Mechanical hand for handling of punched sheet metal and method of movement thereof

Abstract

The application provides a mechanical hand for stamping plate material carrying and a motion method thereof, comprising a rack, a articulated arm assembly and an end gripper, the rack is provided with a first rotating shaft, the first rotating shaft is connected with the articulated arm assembly, the end of the articulated arm assembly is provided with the end gripper, the first articulated rod is a symmetrical crankshaft structure, the connection structure form of the first end of the first articulated rod and the rack through the first rotating shaft is a symmetrical simply supported beam, the connection structure form of the end of the first articulated rod and the first end of the second articulated rod through the second rotating shaft is a symmetrical simply supported beam, and the connection structure form of the end of the second articulated rod and the first end of the third articulated rod through the third rotating shaft is a symmetrical simply supported beam. The application eliminates or reduces the rigid torsional deformation of the mechanical hand in the horizontal plane caused by large momentum moment, solves the problems of poor end positioning accuracy and shaking of the mechanical hand, and solves the problem of improving the overall feeding production rate.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of stamping sheet metal handling, in particular to a mechanical hand for stamping sheet metal handling and a movement method thereof. BACKGROUND

[0002] At present, for a large-scale series stamping production line composed of multiple presses, in order to quickly and smoothly handle stamping parts between the dies of adjacent press stations, a mechanical hand for stamping sheet metal handling is needed.

[0003] The existing mechanical hand for stamping sheet metal handling, although faster and more stable than ordinary robots, still has the following two problems if further speedup is desired:

[0004] 1. As shown in the figure, the existing mechanical hand for stamping sheet metal handling has a certain distance L between the center line of the last section of the articulated rod and the rack, when the mechanical hand moves in the direction perpendicular to the paper, the inertia and acceleration of the mechanical hand will generate a large momentum M in the horizontal plane with the distance L, which will cause the rigid torsional deformation of the mechanical hand, and further cause the poor positioning accuracy and shaking problem of the end of the mechanical hand. Figure 1 2. As shown in the figure, the first end movement trajectory of the last section of the articulated rod of the existing mechanical hand for stamping sheet metal handling is a curve similar to a "person" shape, which makes the movement envelope of the last section of the articulated rod larger, and the larger envelope will require a larger opening space of the upper and lower dies to avoid movement interference and collision, resulting in a small window time ratio of the mechanical hand in a stamping cycle, and further leading to the difficulty of further improving the overall productivity of stamping and feeding.

[0005] Figure 2 To overcome the above problems in the prior art, the present application provides a mechanical hand for stamping sheet metal handling and a movement method thereof, which eliminates or reduces the rigid torsional deformation of the mechanical hand in the horizontal plane caused by the large momentum, solves the poor positioning accuracy and shaking problem of the end of the mechanical hand, and at the same time, reduces the size of the movement envelope of the last section of the articulated rod of the mechanical hand, and improves the overall feeding efficiency. SUMMARY

[0006] To overcome the above problems in the prior art, the present application provides a mechanical hand for stamping sheet metal handling and a movement method thereof, which eliminates or reduces the rigid torsional deformation of the mechanical hand in the horizontal plane caused by the large momentum, solves the poor positioning accuracy and shaking problem of the end of the mechanical hand, and at the same time, reduces the size of the movement envelope of the last section of the articulated rod of the mechanical hand, and improves the overall feeding efficiency.

[0007] ​The present application is realized by the following technical scheme: a mechanical hand for stamping sheet material carrying, comprising a rack, a articulated arm assembly and an end gripper, the rack is provided with a first rotating shaft, the first rotating shaft is connected with the articulated arm assembly, the end of the articulated arm assembly is provided with the end gripper, the end gripper moves under the driving of the articulated arm assembly, the articulated arm assembly comprises a first articulated rod, the first end of the first articulated rod is connected with the rack through the first rotating shaft, the first articulated rod relatively rotates along the first rotating shaft, the end of the first articulated rod is connected with the first end of a second articulated rod through a second rotating shaft, the end of the second articulated rod is connected with the first end of a third articulated rod through a third rotating shaft, the end of the third articulated rod is connected with the end gripper through a fourth rotating shaft, under the driving of the external driving, the first articulated rod, the second articulated rod and the third articulated rod move together and drive the end gripper and the stamping sheet material connected with the end to move, the first articulated rod is a symmetrical crank structure, the connection structure form of the first end of the first articulated rod and the rack through the first rotating shaft is a symmetrical simply supported beam, the connection structure form of the end of the first articulated rod and the first end of the second articulated rod through the second rotating shaft is a symmetrical simply supported beam, and the connection structure form of the end of the second articulated rod and the first end of the third articulated rod through the third rotating shaft is a symmetrical simply supported beam. Compared with the prior art, the symmetrical simply supported beam supporting structure design eliminates or reduces the torsional movement of the mechanical hand in the horizontal plane caused by the large momentum moment, thereby improving the positioning accuracy of the mechanical hand and suppressing the shaking problem.

