Robot motion error compensation device

Abstract

The invention discloses a robot motion error compensation device, belongs to the technical field of industrial robots, and aims to solve the problem of low final precision caused by large influence factors of existing error compensation. After the visual identification camera obtains position information, needed transverse and longitudinal movement amounts are calculated, the telescopic mechanism changes the height of the fixed seat, the movable mechanism drives the sliding block to change the position of the poke rod, the driving mechanism rotates the rotary disc, the rotary disc pushes the transverse and longitudinal moving frames to move through the poke rod, and finally the moving disc drives the working part to move. The position between a working part and a workpiece is accurately measured through a visual recognition camera, the error amount can be accurately recognized, then the position of the working part is accurately adjusted through cooperative work of a telescopic mechanism, a distance adjusting mechanism, a rotary disc and an adjusting executing mechanism, and the position error of the executing end and the workpiece is effectively corrected. The machining or assembling precision is improved, so that the product quality is improved.

Description

Technical Field

[0001] The invention relates to the technical field of industrial robots, and in particular to a robot motion error compensation device. Background Art

[0002] Industrial robots can not only replace humans to complete specific production tasks in harsh environments, but can also perform processing operations in larger spaces compared to traditional machine tools. Therefore, new energy vehicle manufacturing factories use them for drilling, milling, and cutting of lightweight automotive parts. However, compared with traditional machine tool processing, multi-degree-of-freedom serial industrial robots have the disadvantage of low structural stiffness performance, which leads to problems such as large end force deformation, low processing accuracy, and poor product quality during processing.

[0003] The existing error compensation is mostly carried out by conducting end-force deformation experiments on the robot, and then using the algorithm joint stiffness value to verify and improve the robot's positioning accuracy through the end positioning accuracy. The robot's stiffness is not fixed, but will change with different postures. The stiffness difference between two different postures may be very large, and different loads will also lead to different sizes of motion errors. Especially in the robot's assembly process, the error on the plane will directly affect the final quality of its product. Summary of the invention

[0004] The purpose of the present invention is to provide a robot motion error compensation device, which solves the problem that the existing error compensation in the background technology has large influencing factors and leads to low final accuracy.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a robot motion error compensation device, which is installed between the robot end mechanical arm and the working part, including a shell and an adjustment component arranged at the lower part of the shell, the adjustment component includes a visual recognition camera installed at the lower part of the shell, the visual recognition camera is used to measure the position between the working part and the workpiece, the adjustment component also includes a telescopic mechanism, a distance adjustment mechanism, a turntable and an adjustment actuator arranged in sequence from top to bottom inside the shell, the turntable is rotatably arranged inside the shell, and the shell is also provided with a driving mechanism for driving the turntable to rotate, the distance adjustment mechanism includes a sliding block slidably arranged inside the turntable, and also includes a fixed seat installed below the telescopic mechanism, the distance adjustment mechanism also includes a movable mechanism arranged between the fixed seat and the sliding block and a toggle rod fixedly installed at the bottom of the sliding block, and the toggle rod extends to the bottom of the turntable, the telescopic mechanism is used to adjust the position of the fixed seat up and down, and the fixed seat moves up and down to change the position of the sliding block and the toggle rod inside the turntable through the movable mechanism, and the adjustment actuator includes a sliding connection to the shell The horizontal movable frame and the longitudinal movable frame at the lower part of the interior, the adjusting actuator also includes a movable disk movably arranged at the lower part of the interior of the shell, the horizontal movable frame, the longitudinal movable frame and the movable disk are fixedly connected, and a movable shaft is fixedly connected to the bottom of the movable disk, and the movable shaft is connected to the working part; the position between the execution end of the working part and the workpiece is monitored by a visual recognition camera, and then the error amount is identified, and the position of the adjusting actuator is changed by the telescopic mechanism, the distance adjustment mechanism and the turntable to make adjustments. Specifically, after the error amount is identified, the required horizontal and longitudinal movement amounts are calculated, the height position of the fixed seat is changed by the telescopic mechanism, and then the position of the sliding block inside the turntable is changed by the movable mechanism, thereby changing the length of the toggle rod from the center of the turntable, and then the turntable is driven to rotate by the driving mechanism. During the rotation of the turntable, the toggle rod under the turntable pushes the horizontal movable frame and the longitudinal movable frame to move, and the movement amount of the horizontal movable frame is the calculated horizontal movement amount, and the movement amount of the longitudinal movable frame is the calculated longitudinal movement amount. Finally, the working part is driven to move by the moving shaft under the movable disk, and finally the position error correction between the execution end of the working part and the workpiece is realized.

