A three-finger robotic hand with flat gripping and self-adaptive capabilities

Abstract

A three-fingered robotic hand with flat-grip adaptive capabilities relates to the field of intelligent robotics. The base joint axis is fixed to the top of the finger base and hinged to the proximal phalanx. A cavity is provided at the bottom, and a DC motor is fixed to the front end. A ball screw is installed at the rear end and driven by the DC motor. The middle joint axis is fixed to the top of the proximal phalanx and hinged to the distal phalanx. The front and rear connecting rods are hinged to the base joint axis. The drive rod is hinged to the screw nut. The upper end is hinged to the front connecting rod and the transmission rod. The transmission rod is hinged to the front end of the distal phalanx. The coupling rod is hinged to the rear connecting rod. A tension spring connects the proximal phalanx to the connecting rod. The connecting rod and coupling rod are hinged to the rear end of the distal phalanx. One finger assembly is fixed, and the two finger assemblies can be deflected and adjusted by adjusting the motor in combination with a gear set. The palm assembly can control the deflection adjustment of the two movable fingers, and has the ability of flat-grip adaptive grasping, meeting the needs of three types of grasping actions.

Description

Technical Field

[0001] The present invention relates to the technical field of intelligent robots, in particular to a three-finger robot hand with flat clamping and self-adaptation capabilities. Background Art

[0002] At present, the design trend of fully-driven dexterous hands is mainly modularization and integration. According to current research, fully-driven dexterous hands have a large number of joints, many degrees of freedom, and a large number of drives, so they have high dexterity and strong operational capabilities. However, this also brings complex control systems, complex mechanical structures and high manufacturing costs, which limit the market application of dexterous hands.

[0003] In addition, most existing under-actuated dexterous hands are five-fingered hands, and have achieved a lot of results in simulating human hands from appearance to function, but this often leads to an increase in the size and weight of the dexterous hands, which is not conducive to grasping tasks.

[0004] Therefore, under the premise of meeting the requirements of different grasping actions on objects, it is necessary to streamline the number of fingers and drive structure of the dexterous hand to achieve the purpose of structural optimization and cost control, which is of great significance for the application of dexterous hands. Summary of the Invention

[0005] In order to address the shortcomings of the background technology, the present invention provides a three-finger robotic hand with flat clamping and self-adaptive capability. Its finger assembly is divided into a fixed finger and two movable fingers, and has the ability of flat clamping and self-adaptive grasping. The palm assembly can control the two movable fingers to achieve deflection adjustment of the same angle in relative directions, and has three configurations of grasping actions, achieving the purpose of structural optimization and cost control.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a three-finger robot hand with flat clamping-adaptive ability, including a palm assembly and three finger assemblies, the finger assembly including a finger base, a DC motor, a ball screw, a driving rod, a front connecting rod, a proximal knuckle, a distal knuckle, a transmission rod, a rear connecting rod, a coupling rod and a tension spring, a connecting ear is provided on the top of the finger base to fix the base joint axis, a cavity is provided at the bottom of the finger base and a sleeve is extended downward from the front end to fix the DC motor, the output shaft of the DC motor is located in the cavity, the ball screw is vertically rotatably installed at the rear end of the cavity and cooperates with the screw nut to be installed, the upper end of the ball screw and the output shaft of the DC motor are meshed and transmitted by gears, the bottom end of the proximal knuckle is hinged to the base joint axis, the top end of the proximal knuckle is provided to fix the middle joint axis, the bottom of the distal knuckle is provided with a connecting plate and its middle position is hinged to the middle joint axis, the front end is connected The top end of the tension spring is hinged with the bottom end of the connecting rod, and the top end of the connecting rod and the upper end of the coupling rod are hinged with the rear end of the connecting piece at the bottom of the distal finger joint.

[0007] Furthermore, the output shaft of the adjustment motor extends into the palm base and is coaxially fixed with the palm driving gear, the bottoms of the remaining two finger assemblies extend into the palm base and are coaxially fixed with the palm driven gear 1 and the palm driven gear 2, respectively, and the palm transfer gear 1 and the palm transfer gear 2 with the same number of teeth are rotatably installed on the inner wall of the top of the palm base, the palm driving gear is meshed with the palm transfer gear 1, the palm transfer gear 1 is simultaneously meshed with the palm driven gear 1 and the palm transfer gear 2, and the palm transfer gear 2 is meshed with the palm driven gear 2.

