A method for automatically connecting trajectories between programs in robot grinding and polishing

Abstract

The present invention relates to the field of robotic grinding and polishing technology, and in particular to a method for automatically connecting trajectories between programs in robotic grinding and polishing processing, comprising: establishing a workpiece blank envelope; obtaining the projection coordinates of the four endpoints of the upper surface of the blank on the workpiece coordinate system XY plane and the distance from the coordinate system XY plane to the upper surface of the blank; inserting the above information into a structure tree using the text insertion function of CAM, and automatically outputting it with a pre-set APT file; dividing different operations between programs based on the operation terminator in the program; judging whether the angle between the two normal vectors before and after the operation exceeds a limit value, and if not, continuing to the next operation; if it exceeds the limit value, continuing to judge whether the four endpoints of the blank are on the same side of the line connecting the two points before and after the operation, and if so, continuing to the next operation; if not, performing automatic trajectories connection processing between the operations, and after processing, continuing to the next operation. By using this method, the problem of low programming efficiency can be effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of robot grinding and polishing, and in particular to a method for automatically connecting tracks between programs in robot grinding and polishing processing. Background Art

[0002] With the development of science and technology, industrial robots have been widely used in the manufacturing field. In the field of aviation manufacturing, robotic processing has also been widely studied, especially in civil aviation manufacturing companies. World-renowned aviation manufacturing giants such as Boeing and Airbus have successfully applied robotic technology to aircraft drilling, riveting, spraying, grinding, welding and other applications, and have been widely promoted.

[0003] When performing offline programming for robot grinding and polishing, it is necessary to consider the transition between programs. This requires process personnel to add obstacle avoidance points between programs and compile transition trajectories based on their experience. This requires a high level of experience from process personnel and involves repeated modifications, which seriously restricts the improvement of offline programming efficiency. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention proposes a method for automatically connecting trajectories between programs in robot grinding and polishing processing, which can effectively solve the problem of low programming efficiency caused by relying on manual addition of obstacle avoidance points and compilation of transition trajectories in the current robot grinding and polishing processing program compilation process.

[0005] The present invention is achieved by adopting the following technical solutions:

[0006] A method for automatically connecting trajectories between programs in robot grinding and polishing processing comprises the following steps:

[0007] Step 1. Based on the workpiece coordinate system, establish the workpiece blank envelope along the X / Y / Z directions according to the minimization principle;

[0008] Step 2. Obtain the projection coordinates (X1, Y1), (X2, Y2), (X3, Y3), (X4, Y4) of the four endpoints of the upper surface of the blank on the XY plane of the workpiece coordinate system and the distance H from the XY plane of the coordinate system to the upper surface of the blank;

[0009] Step 3. Insert the above information into the structure tree through the text insertion function of CAM, and automatically output it along with the pre-APT file;

[0010] Step 4. Divide different operations between programs based on the operation terminators in the programs;

[0011] Step 5. Determine whether the angle between the two normal vectors before and after the operation exceeds the limit value. If it does not exceed the limit value, continue to the next operation until the end; if it exceeds the limit value, continue to determine whether the four endpoints of the blank are on the same side of the line connecting the two points before and after the operation. If they are on the same side, continue to the next operation until the end. If they are not on the same side, perform automatic connection processing of the trajectory between operations. After processing, continue to the next operation until the end.

[0012] The automatic connection process of the trajectory between operations in step 5 specifically includes the following steps:

[0013] Step S1. Assume that the point position and normal vector coordinates corresponding to the end of the previous operation are P A (X A , Y A , Z A ) and τ A (I A , J A , K A ), insert obstacle avoidance point M(X A , Y A , H+L); in P A The point keeps the normal vector unchanged and drives the TCP point to move to point M; where L is the distance from the upper surface of the blank to the virtual safety plane;

[0014] Step S2. Assume that the point position and normal vector coordinates corresponding to the start of the next operation are P B (X B , Y B , Z B ) and τ B (I B , J B , K B ), insert obstacle avoidance point N(X B , Y B , H+L), drive the TCP point from point M to point N, and then move the normal vector τ at point N A (I a , J a , K a ) changes to τ b (I b , J B , K B ), that is, the change of the swing angle;

[0015] Step S3. Drive the TCP point from point N to point P B , that is, the automatic connection of trajectories between operations is completed.