[0006] Furthermore, the telescopic mechanism includes a large sleeve and a small sleeve fixedly installed in the middle of the shell, a telescopic cylinder is fixedly installed on the upper part of the interior of the shell, a small piston is fixedly installed on the output end of the telescopic cylinder downward, the small piston is slidably connected to the inside of the small sleeve and fits the inner wall of the small sleeve, and the telescopic mechanism also includes a large piston slidably connected to the inside of the large sleeve, and the large piston fits the inner wall of the large sleeve.

[0007] Furthermore, the bottom of the large sleeve is open, the top of the small sleeve is open, a thread groove is arranged on the outside of the fixing seat, and the fixing seat is threadedly installed in the middle of the large piston through the thread groove.

[0008] Furthermore, the movable mechanism includes a connecting rod and a first movable ball and a second movable ball respectively fixedly connected to two ends of the connecting rod.

[0009] Furthermore, the sliding block is formed by molding a front and a rear part, and the fixed seat is formed by molding a left and a right part. A first movable groove corresponding to the first movable ball is arranged at the upper part of the interior of the sliding block, and a second movable groove corresponding to the second movable ball is arranged at the lower part of the interior of the fixed seat. The first movable groove is evenly distributed with first balls corresponding to the first movable ball, and the second movable groove is evenly distributed with second balls corresponding to the second movable ball. The first movable groove and the second movable groove are arc-shaped chambers larger than a semicircle.

[0010] Furthermore, a sliding groove opening upward is arranged on the upper part of the interior of the turntable, and the sliding groove is used for the sliding block to slide. A through groove for the movement of the toggle rod is arranged on the lower part of the interior of the turntable.

[0011] Furthermore, the transverse movable frame and the longitudinal movable frame are both rectangular components composed of two groups of parallel frame rods and threaded rods connecting the two groups of frame rods. The movable disk is movably arranged at the lower part of the interior of the outer shell. The lower part of the outer shell is an opening, and the size of the opening at the lower part of the outer shell is smaller than the size of the movable disk. The top of the movable disk is fixedly connected to the transverse movable frame and the longitudinal movable frame through a connecting shaft.

[0012] Furthermore, the driving mechanism includes a motor fixedly mounted on the inner side of the shell, and also includes a transverse transmission rod and a longitudinal transmission rod rotatably connected to the inside of the shell, a first transmission assembly is installed between the output end of the motor and one end of the transverse transmission rod, and a second transmission assembly is installed between the other end of the transverse transmission rod and the top of the longitudinal transmission rod, the driving mechanism also includes a spur gear fixedly connected to the bottom of the longitudinal transmission rod, and the spur gear is meshed with the turntable, and the first transmission assembly and the second transmission assembly are both composed of end face gears and transmission structures meshed with the end face gears.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] The present invention provides a robot motion error compensation device. After a visual recognition camera obtains position information, it calculates the required lateral and longitudinal movement amounts, a telescopic mechanism changes the height of a fixed seat, a movable mechanism drives a sliding block to change the position of a toggle rod, a driving mechanism rotates a turntable, and the turntable drives the lateral and longitudinal moving frames to move through the toggle rod, and finally the moving disk drives the working part to move, thereby achieving error correction. The visual recognition camera accurately measures the position between the working part and the workpiece, and can accurately identify the error amount. Then, the telescopic mechanism, the distance adjustment mechanism, the turntable and the adjustment actuator work in coordination to achieve accurate adjustment of the position of the working part, effectively correct the position error between the actuator end and the workpiece, and improve the processing or assembly accuracy, thereby improving product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the industrial robot of the present invention;

