Method for rapidly calculating stacking coordinate system

Abstract

The invention discloses a method for rapidly calculating a stacking coordinate system, and relates to the field of industrial automation and robots. By introducing a coordinate system offset calculation technology based on homogeneous transformation, the stacking precision and the operation efficiency are remarkably improved. A 4 * 4 homogeneous transformation matrix is utilized, translation and rotation are integrated into one matrix to be processed, accurate conversion between a reference coordinate system and an offset coordinate system of the robot is achieved, and it is ensured that accurate positioning can be achieved under the condition of any position and angle offset. Meanwhile, by dynamically adjusting a stacking coordinate system, the stacking device can flexibly adapt to changes of objects of different sizes and shapes, and especially when the stacking range of the objects exceeds the boundary of a stacking disc, accurate positioning and stacking can still be achieved. In addition, the robot keeps the fixed angle of the tail end tool relative to the base in the moving process, the consistency of the operation posture is ensured, and the stacking precision is further improved.

Description

Technical Field

[0001] The present invention relates to the field of industrial automation and robotics, and particularly to a method for quickly calculating a palletizing coordinate system. Background Art

[0002] The origin of the palletizing coordinate system is generally set at a certain fixed corner point of the pallet or tray. This origin is selected to align with the edge of the pallet or tray, so that the coordinate system can cover the entire stacking area. However, in practical applications, if the size of the stacked objects is large or the placement requirements exceed the boundary of the pallet, the original coordinate system may not be able to fully cover the new stacking range. In this case, to ensure the accuracy and consistency of the entire stacking area, the origin of the palletizing coordinate system is usually reset at the outermost corner of the first item, and this point is used as the origin of the new starting coordinate system.

[0003] In the palletizing industry, robots usually use the "three-point method" to determine the coordinate system on the pallet. The three-point method is a common coordinate system establishment method in the palletizing process of industrial robots. This method determines a local coordinate system by selecting three non-collinear reference points on the pallet, providing a reference for the position calibration of the robot. These three points respectively define the origin, the X-axis direction, and the Y-axis direction of the coordinate system, enabling the robot to calculate the exact position and placement angle of the object based on this coordinate system, and thus complete precise palletizing operations.

[0004] The advantage of the three-point method is that it is simple to operate and has stable calculations, and is suitable for pallets with fixed positions in a standardized production environment. The control system of the robot can clearly identify the boundary and position of the pallet through the coordinate system generated by these three reference points, ensuring the placement accuracy of the object. However, this method relies on fixed reference points. When the object or stacking position exceeds the boundary of the pallet, the three-point method may not provide sufficient coordinate references, limiting its application in complex and flexible palletizing scenarios. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a method for quickly calculating a palletizing coordinate system, which is used in the palletizing industry, especially for quickly positioning the palletizing coordinate system during palletizing, so as to solve the problems of robot teaching efficiency and accuracy in scenarios where the object size is not fixed and the types are diverse.

[0006] To achieve the above object, the present application discloses a method for quickly calculating a palletizing coordinate system, including the following steps: (1). Calibrate the zero position of the robot and the tool coordinate system at the mechanical end; (2). Set a fixed center point on the left side ground of the robot and mark this point as point A; (3). Teach the fixed center point position. During the process of moving the robot, record the coordinate value P after reaching the point. 1(x, y, z, a, b, c) (4). Move in the tool coordinate system. After switching the robot to the tool coordinate system, move 1000 mm in the X+ direction of the tool coordinate system and stop. Mark the position of the robot's end point B on the ground; after moving the robot back to point P 1 , move 1000 mm in the Y+ direction of the tool coordinate system and stop. Mark the position of the robot's end point C on the ground; (5). After connecting AB and AC, make a scribed mark, and at the same time measure the length, width and height values of the pallet (L 1 , W 1 , H 1 ); (6). Place the two vertical sides of the pallet parallel to and close to the AB and AC lines respectively; (7). Move the pallet. Move a distance of L 1 / 2 in the opposite direction of AB and a distance of W 1 / 2 in the opposite direction of AC. At this time, the center of the plane of the pallet coincides with point A. Mark the four corner positions of the pallet, which are the placement positions of this type of pallet; (8). According to the length, width, number of rows and columns, and row and column styles of the items placed on the pallet as needed, calculate the length and width of the plane after each layer is placed (L 2 , W 2 ), and then obtain the offset of the fixed center point P 1 to the origin P c of the coordinate system is (-L 2 / 2, -W 2 / 2, H 1 , 0, 0, 0); (9). The origin coordinates of the coordinate system can be obtained through the coordinate homogeneous transformation matrix formula T new = T base · T offset . After applying the data (x', y', z', a', b', c') = (x + (-L 2 ) / 2, y + (-W 2 ) / 2, z + H 1 , a, b, c), and calculate the origin of the coordinate system as P c (x', y', z', a', b', c').

