Three-degree-of-freedom robot wrist with bidirectional active clutch and brake functions

Abstract

The invention discloses a three-degree-of-freedom robot wrist with bidirectional active clutch and brake functions, and relates to the technical field of mechatronics. The tail end parallel joint is installed on the top of the rack through the universal joint, the two linear motors are installed on the two sides of the tail end parallel joint, the bottom shell is rotationally connected with the top shell, the bottom rotating base is fixed in the bottom shell, the top rotating base is rotationally connected with the bottom rotating base, the bottom of the rack is fixed to the top rotating base, and the upper end of the rack is fixedly connected with the top shell. The rotating motor is fixed to the bottom in the rack and connected with the two-way clutch through the planetary gear reducer, and a rotating shaft of the two-way clutch is fixedly connected with the bottom rotating base. The torsion action is added on the basis of pitching and yawing, three-degree-of-freedom motion output is achieved, the three-degree-of-freedom motion output is intensively designed in the shell mechanism in a series-parallel mode, the axial size is reasonably controlled, bidirectional unlocking and locking of torsion are achieved through the bidirectional clutch, and the flexibility of the robot wrist is effectively improved.

Description

Technical Field

[0001] The invention relates to the technical field of mechatronics, and in particular to a three-degree-of-freedom robot wrist with bidirectional active clutch and braking functions. Background Art

[0002] The robot wrist used to connect the hand and arm in conventional anthropomorphic mechatronic robotic arms generally extends and retracts in both directions through a parallel mechanism, and has two degrees of freedom, pitch and yaw. As the requirements for robot operational flexibility become increasingly stringent, it has gradually become difficult to meet the robot's hand movement requirements.

[0003] In addition, scholars in the field have also conducted some research and design on this kind of problem. Generally, the three-degree-of-freedom motion output is achieved by attaching a rotary motor at the end of the wrist joint. However, this will greatly increase the axial size of the wrist joint and cannot be applied in situations where the wrist joint size, especially the axial size, is strictly required. In addition, the twisting action of the wrist joint needs to be quickly locked after reaching the specified angle. The angle control by the rotary motor alone is prone to excessive twisting, and it is difficult to achieve accurate braking of the twisting angle. Summary of the invention

[0004] In order to address the shortcomings of the background technology, the present invention provides a three-degree-of-freedom robot wrist with two-way active clutch and braking functions, which adds a twisting action on the basis of pitch and yaw to achieve three-degree-of-freedom motion output. It is centrally designed in a shell mechanism using a series-parallel hybrid method, and the axial size is reasonably controlled. The two-way unlocking and locking of the twisting is achieved through a two-way clutch, which effectively improves the flexibility of the robot wrist.

[0005] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a three-degree-of-freedom robot wrist with bidirectional active clutch and braking functions, including a frame, an end parallel joint and two linear motors, the end parallel joint body is disc-shaped and its bottom center is installed on the top of the frame through a universal joint, the two linear motors are arranged in parallel and eccentrically arranged with the end parallel joint, the bottom ends of the two linear motors are respectively connected to the bottom of the frame through ball joints, an n-shaped connecting beam is arranged at the eccentric position of the bottom of the end parallel joint, and the telescopic ends of the two linear motors are respectively hinged to the two ends of the n-shaped connecting beam through connecting pieces, the robot wrist also includes a bottom shell, a top shell, a top rotating seat, a rotating motor, a planetary gear reducer, a bidirectional clutch and a bottom rotating seat, the bottom shell and the top shell are two cylindrical shells arranged coaxially and rotatingly connected. The bottom rotating seat is fixed inside the bottom shell, the top rotating seat is arranged at the lower end inside the top shell and is rotatably connected to the bottom rotating seat, the top rotating seat and the bottom rotating seat both adopt an annular structure, the bottom of the frame is fixed at the center position of the upper surface of the top rotating seat, the upper end of the frame is connected and fixed to the top shell, and the end parallel joint extends out of the top shell, the rotating motor is longitudinally fixed at the bottom inside the frame, the planetary gear reducer is longitudinally fixed below the frame, the output shaft of the rotating motor passes through the frame and is connected to the input end of the planetary gear reducer, the two-way clutch is longitudinally fixed below the planetary gear reducer, the two-way clutch is coaxially provided with a rotating shaft, which allows and limits the forward and reverse rotation of the rotating shaft in the unlocked and locked states respectively, the upper end of the rotating shaft is connected to the output end of the planetary gear reducer, and the lower end of the rotating shaft is connected and fixed to the bottom rotating seat.