[0016] In the step 1, the envelope of the workpiece blank is a rectangular parallelepiped structure, and the farthest point on the periphery of the workpiece has a safety margin of 3 mm from the boundary surface of the envelope.

[0017] The calculation method of the angle between the two normal vectors in step 5 is:

[0018] θ=arccos(ab / (|a|·|b|)),

[0019] Among them, a and b are the two normal vectors before and after the operation respectively.

[0020] In step 5, the method for determining whether the four endpoints of the blank are located on the same side of the line connecting the front and rear points of the operation room is as follows:

[0021] Assume the end point of the previous operation is P a (X a , Y A , Z A ), corresponding to the last retraction point; the starting point of the next operation is P B (X B , Y B , Z B ), corresponding to the starting point of feed; then the projection vector of the vector formed by the line connecting the two points on the XY plane of the workpiece coordinate system is

[0022] The projection coordinates of the four endpoints of the upper surface of the blank on the XY plane of the workpiece coordinate system are (X1, Y1), (X2, Y2), (X3, Y3), and (X4, Y4). The four vectors formed by the projection points of the four endpoints and the origin P0 (X0, Y0) of the workpiece coordinate system on the XY plane of the workpiece coordinate system are:

[0023] make

[0024] if The same sign, that is, both facing Z + Or both facing down Z - , it means that the four endpoints of the blank are on the same side of the line connecting the front and back points of the operation room; otherwise, it means that the four endpoints of the blank are not on the same side of the line connecting the front and back points of the operation room.

[0025] In the step 2, the projection coordinates of the four endpoints of the upper surface of the blank on the XY plane of the workpiece coordinate system are obtained in the CAM offline programming system.

[0026] In the step 4, the END character exists in the terminator as a segmentation mark.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] Currently, the transition between robotic grinding and polishing programs requires manual experience to add obstacle avoidance points and compile trajectories. This process requires repeated adjustments and determinations in a simulation environment, resulting in a high workload and time-consuming offline programming. This method overcomes the inefficiency of existing programs that rely on manual experience to plan obstacle avoidance points and grinding and polishing trajectories. Specifically, the present invention eliminates the need to consider transitions between programs during the offline programming phase, avoiding the inefficiency associated with manually adding obstacle avoidance points and compiling transition trajectories. It automatically plans transition trajectories between programs to avoid interference and collisions, significantly improving the efficiency and intelligence of offline programming.

[0029] 2. This method was compared with the traditional method (relying on experience to set obstacle avoidance points and generate trajectories). With the traditional method, setting points between programs typically takes 0.3 hours, generating trajectories between programs typically takes 0.5 hours, and the total time required is 0.8 hours. In contrast, this method takes 0 hours to set points between programs, 0 hours to generate trajectories between programs, and 0 hours in total, significantly improving processing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, wherein:

[0031] Figure 1 It is a schematic diagram of the process of the present invention;

[0032] Figure 2 Schematic diagram of the collision between the entry and exit points of the present invention and the envelope size of the part blank;

[0033] Figure 3 This is a simulation diagram of the grinding and polishing of typical parts in the present invention. DETAILED DESCRIPTION

[0034] Example 1

[0035] As a basic embodiment of the present invention, the present invention includes a method for automatically connecting trajectories between programs in robot grinding and polishing processing, comprising the following steps:

[0036] Step 1. Based on the workpiece coordinate system, establish the workpiece blank envelope along the X / Y / Z directions according to the minimization principle.

