A laser cutting head posture transformation device and a control system thereof

Abstract

The application discloses a laser cutting head posture transformation device and a control system thereof, which comprises a base, three motors, a three-degree-of-freedom spherical parallel mechanism and a laser cutting head, the three motors are fixedly arranged on the base, one end of the three-degree-of-freedom spherical parallel mechanism is connected with output shafts of the three motors, and the other end is fixedly connected with the laser cutting head; the three-degree-of-freedom spherical parallel mechanism comprises three groups of connecting rod assemblies, each group of connecting rod assemblies is distributed along the circumference of the base, each group of connecting rod assemblies comprises a first connecting rod, a second connecting rod and a third connecting rod, the first connecting rod is fixedly connected with the output shaft of the corresponding motor, the first connecting rod is fixedly connected with the second connecting rod, the second connecting rod is rotationally connected with the third connecting rod, and the third connecting rod is rotationally connected with the laser cutting head. The three-degree-of-freedom spherical parallel mechanism is used for carrying the laser cutting head, so that the laser cutting head has three rotational degrees of freedom, and the number of degrees of freedom required by the workbench is reduced, thereby reducing energy consumption and improving control precision.

Description

Technical Field

[0001] This invention relates to the field of laser cutting machine technology, specifically to a laser cutting head posture changing device and its control system. Background Technology

[0002] Laser cutting machines, as high-quality, high-precision, and high-efficiency processing equipment, have been widely used in the manufacturing of automobiles, ships, and aircraft. Among them, 3D five-axis laser cutting machines can process complex workpieces and have a wide market demand. A typical 3D five-axis laser cutting machine requires five degrees of freedom between the laser cutting head and the worktable. In existing 3D five-axis laser cutting machines, the laser cutting head is fixed, or only configured with 1-2 degrees of freedom. The workpiece's pose is mainly changed by the movement and rotation of the worktable, thus achieving the purpose of 3D five-axis laser cutting.

[0003] However, some 3D five-axis laser cutting machines have heavy worktables, and the workpieces being processed also have a certain weight. Relying mainly on the worktable to achieve workpiece pose changes consumes a lot of energy and has a large inertia, making it difficult to obtain high control precision. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art. This invention provides a laser cutting head posture transformation device and its control system. The laser cutting head is mounted on a three-degree-of-freedom spherical parallel mechanism, so that the laser cutting head has three rotational degrees of freedom, thereby reducing the number of degrees of freedom required for the worktable, which reduces energy consumption and improves control accuracy.

[0005] This invention provides a laser cutting head attitude transformation device, which includes a base, three motors, a three-degree-of-freedom spherical parallel mechanism, and a laser cutting head. The three motors are fixedly mounted on the base. One end of the three-degree-of-freedom spherical parallel mechanism is connected to the output shaft of the three motors, and the other end of the three-degree-of-freedom spherical parallel mechanism is fixedly connected to the laser cutting head. The three-degree-of-freedom spherical parallel mechanism surrounds the laser cutting head.

[0006] The three-degree-of-freedom spherical parallel mechanism includes three sets of linkage assemblies. Each set of linkage assemblies is distributed along the circumference of the base. Each set of linkage assemblies includes a first link, a second link, and a third link. The first end of the first link is fixedly connected to the output shaft of the corresponding motor. The second end of the first link is fixedly connected to the first end of the second link. The second end of the second link is rotatably connected to the first end of the third link. The second end of the third link is rotatably connected to the laser cutting head.

[0007] Specifically, each group of connecting rod assemblies is arranged at 120° intervals.

[0008] Specifically, the first link, the second link, and the third link are all arc-shaped links. The first link is located on the first spherical surface, the second link is located on the second spherical surface, and the third link is located on the third spherical surface. The centers of the first spherical surface, the second spherical surface, and the third spherical surface coincide. The nozzle of the laser cutting head is located at the center of the third spherical surface.

[0009] And / or the plane containing the first link and the plane containing the second link are perpendicular to each other.

[0010] Specifically, each of the three motors is a servo motor, and the three motors are of the same model.

[0011] And / or each of the three motors is fixedly mounted on the base based on a motor mounting bracket.