[0008] Further, the end gripper is a beam-like structure, the end gripper is located on a plane perpendicular to the movement plane of the articulated arm assembly, the axis of the end gripper is connected with the end of the third articulated rod through the fourth rotating shaft, the end gripper moves under the driving of the third articulated rod and relatively rotates through the fourth rotating shaft, and left-right horizontal movement on the stamping sheet material taking and placing plane is realized.

[0009] Further, the second articulated rod is provided with a second rotating shaft motor and a second rotating shaft transmission, the second rotating shaft motor and the second rotating shaft transmission are fixedly installed, and the driving shaft of the second rotating shaft motor is connected with the input shaft of the second rotating shaft transmission; the second rotating shaft transmission is fixedly connected with the first end of the second articulated rod, the output shaft of the second rotating shaft transmission is fixedly connected with the end of the first articulated rod, and the output shaft of the second rotating shaft transmission is the second rotating shaft, and the input shaft and the output shaft of the second rotating shaft transmission are perpendicular to each other. The second rotating shaft motor can be installed in the second articulated rod, thereby avoiding the movement interference caused by the direct connection of the motor and the rotating shaft.

[0010] Further, the rack further comprises a linear guide rail and a linear actuator, and the rack can move up and down along the linear guide rail. By adjusting the height position of the rack, the height position of the mechanical hand can be adjusted to adapt to the requirements of different molds on the height of the taking and placing material position.

[0011] Further, the length of the first articulated rod is L1, the length of the second articulated rod is L2, and the length of the third articulated rod is L3; wherein L2>L1.

[0012] The present application also provides a movement method of the mechanical hand, which adopts the above-mentioned mechanical hand for stamping sheet material carrying. The movement track of the second rotation axis, which is connected between the first end of the first articulated rod and the first end of the second articulated rod, is a circular curve c, the radius of the circular curve c is Rc=L1, and the center of the circular curve c is coincident with the axis of the first rotation axis. The movement track of the third rotation axis, which is connected between the second end of the second articulated rod and the first end of the third articulated rod, is a lobed curve d, the lobed curve d is a lobed spline curve of the third order or higher, the lobed segment of the lobed curve d has at least one coincident point with the circular curve a, the radius of the circular curve a is Ra=L2-L1, and the center of the circular curve a is coincident with the axis of the first rotation axis. When the end gripper carries the sheet material, the movement track of the fourth rotation axis, which is connected between the axis center of the end gripper and the second end of the third articulated rod, is a spline curve e, the spline curve e is a spline curve of the third order or higher set according to the dies of two adjacent work stations, the spline curve e has at least one intersection point with the circular curve b, the radius of the circular curve b is Rb=L2-L1+L3, and the center of the circular curve b is coincident with the axis of the first rotation axis. The distance between the left end point d1 of the lobed curve d and the left end point e1 of the spline curve e is equal to the distance between the right end point d2 of the lobed curve d and the right end point e2 of the spline curve e, and both distances are equal to the length L3 of the third articulated rod. When the end gripper does not carry the sheet material, the movement track of the fourth rotation axis, which is connected between the axis center of the end gripper and the second end of the third articulated rod, is a spline curve f, the spline curve f is a spline curve of the third order or higher set according to the dies of two adjacent work stations, and the spline curve f has at least one intersection point with the circular curve b. The left end point f1 and the right end point f2 of the spline curve f are coincident with the left end point e1 and the right end point e2 of the spline curve e, respectively.

[0013] Compared with the prior art, the movement method of the present application can significantly reduce the size of the movement envelope of the first end of the third articulated rod in the die area.