[0008] Furthermore, the first driven gear in the palm and the second driven gear in the palm are tightly pressed against the palm base to axially position the remaining two finger assemblies.

[0009] Furthermore, a support member is provided below the rear end connecting rod to limit the backward deflection angle, and the bottom of the support member is connected and fixed to the finger base.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention has three modular finger assemblies, and before a single finger assembly touches an object, the proximal knuckle first approaches the object while the distal knuckle maintains a posture parallel to the finger base, and after the proximal knuckle touches the object and stops moving, the distal knuckle can continue to move until it completes the enveloping of the object, thereby realizing the ability of flat clamping-adaptive grasping. At the same time, the three finger assemblies are divided into one fixed finger and two movable fingers, and the palm assembly can control the two movable fingers to achieve the same angle of deflection adjustment in the relative direction through the driving structure of the gear set, so that the three-finger robot hand has three configurations: three-finger uniform distribution, three-finger grasping and two-finger pinching, which meets the needs of performing different grasping actions on objects ranging from cylindrical, square to irregular shapes. The structure is simple and easy, and the manufacturing and maintenance costs are low, which is conducive to application in industrial robots. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a cross-sectional view of the internal structure of the finger assembly of the present invention;

[0012] Figure 2 is a schematic diagram of the grasping action of the finger assembly of the present invention;

[0013] Figure 3 It is a schematic diagram of the overall structure of the three-finger robot hand of the present invention;

[0014] Figure 4 Schematic diagrams of different configurations of the three-finger robot hand of the present invention.

[0015] In the figure: 1. Finger base; 2. DC motor; 3. Inner finger driving gear; 4. Inner finger driven gear; 5. Annular connector; 6. Ball screw; 7. Screw nut; 8. Driving rod; 9. Front connecting rod; 10. Base joint shaft; 11. Proximal finger joint; 12. Distal finger joint; 13. Middle joint shaft; 14. Transmission rod; 15. Rear connecting rod; 16. Coupling rod; 17. Tension spring; 18. Connecting rod; 19. Support member; 20. Palm base; 21. Fixed finger; 22. Movable finger 1; 23. Movable finger 2; 24. Adjusting motor; 25. Inner palm driving gear; 26. Inner palm transfer gear 1; 27. Inner palm driven gear 1; 28. Inner palm transfer gear 2; 29. ​​Inner palm driven gear 2; 30. Palm bottom cover. DETAILED DESCRIPTION

[0016] The technical solutions 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 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.

[0017] like Figures 1 to 4 As shown, a three-finger robotic hand with flat clamping-adaptive capability includes a palm assembly and three finger assemblies, wherein the finger assembly includes a finger base 1, a DC motor 2, an inner finger driving gear 3, an inner finger driven gear 4, an annular connector 5, a ball screw 6, a screw nut 7, a drive rod 8, a front end connecting rod 9, a base joint shaft 10, a proximal knuckle 11, a distal knuckle 12, a middle joint shaft 13, a transmission rod 14, a rear end connecting rod 15, a coupling rod 16, a tension spring 17, a connecting rod 18 and a support member 19; the palm assembly includes a palm base 20, an adjustment motor 24, an inner palm driving gear 25, an inner palm transfer gear 1 26, an inner palm driven gear 1 27, an inner palm transfer gear 2 28, an inner palm driven gear 2 29 and a palm bottom cover 30.