[0006] Furthermore, the housing portion of the two-way clutch adopts a circular groove-shaped component and a through hole is opened at the center of the groove bottom. The notch end of the housing portion is bolted to the bottom of the planetary gear reducer, and the rotating shaft passes through the through hole of the housing portion. In addition, a rotating body is arranged in the groove of the housing portion. The rotating body is a plate-shaped component and its center is coaxially connected to the rotating shaft for transmission. The edge contour of the rotating body is circular and has a gap with the inner wall of the groove of the housing portion. At the same time, two W-shaped notches are symmetrically processed on the edge of the rotating body, and each of the W-shaped notches is intersected by the long arm end. The invention relates to a method for making a locking device for a locking cam which is adapted to engage a plurality of locking cams in a plurality of L-shaped grooves. The locking cams are preferably configured to engage a plurality of locking cams and have a plurality of locking cams. The locking cams are preferably configured to engage a plurality of locking cams and have a plurality of locking cams.

[0007] Furthermore, a power source is embedded in the rotating body to supply power to the electromagnet, and the electromagnet is switched on and off in a wireless manner.

[0008] Furthermore, the rotating shaft is detachably assembled and connected to the rotating body.

[0009] Furthermore, a special-shaped hole is opened at the center of the rotating body, and the assembly end of the rotating shaft is processed into a shaft rod section whose cross section matches the special-shaped hole.

[0010] Furthermore, the special-shaped hole is a circular hole.

[0011] Furthermore, the rotating shaft and the rotating body are integrated.

[0012] Furthermore, a plurality of hand connection holes are evenly processed on the edge of the terminal parallel joint, and a connection portion is circumferentially arranged on the outer side wall of the upper end of the bottom shell, and a plurality of arm connection holes are evenly processed on the connection portion.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: according to the connection and movement requirements of the humanoid mechatronic mechanical arm in the hand and arm, the present invention designs a three-degree-of-freedom series-parallel hybrid wrist based on two-way active clutch and brake, and realizes pitch and yaw movements by the forward and reverse extension and retraction of two linear motors. On the basis of pitch and yaw, a torsion movement is added by combining a rotating motor with a shell mechanism, and a series-parallel hybrid mode is adopted to centrally design them in the shell mechanism, and the axial size is reasonably controlled. The rotating motor of the series mechanism provides one degree of freedom, and the two linear motors of the parallel mechanism provide two degrees of freedom, which improves the control decoupling, reduces the control complexity, facilitates the design of the control program, and realizes three-degree-of-freedom motion output. The linear motor has a self-locking function, and the output of the rotating motor realizes two-way active unlocking and locking braking of torsion through a two-way clutch, so that the three degrees of freedom can be maintained when the power is off, effectively improving the flexibility of the robot wrist, and having the advantages of high rigidity, stable structure and strong bearing capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram of the appearance of the three-degree-of-freedom robot wrist of the present invention;

[0015] Figure 2 It is an axonometric diagram of the internal structure of the three-degree-of-freedom robot wrist of the present invention;

[0016] Figure 3 It is a schematic diagram of the internal structure of the three-degree-of-freedom robot wrist of the present invention;

[0017] Figure 4 yes Figure 3 The schematic diagram of the front view omitting the frame and the top and bottom rotating seats;

[0018] Figure 5 It is a bottom view schematic diagram of the internal structure of the two-way clutch in the present invention.

[0019] In the figure: 1. bottom shell; 2. top shell; 3. frame; 4. top rotating seat; 5. rotating motor; 6. planetary gear reducer; 7. two-way clutch; 8. rotating shaft; 9. bottom rotating seat; 10. linear motor; 11. ball joint; 12. connecting piece; 13. end parallel joint; 14. universal joint; 15. top positioning screw; 16. hand connecting hole; 17. bottom positioning screw; 18. arm connecting hole; 19. motor positioning screw; 20. pin one; 21. pin two; 22. rotating body; 23. cylindrical roller; 24. electromagnet. DETAILED DESCRIPTION

[0020] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0021] like Figure 1 to Figure 5 As shown, a three-degree-of-freedom robot wrist with two-way active clutch and braking functions includes a bottom shell 1, a top shell 2, a frame 3, a top rotating seat 4, a rotating motor 5, a planetary gear reducer 6, a two-way clutch 7, a rotating shaft 8, a bottom rotating seat 9, a linear motor 10, a ball joint 11, a connecting piece 12, an end parallel joint 13, a universal joint 14, a top positioning screw 15, a hand connecting hole 16, a bottom positioning screw 17, an arm connecting hole 18, a motor positioning screw 19, a pin 1 20, a pin 2 21, a rotating body 22, a cylindrical roller 23 and an electromagnet 24.