[0014] As can be seen from the above technical solutions, the present application has the following advantages. The symmetrical simply supported beam form of the articulated arm assembly is adopted to eliminate or reduce the rigid torsional deformation of the mechanical hand in the horizontal plane caused by the large momentum moment, thereby solving the problems of poor positioning accuracy and shaking of the end of the mechanical hand. Meanwhile, the movement track of the first end of the last articulated rod is controlled to move along the lobed curve, thereby reducing the size of the movement envelope of the last articulated rod of the mechanical hand, lowering the requirement of the mechanical hand for the opening space of the die, and solving the problem of improving the overall feeding rate. BRIEF DESCRIPTION OF DRAWINGS

[0015] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of a robotic arm in the prior art.

[0017] Figure 2 This is a motion path diagram and envelope diagram of the end joint of a robotic arm in the prior art.

[0018] Figure 3 This is a structural schematic diagram of a specific embodiment of the present invention. Figure 1 .

[0019] Figure 4 This is a schematic diagram of the assembly structure of the first hinge rod and the second hinge rod in a specific embodiment of the present invention.

[0020] Figure 5 This is a structural schematic diagram of a specific embodiment of the present invention. Figure 2 .

[0021] Figure 6 This is a structural schematic diagram of a specific embodiment of the present invention. Figure 3 .

[0022] Figure 7 This is a schematic diagram of the assembly structure of the press and a specific embodiment of the present invention.

[0023] Figure 8 This is a structural schematic diagram of a second specific embodiment of the present invention.

[0024] Figure 9 This is a motion path diagram of each hinge rod in the third specific embodiment of the present invention.

[0025] Figure 10 This is a diagram showing the positional changes of each hinge rod in a specific embodiment three of the present invention.

[0026] Figure 11 This is a motion path diagram of the third hinge rod in the third specific embodiment of the present invention.

[0027] Figure 12 This is a comparison diagram of the cooperation relationship between the third hinge rod and the press in the third specific embodiment of the present invention and the cooperation relationship between the last hinge rod and the press in the prior art.

[0028] In the attached image:

[0029] 1. Frame, 2. Knuckle arm assembly, 3. End effector, 4. Stamped sheet metal, 5. First press, 6. Lower die of the first press, 7. Lower die of the second press, 8. Upper die of the first press, 9. Upper die of the second press, 21. First knuckle rod, 22. Second knuckle rod, 23. Third knuckle rod, 24. First rotating shaft, 25. Second rotating shaft, 26. Third rotating shaft, 27. Fourth rotating shaft, 110. Linear actuator, 111. Linear guide rail, 210. Motor of the first rotating shaft, 220. Motor of the second rotating shaft, 221. Transmission of the second rotating shaft, 230. Motor of the third rotating shaft, 240. Motor of the fourth rotating shaft. Detailed implementation manner

[0030] To make the objectives, features, and advantages of the present invention more obvious and understandable, the technical solutions in the present invention will be clearly and completely described below in conjunction with the drawings in the specific embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in this patent, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this patent.

[0031] To make the objectives, features, and advantages of the present invention more obvious and understandable, the technical solutions in the present invention will be clearly and completely described below in conjunction with the drawings in the specific embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in this patent, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this patent.

[0032] First, as Figure 1 shown, there is a certain distance L between the midline of the end knuckle rod of the manipulator for stamping sheet metal handling in the prior art and the frame. When the manipulator moves in the direction perpendicular to the paper plane, the self-inertia and acceleration of the manipulator will generate a relatively large moment of momentum M in the horizontal plane with this distance L. This moment of momentum M will cause the rigid torsional deformation of the manipulator, and further cause problems such as poor end positioning accuracy and jitter of the manipulator.

[0033] Second, as Figure 2 shown, the movement trajectory of the head end of the end knuckle rod of the manipulator for stamping sheet metal handling in the prior art is a curve similar to a "person" shape, making the movement envelope of the end knuckle rod larger. A larger envelope will require a larger opening space for the upper and lower dies of the mold to avoid movement interference and collision, resulting in a smaller proportion of the window time for picking and placing materials by the manipulator in a stamping cycle, and further making it difficult to further improve the overall productivity of stamping and feeding.

