A Determination Method for the Bending Application of a Six-Axis Industrial Robot

Abstract

The present invention relates to a method for determining the bending application of a six-axis industrial robot. This method can deduce the workspace requirements that need to be met for the robot's bending application based on the actual application scenarios of the bending machine, and then correspond to the specification parameters of the six-axis robot to determine the optimal installation distance and height of the robot. By matching the workspace of the robot with the bending range of the bending machine, this method determines whether there is a suitable application installation position for the robot, solving the problem that when a certain type of six-axis robot has been determined, it is impossible to effectively determine the sheet metal bending work of what specifications can be applied only through the load and arm span, and the problem that there is no accurate method to judge whether the robot can meet the usage requirements or how to install it to make the bending space the largest and optimal in practical applications.

Description

Technical Field

[0001] The present invention relates to the technical field of robots, and in particular to a method for determining the bending application of a six-axis industrial robot. Background Art

[0002] Due to the high flexibility of six-axis robots, they are often used in the sheet metal bending process. The general method is to fix the sheet metal to be adsorbed at the end of the robot through devices such as suction cups, and move the corresponding bending points of the sheet metal to the designated position of the bending machine through the movement of the robot. During the bending process of the robot, the end moves along with the bending of the sheet metal, and the precise bending of the sheet metal is achieved by following. However, this method has the following problems: There are few professional bending robots available in the current market. Due to differences in arm span, rotation angle, shape, etc. of general-purpose six-axis robots, there is no accurate method to determine whether the robot can meet the usage requirements or how to install it to maximize the bending space in actual applications; when a certain type of six-axis robot has been determined, it is impossible to effectively determine the sheet metal bending work of what specifications it can be applied to only through the load and arm span. Summary of the Invention

[0003] Based on this, the purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art, and provide a method for determining the bending application of a six-axis industrial robot.

[0004] The embodiment of the present invention provides a method for determining the bending application of a six-axis industrial robot, including the following steps:

[0005] S10: Obtain the height value h of the lower die cutting edge of the bending machine from the bottom surface, the size values a, b, and c of the length, width, and thickness of the bent material sheet metal, and calculate the maximum working radius r with the edge of the sheet metal as the adsorption point;

[0006] S20: Establish a coordinate system with the contact point between the lower die of the bending machine and the sheet metal, and determine the trajectory equation of the adsorption point and the five-axis rotation center p point of the robot;

[0007] S30: Obtain the arm span parameter, rotation angle, and attitude parameter of the robot;

[0008] S40: Establish a rectangular coordinate system with the center of the second axis of the robot, and respectively determine the trajectory equations of the farthest working range and the nearest working range to determine the working space of the robot;

[0009] S50: Match the trajectory equation of the p point with the working space of the robot, and judge whether there is an installation position of the robot such that the space range of the robot covers all the p point ranges;

[0010] S60: If the matching is determined to be successful, it is determined that the robot meets the bending application. If the matching fails, the parameters are adjusted according to the preset adjustment rules, and the verification calculation is performed again.

[0011] Further, the formula for calculating the maximum working radius r in step S10 is:

[0012] 。

[0013] Further, the trajectory equation of the adsorption point in step S20 is:

[0014] ;

[0015] Among them, 、 represent the coordinates of the adsorption point. In addition, the above trajectory is represented by the rotation angle, and its formula is:

[0016] ;

[0017] Among them, θ is set as the angle of the sheet metal rotating clockwise from the horizontal posture, and its range is 0 - 75°;

[0018] Since the distance from the adsorption point to the five-axis rotation center p point of the robot is usually a vertically fixed distance, this distance is the distance from the p point to the mounting flange plus the distance from the mounting flange surface to the adsorption disc. Let this distance be d, then the trajectory equation of the P point is:

[0019] ;

[0020] Among them, the range of θ is 0 - 75°.

[0021] Further, the boom parameters in step S30 include the height from the bottom surface to the two-axis rotation center , the horizontal distance from the one-axis rotation center to the two-axis rotation center , the boom, that is, the distance from the two-axis rotation center to the three-axis rotation center , the forearm, that is, the distance from the three-axis rotation center to the five-axis rotation center ;

[0022] The rotation angles include the rotation angle ranges of the two-axis and three-axis of the robot, which are 、 ;

[0023] The posture parameters include the initial posture included angle α between the boom and the forearm.

