Parallel clamping-self-adaptive under-actuated robot finger based on connecting rod-tendon rope hybrid drive

Abstract

The invention discloses a parallel clamping-self-adaptive under-actuated robot finger based on connecting rod-tendon rope hybrid drive, and relates to the technical field of industrial robots. The tail end of the tip knuckle is hinged to the top end of the root knuckle through a front joint shaft, the front joint shaft is sleeved with a torsional spring to connect and position the tip knuckle and the root knuckle and apply eversion torque to the tip knuckle, and the top end of the base is hinged to the tail end of the root knuckle through a rear joint shaft. The worm wheel and the wheel disc are coaxially installed on the rear joint shaft and are circumferentially positioned, the two ends of the rigid connecting rod are hinged to the tail end of the sharp knuckle and the edge of the wheel disc through positioning pins correspondingly, and the two ends of the coupling tendon rope are fixedly connected with a winding groove prefabricated at a rotating shaft at the tail end of the sharp knuckle and the top end of the base correspondingly; the driving motor is fixedly installed on the base and connected with a transmission worm, and the worm is meshed with the worm gear. The two-degree-of-freedom fingers are driven through the single motor, flexible switching between flat clamping grabbing and self-adaptive grabbing is achieved, the grabbing efficiency, stability and environment adaptability are improved, and the control difficulty is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of industrial robots, in particular to a flat clamping-self-adaptive underactuated robot finger based on a linkage-tendon hybrid drive. BACKGROUND

[0002] With the development of industrial automation, the end effector of an industrial robot as a hand of the robot directly affects the work capacity of the robot. However, in the prior art, the robot finger has the following deficiencies: 1. Generally driven by multiple motors, resulting in complex structure, high energy consumption, low integration, and complicated control logic, which is not conducive to application in a compact space; 2. Single execution function, commonly using parallel clamping for regular objects and commonly using enveloping grasping for irregular objects, which is difficult to simultaneously adapt to various tasks of objects with large differences in shape and size; 3. Although the current underactuated finger can reduce the number of motors, the existing design is mostly joint-coupled motion, which cannot balance flat clamping grasping (ensuring stable object posture) and adaptive grasping (fitting the object shape), resulting in problems such as object ejection, poor stability, and low efficiency during grasping.

[0003] Therefore, designing an underactuated robot finger with simple structure, high integration, and flexible switching between flat clamping grasping and adaptive grasping has been a technical problem to be solved in the field. SUMMARY

[0004] To solve the deficiencies in the background art, the present application provides a flat clamping-adaptive underactuated robot finger based on a linkage-tendon hybrid drive, which drives a two-degree-of-freedom finger by a single motor to achieve flexible switching between flat clamping grasping and adaptive grasping, improve grasping efficiency, stability, and environmental adaptability, and reduce control difficulty.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical solution: a flat clamping-adaptive underactuated robot finger based on a linkage-tendon hybrid drive, comprising a finger body, a transmission assembly, and a driving assembly; The finger body is composed of a tip phalanx, a root phalanx, and a base, the tip phalanx end is hinged to the top end of the root phalanx through a front joint shaft, a torsional spring is sleeved on the front joint shaft, the two ends of the torsional spring are respectively connected and positioned with the tip phalanx and the root phalanx and apply an eversion torque to the tip phalanx, and the top end of the base is hinged to the end of the root phalanx through a rear joint shaft; The transmission assembly is composed of a rigid connecting rod, a coupling tendon, a worm gear and a wheel disc, the worm gear and the wheel disc are coaxially installed on the rear joint shaft and are circumferentially positioned to transmit motion and torque, the front end of the rigid connecting rod is hinged to the edge of the tip of the finger through a front positioning pin, the rear end of the rigid connecting rod is hinged to the edge of the wheel disc through a rear positioning pin, the front end of the coupling tendon is fixedly connected with the pre-prepared winding groove at the rotating shaft of the tip of the finger, and the rear end of the coupling tendon is fixedly connected with the top end of the base. The driving assembly is composed of a driving motor and a worm, the driving motor is fixedly installed on the base and the output shaft thereof is coaxially connected with the transmission worm, and the worm is meshed with the worm gear.