[0016] Figure 2 This is a schematic diagram of the overall structure of the industrial robot of the present invention;

[0017] Figure 3 It is a schematic diagram of the overall structure of the error compensation device of the present invention;

[0018] Figure 4 This is a disassembled diagram of the overall structure of the error compensation device of the present invention;

[0019] Figure 5 It is a schematic diagram of the structure of the telescopic mechanism, the rotating disk, the regulating actuator and the driving mechanism of the present invention;

[0020] Figure 6 It is an exploded view of the telescopic mechanism, distance adjustment mechanism and turntable structure of the present invention;

[0021] Figure 7 It is an exploded view of the distance adjustment mechanism structure of the present invention;

[0022] Figure 8 It is a cross-sectional view of the telescopic mechanism, the distance adjustment mechanism and the turntable structure of the present invention;

[0023] Fig. 9 It is a schematic diagram of the driving mechanism structure of the present invention;

[0024] Fig.10 It is an exploded view of the regulating actuator structure of the present invention.

[0025] In the figure: 1, housing; 2, visual recognition camera; 3, telescopic mechanism; 31, large sleeve; 32, small sleeve; 33, telescopic cylinder; 34, small piston; 35, large piston; 4, distance adjustment mechanism; 41, sliding block; 411, first movable groove; 412, first ball; 42, movable mechanism; 421, connecting rod; 422, first movable ball; 423, second movable ball; 43, fixed seat; 431, threaded groove; 432, second movable groove; 433. Second ball bearing; 44. Toggle rod; 5. Turntable; 51. Slide groove; 52. Through groove; 6. Adjustment actuator; 61. Transverse moving frame; 611. Frame rod; 612. Threaded rod; 62. Longitudinal moving frame; 63. Moving plate; 631. Moving shaft; 632. Connecting shaft; 7. Driving mechanism; 71. Motor; 72. Transverse transmission rod; 73. Longitudinal transmission rod; 74. First transmission assembly; 75. Second transmission assembly; 76. Spur gear. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In order to solve the existing technical problems that the error compensation has a large impact on the factors and leads to low final accuracy, such as Figure 1-Figure 10 As shown, the following preferred technical solutions are provided:

[0028] like Figure 1-Figure 3 As shown, a robot motion error compensation device is installed between the robot end mechanical arm and the working part. The working part can be a clamp, a welding gun, a laser cutting component, a drilling and milling device, etc., including a shell 1 and an adjustment component arranged at the lower part of the shell 1, such as Figure 3-Figure 8As shown, the adjustment component includes a visual recognition camera 2 installed under the housing 1, and the visual recognition camera 2 is used to measure the position between the working part and the workpiece. The adjustment component also includes a telescopic mechanism 3, a distance adjustment mechanism 4, a turntable 5 and an adjustment actuator 6 which are arranged inside the housing 1 from top to bottom. The turntable 5 is rotatably arranged inside the housing 1, and a driving mechanism 7 for driving the turntable 5 to rotate is also arranged inside the housing 1. The distance adjustment mechanism 4 includes a sliding block 41 slidably arranged inside the turntable 5, and also includes a fixed seat 43 installed below the telescopic mechanism 3. The distance adjustment mechanism 4 includes a sliding block 41 slidably arranged inside the turntable 5, and also includes a fixed seat 43 installed below the telescopic mechanism 3. The joint mechanism 4 also includes a movable mechanism 42 arranged between the fixed seat 43 and the sliding block 41 and a toggle rod 44 fixedly installed at the bottom of the sliding block 41, and the toggle rod 44 extends to the bottom of the turntable 5. The telescopic mechanism 3 is used to adjust the position of the fixed seat 43 up and down. The fixed seat 43 moves up and down to change the position of the sliding block 41 and the toggle rod 44 inside the turntable 5 through the movable mechanism 42. The adjusting actuator 6 includes a transverse moving frame 61 and a longitudinal moving frame 62 slidably connected to the lower part of the shell 1. The adjusting actuator 6 also includes a moving frame 61 movably arranged at the lower part of the shell 1. The plate 63, the lateral moving frame 61, the longitudinal moving frame 62 and the moving plate 63 are fixedly connected, and the bottom of the moving plate 63 is fixedly connected with a moving shaft 631, and the moving shaft 631 is connected to the working part; the position between the execution end of the working part and the workpiece is monitored by the visual recognition camera 2, and then the error amount is identified, and the position of the adjusting actuator 6 is changed and adjusted by the telescopic mechanism 3, the distance adjustment mechanism 4 and the turntable 5. Specifically, when the error amount is identified, the required lateral and longitudinal movement amounts are calculated, and the height position of the fixed seat 43 is changed by the telescopic mechanism 3, and then the movable mechanism 42 changes the position of the sliding block 41 inside the turntable 5, thereby changing the length of the toggle rod 44 from the center of the turntable 5, and then the turntable 5 is driven to rotate through the driving mechanism 7. During the rotation of the turntable 5, the toggle rod 44 under the turntable 5 pushes the transverse moving frame 61 and the longitudinal moving frame 62 to move. The movement amount of the transverse moving frame 61 is the calculated transverse movement amount, and the movement amount of the longitudinal moving frame 62 is the calculated longitudinal movement amount. Finally, the working part is driven to move through the moving shaft 631 under the moving disk 63, and finally the position error correction between the execution end of the working part and the workpiece is realized.