[0034] Based on the two problems existing in the prior art mentioned above, in one embodiment of the present invention, by adopting a symmetrical simply supported beam form of the articulated arm assembly, the rigid torsional deformation caused by the large moment of momentum of the manipulator in the horizontal plane is eliminated or reduced, thus solving the problems of poor end-positioning accuracy and jitter of the manipulator; in another embodiment of the present invention, by controlling the motion trajectory of the first end of the end articulated rod to follow the leaf-shaped curve, the motion envelope size of the end articulated rod of the manipulator is reduced, thereby reducing the manipulator's requirement for the opening space of the upper and lower molds, thus solving the problem of improving the overall feeding productivity. Specific Implementation Method 1

[0036] like Figures 3 to 6 As shown in the figure, this specific embodiment provides a robot for handling stamped sheet metal, including a frame 1, a hinged arm assembly 2, and an end effector 3. A first rotating shaft 24 is symmetrically arranged on the frame 1, and the hinged arm assembly 2 is connected to the first rotating shaft 24. An end effector 3 is provided at the end of the hinged arm assembly, and the end effector 3 moves under the drive of the hinged arm assembly 2. The hinged arm assembly 2 includes, from top to bottom, a first hinged rod 21, a second hinged rod 22, and a third hinged rod 23. The first hinged rod 21 rotates relative to the first rotating shaft 24, and the end of the first hinged rod 21 is connected to the beginning of the second hinged rod 22 via a second rotating shaft 25. The end of the hinge rod 22 is connected to the beginning of the third hinge rod 23 via the third rotating shaft 26. The end of the third hinge rod 23 is connected to the end effector 3 via the fourth rotating shaft 27. The connection structure between the end of the first hinge rod 21 and the beginning of the second hinge rod 22 via the second rotating shaft 25 is a symmetrical simply supported beam. The connection structure between the end of the second hinge rod 22 and the beginning of the third hinge rod 23 via the third rotating shaft 26 is also a symmetrical simply supported beam. The end effector 3 is rotatably connected to the third hinge rod 23. The end effector 3 moves under the drive of the hinge arm assembly 2, realizing the transportation of the stamped sheet 4 between the worktable dies of two adjacent presses. By adopting the structural design of the hinge arm assembly 2 in the form of a symmetrical simply supported beam, the rigid torsional deformation caused by the large moment of momentum of the robot in the horizontal plane is eliminated or reduced, and the problems of poor end-positioning accuracy and vibration of the robot are solved.

[0037] like Figures 3 to 5As shown, the first hinge rod 21 has a symmetrical crankshaft structure. The first hinge rod 21 includes a connecting rod and a second rotating shaft 25. The second rotating shaft 25 is fixedly connected to the connecting rod, and the connecting rod is rotatably connected to the frame 1 via the first rotating shaft 24. The first hinge rod 21 can rotate around the first rotating shaft 24. A second hinge rod 22 is rotatably mounted on the second rotating shaft 25. A third rotating shaft 26 is rotatably mounted at the end of the second hinge rod 22 via a bearing. A third hinge rod 23 is mounted on the third rotating shaft 26 via a key connection. A fourth rotating shaft 27 is rotatably mounted at the end of the third hinge rod 23 via a bushing. The fourth rotating shaft 27 is connected to the end effector 3. The fourth rotating shaft 27 is connected to the fourth rotating shaft motor 240, which drives the end effector 3 to rotate. The third rotating shaft motor 230 is provided on the outside of the third hinge rod 23, which can drive the third rotating shaft 26 to rotate. The end effector 3 is a beam-like structure and is located on a plane perpendicular to the plane of motion of the hinge arm assembly 2. The end effector 3 can move horizontally left and right on the platen 4 under the drive of the movement of the third hinge rod 23 and through the rotation of the fourth rotating shaft motor 240.

[0038] The first end of the second hinge rod 22 is connected to the second rotating shaft 25 via a bearing. The second hinge rod 22 is provided with a motor cavity, within which a second rotating shaft motor 220 and a second rotating shaft gearbox 221 are housed. The second rotating shaft motor 220 is arranged along the length of the second hinge rod 22. The drive shaft of the second rotating shaft motor 220 is connected to the input shaft of the second rotating shaft gearbox 221. The second rotating shaft gearbox 221 is fixedly connected to the first end of the second hinge rod 22. The input and output shafts of the second rotating shaft gearbox 221 are perpendicular to each other, and the output shaft of the second rotating shaft gearbox 221 is the second rotating shaft 25. In this specific embodiment, the second rotating shaft gearbox 221 is a bevel gear gearbox; this layout allows the second rotating shaft motor 220 to be installed inside the second hinge rod 22, thereby avoiding direct connection between the second rotating shaft motor 220 and the second rotating shaft 25, which would cause motion interference with the first hinge rod 21.