[0006] Further, the center holes of the worm gear and the wheel disc are all processed with key grooves, the rear joint shaft is provided with a connecting key at a corresponding position, and the circumferential positioning of the worm gear, the wheel disc and the rear joint shaft is realized through the cooperation of the connecting key and the key groove.

[0007] Further, the robot finger adopts two symmetrical and parallel installation on both sides of the palm assembly to form an underactuated dexterous hand, the switching of the two modes of flat clamping and adaptive gripping can be realized by controlling the sequence of the tip joint and the root joint contacting the object.

[0008] Further, in the flat clamping mode, the tip joint contacts the object surface earlier than or at the same time as the root joint, and the tip joint and the root joint are both controlled to stop moving, thereby completing the flat clamping operation.

[0009] Further, in the adaptive gripping mode, the root joint contacts the object surface first, the driving motor continues to drive the wheel disc to rotate and pull the rigid connecting rod, the tip joint continues to rotate around the front joint shaft to compensate the distance, until the tip joint also contacts the object surface, thereby completing the adaptive gripping operation.

[0010] Compared with the prior art, the beneficial effects of the present application are: 1. Fewer motors and high integration: the two-degree-of-freedom finger is driven by a single motor, which reduces the number of motors and the complexity of wiring, reduces energy consumption, improves structural integration, and is suitable for compact space operation; 2. Flexible switching of double postures: the flat clamping and adaptive gripping are flexibly switched through the mechanical structure (force balance of torsion spring and coupling tendon combined with rigid connecting rod transmission), without complex control logic, which reduces the operation difficulty; 3. High stability and adaptability: flat clamping can ensure the stability of the posture of regular objects, while adaptive gripping can fit the shape of irregular objects, improving the adaptability to different objects and improving the gripping efficiency; 4. Optimized and reliable structure: by optimizing the parameters (torque size) of the torsion spring, the parameters (length, elasticity) of the coupling tendon and the size of the wheel disc, the smooth switching of the two modes can be ensured, the mechanism runs stably and has a long service life. Attached Figure Description

[0011] Figure 1 This is an isometric schematic diagram of the robot finger of the present invention; Figure 2 This is a cross-sectional structural diagram of the robot finger of the present invention; Figure 3 This is a schematic diagram of the flat gripping posture of the robot finger of the present invention; Figure 4 This is a schematic diagram of the adaptive grasping posture of the robot finger of the present invention.

[0012] In the diagram: 1. Tip knuckle; 2. Front locating pin; 3. Rigid connecting rod; 4. Coupler tendon ligament; 5. Worm gear; 6. Rear locating pin; 7. Wheel; 8. Rear joint shaft; 9. Base; 10. Drive motor; 11. Worm; 12. Root knuckle; 13. Front joint shaft; 14. Torsion spring. Detailed Implementation

[0013] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0014] like Figures 1-2 As shown, the flat-clamping adaptive underactuated robot finger based on linkage-tendon cord hybrid drive includes a phalanx 1, a front positioning pin 2, a rigid linkage 3, a coupling tendon cord 4, a worm gear 5, a rear positioning pin 6, a wheel 7, a rear joint shaft 8, a base 9, a drive motor 10, a worm 11, a root phalanx 12, a front joint shaft 13, and a torsion spring 14.

[0015] The main body of the finger consists of the tip joint 1, the root joint 12, and the base 9.

[0016] The tip of the phalanx 1 is hinged to the tip of the root phalanx 12 via a front joint axis 13. A torsion spring 14 is sleeved on the front joint axis 13. The two ends of the torsion spring 14 are respectively connected and positioned to the tip of the phalanx 1 and the root phalanx 12. The torsion spring 14 always applies an outward turning torque to the tip of the phalanx 1 (that is, a torque that rotates the tip of the phalanx 1 around the front joint axis 13 away from the root phalanx 12). The tip of the base 9 is hinged to the tip of the root phalanx 12 via a rear joint axis 8. The base 9 is used to connect and fix with the palm assembly, thereby forming a robotic finger base with two degrees of freedom between the tip of the phalanx 1 and the root phalanx 12.

[0017] Transmission assembly: consists of rigid connecting rod 3, coupling tendon rope 4, worm gear 5 and wheel 7.

