Under-actuated robot finger based on hybrid transmission of connecting rod and tendon rope mechanism

Abstract

The invention discloses an under-actuated robot finger based on hybrid transmission of connecting rods and tendon rope mechanisms, and relates to the technical field of intelligent robots. The front end of the base is hinged to the bottom of the lower swing rod, the rear end of the base is connected with the root joint shaft, the lower swing rod is sleeved with the sleeve, and the connecting pin is fixed to the top of the lower swing rod. The driving wheel and the root joint shaft are coaxial and connected with the tendon rope. Connecting pins are fixed to the top of the upper swing rod, a top joint shaft is arranged above the upper swing rod, knuckle shells at the root end, the middle and the tip end are rotationally connected with the corresponding joint shafts at the bottoms respectively, a torsional spring is installed on the middle joint shaft, and the two connecting pins are connected with the corresponding knuckle shells respectively. The connecting rod and tendon rope hybrid transmission is adopted, the transmission efficiency is improved, the smaller size and the lower weight are achieved through the under-actuated control strategy, the coupling-self-adaptive movement function is achieved, and the flexibility and the response speed are improved.

Description

Technical Field

[0001] The invention relates to the technical field of intelligent robots, and in particular to an under-actuated robot finger based on hybrid transmission of a connecting rod and a tendon-rope mechanism. Background Art

[0002] With the rapid development of robotics, the design of robot fingers plays a vital role in humanoid robots and artificial intelligence applications. In order to achieve flexible robot operation, robot fingers not only need to have similar movement capabilities as human fingers, but also must meet the requirements of lightweight, low cost and high efficiency. However, the existing robot finger technology still has some shortcomings, especially in the design of drive mechanism and transmission mode.

[0003] At present, many robot fingers use rope drive to achieve movement. One or more ropes are combined with motor drive to drive the movement of each joint of the robot finger. Although this design is more common in some applications, it still has obvious defects. First, traditional rope-driven robot fingers often require higher driving force and stable control to achieve complex movements, which leads to a more complex drive control structure. Secondly, the transmission accuracy of traditional rope-driven robot fingers is limited. Especially in the process of high-frequency and complex movements, the elasticity and wear of the rope will affect the accuracy of the finger and the stability of long-term use.

[0004] In order to overcome the defects of the single rope-driven method, the present invention designs an under-actuated robot finger based on the hybrid transmission of the connecting rod and tendon-rope mechanism. By combining the connecting rod mechanism and the tendon-rope transmission, a new hybrid transmission mode is formed in the driving aspect, which is of great significance for optimizing and improving the performance of the rope-driven robot finger. Summary of the invention

[0005] In order to address the shortcomings of the background technology, the present invention provides an under-actuated robot finger based on a hybrid transmission of a connecting rod and a tendon mechanism, which adopts a hybrid transmission of a connecting rod and a tendon mechanism to effectively improve the transmission efficiency, achieve a smaller volume and lower weight through an under-actuated control strategy, and has a coupling-adaptive motion function, which can improve the flexibility and response speed of finger movement.

[0006] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: an under-actuated robot finger based on a hybrid transmission of a connecting rod and a tendon mechanism, comprising a base, an arc-shaped connecting rod, an upper swing rod, a tendon, a driving wheel, a lower swing rod, a root joint shaft, a sleeve, a transfer connecting rod, an intermediate joint shaft, a top joint shaft, a root end finger joint shell, an intermediate finger joint shell and a tip end finger joint shell, a connecting ear is arranged at the front end of the top of the base and is hinged to the bottom of the lower swing rod, an intermediate connecting pin is fixed laterally at the top of the lower swing rod, the sleeve is slidably sleeved on the lower swing rod, and a positioning shaft is integrally arranged on the side of the bottom of the outer wall of the sleeve, the root joint shaft is rotatably connected to the through hole at the rear end of the top of the base, the driving wheel is coaxially connected and fixed to the root joint shaft, a winding groove is processed on the top of the driving wheel circumference and its rear end is connected and fixed to the tendon, the tendon is led out from the front end of the driving wheel, an eccentric shaft is integrally arranged at the rear end of the wheel surface on the same side of the driving wheel and the positioning shaft, and shaft holes are processed at both ends of the arc-shaped connecting rod The top end of the upper handle is connected with the bottom end of the lower handlebars by the spring, and the bottom end of the upper handlebars is connected with the spring pin of the control rod.