[0022] Combination Figure 1 As shown, the robot wrist is provided with a shell structure composed of two coaxially arranged cylindrical shells, a bottom shell 1 and a top shell 2.

[0023] The upper end of the bottom shell 1 is rotatably connected to the lower end of the top shell 2 via a bearing, wherein a connecting portion is also circumferentially arranged on the outer side wall of the upper end of the bottom shell 1, and a plurality of arm connecting holes 18 are evenly processed on the connecting portion for assembling the robot arm and the bottom shell 1; an end parallel joint 13 is extended out from the upper end of the top shell 2, and the main body of the end parallel joint 13 is disc-shaped and a plurality of hand connecting holes 16 are evenly processed on its edge for assembling the robot hand and the end parallel joint 13.

[0024] Combination Figure 2 to Figure 4As shown, a control mechanism of the robot wrist is arranged in the shell mechanism, which is used to realize the three-degree-of-freedom motion output of the wrist, including a rotary motor 5, a planetary gear reducer 6, a bidirectional clutch 7 and two linear motors 10.

[0025] A bottom rotating seat 9 is fixedly arranged inside the bottom shell 1 by a bottom positioning screw 17, and a top rotating seat 4 is arranged at the lower end of the top shell 2. The top rotating seat 4 is rotatably connected to the bottom rotating seat 9 by a bearing. Both of them adopt a hollow annular structure to reserve installation space for the planetary gear reducer 6 and the two-way clutch 7. A frame 3 is fixedly arranged at the center position of the upper surface of the top rotating seat 4. The upper end of the frame 3 is fixedly connected to the top shell 2 by a top positioning screw 15. The bottom center position of the disk of the terminal parallel joint 13 is installed on the top of the frame 3 by a universal joint 14. The universal joint 14 allows movement in both pitch and yaw directions.

[0026] The rotating motor 5 is longitudinally fixed to the bottom of the frame 3 by the motor positioning screws 19, and the planetary gear reducer 6 is longitudinally bolted below the frame 3. The output shaft of the rotating motor 5 passes through the frame 3 and is connected to the input end of the planetary gear reducer 6, thereby reducing the rotation speed and increasing the output torque.

[0027] The bidirectional clutch 7 is fixed to the bottom of the planetary gear reducer 6 along the longitudinal bolts. The bidirectional clutch 7 is coaxially provided with a rotating shaft 8. The upper end of the rotating shaft 8 is connected to the output end of the planetary gear reducer 6, and the lower end of the rotating shaft 8 is connected and fixed to the bottom rotating seat 9 through a connecting pin. In the unlocked state, the bidirectional clutch 7 allows the rotating motor 5 to control the rotating shaft 8 to rotate forward and reverse through the planetary gear reducer 6 to drive the relative rotation of the top rotating seat 4 and the bottom rotating seat 9, which is equivalent to the relative rotation of the top shell 2 and the bottom shell 1, and also equivalent to the relative rotation of the terminal parallel joint 13 and the bottom shell 1 (because the frame 3 and the top rotating seat 4 are an integral structure, and the terminal parallel joint 13 is installed on the top of the frame 3, the relative rotation of the top rotating seat 4 is associated with the terminal parallel joint 13), thereby realizing the twisting action of the robot hand and the robot arm, which is a degree of freedom in one direction; and in the locked state, the forward and reverse rotation of the rotating shaft 8 of the bidirectional clutch 7 is restricted, so that the robot hand and the robot arm no longer produce twisting action.

[0028] The two linear motors 10 are arranged in parallel on both sides of the rotary motor 5, and are eccentrically arranged with the terminal parallel joint 13. The bottom ends of the two linear motors 10 are connected to the corresponding positions on both sides of the bottom of the frame 3 through the ball joint 11. An n-shaped connecting beam is integrally arranged at the eccentric position of the bottom of the disk of the terminal parallel joint 13. The telescopic ends of the two linear motors 10 are connected to the two ends of the n-shaped connecting beam through the connecting member 12, wherein the lower end of the connecting member 12 is hinged to the telescopic end of the linear motor 10 through the column pin 1 20, and the upper end of the connecting member 12 is hinged to the end of the n-shaped connecting beam through the column pin 21, and the column pin 1 20 and the column pin 2 21 are arranged vertically. When the telescopic motion of the two linear motors 10 is synchronized, the terminal parallel joint 13 performs a pitch motion relative to the frame 3, which is a degree of freedom in one direction; when the two linear motors 10 perform telescopic motion in opposite directions, the terminal parallel joint 13 performs a yaw motion relative to the frame 3, which is a degree of freedom in one direction. Thus, through the coordination of twisting, pitching and yawing movements, the three-degree-of-freedom motion output of the robot wrist is achieved.

