A dynamic generation method for machining coordinate system of flexible production line

Abstract

The present invention discloses a method for dynamically generating a processing coordinate system for a flexible production line. A fixed position of a standard pallet is selected as a reference point on any machine tool in the production line; the original coordinates of the machine tool are determined in advance; and the user variables are called before product processing to automatically generate the machine tool reference coordinate system. Then, a theoretical position relationship among the three is established in a programming environment including the product to be processed, the tooling, and the standard pallet; a system macro program including the position relationship between the initial processing coordinate system of the product and the machine tool reference coordinate system is created to automatically generate the initial processing coordinate system of the product in the machine tool environment. Finally, an automatic measurement and alignment program is created in the initial processing coordinate system of the product; first, a reference edge of the product is measured, its angle deviation is calculated and automatically compensated, and a transition processing coordinate system is generated; then, the positioning surfaces of the product in the X, Y, and Z directions are measured, and the position deviation between the product position and the transition processing coordinate system in the X, Y, and Z directions is calculated and corrected to generate the final processing coordinate system.

Description

Technical Field

[0001] The invention relates to the technical field of numerical control machining, in particular to a method for dynamically generating numerical control machining coordinate systems of workpieces on multiple numerical control machining machine tools in a flexible production line. Background Art

[0002] In the field of digital processing, all digital control of processing motion is based on the processing coordinate system. For each part processed on a CNC machine tool, a specific processing coordinate system and its mapping relationship with the machine tool's original coordinate system must first be established.

[0003] As processing technology gradually develops towards intelligence, the flexible production line manufacturing model based on digital processing and integrating intelligent control technology is increasingly being applied to the processing and manufacturing field. Since all machine tool processing and logistics processes are unmanned in the flexible production line manufacturing model, the traditional human-machine interactive CNC machine tool operation method is no longer feasible, and the preparatory work before CNC processing, such as tool setting, alignment, and setting the processing coordinate system, can no longer be completed by humans.

[0004] For flexible production lines that are oriented to the manufacturing of "small batches and multiple varieties" products, it has always been difficult to quickly and accurately automatically generate processing coordinate systems for hundreds of ever-changing products. The current common solution is to improve the accuracy of the fixtures for each product as much as possible, pre-adjust the fixed position of the product on the processing machine, and assign a fixed processing coordinate system. However, the shortcomings of this traditional solution are also obvious: the accuracy of product clamping is greatly improved, which increases the difficulty of manufacturing the automated clamping system; the errors caused by the clamping system are difficult to eliminate, resulting in a certain loss of product accuracy, and with the long-term use of the clamping system, the range of error fluctuations is further increased; especially for flexible production lines that use automatic exchange pallet processing, the allocation and scheduling of pallets between machine tools is uncertain, which again increases the error accumulation of products processed on different machine tools; in addition, for flexible production lines, the large variety of product types and large quantities are its main characteristics and advantages, and this solidified coordinate system establishment method reduces the flexibility of the production line for hundreds of ever-changing products.

[0005] Therefore, under the premise of ensuring flexible processing of production line products, forming a method to quickly, accurately and automatically generate processing coordinate systems for all products on the line is of great value for more widely promoting the advanced manufacturing model of flexible production lines and improving the intelligent level of parts processing technology. Summary of the invention

[0006] The present invention provides a method for dynamically generating a workpiece CNC machining coordinate system on multiple CNC machining machine tools in a flexible production line. Through the present invention, any product on the flexible production line can automatically generate a corresponding machining coordinate system in any CNC machine tool in an unmanned manner, and realize adaptive precision compensation to eliminate errors caused by pallet exchange, tooling manufacturing, and workpiece clamping. The present invention is composed of the following contents:

[0007] A method for dynamically generating a machining coordinate system for a flexible production line is provided. The method consists of three parts:

[0008] The first step is to automatically generate the reference coordinate system of the machine tool in the flexible production line. 1) On any CNC machine tool in the flexible production line, select a fixed position on a standard pallet as the reference point. The position of the pallet on the workbench of the CNC machine tool is relatively fixed; 2) During the debugging stage in the flexible production line, for each CNC machine tool in the line, pre-determine the mechanical coordinates of the reference point in the original coordinate system of the machine tool, and store them in the user variable file of the machine tool control system in the form of system user variables; 3) Before the product is automatically processed, the user variables of the mechanical coordinate system containing the reference point are called through the system macro program to automatically generate the reference coordinate system of the machine tool.