[0039] like Figure 7 and Figure 11 As shown, in this specific embodiment, the movement path of this robot is from the first press upper mold 8 and the first press lower mold 6 of the first press 5 to the second press upper mold 9 and the second press lower mold 7 of the second press. The first press 5 and the second press are arranged on both sides of this robot. The end effector 3 moves under the drive of the articulated arm assembly 2 to realize the transportation of the stamped sheet material 4 on the worktable molds on both sides of the press.

[0040] In this specific embodiment, the first hinge rod 21 is a symmetrical crankshaft structure. The connection structure between the first end of the first hinge rod 21 and the frame 1 via the first rotating shaft 24 is a symmetrical simply supported beam. The connection structure between the end of the first hinge rod 21 and the first end of the second hinge rod 22 via the second rotating shaft 25 is also a symmetrical simply supported beam. The connection structure between the end of the second hinge rod 22 and the first end of the third hinge rod 23 via the third rotating shaft 26 is also a symmetrical simply supported beam. Compared with the prior art, this specific embodiment, by adopting the structural design of the hinge arm assembly 2 in the form of a symmetrical simply supported beam, eliminates or reduces the rigid torsional deformation of the manipulator in the horizontal plane caused by the large moment of momentum, thus solving the problems of poor end-effector positioning accuracy and jitter of the manipulator. Specific Implementation Method Two

[0042] like Figure 8 As shown, in order to enable this robot to adapt to the different mold requirements for the height of the material picking and placing position, this specific embodiment is basically the same in structure as the first specific embodiment, except that: a linear guide rail 111 is provided on the frame 1, and a linear actuator 110 is connected to the frame 1. The linear guide rail 111 and the linear actuator 110 can be connected to a press or to a separate gantry frame. The frame 1 can move up and down along the linear guide rail 111. The frame 1 can be adjusted in the height direction through the linear guide rail 111 and the linear actuator 110 to adapt to the different mold requirements for the height of the material picking and placing position. Specific Implementation Method 3

[0044] like Figures 9 to 11 As shown, this specific embodiment provides a motion method for a robotic arm used for handling stamped sheet metal. It employs a robotic arm for handling stamped sheet metal as described in Specific Embodiment 1, wherein the length of the first hinge rod is L1, the length of the second hinge rod is L2, and the length of the third hinge rod is L3; wherein L2 > L1. Figure 10 In the process, the sequence of actions of the robot used for handling stamped sheet metal is (Ⅰ)-(Ⅱ)-(Ⅲ)-(Ⅳ)-(Ⅴ)-(Ⅵ); the motion trajectory of the second rotating shaft 25 is a circular curve c, and the corresponding radius Rc is the length L1 of the first movable rod 21. The center O of the motion trajectory of the second rotating shaft 25 coincides with the origin of the rectangular coordinate system; the motion trajectory of the third rotating shaft 26 is a leaf-shaped curve d, which is a leaf-shaped spline curve of the third or higher order. The leaf-shaped segment of the leaf-shaped curve d coincides with the circular curve a at least once. In this specific embodiment, the leaf-shaped curve d is externally tangent to the circular curve a, that is, the upper vertex of the leaf-shaped curve d coincides with the lower endpoint of the circular curve a on the Y-axis. The circular curve a has the center O as its center and the radius is L2-L1.

[0045] like Figure 2 , Figure 11 , Figure 12 As shown, where Figure 12The left half shows the cooperation relationship between the last segment of the hinge rod (i.e., the third hinge rod 23) and the press in this specific embodiment, while the right half shows the cooperation relationship between the last segment of the hinge rod and the press in the prior art. In this specific embodiment, the movement trajectory of the first end of the last segment of the hinge rod of the robot is a leaf-shaped curve, which makes the movement envelope of the entire last segment of the hinge rod smaller. Under the same working condition of the opening size S of the upper and lower molds as the existing robot, the distance between the last segment of the hinge rod of the robot and the upper and lower molds in this specific embodiment is larger.