[0024] Further, in step S40, the farthest working range is divided into two trajectory lines a1 and a2. a1 is the end trajectory when the two-axis, three-axis, and five-axis rotation centers of the robot are collinear, and its trajectory equation is:

[0025] ;

[0026] When a2 is the trajectory line of the end during the three-axis rotation when the robot's large arm reaches the positive limit of its rotation angle, its trajectory equation is:

[0027] ;

[0028] The above trajectory range is limited by the rotation range of the second axis, and the farthest horizontal distance is ;

[0029] The nearest working range is divided into two trajectory lines a3 and a4. a3 is the range formed by rotating the large arm when the angle between the large arm and the small arm is the smallest, and its trajectory equation is:

[0030] ,

[0031] where is the distance from point p to the center of the second axis at this time, and the calculation formula is:

[0032] ;

[0033] a4 is the range formed by rotating the small arm when the large arm reaches the negative limit of its rotation angle, and its trajectory equation is:

[0034] ;

[0035] Combining the two trajectory lines a3 and a4 of the nearest working range, the farthest horizontal distance that can be calculated is:

[0036] .

[0037] Furthermore, in step S50, a calculation method is used to match the trajectory equation of the p point with the working space of the robot to determine whether there is an installation position of the robot such that the space range of the robot covers all the p point ranges. The calculation method includes the following:

[0038] S501: Calculate the maximum horizontal working space of the robot and the maximum horizontal space of point P. The maximum horizontal working space of the robot is: , and the maximum horizontal space of point P (when y = 0) is: ;

[0039] S502: Take the ratio of the above two calculated values, defined as the working space coverage coefficient k, and the calculation formula is:

[0040]

[0041] Among them, when the value of k is greater than 1, it is considered that the robot meets the requirements.

[0042] Furthermore, calculate the optimal installation position of the robot to make the p-point range required for bending as much as possible at the center of the working space, and the following steps are also included:

[0043] S503: Calculate the optimal horizontal installation distance. The optimal horizontal installation distance is that the midpoint of the farthest trajectory line and the nearest trajectory line in the working space coincides with the midpoint of the horizontal space of the p-point. Then, the horizontal distance from the rotation center of the first axis of the robot to the contact point of the upper and lower dies of the bending machine should be near the calculated point in the following formula:

[0044]

[0045] S504: Calculate the vertical installation distance. The height difference between the bottom surface of the robot and the installation height of the bottom surface of the bending machine is:

[0046] .

[0047] Furthermore, in step S50, the graphical method is used to match the trajectory equation of the p-point and the working space of the robot to determine whether there is an installation position of the robot that enables the spatial range of the robot to cover all the p-point ranges. The graphical method draws the corresponding range diagrams of the trajectory equation of the p-point and the working space of the robot, and finds a suitable installation position through the comparison of the two diagrams.

[0048] Furthermore, the preset adjustment rules in step S60 include at least one of the following modification methods:

[0049] Replace the robot arm reach parameter;

[0050] Reduce the distance between the adsorption point and the p-point of the rotation center of the fifth axis of the robot within the allowable range;

[0051] Reduce the range of sheet metal bending.

[0052] This method determines whether there is a suitable application installation position for the robot by matching the working space of the robot and the bending range of the bending machine, and solves the problem that when a certain type of six-axis robot has been determined, it is impossible to effectively determine which specifications of sheet metal bending work it can be applied to only through the load and arm reach, and the problem that there is no accurate method to judge whether the robot can meet the usage requirements or how to install it to make the bending space the largest and optimal in practical applications. Description of the Drawings

[0053] Figure 1 It is a schematic flow chart of an embodiment of the present invention.

[0054] Figure 2 It is a schematic diagram of the steps of an embodiment of the present invention.

[0055] Figure 3 It is a schematic diagram of a bending machine according to an embodiment of the present invention.

[0056] Figure 4 It is a schematic diagram of the application of a bending machine according to an embodiment of the present invention.

[0057] Figure 5 It is a schematic diagram of the working space of a robot according to an embodiment of the present invention.

[0058] Figure 6 It is a schematic diagram of the bending space according to an embodiment of the present invention.

[0059] Figure 7 It is a schematic diagram of the matching of the working space of a robot according to an embodiment of the present invention. Detailed implementation manners

[0060] The following are specific embodiments of the present invention and, in conjunction with the accompanying drawings, further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0061] It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope protected by the embodiments of the present application.