[0009] The second step is the dynamic generation method of the initial processing coordinate system of the products to be processed in the flexible production line.

[0010] 1) In a CNC programming environment that includes the product to be processed, tooling, and standard pallet, establish the theoretical position relationship between the three and keep it consistent with the actual processing;

[0011] 2) Establish a machine tool reference coordinate system at the pallet reference point, and at the same time establish an initial processing coordinate system of the product in the programming environment at the positioning point of the product. The initial processing coordinate system and the machine tool reference coordinate system can be in a translation relationship or a translation + rotation relationship;

[0012] 3) In the CNC programming environment, create a CNC system macro program that contains the coordinate position relationship between the product's initial processing coordinate system and the machine tool reference coordinate system. This macro program can automatically generate the product's initial processing coordinate system in the machine tool environment through the coordinate position relationship calculation between the machine tool reference coordinate system and the product's initial processing coordinate system; its coordinate position calculation relationship is as follows:

[0013] When the initial processing coordinate system and the machine tool reference coordinate system are in a translation relationship, the coordinate position operation relationship is X3=X2+δX, Y3=Y2+δY, Z3=Z2+δZ, among which, (X3, Y3, Z3) are the coordinates of the origin of the initial processing coordinate system, (X2, Y2, Z2) are the coordinates of the origin of the machine tool reference coordinate system, and (δX, δY, δZ) are the coordinate differences of the origins of the two coordinate systems in the X, Y, and Z directions.

[0014] When the initial machining coordinate system and the machine tool reference coordinate system are in a translation + rotation relationship, the coordinate position calculation relationship is X3 = X2 + δX-Xe, Y3 = Y2 + δY-Ye, Z3 = Z2 + δZ, C3 = C2 + δC;

[0015] Among them, C3 is the angular offset of the initial machining coordinate system, C2 is the angular offset of the machine tool reference coordinate system, δC is the difference in rotation angles between the two coordinate systems; Xe=(X2+δX-X0)-(X2+δX-X0)*COS(-δC)+(Y2+ δY-Y0)*SIN(-δC), Ye=(Y2+δY-Y0)-(Y2+δY-Y0)*COS(-δC)-(X2+ δX-X0)*SIN(-δC); X0, Y0 are the X and Y machine tool original coordinates of the center of the rotary table, respectively.

[0016] 4) In a flexible production line environment, before the product is automatically processed, the system automatically runs the macro program to automatically generate the initial processing coordinate system of the product on the machine tool where the product is located.

[0017] The third step is the adaptive generation method of the final processing coordinate system of the product to be processed. 1) In the CNC programming environment, the initial processing coordinate system of the product is used as the reference to create a probe automatic measurement and alignment program; 2) First, use the probe to measure the coordinates of two points on a reference edge of the product that are far apart or the centers of two positioning holes of the product, calculate the angle deviation between the line connecting the two points and the initial processing coordinate system, and rotate the initial processing coordinate system of the product around the Z axis through the coordinate rotation function of the CNC system, automatically compensate for the angle deviation of the product, and generate a transition processing coordinate system; 3) Then use the probe to measure the positioning surfaces of the product in the X, Y, and Z directions respectively, calculate the position deviation between the actual position of the product in the X, Y, and Z directions and the transition processing coordinate system respectively, and correct the transition processing coordinate system respectively through the coordinate translation function of the CNC system to generate the final processing coordinate system; 4) In the flexible production line environment, before the product is automatically processed, the system automatically runs the automatic measurement and alignment program to automatically generate the final processing coordinate system of the machine tool where the product is located.