[0029] like Figure 5-Figure 6 As shown, the telescopic mechanism 3 includes a large sleeve 31 and a small sleeve 32 fixedly installed in the middle of the shell 1. The large sleeve 31 and the small sleeve 32 can be filled with hydraulic oil. A telescopic cylinder 33 is fixedly installed on the upper part of the interior of the shell 1. The output end of the telescopic cylinder 33 is downward and a small piston 34 is fixedly installed. The small piston 34 is slidably connected to the inside of the small sleeve 32 and fits the inner wall of the small sleeve 32. The telescopic mechanism 3 also includes a large piston 35 slidably connected to the inside of the large sleeve 31, and the large piston 35 fits the inner wall of the large sleeve 31.

[0030] The bottom of the large sleeve 31 is open, the top of the small sleeve 32 is open, a thread groove 431 is provided on the outside of the fixing seat 43 , and the fixing seat 43 is threadedly installed in the middle of the large piston 35 through the thread groove 431 .

[0031] like Figure 7 As shown, the movable mechanism 42 includes a connecting rod 421 and a first movable ball 422 and a second movable ball 423 respectively fixedly connected to two ends of the connecting rod 421 .

[0032] The sliding block 41 is formed by molding a front and a rear part together, and the fixed seat 43 is formed by molding a left and a right part together. A first movable groove 411 corresponding to the first movable ball 422 is provided at the upper part of the interior of the sliding block 41, and a second movable groove 432 corresponding to the second movable ball 423 is provided at the lower part of the interior of the fixed seat 43. The first movable groove 411 is evenly distributed with first rolling balls 412 corresponding to the first movable ball 422, and the second movable groove 432 is evenly distributed with second rolling balls 433 corresponding to the second movable ball 423. The first movable groove 411 and the second movable groove 432 are arc-shaped chambers larger than a semicircle.

[0033] like Figure 8 As shown, a slide groove 51 opening upward is provided on the upper part of the rotating disk 5 , and the slide groove 51 is used for the sliding block 41 to slide. A through groove 52 is provided on the lower part of the rotating disk 5 for the toggle rod 44 to move.

[0034] 8. A robot motion error compensation device as claimed in claim 1, characterized in that: Fig.10 As shown, the transverse moving frame 61 and the longitudinal moving frame 62 are both rectangular components composed of two groups of parallel frame rods 611 and threaded rods 612 connecting the two groups of frame rods 611. The moving plate 63 is movably arranged at the lower part of the inner part of the outer shell 1. The lower part of the outer shell 1 is an opening, and the size of the opening at the lower part of the outer shell 1 is smaller than the size of the moving plate 63. The top of the moving plate 63 is fixedly connected to the transverse moving frame 61 and the longitudinal moving frame 62 through a connecting shaft 632.