[0012] Specifically, the first end of the first connecting rod is provided with a motor output shaft mounting through hole and a motor output shaft limiting hole, and the motor output shaft limiting hole penetrates the side wall of the motor output shaft mounting through hole;

[0013] A wedge groove is provided on the inner wall of the motor output shaft mounting through hole.

[0014] Specifically, a connecting block is provided at the fixed connection between the first connecting rod and the second connecting rod. One end of the connecting block is provided with a first protruding strip, and the other end of the connecting block is provided with a second protruding strip. The first protruding strip and the second protruding strip are perpendicular to each other.

[0015] The connecting block is provided with a screw hole, which passes through the center of the first protruding strip and the second protruding strip;

[0016] The second end of the first connecting rod is provided with a first groove and a first countersunk hole, the first countersunk hole penetrating the middle of the first groove. The first end of the second connecting rod is provided with a second groove and a second countersunk hole, the second countersunk hole penetrating the middle of the second groove. The first groove and the first protrusion cooperate, the second groove and the second protrusion cooperate, one end of the first countersunk hole and the screw hole are bolted together, and the other end of the second countersunk hole and the screw hole are bolted together.

[0017] Specifically, the second link and the third link are rotatably connected based on the first support shaft. The second end of the second link is provided with a first rotatable through hole, and the first end of the third link is provided with a second rotatable through hole. Both ends of the first support shaft are provided with a first rotating part. The first rotatable through hole and the first rotating part at one end of the first support shaft are rotatably engaged, and the second rotatable through hole and the first rotating part at the other end of the first support shaft are rotatably engaged.

[0018] Specifically, the third connecting rod and the laser cutting head are rotatably connected based on the second support shaft. The second end of the third connecting rod is provided with a third rotating through hole. One end of the second support shaft is provided with a second rotating part, and the other end of the second support shaft is provided with a fixed part. The third rotating through hole and the second rotating part are rotatably engaged, and the fixed part is fixedly connected to the laser cutting head.

[0019] Specifically, the base has a circular hole in the center and several flange holes around the circular hole;

[0020] The laser cutting head is connected to an optical fiber, which extends out of the circular hole.

[0021] The present invention also provides a control system for a laser cutting head attitude changing device, the control system comprising:

[0022] The parameter setting module is used to input cutting speed and cutting head parameters;

[0023] The trajectory input module is used to input a given laser cutting trajectory;

[0024] The motor rotation angle calculation module is used to receive the cutting speed, the cutting head parameters, and the given laser cutting trajectory. It generates the motion trajectory of the laser cutting head by transforming the given laser cutting trajectory into a coordinate system and compensating for the laser beam radius. It also extracts the attitude features of the motion trajectory to generate a preset azimuth angle perpendicular to the workpiece surface. The difference between the preset azimuth angle and the current azimuth angle of the laser cutting head is the control quantity. The control quantity is transformed into the corresponding rotation angle of the three motors by inverse kinematics calculation in conjunction with the cutting speed and the cutting head parameters.

[0025] A servo drive module is used to receive the rotation angle and control the three motors to rotate according to the rotation angle.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] The laser cutting head posture transformation device of the present invention has three motors on the base, which drive a three-degree-of-freedom spherical parallel mechanism. Specifically, each motor drives a set of linkage components. The laser cutting head is mounted on the three-degree-of-freedom spherical parallel mechanism, giving the laser cutting head three rotational degrees of freedom. This increases the degrees of freedom of the laser cutting head, thereby reducing the number of degrees of freedom required by the worktable and reducing the dependence of workpiece posture transformation on the worktable. In other words, it reduces the movement frequency of the worktable, thereby reducing the energy consumption of the three-dimensional five-axis laser cutting machine and improving the control accuracy of the three-dimensional five-axis laser cutting machine. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0029] Figure 1 This is a schematic diagram of the laser cutting head attitude transformation device in an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of the connection structure between the motor and the first connecting rod in an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of the connection structure between the first link and the second link in an embodiment of the present invention;

[0032] Figure 4 This is a schematic diagram of the connection structure between the second link and the third link in an embodiment of the present invention;

[0033] Figure 5 This is a schematic diagram of the connection structure between the third link and the laser cutting head in an embodiment of the present invention;

[0034] Figure 6 This is a schematic diagram of the structure of the base and the laser cutting head in an embodiment of the present invention.