[0018] The advantages of the present invention are: it can enable any product on a flexible production line to automatically generate a corresponding processing coordinate system in any CNC machine tool in an unmanned manner, and the processing coordinate system of the product does not need to be fixed on each machine tool; as the product changes, the processing coordinate system will be automatically created and updated, without being limited by the number of products or the number of coordinate systems; the errors caused by pallet exchange, tooling manufacturing, and workpiece clamping are eliminated through adaptive precision compensation; at the same time, when compiling a macro program for dynamically generating a product processing coordinate system, it is not necessary to consider the differences in the original coordinate systems of each CNC machine tool, thereby simplifying the compilation of the macro program. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is the top view of the machine tool reference coordinate system;

[0020] Figure 2 It is the side view of the machine tool reference coordinate system;

[0021] Figure 3 It is a top view of the initial processing coordinate system of the generated product;

[0022] Figure 4 It is the side view of the initial processing coordinate system of the generated product;

[0023] Figure 5 It is a top view of the final processing coordinate system of the generated product;

[0024] Figure 6 It is the side view of the final processing coordinate system of the generated product;

[0025] Explanation of numbers in the figure: 1 machine tool original coordinate system, 2 machine tool worktable, 3 standard pallet, 4 pallet reference hole, 5 machine tool reference coordinate system, 6 pallet auxiliary positioning hole, 7 machine tool worktable center, 8 product tooling, 9 processed product, 10 product initial processing coordinate system, 11 product side positioning point, 12 transition processing coordinate system, 13 final processing coordinate system, 14 probe DETAILED DESCRIPTION

[0026] The present application is described in detail below in conjunction with the accompanying drawings of the embodiments.

[0027] This embodiment takes the dynamic generation process of the machining coordinate system of a pallet exchange flexible production line composed of several CNC machine tools as an example to further illustrate the invention scheme. Among them, the CNC machine tool in the flexible production line is a five-axis CNC machining center, but it is applicable to three-axis CNC machine tools, four-axis CNC machine tools, and six-axis CNC machine tools; the CNC system is Sinumerik840D, but it is applicable to other CNC systems; the product enters and exits the machine tool through automatic pallet exchange, and the pallet is automatically positioned and clamped on the workbench using a zero-point positioning system or other similar methods; the product's reference alignment method is reference edge alignment, but it can also be applied to two-hole alignment and hole-edge alignment methods; the measurement method inside the machine tool is probe measurement.

[0028] The first step is the automatic generation of the reference coordinate system 5, such as Figure 1 , Figure 2As shown. 1) On any CNC machine tool in the flexible production line, a standard pallet 3 is fed in through automatic exchange; the standard pallet is automatically positioned and clamped to the machine tool workbench 2 through the zero-point positioning system; the center of a reference hole 4 on a standard pallet is selected as the pallet reference point; 2) During the debugging stage in the flexible production line, for each CNC machine tool in the line, the mechanical coordinates (X, Y, Z) of the reference point in the machine tool original coordinate system 1 are pre-determined, and stored in the user variable file of each machine tool control system in the form of system user variables (such as CZUOBIAOXI_X, CZUOBIAOXI_Y, CZUOBIAOXI_Z); 3) Before the product 9 is automatically processed, the user variables of the mechanical coordinate system containing the reference point are called through the system macro program, and the reference coordinate system 5 of the machine tool is automatically generated through the coordinate system creation instruction of the control system. The macro program example is as follows:

[0029] N26$P_UIFR[1,X,TR]=CSZUOBIAOXI_X;Set the pallet reference point G54X offset

[0030] N27$P_UIFR[1,Y,TR]=CSZUOBIAOXI_Y;Set the pallet reference point G54Y offset

[0031] N28$P_UIFR[1,Z,TR]=CSZUOBIAOXI_Z;Set the pallet reference point G54Z offset

[0032] If the machine tool table is a rotary table with a C-axis, add the following instructions:

[0033] N29$P_UIFR[1,C,TR]=CSZUOBIAOXI_C;Set the G54C angle offset of the pallet reference point