[0035] like Fig. 9 As shown, the driving mechanism 7 includes a motor 71 fixedly mounted on the inner side of the housing 1, and also includes a transverse transmission rod 72 and a longitudinal transmission rod 73 rotatably connected to the inside of the housing 1, a first transmission assembly 74 is installed between the output end of the motor 71 and one end of the transverse transmission rod 72, and a second transmission assembly 75 is installed between the other end of the transverse transmission rod 72 and the top of the longitudinal transmission rod 73, the driving mechanism 7 also includes a spur gear 76 fixedly connected to the bottom of the longitudinal transmission rod 73, and the spur gear 76 is meshed with the turntable 5, and the first transmission assembly 74 and the second transmission assembly 75 are both composed of end face gears and transmission structures meshed with the end face gears.

[0036] Specifically, the position between the execution end of the working part and the workpiece is monitored by the visual recognition camera 2, and then the error amount is identified. The position of the adjusting actuator 6 is changed and adjusted by the telescopic mechanism 3, the distance adjustment mechanism 4 and the turntable 5. Specifically, after the error amount is identified, the required lateral and longitudinal movement amounts are calculated, and the height position of the fixed seat 43 is changed by the telescopic mechanism 3. When the telescopic cylinder 33 is extended and retracted, the small piston 34 moves inside the small sleeve 32, and the large piston 35 is driven to move inside the large sleeve 31 under the action of atmospheric pressure, and the movement of the large piston 35 is more precise. When the 43 in the middle of 35 moves, the position of the sliding block 41 inside the turntable 5 is changed by the movable mechanism 42. The position is changed, thereby changing the distance of the toggle rod 44 from the center of the turntable 5, and then the turntable 5 is driven to rotate through the driving mechanism 7, and the motor 71 drives the transverse transmission rod 72 to rotate through the first transmission assembly 74, and then drives the turntable 5 to rotate under the action of the longitudinal transmission rod 73 and the spur gear 76. During the rotation of the turntable 5, the toggle rod 44 under the turntable 5 pushes the transverse moving frame 61 and the longitudinal moving frame 62 to move, and the movement amount of the transverse moving frame 61 is the calculated transverse movement amount, and the movement amount of the longitudinal moving frame 62 is the calculated longitudinal movement amount, and finally the working part is driven to move through the moving shaft 631 under the moving disk 63, and finally the position error correction of the executing end of the working part and the workpiece is realized.

[0037] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0038] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A robot motion error compensation device, which is installed between the robot end mechanical arm and the working part, comprises a housing (1) and an adjustment component arranged at the lower part of the housing (1), characterized in that: The adjustment component comprises a visual recognition camera (2) installed below the housing (1), the visual recognition camera (2) being used to measure the position between the working part and the workpiece. The adjustment component also comprises a telescopic mechanism (3), a distance adjustment mechanism (4), a turntable (5) and an adjustment actuator (6) which are arranged inside the housing (1) from top to bottom. The turntable (5) is rotatably arranged inside the housing (1), and a driving mechanism (7) for driving the turntable (5) to rotate is also arranged inside the housing (1). The distance adjustment mechanism (4) comprises a sliding block (41) slidably arranged inside the turntable (5), and also comprises a fixed seat (43) installed below the telescopic mechanism (3). The distance adjustment mechanism (4) also comprises a movable mechanism (42) and a fixed mechanism (43) arranged between the fixed seat (43) and the sliding block (41). A toggle rod (44) is fixedly mounted at the bottom of the sliding block (41), and the toggle rod (44) extends to the bottom of the turntable (5); the telescopic mechanism (3) is used to adjust the position of the fixed seat (43) up and down; the fixed seat (43) moves up and down to change the position of the sliding block (41) and the toggle rod (44) inside the turntable (5) through the movable mechanism (42); the adjusting actuator (6) comprises a transverse moving frame (61) and a longitudinal moving frame (62) slidably connected to the lower part of the inner part of the shell (1); the adjusting actuator (6) also comprises a moving disk (63) movably arranged at the lower part of the inner part of the shell (1); the transverse moving frame (61), the longitudinal moving frame (62) and the moving disk (63) are fixedly connected; a moving shaft (631) is fixedly connected to the bottom of the moving disk (63); and the moving shaft (631) is connected to the working component.