[0035] In the attached diagram, 10 is a connecting block; 11 is a first protruding strip; 12 is a second protruding strip; 13 is a screw hole; 20 is a first support shaft; 21 is a first rotating part; 22 is a first slot; 30 is a second support shaft; 31 is a second rotating part; 32 is a fixing part; 33 is a second slot; 100 is a base; 110 is a round hole; 120 is a flange hole; 200 is a motor; 201 is a mating limit hole; 202 is a mating wedge groove; 210 is a motor mounting bracket; 220 is a motor fixing plate; and 230 is a motor bearing anti-reflective element. Dust cover; 300, Three-degree-of-freedom spherical parallel mechanism; 310, First connecting rod; 311, Motor output shaft mounting through hole; 312, Motor output shaft limiting hole; 313, Wedge groove; 314, First groove; 315, First countersunk hole; 320, Second connecting rod; 321, Second groove; 322, Second countersunk hole; 323, First rotating through hole; 330, Third connecting rod; 331, Second rotating through hole; 332, Third rotating through hole; 400, Laser cutting head; 410, Nozzle; 420, Optical fiber. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Figure 1 A schematic diagram of the laser cutting head attitude transformation device in an embodiment of the present invention is shown. The laser cutting head attitude transformation device includes a base 100, three motors 200, a three-degree-of-freedom spherical parallel mechanism 300, and a laser cutting head 400. The three motors 200 are fixedly mounted on the base 100. One end of the three-degree-of-freedom spherical parallel mechanism 300 is connected to the output shaft of the three motors 200, and the other end of the three-degree-of-freedom spherical parallel mechanism 300 is fixedly connected to the laser cutting head 400. The three-degree-of-freedom spherical parallel mechanism 300 surrounds the laser cutting head 400.

[0038] The three-degree-of-freedom spherical parallel mechanism 300 includes three sets of linkage assemblies. Each set of linkage assemblies is distributed along the circumference of the base 100. Each set of linkage assemblies includes a first link 310, a second link 320, and a third link 330. The first end of the first link 310 is fixedly connected to the output shaft of the corresponding motor 200. The second end of the first link 310 is fixedly connected to the first end of the second link 320. The second end of the second link 320 is rotatably connected to the first end of the third link 330. The second end of the third link 330 is rotatably connected to the laser cutting head 400.

[0039] The laser cutting head posture transformation device of the present invention has three motors 200 set on the base 100. The three motors 200 drive a three-degree-of-freedom spherical parallel mechanism 300. Specifically, each motor 200 drives a set of linkage components. The laser cutting head 400 is mounted on the three-degree-of-freedom spherical parallel mechanism 300, so that the laser cutting head 400 has three rotational degrees of freedom. This increases the degrees of freedom of the laser cutting head 400, thereby reducing the number of degrees of freedom required by the worktable and reducing the dependence of workpiece posture transformation on the worktable. That is, it reduces the movement frequency of the worktable, thereby reducing the energy consumption of the three-dimensional five-axis laser cutting machine and improving the control accuracy of the three-dimensional five-axis laser cutting machine.

[0040] The laser cutting head attitude transformation device of the present invention takes the rotation angle of three motors 200 as input and the attitude of the laser cutting head 400 as output, and can realize the spatial attitude transformation of the laser cutting head 400 within a small range.

[0041] Furthermore, each set of connecting rod assemblies is arranged at 120° intervals. The first connecting rod 310, the second connecting rod 320, and the third connecting rod 330 are all arc-shaped connecting rods. The first connecting rod 310 is located on the first spherical surface, the second connecting rod 320 is located on the second spherical surface, and the third connecting rod 330 is located on the third spherical surface. The centers of the first, second, and third spherical surfaces coincide. The nozzle 410 of the laser cutting head 400 is located at the center of the third spherical surface. The plane containing the first connecting rod 310 and the plane containing the second connecting rod 320 are perpendicular to each other. Each set of connecting rod assemblies is rotationally symmetrical and surrounds the laser cutting head 400. A three-degree-of-freedom spherical parallel mechanism 300 is used to achieve three-degree-of-freedom rotation of the laser cutting head 400. Specifically, the laser cutting head 400 can only change its posture and has no relative position movement. This mechanism has high precision and no cumulative error; it is lightweight, has good dynamic response, a compact structure, high rigidity, and a large load-bearing capacity.