[0062] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application. The singular forms of "a", "the" and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0063] When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all the embodiments consistent with the present application. On the contrary, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims. In the description of the present application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects, and do not have to be used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0064] In addition, in the description of this application, unless otherwise specified, "a plurality of" means two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, both A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0065] Aiming at the technical problems in the background art, the present invention provides a method for determining the bending application of a six-axis industrial robot. This method can calculate the working space requirements that need to be met for the application of the bending robot through the actual application scenario of the bending machine, and then correspond to the specification parameters of the bending robot to determine the optimal installation distance and height of the robot. As Figure 1 and 2 shown, the method for determining the bending application of a six-axis industrial robot includes the following steps:

[0066] S10: Obtain the height value h of the lower die cutting edge of the bending machine from the bottom surface, the size values a, b, and c of the length, width, and thickness of the bent sheet metal, and calculate the maximum working radius r with the edge of the sheet metal as the adsorption point. As Figure 3 and 4 shown, the calculation formula for the maximum working radius r is: . In other embodiments, the adsorption point of the sheet metal can also be the center of the sheet metal or other positions as the maximum working radius.

[0067] S20: Establish a coordinate system with the contact point between the lower die of the bending machine and the sheet metal, and determine the trajectory equation of the adsorption point and the five-axis rotation center p point of the robot. As Figure 4 and 6 shown, based on the bending principle of the bending machine, when the upper die presses down, the sheet metal can be approximated as a movement that rotates at the contact point between the lower die and the sheet metal. At this time, the movement trajectory of the adsorption point is an arc with this contact point as the center. Therefore, establish a coordinate system with the contact point between the lower die and the sheet metal, and the trajectory equation of the adsorption point is:

[0068] ;

[0069] Among them, , represent the coordinates of the adsorption point. To conveniently represent the rotation position of the point, the above trajectory is represented by the rotation angle, and its formula is:

[0070] ;

[0071] Among them, θ is set as the angle of the sheet metal rotating clockwise from the horizontal posture. According to the general bending angle requirements of the sheet metal, its range is 0 - 75°;

[0072] Further, since the adsorption point is usually at a fixed vertical distance from the five-axis rotation center p of the robot, this distance is the distance from point p to the mounting flange plus the distance from the mounting flange surface to the adsorption disc. Let this distance be d, then the trajectory equation of point P is:

[0073] ;

[0074] where the range of θ is 0 - 75°.

[0075] In the above formula, r is the maximum working radius. Therefore, the actual trajectory range of point p of the bending robot should be a space range that takes the above formula as the maximum boundary and continuously shrinks inward (r decreases). Therefore, the range of point p of the robot adopted should meet the above working space requirements.

[0076] S30: Obtain the arm span parameters, rotation angles, and attitude parameters of the robot, where the arm span parameters include the height from the bottom surface to the two-axis rotation center , the horizontal distance from the one-axis rotation center to the two-axis rotation center , the length of the large arm, that is, the distance from the two-axis rotation center to the three-axis rotation center , the length of the small arm, that is, the distance from the three-axis rotation center to the five-axis rotation center ; The rotation angles include the rotation angle ranges of the second axis and the third axis of the robot, which are , respectively; The attitude parameters include the initial attitude angle α between the large arm and the small arm. For some six-axis robots, the five-axis center and the three-axis center are not on the same horizontal line in the initial state, and there will be a certain offset. When there is no offset, the value of α is 90 degrees.

[0077] S40: Establish a rectangular coordinate system with the two-axis center of the robot, and determine the trajectory equations of the farthest working range and the nearest working range respectively to determine the working space of the robot.

[0078] As Figure 5 shown, the farthest range can be divided into two trajectory lines a1 and a2. a1 is the end trajectory when the second, third, and fifth axis rotation centers of the robot are collinear, and its trajectory equation is:

[0079] ;

[0080] a2 is the trajectory line of the end when the large arm of the robot reaches the positive limit of its rotation angle and the third axis rotates, and its trajectory equation is:

[0081] ;

[0082] The above trajectory range is limited by the rotation range of the second axis, and the farthest horizontal distance is , when the rotation angle of the second axis can reach 90 degrees, its horizontal farthest range is the posture where the boom is horizontally placed, and the farthest distance is .

[0083] The nearest working range is divided into two trajectory lines a3 and a4. a3 is the range formed by rotating the boom when the angle between the boom and the forearm is the smallest. Its trajectory equation is:

[0084] ,

[0085] where is the distance from point p to the center of the second axis at this time, and the calculation formula is:

[0086] ;

[0087] a4 is the range formed by rotating the forearm when the boom reaches the negative limit of its rotation angle. Its trajectory equation is:

[0088] ;

[0089] Combining the two trajectory lines a3 and a4 of the nearest working range, the farthest horizontal distance that can be calculated is:

[0090] .