[0046] like Figure 2 , Figure 11 , Figure 12 As shown, S2 is the travel stroke of the upper mold when the last segment of the hinge rod (i.e., the third hinge rod 23) can pick up and unload material in this specific embodiment, i.e., the material picking window stroke. S2' is the travel stroke of the upper mold when the last segment of the hinge rod can pick up and unload material in the prior art. In this specific embodiment, the last segment of the hinge rod can enter between the upper and lower molds along a route that is closer to the horizontal direction, which can significantly reduce the size of the motion envelope of the last segment of the hinge rod entering and exiting the mold area, thereby reducing the opening height of the upper and lower molds of the press, shortening the opening height of the upper and lower molds from the original S1' to S1. When the travel stroke of the press slide is the same, there exists S1+S2=S1'+S2', that is, S2 is greater than S2'. Therefore, when the travel time of the material pick-up window S2 and S2' is the same, that is, the material pick-up and unpick-up time is the same in this specific embodiment and the prior art, it means that the moving speed of the upper mold in this specific embodiment is greater than the moving speed in the prior art. This makes the total travel time of S1+S2 less than the total travel time of S1'+S2', thereby further improving the overall productivity of the press with robot arm cooperation in this specific embodiment.

[0047] like Figures 9 to 10As shown, to avoid interference between the end effector 3 and the mold, when the end effector 3 is carrying material, the movement trajectory of the fourth rotating shaft 27 is a spline curve e. The spline curve e is a cubic or higher-order spline curve set according to the molds of two adjacent stations. The endpoints e1 and e2 of the spline curve e are set according to the mold position. The spline curve e intersects the circular curve b at least once. The center of the circular curve b is the center O, which coincides with the axis of the first rotating shaft 24, and the radius of the circular curve b is L2-L1+L3. In this specific embodiment, the spline curve e is externally tangent to the circular curve b. The distance between the left (right) endpoint e1 (e2) of the spline curve e and the left (right) endpoint d1 (d2) of the leaf-shaped curve d is equal to the length L3 of the third hinge rod 23. When the end effector 3 is not carrying material, the movement trajectory of the fourth rotating shaft 27 is a spline curve f. The spline curve f is a cubic or higher-order spline curve set according to the molds of two adjacent stations. The spline curve f and the circular curve b have at least one intersection point, and the left and right endpoints f1 and f2 of the spline curve f coincide with the left and right endpoints e1 and e2 of the spline curve e, respectively. By setting the motion trajectory spline curves e and f, the end effector 3 can avoid interference with the mold when moving with or without material.

[0048] Those skilled in the art can solve for the motion states of the first rotating shaft motor 210, the second rotating shaft motor 220, the third rotating shaft motor 230, and the fourth rotating shaft motor 240 based on the motion trajectory curves c, d, e, or f of the second rotating shaft 25, the third rotating shaft 26, and the fourth rotating shaft 27, respectively, and obtain the characteristic curves of the rotation angle and time of the corresponding rotating shaft motors. The controller on the robot arm controls and drives each rotating shaft motor to move according to the characteristic curves, thereby driving each hinge rod to move and making it move according to the corresponding trajectory, completing the handling of the stamped sheet and avoiding motion interference.

[0049] As can be seen from the above specific embodiments, the present invention has the following beneficial effects:

[0050] By adopting the structural design of the hinge arm assembly 2 in the form of a symmetrical simply supported beam, the rigid torsional deformation of the robot arm caused by the large moment of momentum in the horizontal plane is eliminated or reduced, thus solving the problems of poor end-positioning accuracy and jitter of the robot arm.

[0051] By placing the second rotating shaft motor 220 inside the second hinge rod 22, interference between the second hinge rod 22 and the first hinge rod 21 can be avoided, ensuring smooth movement.

[0052] The linear guide 111 and the linear actuator 110 enable the frame 1 to be adjusted in height to adapt to the different mold requirements for the height of the material loading and unloading position;

[0053] By controlling the motion trajectory of the first end of the last segment of the connecting rod (i.e., the third connecting rod 23) to follow the leaf-shaped curve, the size of the motion envelope of the last segment of the manipulator is reduced, thereby reducing the manipulator's requirement for the opening space of the upper and lower molds and solving the problem of improving the overall feeding productivity.

[0054] The terms “upper,” “lower,” “outer,” “inner,” etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish relative positional relationships and are not necessarily qualitative. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion.