[0037] Step 2. Obtain the projection coordinates (X1, Y1), (X2, Y2), (Y3, Y3), (X4, Y4) of the four endpoints of the upper surface of the blank on the XY plane of the workpiece coordinate system and the distance H from the XY plane of the coordinate system to the upper surface of the blank.

[0038] Step 3. Insert the above information into the structure tree through the text insertion function of CAM, and automatically output it with the preceding APT file.

[0039] Step 4. Divide different operations between programs based on the operation terminators in the programs.

[0040] Step 5. Determine whether the angle between the two normal vectors before and after the operation exceeds the limit value. If the angle between the two normal vectors before and after is too large, it means that the angle difference between the trajectory planning surface of the previous operation and the trajectory planning surface of the next operation is large, that is, the trajectory planning span is large, which is easy to cause interference collision. Therefore, if it does not exceed the limit value, continue to the next operation until the end. If it exceeds the limit value, continue to determine whether the four endpoints of the blank are on the same side of the line connecting the two points before and after the operation. If they are on the same side, it means that even if the span is large, but changes are made on the outside of the blank, it is believed that the trajectory will not intersect with the blank, that is, no interference collision will occur. Therefore, if they are on the same side, continue to the next operation until the end. If they are not on the same side, the trajectory between operations is automatically connected. After processing, continue to the next operation until the end.

[0041] The program has been divided into multiple operations based on identification symbols, and continuing the next operation refers to continuing the processing of the next operation program segment.

[0042] Example 2

[0043] As a preferred embodiment of the present invention, the present invention includes a method for automatically connecting trajectories between programs in a robot grinding and polishing process, comprising the following steps:

[0044] Step 1. Based on the workpiece coordinate system, establish the workpiece blank envelope along the X / Y / Z directions according to the minimization principle.

[0045] Step 2. Obtain the projection coordinates (X1, Y1), (X2, Y2), (Y3, Y3), (X4, Y4) of the four endpoints of the upper surface of the blank on the XY plane of the workpiece coordinate system and the distance H from the XY plane of the coordinate system to the upper surface of the blank.

[0046] Step 3. Insert the above information into the structure tree through the text insertion function of CAM, and automatically output it with the preceding APT file.

[0047] Step 4. Divide different operations between programs based on the operation terminators in the programs.

[0048] Step 5. Determine whether the angle between the two normal vectors before and after the operation exceeds the limit value. If it does not exceed the limit value, continue to the next operation until the end; if it exceeds the limit value, continue to determine whether the four endpoints of the blank are on the same side of the line connecting the two points before and after the operation. If they are on the same side, continue to the next operation until the end. If they are not on the same side, perform automatic connection processing of the trajectory between operations. After processing, continue to the next operation until the end.

[0049] The automatic connection process between operation trajectories specifically includes the following steps:

[0050] Step S1. Assume that the point position and normal vector coordinates corresponding to the end of the previous operation are P A (X A , Y A , Z A ) and τ A (I A , J A , K A ), insert obstacle avoidance point M(X A , Y A , H+L); in P A The point keeps the normal vector unchanged and drives the TCP point to move to point M; where L is the distance from the upper surface of the blank to the virtual safety plane.

[0051] Step S2. Assume that the point position and normal vector coordinates corresponding to the start of the next operation are P B (X B , Y B , Z B ) and τ B (I B , J B , K B ), insert obstacle avoidance point N(X B , Y B , H+L), drive the TCP point from point M to point N, and then move the normal vector τ at point N A (I A , J A , K A ) changes to τ B (I B , J B , K B ), that is, changing the swing angle.

[0052] Step S3. Drive the TCP point from point N to point P B , that is, the automatic connection of trajectories between operations is completed.

[0053] Example 3

[0054] As the best embodiment of the present invention, the present invention includes a method for automatically connecting the trajectories between programs in a robot grinding and polishing process, Figure 1 , including the following steps:

[0055] Step 1. Using the workpiece coordinate system as a reference, establish the workpiece blank envelope along the X / Y / Z directions using the principle of minimization. The blank envelope should be a strict rectangular parallelepiped structure that completely encloses the workpiece, with a 3mm safety margin between the farthest point on the workpiece periphery and the envelope boundary surface.