[0042] In some specific embodiments, each of the three motors 200 is a servo motor, and the three motors 200 are of the same model. The control speed and position accuracy of the servo motor are very accurate and the response is sensitive. Using three servo motors of the same model to drive the three-degree-of-freedom spherical parallel mechanism 300 is beneficial to further improve the working accuracy and dynamic response sensitivity of the laser cutting head 400.

[0043] For further details, please refer to Figure 1 Each of the three motors 200 is fixedly mounted on the base 100 based on a motor mounting bracket 210. The motor mounting brackets 210 are arranged in a ring on the base 100, with each motor mounting bracket 210 spaced 120° apart. The axes of the front faces of each motor mounting bracket 210 intersect at a point located at the laser cutting head 400. Specifically, the output shaft of each motor 200 passes from the back to the front of the motor mounting bracket 210, and the housing of each motor 200 is fixedly mounted on the base 100. On the back of the motor mounting bracket 210, a motor mounting plate 220 is fixedly installed on the front of the motor mounting bracket 210. A bearing is fixedly fitted in the center of the motor mounting plate 220, and the output shaft of the motor 200 passes through the bearing. The output shaft of the motor 200 is transitionally fitted with the inner ring of the bearing. A motor bearing dust cover 230 is fixedly installed on the motor mounting plate 220. The motor bearing dust cover 230 has a ring structure, and the output shaft of the motor 200 passes through the motor bearing dust cover 230.

[0044] The motor mounting bracket 210 facilitates the secure fixing of the motor 200 to the base 100, improving the working stability of the motor 200. At the same time, the motor mounting bracket 210 has the function of limiting the position and orientation, so that the output shaft of the motor 200 points to a point on the laser cutting head 400, which facilitates cooperation with the three-degree-of-freedom spherical parallel mechanism 300.

[0045] In some specific embodiments, please refer to Figure 2 The first end of the first connecting rod 310 is provided with a motor output shaft mounting through hole 311 and a motor output shaft limiting hole 312. The motor output shaft limiting hole 312 penetrates the side wall of the motor output shaft mounting through hole 311. A wedge groove 313 is provided on the inner wall of the motor output shaft mounting through hole 311.

[0046] The output shaft of the motor 200 passes through the motor output shaft mounting through hole 311. The output shaft of the motor 200 is provided with a corresponding fitting limiting hole 201 and a fitting wedge groove 202. The motor output shaft limiting hole 312 and the fitting limiting hole 201 are engaged together based on a limiting pin, and the wedge groove 313 and the fitting wedge groove 202 are engaged together based on a wedge. This can strongly fix the first connecting rod 310 and the output shaft of the motor 200 together, prevent the first connecting rod 310 and the output shaft of the motor 200 from loosening, and ensure that the rotation angle of the output shaft of the motor 200 is transmitted to the first connecting rod 310 without loss, which is beneficial to improving the working accuracy of the laser cutting head 400.

[0047] In some specific embodiments, please refer to Figure 3 A connecting block 10 is provided at the fixed connection between the first connecting rod 310 and the second connecting rod 320. One end of the connecting block 10 is provided with a first protruding strip 11, and the other end of the connecting block 10 is provided with a second protruding strip 12. The first protruding strip 11 and the second protruding strip 12 are perpendicular to each other. The connecting block 10 is provided with a screw hole 13, which passes through the center of the first protruding strip 11 and the second protruding strip 12. The second end of the first connecting rod 310 is provided with a first groove 314 and a first countersunk hole 315. The first countersunk hole 315 penetrates the middle of the first groove 314. The first end of the second connecting rod 320 is provided with a second groove 321 and a second countersunk hole 322. The second countersunk hole 322 penetrates the middle of the second groove 321. The first groove 314 and the first protruding strip 11 cooperate. The second groove 321 and the second protruding strip 12 cooperate. One end of the first countersunk hole 315 and the screw hole 13 are bolted together. The other end of the second countersunk hole 322 and the screw hole 13 are bolted together.