[0055] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A robotic arm for handling stamped sheet metal, comprising a frame, a hinged arm assembly, and an end effector, characterized in that: A first rotating shaft is provided on the frame, and a hinge arm assembly is connected to the first rotating shaft. An end effector is provided at the end of the hinge arm assembly, and the end effector moves under the drive of the hinge arm assembly. The hinge arm assembly includes a first hinge rod, the head end of which is connected to the frame via the first rotating shaft. The first hinge rod rotates relative to the frame along the first rotating shaft. The end of the first hinge rod is connected to the head end of a second hinge rod via a second rotating shaft. The end of the second hinge rod is connected to the head end of a third hinge rod via a third rotating shaft. The end of the third hinge rod is connected to the head end of a fourth rotating shaft. The shaft is connected to the end effector. Under external driving force, the first, second, and third hinge rods move together and drive the end effector and the stamping sheet connected at the end to move. The first hinge rod is a symmetrical crankshaft structure. The connection structure between the first end of the first hinge rod and the frame through the first rotating shaft is a symmetrical simply supported beam. The connection structure between the end of the first hinge rod and the first end of the second hinge rod through the second rotating shaft is a symmetrical simply supported beam. The connection structure between the end of the second hinge rod and the first end of the third hinge rod through the third rotating shaft is a symmetrical simply supported beam.

2. The robotic arm for handling stamped sheet metal as described in claim 1, characterized in that: The end effector is a beam-like structure. The end effector is located on a plane perpendicular to the plane of motion of the relative hinge arm assembly. The axis of the end effector is connected to the end of the third hinge rod through the fourth rotating shaft. Driven by the movement of the third hinge rod, the end effector rotates relative to the fourth rotating shaft, realizing horizontal movement on the stamping sheet material picking and placing plane.

3. The robotic arm for handling stamped sheet metal as described in claim 1, characterized in that: The second hinge rod is equipped with a second rotating shaft motor and a second rotating shaft gearbox. The second rotating shaft motor and the second rotating shaft gearbox are fixedly installed, and the drive shaft of the second rotating shaft motor is connected to the input shaft of the second rotating shaft gearbox. The second rotating shaft transmission is fixedly connected to the first end of the second hinge lever, and the output shaft of the second rotating shaft transmission is fixedly connected to the end of the first hinge lever. The output shaft of the second rotating shaft transmission is the second rotating shaft, and the input shaft and output shaft of the second rotating shaft transmission are perpendicular to each other.

4. The robotic arm for handling stamped sheet metal as described in claim 1, characterized in that: The frame also includes linear guides and linear actuators, and the frame can move up and down along the linear guides.

5. The robotic arm for handling stamped sheet metal as described in claim 4, characterized in that: The length of the first joint is L1, the length of the second joint is L2, and the length of the third joint is L3; where L2 > L1.

6. A method for moving a robotic arm used for handling stamped sheet metal, characterized in that: Using the robotic arm for handling stamped sheet metal as described in claim 5, the motion trajectory of the second rotating shaft, connected to the end of the first movable rod and the beginning of the second movable rod, is a circular curve c, with radius Rc = L1, and its center coincides with the axis of the first rotating shaft; the motion trajectory of the third rotating shaft, connected to the end of the second movable rod and the beginning of the third movable rod, is a leaf-shaped curve d, which is a cubic or higher-order leaf-shaped spline curve, with at least one coincidence point between the leaf-shaped segment of the leaf-shaped curve d and the circular curve a, and half-Ra = L2 - L1 of the circular curve a, whose center coincides with the axis of the first rotating shaft; when the end effector carries the sheet metal, the motion trajectory of the fourth rotating shaft, connected to the end effector shaft and the end of the third movable rod, is a spline curve e, which is a cubic or higher-order spline curve set according to the molds of two adjacent workstations. The spline curve e intersects the circular curve b at at least one point. The radius of the circular curve b is Rb = L2 - L1 + L3, and the center of the circular curve b coincides with the axis of the first rotating shaft. The distance between the left endpoint d1 of the leaf-shaped curve d and the left endpoint e1 of the spline curve e is equal to the distance between the right endpoint d2 of the leaf-shaped curve d and the right endpoint e2 of the spline curve e, and both are equal to the length of the third hinge rod, which is L3. When the end effector is not carrying a sheet metal, the trajectory of the fourth rotating shaft connected to the end of the end effector shaft and the end of the third hinge rod is the spline curve f. The spline curve f is a cubic or higher order spline curve set according to the molds of two adjacent workstations, and it intersects the circular curve b at at least one point. The left endpoint f1 and the right endpoint f2 of the spline curve f coincide with the left endpoint e1 and the right endpoint e2 of the spline curve e, respectively.

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