[0029] Combination Figure 5 As shown, the robot wrist adopts an optimized bidirectional clutch 7, the shell part of which adopts a circular groove-shaped component and a through hole is opened at the center of the bottom of the groove. The notch end of the shell part is bolted to the bottom of the planetary gear reducer 6, and the shaft 8 passes through the through hole of the shell part. On this basis, a rotating body 22 is arranged in the groove of the shell part. The rotating body 22 is a plate-shaped component and its center is coaxially connected with the shaft 8 for transmission. The edge contour of the rotating body 22 is circular and has a gap with the inner wall of the groove of the shell part. At the same time, two W-shaped notches are symmetrically processed on the edge of the rotating body 22. Each of the W-shaped notches is composed of two L-shaped notches intersecting at the long arm end, and each of the L-shaped notches is equipped with a self-locking module. The self-locking module includes a cylindrical roller 23 and an electromagnet 24. The cylindrical roller 23 is placed at the corner of the L-shaped notch, and a spring is supported and arranged between the corner of the L-shaped notch and the side wall of the cylindrical roller 23. The electromagnet 24 is embedded and fixed on the inner side of the short arm of the L-shaped notch.

[0030] The specific working principle is described as follows:

[0031] When the rotating shaft 8 needs to rotate, the electromagnet 24 starts magnetically attracting the fixed cylindrical roller 23 so that there is a gap between it and the inner wall of the groove of the housing part, which is an unlocked state. At this time, the rotating shaft 8 does not produce a restrictive effect and allows the rotating motor 5 to rotate forward and reverse as required;

[0032] When the rotating shaft 8 does not need to rotate, the electromagnet 24 is closed and the cylindrical roller 23 is elastically supported on the inner wall of the groove of the shell part through the spring. At this time, no matter the movement trend of the rotating body 22 in the forward and reverse rotation, there will be two diagonal cylindrical rollers 23 that are squeezed by the corresponding long arm ends of the L-shaped notch, increasing the friction between the cylindrical roller 23 and the inner wall of the groove of the shell part. At this time, the force of the cylindrical roller 23 is almost perpendicular to the contact surface, forming a self-locking, thereby limiting the rotation of the rotating body 22 and the rotating shaft 8.

[0033] Among them, the rotating body 22 and the rotating shaft 8 can be made into one piece, or a detachable assembly connection can be adopted, for example, a special-shaped hole is processed in the center of the rotating body 22, and the assembly end of the rotating shaft 8 is processed into a shaft rod section whose cross section matches the special-shaped hole, so that the rotating shaft 8 and the rotating body 22 are inserted and positioned. In order to facilitate the processing of the rotating shaft 8, the special-shaped hole is preferably a circular hole, so that only a plane needs to be processed on the side wall of the rotating shaft 8.

[0034] In addition, if the electromagnet 24 is connected to an external power source through wires, the wires may easily become tangled during the rotation of the rotating body 22. Therefore, a power source may be embedded inside the rotating body 22 to power the electromagnet 24, and the electromagnet 24 may be switched on and off wirelessly.

[0035] Through the optimized design of the above-mentioned two-way clutch 7, there is no distinction between the driving shaft and the driven shaft, which greatly reduces the number of parts and the axial thickness of the clutch, making the overall structure simpler and the volume more compact, which helps to further reduce the axial size of the robot wrist and provide technical support for the size optimization of the robot wrist.