[0048] The connecting block 10 increases the distance between the first connecting rod 310 and the second connecting rod 320, allowing the second connecting rod 320 to be closer to the laser cutting head 400. The protrusion on the connecting block 10 engages with the groove on the connecting rod, ensuring that the plane containing the first connecting rod 310 and the plane containing the second connecting rod 320 remain stably perpendicular. The countersunk hole on the connecting rod engages with the screw hole 13 on the connecting block 10 based on a bolt, ensuring that the first connecting rod 310 and the second connecting rod 320 are tightly fixed. The countersunk hole also prevents the bolt from protruding and does not hinder the relative movement between the connecting rods.

[0049] In some specific embodiments, please refer to Figure 4 The second connecting rod 320 and the third connecting rod 330 are rotatably connected based on the first support shaft 20. The second end of the second connecting rod 320 is provided with a first rotating through hole 323, and the first end of the third connecting rod 330 is provided with a second rotating through hole 331. Both ends of the first support shaft 20 are provided with a first rotating part 21. The first rotating through hole 323 and the first rotating part 21 at one end of the first support shaft 20 are rotatably engaged, and the second rotating through hole 331 and the first rotating part 21 at the other end of the first support shaft 20 are rotatably engaged. The first support shaft 20 can increase the distance between the second connecting rod 320 and the third connecting rod 330, so that the third connecting rod 330 is closer to the laser cutting head 400. The first rotating parts 21 at both ends of the first support shaft 20 are engaged with the corresponding rotating through holes, so that the second connecting rod 320 and the third connecting rod 330 can rotate flexibly.

[0050] Furthermore, the first support shaft 20 is provided with first slots 22 at both ends. The first slots 22 are located on the outside of the first rotating part 21. The first slots 22 are engaged with retaining rings. The diameter of the retaining rings is larger than the diameter of the rotating through hole, which can block the connecting rod and prevent the connecting rod from coming out of the first rotating part 21.

[0051] In some specific embodiments, please refer to Figure 5 The third connecting rod 330 and the laser cutting head 400 are rotatably connected based on the second support shaft 30. The second end of the third connecting rod 330 is provided with a third rotating through hole 332. One end of the second support shaft 30 is provided with a second rotating part 31, and the other end of the second support shaft 30 is provided with a fixing part 32. The third rotating through hole 332 and the second rotating part 31 are rotatably engaged, and the fixing part 32 is fixedly connected to the laser cutting head 400.

[0052] Furthermore, a second groove 33 is provided on the outer side of the second rotating part 31, and a retaining ring is also engaged in the second groove 33. The diameter of the retaining ring is larger than the diameter of the rotating through hole, which can block the connecting rod and prevent the connecting rod from coming out of the second rotating part 31.

[0053] The second support shaft 30 maintains a certain distance between the third link 330 and the laser cutting head 400, which facilitates the spatial attitude change of the laser cutting head 400; the second support shaft 30 fixes the nozzle 410 of the laser cutting head 400 at the center of the three-degree-of-freedom spherical parallel mechanism 300, which facilitates the adjustment of the attitude of the laser cutting head 400.

[0054] In some specific embodiments, please refer to Figure 6 The base 100 has a central circular hole 110 and a plurality of flange holes 120 surrounding the circular hole 110; the laser cutting head 400 is connected to an optical fiber 420, which passes through the circular hole 110; the entire laser cutting head attitude transformation device can be fixed to the worktable of a three-dimensional five-axis laser cutting machine or the end of an industrial robot based on the plurality of flange holes 120.

[0055] In some specific embodiments, the laser cutting head posture changing device further includes a control system, which is electrically connected to the three motors 200; wherein the control system includes:

[0056] The parameter setting module is used to input the cutting speed and cutting head parameters; specifically, the cutting head parameters include focal position, laser power, cutting height, etc.

[0057] The trajectory input module is used to input a given laser cutting trajectory;

[0058] The motor rotation angle calculation module is used to receive the cutting speed, the cutting head parameters, and the given laser cutting trajectory. It generates the motion trajectory of the laser cutting head 400 by transforming the given laser cutting trajectory into a coordinate system and compensating for the laser beam radius. It also extracts the attitude features of the motion trajectory to generate a preset azimuth angle perpendicular to the workpiece surface. The difference between the preset azimuth angle and the current azimuth angle of the laser cutting head 400 is the control quantity. The control quantity is transformed into the corresponding rotation angle of the three motors 200 by inverse kinematics calculation in conjunction with the cutting speed and the cutting head parameters.

[0059] A servo drive module is used to receive the rotation angle and control the three motors 200 to rotate according to the rotation angle.