[0018] Combine Figure 1As shown, the top of the finger base 1 is provided with connecting ears, and the base joint shaft 10 is transversely fixed between the connecting ears of the finger base 1. The bottom of the finger base 1 is provided with a cavity, and a sleeve is provided at its front end extending downward. The DC motor 2 is fixed within the sleeve of the finger base 1 by screws, and the bottom of the DC motor 2 extends out of the finger base 1. The output shaft of the DC motor 2 is located in the cavity of the finger base 1 and is coaxially fixed to the finger internal driving gear 3 by screws. The ball screw 6 is vertically arranged at the rear end of the cavity of the finger base 1. The middle section of the ball screw 6 is equipped with a screw nut 7. The upper and lower ends of the ball screw 6 are respectively equipped with bearings and are connected and fixed to the corresponding positions of the cavity of the finger base 1 by an annular connector 5. The upper end of the ball screw 6 is coaxially fixed to the finger internal driven gear 4 by screws. The finger internal driven gear 4 is meshed with the finger internal driving gear 3. The bottom end of the proximal phalanx 11 is hinged to the base joint axis 10, allowing it to swing back and forth about it. A connecting ear is provided at the top of the proximal phalanx 11. The middle joint axis 13 is laterally fixed between the connecting ears of the proximal phalanx 11. The bottom of the distal phalanx 12 is provided with a connecting piece, and its middle position is hinged to the middle joint axis 13, allowing it to swing back and forth about it. The ends of the front connecting rod 9 and the rear connecting rod 15 are respectively hinged to the base joint axis 10. A support member 19 is provided below the rear connecting rod 15 to limit its maximum backward deflection angle. The bottom of the support member 19 is fixedly connected to the finger base 1. The lower end of the drive rod 8 is hinged to the lead screw nut 7 via a pin, and the upper end of the drive rod 8 is hinged to the outer end of the front connecting rod 9 and the lower end of the transmission rod 14 via a pin. The upper end of the transmission rod 14 is hinged to the front end of the bottom connecting piece of the distal phalanx 12 via a pin. The rotation of the ball screw 6 drives the lead screw nut 7 to move up and down, thereby causing the drive rod 8 to drive the front connecting rod 9 to rotate about the base joint axis 10 and the distal phalanx 12 to move via the transmission rod 14. The lower end of the coupling rod 16 is hinged to the outer end of the rear connecting rod 15 via a pin. The lower end of the tension spring 17 is connected to a fixed hook pin at the front end of the middle position of the proximal phalanx 11 for positioning. The top end of the tension spring 17 is hinged to the bottom end of the connecting rod 18. The top end of the connecting rod 18 and the upper end of the coupling rod 16 are hinged to the rear end of the bottom connecting piece of the distal phalanx 12 via a pin.

[0019] Combine Figures 1 and 2 As shown, when the finger assembly moves in the free space, the rear connecting rod 15 remains in the same position under the action of the tension spring 17, so that the surface of the distal phalanx 12 can be kept parallel to the finger base 1. Figure 2 As shown in parts a)-b); when the proximal knuckle 11 stops moving after contacting the object, the distal knuckle 12 can continue to move. At this time, the rear connecting rod 15 will rotate around the base joint axis 10, thereby achieving the distal knuckle 12 to continue moving until the finger assembly completes the enveloping of the object. This process is referred to Figure 2 As shown in parts b)-c) in.

[0020] Combine Figure 3 As shown, the palm base 20 is a cylindrical, hollow housing with a closed top. The adjustment motor 24 is coaxially fixed to the exterior of the closed end of the palm base 20 by screws. The output shaft of the adjustment motor 24 extends into the cavity of the palm base 20 and is coaxially fixed to the palm drive gear 25 by screws. Three mounting holes are evenly spaced around the closed end of the palm base 20, each for mounting the three finger assemblies. The three finger assemblies are divided into a fixed finger 21, a movable finger 1 22 and a movable finger 2 23. In the initial state, the three finger assemblies are arranged radially inward along the palm base 20, wherein the bottom of the fixed finger 21 is inserted into the corresponding mounting hole and fixed to the palm base 20 by screws, and the bottoms of the movable finger 1 22 and the movable finger 2 23 are respectively inserted into the corresponding mounting holes and coaxially fixed to the palm driven gear 1 27 and the palm driven gear 2 29 by screws. At the same time, the palm driven gear 1 27 and the palm driven gear 2 29 are tightly attached to the palm base 20 to axially position the movable finger 1 22 and the movable finger 2 23 to prevent them from loosening. The inner wall of the closed end of the palm base 20 is rotatably mounted with a palm transfer gear 1 26 and a palm transfer gear 2 28. The palm driving gear 25 is meshed with the palm transfer gear 1 26. The palm transfer gear 1 26 is also meshed with the palm driven gear 1 27 and the palm transfer gear 2 28. The palm transfer gear 2 28 is meshed with the palm driven gear 2 29. To achieve the same-angle deflection of the movable finger 1 22 and the movable finger 2 23, the palm transfer gear 1 26 and the palm transfer gear 2 28 have the same number of teeth. The palm bottom cover 30 is fixed to the bottom of the palm base 20 by screws.