[0018] The worm wheel 5 and the wheel disc 7 are coaxially installed on the rear joint shaft 8, so that the worm wheel 5, the wheel disc 7 and the base 9, the root finger joint 12 are connected in series through the rear joint shaft 8, wherein the central holes of the worm wheel 5 and the wheel disc 7 are all processed with key grooves, the rear joint shaft 8 is provided with connecting keys at the corresponding positions, the worm wheel 5, the wheel disc 7 and the rear joint shaft 8 are circumferentially positioned to transmit motion and torque, and the worm wheel 5 can drive the wheel disc 7 to synchronously rotate through the rear joint shaft 8; The front end of the rigid connecting rod 3 is hinged to the end edge of the sharp finger joint 1 through the front positioning pin 2, and the rear end of the rigid connecting rod 3 is hinged to the edge of the wheel disc 7 through the rear positioning pin 6. The front end of the coupling tendon 4 is connected and fixed with the pre-prepared winding groove at the rotating shaft of the end of the sharp finger joint 1, and the rear end of the coupling tendon 4 is connected and fixed with the top end of the base 9, so as to limit the excessive eversion of the sharp finger joint 1.

[0019] The driving assembly adopts a driving motor 10 and a worm 11.

[0020] The driving motor 10 is fixedly installed on the base 9 and the output shaft thereof is coaxially connected with the transmission worm 11, and the worm 11 is meshed with the worm wheel 5.

[0021] Through the above design, the robot finger has two degrees of freedom and can be driven by a single motor, and two robot fingers of the basic application can be symmetrically installed on both sides of the palm assembly to form an underactuated dexterous hand. By combining the sequence of the sharp finger joint 1 and the root finger joint 12 contacting the object, the switching of the two modes of flat clamping and adaptive gripping can be realized, the working capacity of the underactuated dexterous hand is greatly improved, and the underactuated dexterous hand is suitable for more working scenes, and the principle is as follows: Flat clamping mode: In this mode, the two sharp finger joints 1 of the underactuated dexterous hand first contact the object, and the overall configuration combines Figure 3 As shown in the figure, after the driving motor 10 is started, the worm 11 controls the rotation of the worm wheel 5, and under the action of the key groove connection, the worm wheel 5 drives the wheel disc 7 to synchronously rotate through the rear joint shaft 8, and when the wheel disc 7 rotates, the rigid connecting rod 3 is pulled to make the root finger joint 12 move towards the object around the rear joint shaft 8; In this process, the eversion torque of the torsional spring 14 tries to make the sharp finger joint 1 eversion around the front joint shaft 13 away from the root finger joint 12, while the tension of the coupling tendon 4 limits the eversion action, and the balance between the two keeps the posture of the sharp finger joint 1 unchanged, and only translation with the root finger joint 12 is performed.

[0022] When the two sharp finger joints 1 of the underactuated dexterous hand contact the object surface earlier than or at the same time as the root finger joint 12, the sharp finger joint 1 and the root finger joint 12 are both stopped, and the flat clamping operation is completed.

[0023] Adaptive gripping mode: In this mode, the two root knuckles 12 of the underactuated dexterous hand first contact the object, and the overall configuration is combined Figure 4 As shown, when the two root knuckles 12 of the underactuated dexterous hand first contact the object surface, and the two sharp knuckles 1 do not contact the object, the driving motor 10 continues to drive the wheel disc 7 to rotate and pull the rigid connecting rod 3, since the root knuckles 12 have contacted the object at this time, the distance between the two ends of the rigid connecting rod 3 cannot be maintained unchanged by rotating, and the sharp knuckles 1 will continue to rotate around the front joint shaft 13 to compensate the distance until the sharp knuckles 1 also contact the object surface.

[0024] At this time, the sharp knuckles 1 and the root knuckles 12 are both attached to the object surface, and the posture is adaptively adjusted according to the shape of the object, and the adaptive grasping operation is completed.