[0007] Furthermore, in step (3), when teaching the fixed center point, keep the posture of the robot's end tool unchanged.

[0008] Furthermore, if the length and width of the plane pattern of the pallet change, repeat steps (8)-(9) to calculate the new origin P c of the coordinate system.

[0009] Advantages of the technical solution of the present invention 1. Improve palletizing accuracy. The patent adopts the coordinate system offset calculation technology based on homogeneous transformation, which significantly improves the accuracy of coordinate transformation and offset, making the positioning of the robot in the complex three-dimensional space more accurate, especially suitable for the stacking scenarios where the object exceeds the boundary of the pallet. Through accurate coordinate system calculation, the positioning error caused by manual setting or repeated teaching is effectively reduced.

[0010] 2. Adaptability, support diverse stacking. The patent has the function of dynamically adjusting the palletizing coordinate system, enabling the robot to flexibly cope with the changes of objects with different sizes and shapes, and meeting the complex and diverse stacking requirements. The automatic offset setting and adaptive coordinate adjustment mechanism support the rapid switching of stacking scenarios, reduce the need for frequently resetting the reference point, and greatly improve the flexibility of production.

[0011] 3. Operating efficiency, reduce manual intervention. The traditional manual teaching and reference point resetting processes are complex, especially with low efficiency when frequently changing objects or pallets. This patent reduces the manual teaching operation through intelligent offset coordinate system calculation, thus accelerating the execution speed of the palletizing task, saving operation time and reducing labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0013] Figure 1 It is a schematic diagram of step (4) of the present invention; Figure 2 It is a schematic diagram of step (7) of the present invention; Figure 3 It is a schematic diagram of the coordinate origin P C of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0015] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "communication" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0016] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0017] Reference Figure 1-2 , (1). Calibrate the zero position of the robot and the tool coordinate system at the mechanical end; (2). Set a fixed center point on the ground on the left side of the robot and mark this point as point A; (3). Teach the fixed center point position. During the process of moving the robot, record the coordinate value P 1 (x, y, z, a, b, c) (4). Move under the tool coordinate system. After switching the robot to the tool coordinate system, stop when moving 1000 mm in the X+ direction of the tool coordinate system, and mark the end point of the robot on the ground as point B; After moving the robot back to point P 1 , stop when moving 1000 mm in the Y+ direction of the tool coordinate system, and mark the end point of the robot on the ground as point C; (5). After connecting AB and AC, make a scribed mark, and at the same time measure the length, width, and height values (L 1 , W 1 , H 1 ) of the pallet; (6). Make the two vertical sides of the pallet parallel to and close to the AB and AC lines respectively; (7). Move the pallet and move L 1 / 2 distance in the opposite direction of AB, and move W 1 / 2 distance in the opposite direction of AC. At this time, the center of the plane of the pallet coincides with point A, and mark the four corner points of the pallet as the placement points of this type of pallet; (8). According to the length, width, number of rows and columns, and row and column styles of the items to be placed on the pallet, calculate the length and width (L 2 , W 2), thereby obtaining the fixed center point P 1 to the origin P of the coordinate system c The offset is (-L 2 / 2, -W 2 / 2, H 1 , 0, 0, 0); (9). The origin coordinates of the coordinate system can be obtained through the coordinate homogeneous transformation matrix formula T new = T base ·T offset , after applying the data (x', y', z', a', b', c') = (x + (-L 2 ) / 2, y + (-W 2 ) / 2, z + H 1 , a, b, c), and calculating to obtain the origin of the coordinate system as P c (x', y', z', a', b', c').