[0056] Step 2. Obtain the projection coordinates (X1, Y1), (X2, Y2), (X3, Y3), (X4, Y4) of the four endpoints of the upper surface of the blank on the XY plane of the workpiece coordinate system and the distance H from the XY plane of the coordinate system to the upper surface of the blank in the CAM offline programming system.

[0057] Step 3. Insert the above information into the structure tree through the text insertion function of CAM, and automatically output it with the preceding APT file.

[0058] Step 4. Divide different operations between programs based on the operation terminator in the program. Generally, the terminator contains the END character as a separation marker.

[0059] Step 5. Determine whether the angle between the two normal vectors before and after the operation exceeds the limit. If it does not exceed the limit, continue to the next operation until the end; if it exceeds the limit, continue to determine whether the four endpoints of the blank are on the same side of the line connecting the two points before and after the operation.

[0060] Among them, the calculation method of the angle between the two normal vectors before and after the operation is:

[0061] θ=arccos(ab / (|a|·|b|)),

[0062] Where a and b are the two normal vectors before and after the operation respectively.

[0063] The method for judging whether the four endpoints of the blank are on the same side of the line connecting the front and back points of the operation room is:

[0064] Assume the end point of the previous operation is P A (X A , Y A , Z A ), corresponding to the last retraction point; the starting point of the next operation is P B (X B , Y B , Z B ), corresponding to the starting point of feed. Then the projection vector of the vector formed by the line connecting the two points on the XY plane of the workpiece coordinate system is

[0065] The projection coordinates of the four endpoints of the upper surface of the blank on the XY plane of the workpiece coordinate system are (X1, Y1), (X2, Y2), (X3, Y3), (X4, Y4), and the four vectors formed by the projection points of the four endpoints and the origin of the workpiece coordinate system P0 (X0, Y0) on the XY plane of the workpiece coordinate system are

[0066] make if The same sign, that is, both facing Z + Or both facing down Z- , it means that the four endpoints of the blank are on the same side of the line connecting the front and back points of the operation room; otherwise, it means that the four endpoints of the blank are not on the same side of the line connecting the front and back points of the operation room.

[0067] Refer to the instruction manual Figure 2 If the two are on the same side, then even if the span is large, if the change is made outside the blank, then the trajectory will not intersect with the blank, that is, no interference collision will occur. Therefore, if it is determined to be on the same side, the next operation will be continued until the end; if it is not on the same side, the trajectory between operations will be automatically connected. After processing, the next operation will be continued until the end.

[0068] Among them, refer to the instructions attached Figure 3 , the automatic connection processing of the trajectory between operations specifically includes the following steps:

[0069] Step S1. Assume that the point position and normal vector coordinates corresponding to the end of the previous operation are P A (X A , Y A , Z A ) and τ A (I A , J A , K A ), insert obstacle avoidance point M(X A , Y A , H+L); in P A The point keeps the normal vector unchanged and drives the TCP point to move to point M. Among them, L is the distance from the upper surface of the blank to the virtual safety plane. The L value can be adjusted appropriately according to the actual situation and is generally between 50-100.

[0070] Step S2. Assume that the point position and normal vector coordinates corresponding to the start of the next operation are P B (X B , Y B , Z B ) and τ B (I B , J B , K B ), insert obstacle avoidance point N(X B , Y B , H+L), drive the TCP point from point M to point N, and then move the normal vector τ at point N A (I A , J A , K A ) changes to τ B (I B , J B , K B ), that is, changing the swing angle.

[0071] Step S3. Drive the TCP point from point N to point P B , that is, the automatic connection of trajectories between operations is completed.

[0072] In summary, after reading the present invention document, ordinary technicians in this field can make various other corresponding transformation schemes based on the technical solutions and technical concepts of the present invention without creative mental work, which all fall within the scope of protection of the present invention.