[0025] In summary, the robot finger of the present application is different from the joint coupling motion grasping method of the general underactuated finger, and in the grasping process, compared with the existing finger, the sharp knuckles 1 can be first grasped in a flat clamping mode with the posture unchanged, and after the root knuckles 12 contact the object, it is changed to adaptive grasping according to the shape and size of the object, which helps to avoid the ejection of the target object during grasping of the dexterous hand, and enhances the adaptability in different environments, thereby improving the efficiency and stability in the grasping process of the dexterous hand. In addition, in the structure, the parameters of the mechanical structure such as the wheel disc 7 and the torsional spring 14 can be optimized to meet the grasping operation of objects of different shapes and sizes in the scene of industrial automation and intelligent manufacturing, thereby reducing the operation difficulty of the dexterous hand in performing different grasping tasks.

[0026] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and the present application can be implemented in other embodiments without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present application is defined by the appended claims rather than the above description, and therefore all changes falling within the meaning and scope of the equivalent conditions of the claims are intended to be included in the present application. Any reference signs in the claims should not be regarded as limiting the claims involved.

[0027] In addition, it should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity, and those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A flat-grip-adaptive underactuated robot finger based on a linkage-tendon hybrid drive, characterized in that: Includes the finger body, transmission components, and drive components; The main body of the finger is composed of a tip phalanx (1), a root phalanx (12) and a base (9). The end of the tip phalanx (1) is hinged to the top of the root phalanx (12) through a front joint axis (13). A torsion spring (14) is sleeved on the front joint axis (13). The two ends of the torsion spring (14) are respectively connected and positioned to the tip phalanx (1) and the root phalanx (12) and apply an outward turning torque to the tip phalanx (1). The top of the base (9) is hinged to the end of the root phalanx (12) through a rear joint axis (8). The transmission assembly consists of a rigid connecting rod (3), a coupling tendon rope (4), a worm gear (5) and a wheel (7). The worm gear (5) and the wheel (7) are coaxially mounted on the rear joint shaft (8) and circumferentially positioned to transmit motion and torque. The front end of the rigid connecting rod (3) is hinged to the end edge of the finger joint (1) through a front positioning pin (2), and the rear end of the rigid connecting rod (3) is hinged to the edge of the wheel (7) through a rear positioning pin (6). The front end of the coupling tendon rope (4) is connected and fixed to the pre-made winding groove at the end shaft of the finger joint (1), and the rear end of the coupling tendon rope (4) is connected and fixed to the top of the base (9). The drive assembly consists of a drive motor (10) and a worm gear (11). The drive motor (10) is fixedly mounted on the base (9) and its output shaft is coaxially connected to the transmission worm gear (11). The worm gear (11) is meshed with the worm wheel (5).

2. The flat-grip-adaptive underactuated robot finger based on linkage-tendon cord hybrid drive according to claim 1, characterized in that: The worm gear (5) and the wheel disk (7) are both machined with keyways in their center holes. The rear joint shaft (8) is provided with a connecting key at the corresponding position. The circumferential positioning of the worm gear (5), the wheel disk (7) and the rear joint shaft (8) is achieved through the cooperation of the connecting key and the keyway.

3. The flat-grip-adaptive underactuated robot finger based on linkage-tendon cord hybrid drive according to claim 1 or 2, characterized in that: The robot's fingers consist of two fingers symmetrically mounted on both sides of the palm assembly to form an underactuated dexterous hand. By controlling the order in which the tip phalanx (1) and the root phalanx (12) contact the object, it can switch between two modes: flat gripping and adaptive gripping.

4. The flat-grip-adaptive underactuated robot finger based on linkage-tendon cord hybrid drive according to claim 3, characterized in that: In the flat gripping mode, the tip of the finger (1) contacts the surface of the object before or simultaneously with the root of the finger (12), and controls both the tip of the finger (1) and the root of the finger (12) to stop moving, thus completing the flat gripping operation.

5. The flat-grip-adaptive underactuated robot finger based on linkage-tendon hybrid drive according to claim 3, characterized in that: In the adaptive gripping mode, the root phalanx (12) first contacts the object surface, and the drive motor (10) continues to drive the wheel (7) to rotate and pull the rigid connecting rod (3). The tip phalanx (1) continues to rotate around the front joint axis (13) to perform distance compensation until the tip phalanx (1) also contacts the object surface, thus completing the adaptive gripping operation.

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