[0060] The control process of the laser cutting head attitude transformation device of the present invention is as follows:

[0061] Input the cutting speed and cutting head parameters into the parameter setting module;

[0062] Input the given laser cutting trajectory into the trajectory setting module;

[0063] The motor rotation angle calculation module performs coordinate system transformation and laser beam radius compensation on the given laser cutting trajectory based on the RTCP (rotation tool center point, i.e., the center point of the laser beam) parameter, and then generates the motion trajectory of the laser cutting head 400. The motor rotation angle calculation module continues to perform pose decomposition on the motion trajectory, and then extracts the posture features of the motion trajectory to generate a preset azimuth angle perpendicular to the workpiece surface. The preset azimuth angle includes three sub-azimuth angles, and the difference between these three sub-azimuth angles and the current azimuth angle of the laser cutting head 400 is the control quantity. Then, the motor rotation angle calculation module, together with the cutting speed and cutting head parameters, transforms the control quantity into the corresponding rotation angles of the three motors 200 through inverse kinematics calculation.

[0064] Finally, the servo drive module receives the instruction and controls the three motors 200 to rotate according to the rotation angle, which in turn drives the corresponding linkage components in the three-degree-of-freedom spherical parallel mechanism 300, thereby realizing the effect of the laser cutting head 400 dynamically changing its posture according to the predetermined trajectory.

[0065] Three motors 200 rotate according to instructions. The output shaft of each motor 200 drives the corresponding first link 310, the first link 310 drives the corresponding second link 320, the second link 320 drives the corresponding third link 330, and the third link 330 drives the laser cutting head 400. The three motors 200 and the three sets of link assemblies cooperate with each other to achieve the effect of the laser cutting head 400 dynamically changing its posture according to a predetermined trajectory.

[0066] The laser cutting head posture transformation device of the present invention has three rotational degrees of freedom. Based on this, it can be installed on a multi-degree-of-freedom position moving device to form a three-dimensional five-axis CNC cutting system, realizing laser cutting of complex workpieces, especially curved surfaces.

[0067] The laser cutting head posture transformation device of the present invention uses a three-degree-of-freedom spherical parallel mechanism 300 to mount a laser cutting head 400, and uses three motors 200 to drive the three-degree-of-freedom spherical parallel mechanism 300, so that the laser cutting head 400 has three rotational degrees of freedom, which increases the degrees of freedom of the laser cutting head 400. This reduces the number of degrees of freedom required by the worktable, reduces the dependence of workpiece posture transformation on the worktable, that is, reduces the movement frequency of the worktable, thereby reducing the energy consumption of the three-dimensional five-axis laser cutting machine, and also helps to improve the control accuracy of the three-dimensional five-axis laser cutting machine.

[0068] The laser cutting head attitude transformation device of the present invention takes the rotation angle of three motors 200 as input, a three-degree-of-freedom spherical parallel mechanism 300 as transmission link, and the attitude of the laser cutting head 400 as output, which can realize the spatial attitude transformation of the laser cutting head 400 within a small range. The device has high precision, no cumulative error, light weight, good dynamic response, compact structure, high rigidity, and large load-bearing capacity.

[0069] The foregoing has provided a detailed description of a laser cutting head posture transformation device and its control system provided by embodiments of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A laser cutting head posture changing device, characterized in that, The laser cutting head attitude transformation device includes a base, three motors, a three-degree-of-freedom spherical parallel mechanism, and a laser cutting head. The three motors are fixedly mounted on the base. One end of the three-degree-of-freedom spherical parallel mechanism is connected to the output shaft of the three motors, and the other end of the three-degree-of-freedom spherical parallel mechanism is fixedly connected to the laser cutting head. The three-degree-of-freedom spherical parallel mechanism surrounds the laser cutting head. Each of the three motors is fixedly mounted on the base based on a motor mounting bracket. The motor mounting brackets are arranged in a ring on the base, with each motor mounting bracket spaced 120° apart. The axes of the front faces of each motor mounting bracket intersect at a point on the laser cutting head. The three-degree-of-freedom spherical parallel mechanism includes three sets of linkage assemblies. Each set of linkage assemblies is distributed along the circumference of the base. Each set of linkage assemblies is arranged at 120° intervals and is rotationally symmetrical. Each linkage assembly includes a first linkage, a second linkage, and a third linkage. The first end of the first linkage is fixedly connected to the output shaft of the corresponding motor. The second end of the first linkage is fixedly connected to the first end of the second linkage. The second end of the second linkage is rotatably connected to the first end of the third linkage. The second end of the third linkage is rotatably connected to the laser cutting head. The first link, the second link, and the third link are all arc-shaped links. The first link is located on the first spherical surface, the second link is located on the second spherical surface, and the third link is located on the third spherical surface. The centers of the first, second, and third spherical surfaces coincide. The nozzle of the laser cutting head is located at the center of the third spherical surface. The plane containing the first link and the plane containing the second link are perpendicular to each other. The three-degree-of-freedom spherical parallel mechanism is configured to enable the laser cutting head to achieve pure attitude change at the center of the third sphere without displacement relative to the base.