[0036] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other forms of assembly without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations within the meaning and range of equivalents of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0037] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A three-degree-of-freedom robot wrist with bidirectional active clutch and braking functions, comprising a frame (3), a terminal parallel joint (13) and two linear motors (10), wherein the terminal parallel joint (13) is disc-shaped and its bottom center is mounted on the top of the frame (3) through a universal joint (14), the two linear motors (10) are arranged in parallel and eccentrically arranged with the terminal parallel joint (13), the bottom ends of the two linear motors (10) are respectively connected to the bottom of the frame (3) through ball joints (11), an n-shaped connecting beam is arranged at an eccentric position at the bottom of the terminal parallel joint (13), and the telescopic ends of the two linear motors (10) are respectively hinged to the two ends of the n-shaped connecting beam through connecting pieces (12), characterized in that: The robot wrist further comprises a bottom shell (1), a top shell (2), a top rotating seat (4), a rotating motor (5), a planetary gear reducer (6), a two-way clutch (7) and a bottom rotating seat (9); the bottom shell (1) and the top shell (2) are two cylindrical shells arranged coaxially and rotatably connected; the bottom rotating seat (9) is fixed inside the bottom shell (1); the top rotating seat (4) is arranged at the lower end inside the top shell (2) and is rotatably connected to the bottom rotating seat (9); the top rotating seat (4) and the bottom rotating seat (9) both adopt an annular structure; the bottom of the frame (3) is fixed at the center position of the upper surface of the top rotating seat (4); the upper end of the frame (3) and the top shell ( 2) connected and fixed, the terminal parallel joint (13) extends out of the top shell (2), the rotating motor (5) is longitudinally fixed at the bottom of the frame (3), the planetary gear reducer (6) is longitudinally fixed below the frame (3), the output shaft of the rotating motor (5) passes through the frame (3) and is connected to the input end of the planetary gear reducer (6), the two-way clutch (7) is longitudinally fixed below the planetary gear reducer (6), the two-way clutch (7) is coaxially provided with a rotating shaft (8), and the positive and negative rotation of the rotating shaft (8) is allowed and restricted in the unlocked and locked states respectively, the upper end of the rotating shaft (8) is connected to the output end of the planetary gear reducer (6), and the lower end of the rotating shaft (8) is connected and fixed to the bottom rotating seat (9).

2. A three-degree-of-freedom robot wrist with two-way active clutch and braking functions according to claim 1, characterized in that: The housing portion of the two-way clutch (7) is a circular groove-shaped member and a through hole is provided at the center of the groove bottom. The groove end of the housing portion is bolted to the bottom of the planetary gear reducer (6). The rotating shaft (8) passes through the through hole of the housing portion. In addition, a rotating body (22) is provided in the groove of the housing portion. The rotating body (22) is a plate-shaped member and its center is coaxially connected to the rotating shaft 8 for transmission. The edge profile of the rotating body (22) is circular and has a gap with the inner wall of the groove of the housing portion. At the same time, two W-shaped notches are symmetrically processed on the edge of the rotating body (22), and each of the W-shaped notches is composed of two L-shaped notches intersecting at the long arm end. Each of the L-shaped notches is equipped with a self-locking module, and the self-locking module includes a cylindrical roller (23) and an electromagnet (24). The cylindrical roller (23) is placed at the corner of the L-shaped notch, and a spring is supported and arranged between the corner of the L-shaped notch and the side wall of the cylindrical roller (23). The electromagnet (24) is embedded and fixed on the inner side of the short arm of the L-shaped notch. When the electromagnet (24) is turned on, the cylindrical roller (23) is magnetically fixed so that a gap is left between it and the inner wall of the groove of the shell part to form an unlocked state. When the electromagnet (24) is turned off, the cylindrical roller (3) is elastically supported on the inner wall of the groove of the shell part through the spring to form a locked state.

3. A three-degree-of-freedom robot wrist with two-way active clutch and braking functions according to claim 2, characterized in that: A power source is embedded in the rotating body (22) to supply power to the electromagnet (24), and the electromagnet (24) is switched on and off in a wireless manner.

4. A three-degree-of-freedom robot wrist with two-way active clutch and braking functions according to claim 3, characterized in that: The rotating shaft (8) is detachably assembled and connected to the rotating body (22).

5. A three-degree-of-freedom robot wrist with two-way active clutch and braking functions according to claim 4, characterized in that: A special-shaped hole is provided at the center of the rotating body (22), and the assembly end of the rotating shaft (8) is processed into a shaft section whose cross section matches the special-shaped hole.

6. A three-degree-of-freedom robot wrist with two-way active clutch and braking functions according to claim 5, characterized in that: The special-shaped hole is a circular hole.

7. The three-degree-of-freedom robot wrist with two-way active clutch and braking functions according to claim 3, characterized in that: The rotating shaft (8) and the rotating body (22) are made as one piece.

8. The three-degree-of-freedom robot wrist with two-way active clutch and braking functions according to claim 1, characterized in that: A plurality of hand connection holes (16) are evenly processed on the edge of the terminal parallel joint (13), and a connection portion is circumferentially arranged on the outer side wall of the upper end of the bottom shell (1), and a plurality of arm connection holes (18) are evenly processed on the connection portion.

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