[0091] S50: Match the trajectory equation of point p with the working space of the robot to determine whether there is an installation position of the robot so that the space range of the robot covers all the p-point ranges. In a preferred example, the maximum horizontal working space of the robot and the maximum horizontal space of point P are directly calculated by a simple calculation method and then the vertical distance is calculated. The specific steps are as follows:

[0092] S501: Calculate the maximum horizontal working space of the robot and the maximum horizontal space of point P. Among them, the maximum horizontal working space of the robot is: , and the maximum horizontal space of point P (when y = 0) is: ;

[0093] S502: Take the ratio of the above two calculated values, which is defined as the working space coverage coefficient k. The calculation formula is:

[0094]

[0095] Among them, when the value of k is greater than 1, it is considered that the robot meets the requirements.

[0096] Generally, when the value of k is greater than 1, it can be considered that the robot meets the bending requirements. However, since the calculated working space is the range calculated based on the most extreme positions of the robot, in order to reserve a certain safety margin, the parameter preferably should be greater than 1.2.

[0097] Furthermore, at this time, it is necessary to calculate the optimal installation position of the robot, and the p-point range required for bending should be as much as possible at the center of the working space. Then it also includes the following steps:

[0098] S503: Calculate the optimal horizontal installation distance. The optimal horizontal installation distance is that the midpoint of the farthest trajectory line and the nearest trajectory line of the working space coincides with the midpoint of the horizontal space of the p point. Then the horizontal distance from the rotation center of the first axis of the robot to the contact point of the upper and lower dies of the bending machine should be near the calculated point in the following formula:

[0099]

[0100] S504: Calculate the vertical installation distance. The height difference between the bottom surface of the robot and the installation height of the bottom surface of the bending machine is:

[0101] 。

[0102] In another preferred example, as Figure 7 shown, the trajectory equation of the p point and the working space of the robot are matched by the graphical method to determine whether there is an installation position of the robot such that the spatial range of the robot covers all the p-point ranges. This graphical method draws the corresponding range diagrams of the trajectory equation of the p point and the working space of the robot, and finds a suitable installation position by comparing the two diagrams.

[0103] S60: If the judgment of matching is successful, it is determined that the robot meets the bending application. When the judgment of matching fails, that is, when the maximum horizontal working space of the bending robot is less than the maximum horizontal space of the P point, or when the spatial coverage coefficient k is less than 1 (or 1.2), adjust the parameters according to the preset adjustment rules, and re-perform the verification calculation to judge the optimal installation position. The preset adjustment rules include at least one of the following modification methods:

[0104] 1. Replace the robot arm reach parameter. Generally, the length of the forearm of the bending robot is much greater than that of the upper arm. Therefore, it is necessary to select a robot with a longer forearm as much as possible;

[0105] 2. Reduce the distance from the adsorption point to the p point of the rotation center of the fifth axis of the robot within the allowable range;

[0106] 3. Reduce the range of sheet metal bending.

[0107] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention.

Claims

1. A method for determining the bending application of a six-axis industrial robot, characterized in that, It includes the following steps: S10: Obtain the height value h of the lower die cutting edge of the bending machine from the bottom surface, the dimensional values a, b, and c of the length, width, and thickness of the bent sheet metal, and calculate the maximum working radius r with the edge of the sheet metal as the adsorption point; S20: Establish a coordinate system with the contact point between the lower die of the bending machine and the sheet metal, and determine the trajectory equation of the adsorption point and the five-axis rotation center p point of the robot; S30: Obtain the arm reach parameters, rotation angles, and pose parameters of the robot; S40: Establish a rectangular coordinate system with the center of the second axis of the robot, and determine the trajectory equations of the farthest working range and the nearest working range respectively to determine the working space of the robot; S50: Match the trajectory equation of the p point with the working space of the robot, and determine whether there is an installation position of the robot such that the space range of the robot covers all the p point ranges; S60: If it is determined that the match is successful, determine that the robot meets the bending application. If it is determined that the match fails, adjust the parameters according to the preset adjustment rules and re-perform the verification calculation.