2. The laser cutting head posture transformation device as described in claim 1, characterized in that, Each of the three motors is a servo motor, and the three motors are of the same model.

3. The laser cutting head posture transformation device as described in claim 1, characterized in that, The first end of the first connecting rod is provided with a motor output shaft mounting through hole and a motor output shaft limiting hole, wherein the motor output shaft limiting hole penetrates the side wall of the motor output shaft mounting through hole; A wedge groove is provided on the inner wall of the motor output shaft mounting through hole.

4. The laser cutting head posture transformation device as described in claim 1, characterized in that, A connecting block is provided at the fixed connection between the first connecting rod and the second connecting rod. A first protruding strip is provided at one end of the connecting block, and a second protruding strip is provided at the other end of the connecting block. The first protruding strip and the second protruding strip are perpendicular to each other. The connecting block is provided with a screw hole, which passes through the center of the first protruding strip and the second protruding strip; The second end of the first connecting rod is provided with a first groove and a first countersunk hole, the first countersunk hole penetrating the middle of the first groove. The first end of the second connecting rod is provided with a second groove and a second countersunk hole, the second countersunk hole penetrating the middle of the second groove. The first groove and the first protrusion cooperate, the second groove and the second protrusion cooperate, one end of the first countersunk hole and the screw hole are bolted together, and the other end of the second countersunk hole and the screw hole are bolted together.

5. The laser cutting head posture transformation device as described in claim 1, characterized in that, The second link and the third link are rotatably connected based on the first support shaft. The second end of the second link is provided with a first rotatable through hole, and the first end of the third link is provided with a second rotatable through hole. Both ends of the first support shaft are provided with a first rotating part. The first rotatable through hole and the first rotating part at one end of the first support shaft are rotatably engaged, and the second rotatable through hole and the first rotating part at the other end of the first support shaft are rotatably engaged.

6. The laser cutting head posture transformation device as described in claim 1, characterized in that, The third link and the laser cutting head are rotatably connected based on the second support shaft. The second end of the third link is provided with a third rotating through hole. One end of the second support shaft is provided with a second rotating part, and the other end of the second support shaft is provided with a fixed part. The third rotating through hole and the second rotating part are rotatably engaged, and the fixed part is fixedly connected to the laser cutting head.

7. The laser cutting head posture transformation device as described in claim 1, characterized in that, The base has a central circular hole, and several flange holes are arranged around the circular hole; The laser cutting head is connected to an optical fiber, which extends out of the circular hole.

8. A control system for the laser cutting head attitude transformation device according to any one of claims 1 to 7, characterized in that, The control system includes: The parameter setting module is used to input cutting speed and cutting head parameters; The trajectory input module is used to input a given laser cutting trajectory; The motor rotation angle calculation module is used to receive the cutting speed, the cutting head parameters, and the given laser cutting trajectory. It generates the motion trajectory of the laser cutting head by transforming the given laser cutting trajectory into a coordinate system and compensating for the laser beam radius. It also extracts the attitude features of the motion trajectory to generate a preset azimuth angle perpendicular to the workpiece surface. The difference between the preset azimuth angle and the current azimuth angle of the laser cutting head is the control quantity. The control quantity is transformed into the corresponding rotation angle of the three motors by inverse kinematics calculation in conjunction with the cutting speed and the cutting head parameters. A servo drive module is used to receive the rotation angle and control the three motors to rotate according to the rotation angle.

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