[0018] This patent significantly improves the palletizing accuracy and operation efficiency by introducing the coordinate system offset calculation technology based on homogeneous transformation. Using the 4x4 homogeneous transformation matrix, translation and rotation are integrated and processed in one matrix to achieve accurate conversion between the robot's reference coordinate system and the offset coordinate system, ensuring accurate positioning under any position and angle offset conditions. At the same time, by dynamically adjusting the palletizing coordinate system, it can flexibly adapt to the changes of objects with different sizes and shapes. Especially when the stacking range of the object exceeds the pallet boundary, accurate positioning and stacking can still be achieved. In addition, the robot maintains a fixed angle of the end tool relative to the base during movement, ensuring the consistency of the operation posture and further improving the stacking accuracy.

[0019] The innovation of this patent lies in its efficient coordinate offset calculation method and dynamic coordinate system reset technology. Through the homogeneous transformation matrix, the offset calculation is more accurate and applicable to palletizing operations in complex three-dimensional spaces. When the object size changes or the stacking range exceeds the pallet boundary, the system can automatically adjust the origin of the palletizing coordinate system to the edge corner point of the first object, ensuring that the new palletizing area has an accurate coordinate reference. In addition, only one point needs to be taught to automatically adjust the offset and the coordinate system, reducing frequent reference point resetting and teaching operations, and significantly improving the flexibility and efficiency of the production line.

[0020] The core protection point of this patent lies in its dynamic coordinate system origin setting method, that is, the technical solution of dynamically resetting the coordinate system by adjusting the origin of the palletizing coordinate system when the object size or stacking range exceeds the pallet boundary. This technology not only improves the palletizing accuracy but also greatly reduces the need for manual intervention, providing an efficient and flexible solution for complex palletizing scenarios.

[0021] Preferably, in the step (3), when teaching and fixing the central point, the posture of the end tool of the robot is kept unchanged.

[0022] In addition, if the length and width of the planar pattern of the palletizing change, repeating the steps (8)-(9) can calculate the origin P of the new coordinate system. c .

[0023] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for quickly calculating a palletizing coordinate system, characterized in that: The steps include: (1). Calibrate the robot zero point position and the mechanical end tool coordinate system; (2) Set a fixed center point on the left side of the robot and mark it as point A. (3). Teach the fixed center point. When the robot moves, record the coordinate value P1 (x, y, z, a, b, c) after reaching the point. (4) Move in the tool coordinate system. After switching the robot to the tool coordinate system, move 1000 mm at the X+ of the tool coordinate system and stop, and mark the robot end point B on the ground. After moving the robot back to point P1, move 1000 mm at the Y+ of the tool coordinate system and stop, and mark the robot end point C on the ground. (5) After connecting AB and AC, make a line mark and measure the length, width and height of the encoder (L1, W1, H1); (6) Place the two vertical sides of the tray parallel and close to the AB and AC lines respectively; (7) Move the code disk a distance of L1 / 2 in the opposite direction of AB and a distance of W1 / 2 in the opposite direction of AC. At this time, the center of the plane of the code disk coincides with point A. Mark the four corner points of the code disk as the placement points of this type of code disk. (8) According to the length and width of the items placed on the code disk, the number of rows and columns, and the row and column style, the length and width (L2, W2) of each layer after placement are calculated, and then the fixed center point P1 to the origin of the coordinate system P is obtained. c The offset is (-L2 / 2,-W2 / 2,H1,0,0,0); (9) The coordinates of the origin of the coordinate system can be obtained by the coordinate homogeneous transformation matrix formula T new =T base ·T offset , after applying the data (x',y',z',a',b',c')=(x+(-L2) / 2,y+(-W2) / 2,z+H1,a,b,c), the origin of the coordinate system is calculated to be P c (x',y',z',a',b',c').

2. The method for quickly calculating a palletizing coordinate system according to claim 1, characterized in that: In the step (3), when teaching the fixed center point, the posture of the robot end tool is kept unchanged.

3. The method for quickly calculating a palletizing coordinate system according to claim 1, characterized in that: If the length and width of the palletizing plane are changed, repeat steps (8)-(9) to calculate the new coordinate system origin P. c .

Images