[0034] The second step is the dynamic generation of the initial processing coordinate system 10 of the product, such as Figure 3 , Figure 4As shown. 1) In a CNC programming environment that includes a model of a product to be processed 9, a tooling 8, and a standard pallet 3, a theoretical positional relationship between the three is established and kept consistent with the actual processing; 2) A machine tool reference coordinate system 5 is established at the pallet reference point, and the direction of the coordinate system is consistent with the actual machine tool; at the same time, an initial processing coordinate system 10 of the product in the programming environment is established at the positioning point of the product for CNC programming of the product; 3) In a CNC programming environment, a CNC system macro program is created that includes the coordinate position relationship between the initial processing coordinate system 10 of the product and the machine tool reference coordinate system 5. The macro program can automatically generate the initial processing coordinate system of the product in the machine tool environment through the coordinate position relationship calculation between the machine tool reference coordinate system 5 and the initial processing coordinate system 10 of the product; 4) In a flexible production line environment, before the product 9 is automatically processed, the system automatically runs the macro program to automatically generate the initial processing coordinate system 10 of the product on the machine tool where the product is located; the initial processing coordinate system of the product is automatically updated as the product is replaced. Examples of macro programs are as follows:

[0035] N20 R282 = -385; read the X offset of the programming coordinate origin in the machine tool reference coordinate system and store it in the R variable

[0036] N21 R283 = -285; read the Y offset of the programming coordinate origin in the machine tool reference coordinate system and store it in the R variable

[0037] N22 R284=369.5; read the Z offset of the programming coordinate origin in the machine tool reference coordinate system and store it in the R variable

[0038] N30$P_UIFR[1,X,TR]=$P_UIFR[1,X,TR]+R282; Set the initial machining coordinate system G54X offset

[0039] N31$P_UIFR[1,Y,TR]=$P_UIFR[1,Y,TR]+R283; Set the initial machining coordinate system G54Y offset

[0040] N32$P_UIFR[1,Z,TR]=$P_UIFR[1,Z,TR]+R284; Set the initial machining coordinate system G54Z offset

[0041] If the machine tool table is a rotary table with a C-axis, and there is a rotation angle between the product processing coordinate system and the reference coordinate system, the macro program example is as follows:

[0042] N20 R282 = -385; read the X offset of the programming coordinate origin in the machine tool reference coordinate system

[0043] N21 R283 = -285; read the Y offset of the programming coordinate origin in the machine tool reference coordinate system

[0044] N22 R284=369.5; read the Z offset of the programming coordinate origin in the machine tool reference coordinate system

[0045] N23 R285=90; read the programming coordinate rotation angle under the machine tool reference coordinate system

[0046] N24 R275=$TC_CARR15[1]; Read the original coordinate of the rotary table center X machine tool

[0047] N25 R276=$TC_CARR16[1]; Read the original Y coordinate of the rotary table center

[0048] N30$P_UIFR[1,X,TR]=$P_UIFR[1,X,TR]+R282; Set the product initial processing coordinate system G54X offset

[0049] N31$P_UIFR[1,Y,TR]=$P_UIFR[1,Y,TR]+R283; Set the product initial processing coordinate system G54Y offset

[0050] N32$P_UIFR[1,Z,TR]=$P_UIFR[1,Z,TR]+R284; Set the product initial processing coordinate system G54Z offset

[0051] N33$P_UIFR[1,C,TR]=$P_UIFR[1,C,TR]+R285; Set the G54C angle offset of the initial processing coordinate system of the product

[0052] N34 R277=$P_UIFR[1,X,TR]-R275; Calculate the difference between X offset and turntable center

[0053] N35 R278=$P_UIFR[1,Y,TR]-R276; Calculate the difference between Y offset and turntable center

[0054] N36 R279=-R285; Angle reverse

[0055] N37 R280=R277-R277*COS(R279)+R278*SIN(R279); calculate the X offset correction with C angle rotation

[0056] N38 R281=R278-R278*COS(R279)-R277*SIN(R279); calculate the Y offset correction with C angle rotation