2. The method for determining the bending application of a six-axis industrial robot according to claim 1, wherein The formula for calculating the maximum working radius r in step S10 is: 。 3. The method for determining the bending application of a six-axis industrial robot according to claim 2, wherein The trajectory equation of the adsorption point in step S20 is: ； Among them, , represent the coordinates of the adsorption points. In addition, the above trajectory is represented by a rotation angle, and its formula is: ； where, θ is set as the angle of the sheet metal rotating clockwise from the horizontal posture, and its range is 0 - 75°; Since the adsorption point is at a fixed vertical distance from the five-axis rotation center p point of the robot, this distance is the distance from the p point to the mounting flange plus the distance from the mounting flange surface to the adsorption disc. Let this distance be d, then the trajectory equation of the p point is: ； where, the range of θ is 0 - 75°.

4. A method for determining the bending application of a six-axis industrial robot according to claim 3, characterized in that, The arm span parameters described in step S30 include the height from the bottom surface to the rotation center of the second axis , the horizontal distance from the rotation center of the first axis to the rotation center of the second axis , the length of the upper arm, i.e., the distance from the rotation center of the second axis to the rotation center of the third axis , the length of the forearm, i.e., the distance from the rotation center of the third axis to the rotation center of the fifth axis ; The rotation angles include the rotation angle ranges of the second axis and the third axis of the robot, which are respectively , ; The pose parameters include the initial pose included angle α between the upper arm and the lower arm.

5. A method for determining the bending application of a six-axis industrial robot according to claim 4, characterized in that, In step S40, the farthest working range is divided into two trajectory lines a1 and a2. a1 is the end trajectory when the second, third, and fifth axis rotation centers of the robot are collinear, and its trajectory equation is: ； a2 is the trajectory line at the end when the third axis rotates when the upper arm of the robot reaches the positive limit of its rotation angle, and its trajectory equation is: ； The above trajectory range is limited by the rotation range of the two axes, and the farthest horizontal distance is ; The nearest working range is divided into two trajectory lines a3 and a4. a3 is the range formed by rotating the upper arm when the angle between the upper arm and the lower arm is the smallest, and its trajectory equation is: ， wherein is the distance from point p to the rotation center of the two axes at this time, and the calculation formula is: ； a4 is the range formed by rotating the lower arm when the upper arm reaches the negative limit of its rotation angle, and its trajectory equation is: ； Combining the two trajectory lines a3 and a4 of the nearest working range, the farthest horizontal distance that can be calculated is: 。 6. The method for determining the bending application of a six-axis industrial robot according to claim 5, characterized in that In step S50, a calculation method is used to match the trajectory equation of the p point with the working space of the robot, and determine whether there is an installation position of the robot such that the space range of the robot covers all the p point ranges. The calculation method includes the following: S501: Calculate the maximum horizontal working space of the robot and the maximum horizontal space of the p point, where the maximum horizontal working space of the robot is: , the maximum horizontal space of point p is: ； S502: Take the ratio of the above two calculated values, defined as the working space coverage coefficient k, and the calculation formula is: where, when the k value is greater than 1, it is considered that the robot meets the requirements.

7. A method for determining the bending application of a six-axis industrial robot according to claim 6, characterized in that, Calculating the best installation position of the robot so that the p point range required for bending is at the center of the working space further includes the following steps: S503: Calculate the optimal horizontal installation distance. The optimal horizontal installation distance is such that the midpoint of the farthest and nearest trajectory lines in the working space coincides with the midpoint of the horizontal space of point p. Then, the horizontal distance from the rotation center of the first axis of the robot to the contact point between the upper and lower dies of the bending machine should be near the calculated point in the following formula: S504: Calculate the vertical installation distance. The height difference between the bottom surface of the robot and the installation height of the bottom surface of the bending machine is: 。 8. A method for determining the bending application of a six-axis industrial robot according to claim 1, characterized in that, In step S50, the trajectory equation of point p and the working space of the robot are matched using the graphical method to determine whether there is an installation position for the robot such that the spatial range of the robot covers all the ranges of point p. The graphical method plots the corresponding range diagrams of the trajectory equation of point p and the working space of the robot, and by comparing the two diagrams, a suitable installation position is found.

9. The method for determining the bending application of a six-axis industrial robot according to claim 1, wherein In step S60, the preset adjustment rules include at least one of the following modification methods: Replace the robot arm reach parameter; Reduce the distance from the adsorption point to the five-axis rotation center p point of the robot within the allowable range; Reduce the range of sheet metal bending.

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