Claims

1. A method for automatically connecting trajectories between programs in robot grinding and polishing, characterized by: The following steps are involved: Step 1. Based on the workpiece coordinate system, establish the workpiece blank envelope along the X / Y / Z directions using the minimization principle. Step 2. Obtain the projection coordinates of the four endpoints of the upper surface of the blank on the XY plane of the workpiece coordinate system ( )、( )、( )、( ) and the distance H from the XY plane of the coordinate system to the upper surface of the blank; Step 3. Insert the above information into the structure tree using CAM's built-in text insertion function, and automatically output it along with the pre-APT file. Step 4. Classify different operations between programs based on the operation terminators in the program; Step 5. Determine whether the angle between the two normal vectors before and after the operation exceeds the limit value. If it does not exceed the limit value, continue to the next operation until the end; if it exceeds the limit value, continue to determine whether the four endpoints of the blank are on the same side of the line connecting the two points before and after the operation. If they are on the same side, continue to the next operation until the end. If they are not on the same side, perform automatic connection processing of the trajectory between the operations. After processing, continue to the next operation until the end.

2. The method for automatically connecting trajectories between programs in robot grinding and polishing according to claim 1, characterized in that: The automatic connection process of the trajectory between operations in step 5 specifically includes the following steps: Step S1. Assume that the point position and normal vector coordinates corresponding to the end of the previous operation are and , insert obstacle avoidance point M ( );exist The point keeps the normal vector unchanged and drives the TCP point to move to point M; where L is the distance from the upper surface of the blank to the virtual safety plane; Step S2. Set the point position and normal vector coordinates corresponding to the start of the next operation to be and , insert obstacle avoidance point N( ), drive the TCP point from point M to point N, and then move the normal vector at point N for ; Step S3. Drive the TCP point from point N to point , that is, the automatic connection of trajectories between operations is completed.

3. The method for automatically connecting trajectories between programs in robot grinding and polishing according to claim 1, characterized in that: In the step 1, the envelope of the workpiece blank is a rectangular parallelepiped structure, and the farthest point on the periphery of the workpiece has a safety margin of 3 mm from the boundary surface of the envelope.

4. The method for automatically connecting trajectories between programs in a robot grinding and polishing process according to claim 1, characterized in that: The calculation method of the angle between the two normal vectors in step 5 is: ， Among them, a and b are the two normal vectors before and after the operation respectively.

5. The method for automatically connecting trajectories between programs in robot grinding and polishing according to claim 2, characterized in that: In step 5, the method for determining whether the four endpoints of the blank are located on the same side of the line connecting the front and rear points of the operation room is as follows: Assume the end point of the previous operation is , corresponding to the last retraction point; the starting point of the next operation is , corresponding to the starting point of feed; then the projection vector of the vector formed by the line connecting the two points on the XY plane of the workpiece coordinate system is ( ); The projection coordinates of the four endpoints of the upper surface of the blank on the XY plane of the workpiece coordinate system are ( )、( )、( )、( ), four endpoints and the origin of the workpiece coordinate system The four vectors formed by the projection points on the XY plane of the workpiece coordinate system are: ( ), ( ), ( ), ( ); make = , = , = , = ; if The same sign means both Or both , it means that the four endpoints of the blank are on the same side of the line connecting the front and back points of the operation room; otherwise, it means that the four endpoints of the blank are not on the same side of the line connecting the front and back points of the operation room.

6. The method for automatically connecting trajectories between programs in a robot grinding and polishing process according to claim 2, characterized in that: In the step 2, the projection coordinates of the four endpoints of the upper surface of the blank on the XY plane of the workpiece coordinate system are obtained in the CAM offline programming system.

7. The method for automatically connecting trajectories between programs in a robot grinding and polishing process according to claim 2, characterized in that: In the step 4, the END character exists in the terminator as a segmentation mark.

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