2. A robot motion error compensation device as claimed in claim 1, characterized in that: The telescopic mechanism (3) comprises a large sleeve (31) and a small sleeve (32) fixedly mounted in the middle of the housing (1); a telescopic cylinder (33) is fixedly mounted on the upper part of the housing (1); a small piston (34) is fixedly mounted on the output end of the telescopic cylinder (33) downwardly facing; the small piston (34) is slidably connected to the inside of the small sleeve (32) and fits against the inner wall of the small sleeve (32); the telescopic mechanism (3) also comprises a large piston (35) slidably connected to the inside of the large sleeve (31); the large piston (35) fits against the inner wall of the large sleeve (31).

3. A robot motion error compensation device as claimed in claim 2, characterized in that: The bottom of the large sleeve (31) is open, and the top of the small sleeve (32) is open.

4. A robot motion error compensation device as claimed in claim 2, characterized in that: The fixing seat (43) is provided with a thread groove (431) on the outside, and the fixing seat (43) is threadably mounted in the middle of the large piston (35) via the thread groove (431).

5. A robot motion error compensation device as claimed in claim 4, characterized in that: The movable mechanism (42) comprises a connecting rod (421) and a first movable ball (422) and a second movable ball (423) respectively fixedly connected to two ends of the connecting rod (421).

6. A robot motion error compensation device as claimed in claim 5, characterized in that: The sliding block (41) is formed by combining two parts, front and rear, by molding; the fixed seat (43) is formed by combining two parts, left and right, by molding; a first movable groove (411) corresponding to the first movable ball (422) is arranged at the upper part of the interior of the sliding block (41); a second movable groove (432) corresponding to the second movable ball (423) is arranged at the lower part of the interior of the fixed seat (43); first rolling balls (412) corresponding to the first movable ball (422) are evenly distributed inside the first movable groove (411); second rolling balls (433) corresponding to the second movable ball (423) are evenly distributed inside the second movable groove (432); the first movable groove (411) and the second movable groove (432) are arc-shaped chambers larger than a semicircle.

7. A robot motion error compensation device as claimed in claim 6, characterized in that: The upper part of the rotating disk (5) is provided with a sliding groove (51) which is open upwards. The sliding groove (51) is used for the sliding block (41) to slide. The lower part of the rotating disk (5) is provided with a through groove (52) for the toggle rod (44) to move.

8. A robot motion error compensation device as claimed in claim 1, characterized in that: The transverse movable frame (61) and the longitudinal movable frame (62) are both rectangular components consisting of two groups of parallel frame rods (611) and threaded rods (612) connecting the two groups of frame rods (611).

9. A robot motion error compensation device as claimed in claim 8, characterized in that: The movable plate (63) is movably arranged at the lower part of the inner part of the outer shell (1); the lower part of the outer shell (1) is provided with an opening, and the size of the opening at the lower part of the outer shell (1) is smaller than the size of the movable plate (63); the top of the movable plate (63) is fixedly connected to the transverse movable frame (61) and the longitudinal movable frame (62) via a connecting shaft (632).

10. A robot motion error compensation device as claimed in claim 1, characterized in that: The driving mechanism (7) comprises a motor (71) fixedly mounted on the inner side of the housing (1), and also comprises a transverse transmission rod (72) and a longitudinal transmission rod (73) rotatably connected to the inner side of the housing (1); a first transmission assembly (74) is mounted between the output end of the motor (71) and one end of the transverse transmission rod (72); a second transmission assembly (75) is mounted between the other end of the transverse transmission rod (72) and the top of the longitudinal transmission rod (73); the driving mechanism (7) also comprises a spur gear (76) fixedly connected to the bottom of the longitudinal transmission rod (73), and the spur gear (76) is meshedly connected to the turntable (5); the first transmission assembly (74) and the second transmission assembly (75) are both transmission structures composed of end face gears and meshed end face gears.

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