[0057] N39$P_UIFR[1,X,TR]=$P_UIFR[1,X,TR]-R280; G54X offset of the initial machining coordinate system of the product after rotation correction

[0058] N40$P_UIFR[1,Y,TR]=$P_UIFR[1,Y,TR]-R281; G54Y offset of the initial processing coordinate system of the product after rotation correction

[0059] The third step is the adaptive generation of the final machining coordinate system 13, such as Figure 5 , Figure 6 As shown. 1) In the CNC programming environment, create a probe automatic measurement and alignment program based on the product's initial processing coordinate system 10; 2) First use the probe 14 to measure the coordinates of two points 11 that are far apart on a reference edge of the product, and calculate the angular deviation between the line connecting the two points and the product's initial processing coordinate system 10 through the program. The product's initial processing coordinate system 10 is rotated around the Z axis through the CNC system's coordinate rotation function to automatically compensate for the product's angular deviation and generate a transition processing coordinate system 12; 3) Then use the probe 14 to measure the product's positioning surfaces in the X, Y, and Z directions, respectively, and calculate the position deviation between the actual product position in the X, Y, and Z directions and the transition processing coordinate system 12, and correct the transition processing coordinate system through the CNC system's coordinate translation function to generate the final processing coordinate system 13; 4) In a flexible production line environment, before the product is automatically processed, the system automatically runs the automatic measurement and alignment program to automatically generate the final processing coordinate system 13 of the machine tool where the product is located, which is used for subsequent product processing. The macro program example is as follows:

[0060] …………

[0061] ;POINT:1 position measurement

[0062] N35 G0 X 215.197Y70.Z355.654; close to

[0063] N35 G1 X 215.197Y 70.Z 325.654F3000.; close to

[0064] N36 L9632(1.000,270,215.197,47.,325.654,50.,9999,9999); first point position measurement

[0065] N37 R80 = POS_Y; Y coordinate of the first point

[0066] N38 R81=$AA_IW[X];X coordinate of the first point

[0067] …………

[0068] ;POINT:2 position measurement

[0069] N45 G0 X-146.056Y70.Z355.362; position close

[0070] N45 G1 X-146.056Y70.Z325.362F3000.; close to

[0071] N46 L9632(1.000,270,-146.056,47.,325.362,50.,9999,9999); second point position measurement

[0072] N47 R82 = POS_Y; Y coordinate of the second point

[0073] N48 R83=$AA_IW[X];X coordinate of the first point

[0074] …………

[0075] N49 R85=R82-R80; Y coordinate difference

[0076] N50 R84=R83-R81; X coordinate difference

[0077] N51 R86=ATAN2(R85,R84); calculate angle deviation

[0078] N52$P_UIFR[1,C,TR]=$P_UIFR[1,C,TR]+(R86+180.); Compensate for the angular deviation of the product processing coordinate system

[0079] ; X reference position measurement

[0080] …………

[0081] N35 G0 X-146.056Y70.Z355.654; position close

[0082] N35 G1 X-146.056Y 70.Z 325.654F3000.; position close

[0083] N36 L9632 (1.000, 270, -146.056, 47., 325.654, 50., 9999, 9999); X reference position measurement

[0084] N37 R87 = POS_X; X reference position

[0085] N30$P_UIFR[1,X,TR]=R87; Set the product processing coordinate system G54X offset

[0086] ;Y reference position measurement

[0087] …………

[0088] N35 G0 X 215.197Y70.Z355.654; close to

[0089] N35 G1 X 215.197Y 70.Z 325.654F3000.; close to

[0090] N36 L9632 (1.000, 270, 215.197, 47., 325.654, 50., 9999, 9999); Y reference position measurement

[0091] N37 R87 = POS_Y; Y reference position

[0092] N30$P_UIFR[1,Y,TR]=R87; Set the product processing coordinate system G54Y offset

[0093] ; Z reference position measurement

[0094] …………

[0095] N35 G0 X 215.197Y70.Z355.654; close to

[0096] N35 G1 X 215.197Y 70.Z 305.654F3000.; close to

[0097] N36 L9632 (1.000, 270, 215.197, 47., 305.654, 50., 9999, 9999); Z reference position measurement

[0098] N37 R87 = POS_Z; Z reference position

[0099] N30$P_UIFR[1,Z,TR]=R87; Set the product processing coordinate system G54Z offset.