[0021] Combine Figures 3 and 4 As shown, the first moving finger 22 and the second moving finger 23 are stationary. In the initial state, the three finger assemblies are spaced 120 degrees apart from each other, forming a three-finger evenly distributed configuration. Figure 4 As shown in part a), it can grasp irregular shaped objects; by adjusting the motor 24 to control the moving finger 1 22 and the moving finger 2 23 to rotate 60° clockwise and counterclockwise respectively, the three finger assemblies are staggered to form a three-finger grasping configuration, see Figure 4 As shown in part b), cylindrical objects can be grasped; by adjusting the motor 24 to control the movable finger 1 22 and the movable finger 2 23 to rotate 90 degrees clockwise and counterclockwise respectively on the basis of the three-finger grasping configuration, the movable finger 1 22 and the movable finger 2 23 are arranged face to face, forming a two-finger pinching configuration, see Figure 4 As shown in part c), it can grasp square objects.

[0022] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other configurations without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations coming within the meaning and range of equivalents of the claims are intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0023] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method 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 can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A three-finger robotic hand with flat gripping and self-adaptive capabilities, characterized by: The invention comprises a palm assembly and three finger assemblies, wherein the finger assembly comprises a finger base (1), a DC motor (2), a ball screw (6), a driving rod (8), a front connecting rod (9), a proximal knuckle (11), a distal knuckle (12), a transmission rod (14), a rear connecting rod (15), a coupling rod (16) and a tension spring (17). A connecting ear is provided at the top of the finger base (1) to fix the base joint shaft (10). A cavity is provided at the bottom of the finger base (1) and a sleeve is provided at the front end thereof to fix the DC motor (2). The output shaft of the DC motor (2) is Located in the cavity, the ball screw (6) is vertically rotatably installed at the rear end of the cavity and is matched with the screw nut (7). The upper end of the ball screw (6) is meshed with the output shaft of the DC motor (2) through a gear transmission. The bottom end of the proximal phalanx (11) is hinged to the base joint shaft (10). The top end of the proximal phalanx (11) is provided with a connecting ear and fixes the middle joint shaft (13). The bottom of the distal phalanx (12) is provided with a connecting plate and its middle position is hinged to the middle joint shaft (13). The ends of the front connecting rod (9) and the rear connecting rod (15) are respectively connected to the base joint shaft (10). ) is hinged, the lower end of the driving rod (8) is hinged to the screw nut (7), the upper end of the driving rod (8) is hinged to the outer end of the front connecting rod (9) and the lower end of the transmission rod (14), the upper end of the transmission rod (14) is hinged to the front end of the bottom connecting piece of the distal knuckle (12), the lower end of the coupling rod (16) is hinged to the outer end of the rear connecting rod (15), the bottom end of the tension spring (17) is connected and positioned with a fixed hook pin at the front end of the middle position of the proximal knuckle (11), the top end of the tension spring (17) is hinged to the bottom end of the connecting rod (18), the top end of the connecting rod (18) and the upper end of the coupling rod (16) are hinged to The rear end of the bottom connecting piece of the distal phalanx (12) is hinged, and the palm assembly includes a palm base (20) and an adjustment motor (24). The palm base (20) is a cylindrical cavity shell. The adjustment motor (24) is coaxially fixed to the top of the palm base (20). The bottoms of the three finger assemblies are installed on the top of the palm base (20) and are evenly arranged around the adjustment motor (24). One of the finger assemblies is fixedly arranged, and a gear set is arranged in the palm base (20) to control the remaining two finger assemblies to deflect and adjust at the same angle in relative directions through the adjustment motor (24).

2. The three-finger robot hand with flat clamping and self-adaptive capability according to claim 1, characterized in that: The output shaft of the regulating motor (24) extends into the palm base (20) and is coaxially fixedly installed with the palm driving gear (25). The bottoms of the remaining two finger assemblies extend into the palm base (20) and are coaxially fixed with the palm driven gear 1 (27) and the palm driven gear 2 (29). The palm transfer gear 1 (26) and the palm transfer gear 2 (28) having the same number of teeth are rotatably installed on the inner wall of the top of the palm base (20). The palm driving gear (25) is meshed with the palm transfer gear 1 (26). The palm transfer gear 1 (26) is simultaneously meshed with the palm driven gear 1 (27) and the palm transfer gear 2 (28). The palm transfer gear 2 (28) is meshed with the palm driven gear 2 (29).

3. The three-finger robot hand with flat clamping and self-adaptive capability according to claim 2, characterized in that: The palm driven gear 1 (27) and the palm driven gear 2 (29) are tightly attached to the palm base (20) to axially position the remaining two finger assemblies.

4. The three-finger robot hand with flat clamping and self-adaptive capability according to claim 1, characterized in that: A support member (19) is provided below the rear end connecting rod (15) to limit the backward deflection angle, and the bottom of the support member (19) is connected and fixed to the finger base (1).

Images