of the robot (4) is established with the same system reference as step 1; According to the calculated cutting amount, the robot (4) is processed by error compensation processing mode for multiple times of milling edge processing, and deformation compensation processing is performed every time of milling, and finally the A skin (1) milling edge in the milling edge area is completed; Step 5, A skin (1) robot (4) transfer station positioning and milling edge The robot (4) is moved to the next milling edge area, and the coordinate system of the robot (4) is established again with the same system reference as step 1; the robot (4) is processed by error compensation processing mode for multiple times of milling edge processing in the milling edge area to solve the transfer station tool change difference and various errors, and deformation compensation processing is performed every time of milling; Repeat step 5 until the A skin (1) completes the milling edge processing of all milling edge areas; Step 6, measuring the edge position of the A component after milling edge The coordinate system of the measuring device is established with the same system reference as in step 1, and the edge position of the A skin (1) after milling edge is measured; Step 7, moving out the A component The A component is moved out of the work station to leave space for the robot (4) to process the B component; Step 8, positioning and fixing the B component The tooling bearing the B component is moved to the work station, the coordinate system of the measuring device is established with the same system reference as in step 1, the position and attitude of the B component are adjusted to the theoretical position by means of the measuring device, and then the B component is fixed; Step 9, measuring the B skin (2) milling edge The measuring device is used to measure the B skin (2) milling edge, and the milling value of the B skin (2) is determined by comparing with the edge position of the A skin (1) after milling edge measured in step 6; Step 10, B skin (2) robot (4) first station positioning and milling edge The B skin (2) to be cut part is divided into multiple milling edge areas, the robot (4) is moved to the workstation position of the first milling edge area, and the coordinate system of the robot (4) is established with the same establishment reference as step 1; the first station milling edge processing of the B skin (2) is carried out in the same error compensation processing mode as step 5; Step 11, the robot (4) of the B skin (2) is positioned and milled The robot (4) is moved to the workstation position of the next milling edge area, and the coordinate system of the robot (4) is established with the same establishment reference as step 1; the milling edge processing of each milling edge area is carried out in turn in the same error compensation processing mode as step 5 to the theoretical position, and deformation compensation processing is carried out for each milling cut; Step 11 is repeated until the milling edge processing of all milling edge areas of the B skin (2) is completed; Step 12, A component and B component are combined The robot (4) is moved out of the workstation position, the tooling carrying the A component is moved to the workstation position, the coordinate system of the measuring device is established with the same establishment reference as step 1, and the position and attitude of the A component are adjusted to the theoretical position by means of the measuring device, and the A component and the B component are combined.

2. The method of claim 1, wherein, In step 4, the number of milling edge areas into which the A skin (1) to be cut part is divided is determined according to the working parameters of the robot (4).

3. The method of claim 1, wherein, In step 4, the error compensation processing mode refers to the method of cutting in several times to compensate for the processing error of the robot (4) and the deviation of the actual measurement value from the theoretical value after processing.

4. The method of claim 1, wherein, In step 4, the deformation compensation processing mode is that the milling cutter mills the skin in the reverse direction along the processing path.

5. The method of claim 1, wherein, The specific process of step 5 is: The height difference h1 between the edge to be milled in the current milling edge area and the milled edge in the previous milling edge area is measured; the processing value H1 is calculated according to the actual situation of the processing site, and the first milling edge is milled with the processing value H1 and deformation compensation processing; The height difference h2 between the milled edge after the first milling edge and the milled edge in the previous milling edge area is measured again, and the processing value H2 is calculated; the second milling edge is milled with the processing value H2 and deformation compensation processing, and during the processing, the compensation value h2-(h1-H1) is used for milling edge processing; In the same way, multiple milling is performed until the A skin (1) in the current milling area is processed to the theoretical edge, and the total milling number i is determined according to the actual processing condition; before each milling, the height difference h between the edge after the previous milling and the edge after the milling in the previous milling area is measured n , and the processing value H is calculated n , and the processing value H is calculated n The n-th milling is performed, and deformation compensation processing is performed, where n=1, 2, …, i; during each processing, h n - (h n-1 -H n-1 ) is taken as the compensation value of the n-th milling to perform the milling processing.

6. A method of large component coining skin milling edge based on robot transfer station as claimed in claim 5 wherein, The processing value H1 is calculated according to the principle that the extension amount of the butt edge is equal and the processing amount is minimum.

7. The method of claim 5, wherein, The total milling times i≥3.

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