Claims

1. A method for dynamically generating a processing coordinate system for a flexible production line, characterized in that Include: Step 1: Automatic generation method of machine tool reference coordinate system in flexible production line, the specific process includes: 1-1 On any CNC machine tool in the flexible production line, select a fixed position on a standard pallet as the reference point; 1-2 For each CNC machine tool in the flexible production line, the mechanical coordinates of the standard pallet reference point in the original coordinate system of the machine tool are determined in advance and stored in the user variable file of the machine tool control system in the form of system user variables; 1-3 Before the product is automatically processed, the user variables of the mechanical coordinate system containing the reference point are called through the system macro program to automatically generate the reference coordinate system of the machine tool; Step 2: Dynamic generation method of the initial processing coordinate system of the product to be processed in the flexible production line. The specific process is as follows: 2-1 In the CNC programming environment including the product to be processed, tooling, and standard pallet, establish the theoretical position relationship between the three and keep it consistent with the actual processing; 2-2 Establish a machine tool reference coordinate system at the standard pallet reference point, and at the same time establish a first product initial processing coordinate system in the programming environment at the product positioning point. The first product initial processing coordinate system and the machine tool reference coordinate system are in a translation relationship, or a translation + rotation relationship; 2-3 Create a CNC system macro program in the CNC programming environment. The macro program can automatically generate the second product initial processing coordinate system in the machine tool environment through the coordinate position relationship calculation between the machine tool reference coordinate system and the first product initial processing coordinate system. When the first product initial processing coordinate system and the machine tool reference coordinate system are in a translation relationship, the coordinate position calculation relationship is: X3=X2+δX,Y3=Y2+δY,Z3=Z2+δZ,where (X3,Y3,Z3) are the coordinates of the origin of the initial processing coordinate system of the first product, (X2,Y2,Z2) are the coordinates of the origin of the machine tool reference coordinate system, (δX,δY,δZ) are the coordinate differences of the origins of the two coordinate systems in the X, Y, and Z directions. When the initial processing coordinate system of the first product and the machine tool reference coordinate system are in a translation + rotation relationship, the coordinate position calculation relationship is: X3=X2+δX-Xe, Y3=Y2+δY-Ye, Z3=Z2+δZ, C3=C2+δC Wherein, C3 is the angular offset of the initial processing coordinate system of the first product, C2 is the angular offset of the machine tool reference coordinate system, δC is the difference in rotation angle between the two coordinate systems; Xe=(X2+δX-X0)-(X2+δX-X0)*COS(-δC)+(Y2+δY-Y0)*SIN(-δC), Ye=(Y2+δY-Y0)-(Y2+δY-Y0)*COS(-δC)-(X2+δX-X0)*SIN(-δC); X0, Y0 are the original X and Y machine tool coordinates of the center of the rotary table, respectively; 2-4 Run the CNC system macro program created in 2-3 in the CNC machine tool environment in the flexible production line, which will automatically generate the second product initial processing coordinate system of the CNC machine tool where the product is located; Step 3: Adaptive generation method of the final processing coordinate system of the product to be processed. The specific process is as follows: 3-1 Create a probe automatic measurement and alignment program; 3-2 The alignment program can use the probe to measure the angle deviation between a reference edge of the product or the line connecting the two hole centers and the initial processing coordinate system of the second product, automatically compensate for the angle deviation of the product reference edge, and generate a transition processing coordinate system; 3-3 Then measure the positioning surfaces of the product in the X, Y, and Z directions, calculate and correct the position deviations between the actual product position in the X, Y, and Z directions and the transition processing coordinate system, and generate the final processing coordinate system for automated processing.

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