[0007] Furthermore, a sensing communication module is fixedly installed inside the tip knuckle shell, and a proximity sensor is connected to the front surface of the sensing communication module. The proximity sensor is exposed to the outside through a window at the front end of the tip knuckle shell, and is used to measure the proximity information between the tip knuckle shell and the grasped object.

[0008] Furthermore, the sensing communication module is connected to a root angle sensor and a top angle sensor, the root angle sensor is fixedly installed on the inner wall of the root end knuckle shell and is sleeved on the root joint shaft, and is used to measure the rotational position information of the driving wheel relative to the root end knuckle shell, and the top angle sensor is fixedly installed on the inner wall of the tip knuckle shell and is sleeved on the top joint shaft, and is used to measure the rotational position information of the tip knuckle shell relative to the top joint shaft.

[0009] Furthermore, a positioning beam is arranged on the top of the middle knuckle shell, and a nesting hole is arranged laterally on the top of the positioning beam to be rotatably connected to the top joint shaft. The sensing communication module is connected to strain gauge 1 and strain gauge 2, and strain gauge 1 and strain gauge 2 are respectively fixed on the side and front end of the positioning beam for measuring the force condition of the positioning beam.

[0010] Compared with the prior art, the present invention has the following beneficial effects: the present invention optimizes the transmission structure by using a hybrid method of connecting rods and tendons, which can effectively improve the transmission efficiency and reduce the mechanical loss in the traditional single rope drive method. At the same time, the underactuated control strategy can realize adaptive finger movements without the need to drive each joint separately, thereby effectively optimizing the complex structure of the motor control in the traditional solution, ensuring that the robot finger can have a smaller volume and lower weight while maintaining efficient motion ability, and the underactuated robot finger has a coupling-adaptive motion function, including:

[0011] 1) Anthropomorphic coupled motion in free space: When not in contact with the grasped object, the finger joints perform a fixed-ratio linkage to present an anthropomorphic pre-grasping action;

[0012] 2) Adaptive movement after the proximal knuckle contacts the object: After the root knuckle contacts the object, the movement stops, while the middle knuckle and the tip knuckle continue to move, achieving adaptive enveloping grasping of the object;

[0013] In summary, compared with the robot fingers in the traditional single rope drive mode, the present invention not only achieves a lighter structure in design, which helps to significantly reduce production costs, but also improves the flexibility and response speed of finger movement, and can meet a wider range of application needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the internal structure of the underactuated robot finger of the present invention;

[0015] Figure 2 Schematic diagram of the external structure of the underactuated robot finger of the present invention;

[0016] Figure 3 It is a schematic diagram of the effect of applying the underactuated robot finger of the present invention to a humanoid robot hand.

[0017] In the figure: 1, base; 2, root pin; 3, root bearing 1; 4, arc connecting rod; 5, positioning shaft; 6, intermediate connecting pin; 7, intermediate pin; 8, intermediate bearing 1; 9, upper swing rod; 10, top connecting pin; 11, top bearing 1; 12, sensor communication module; 13, tendon rope; 14, driving wheel; 15, root bearing 2; 16, lower swing rod; 17, root angle sensor; 18, root joint shaft; 19, sleeve; 20, transfer connecting rod; 21, intermediate bearing 2; 2 2. Torsion spring; 23. Middle joint shaft; 24. Top bearing 2; 25. Top angle sensor; 26. Top joint shaft; 27. Proximity sensor; 28. Root knuckle shell; 29. ​​Middle knuckle shell; 30. Tip knuckle shell; 31. Strain gauge 1; 32. Strain gauge 2; 33. Little finger winding motor; 34. Ring finger winding motor; 35. Middle finger winding motor; 36. Index finger winding motor; 37. Thumb winding motor; 38. Thumb linear motor; 39. Rotary joint. DETAILED DESCRIPTION

[0018] 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.

[0019] like Figure 1-2 As shown, an under-actuated robot finger based on a hybrid transmission of a connecting rod and a tendon mechanism includes a base 1, a root pin 2, a root bearing 1 3, an arc connecting rod 4, a positioning shaft 5, an intermediate connecting pin 6, an intermediate pin 7, an intermediate bearing 1 8, an upper swing rod 9, a top connecting pin 10, a top bearing 1 11, a sensor communication module 12, a tendon 13, a driving wheel 14, a root bearing 2 15, a lower swing rod 16, a root angle sensor 17, a root joint shaft 18, a sleeve 19, a transfer connecting rod 20, an intermediate bearing 2 21, a torsion spring 22, an intermediate joint shaft 23, a top bearing 2 24, a top angle sensor 25, a top joint shaft 26, a proximity sensor 27, a root knuckle shell 28, an intermediate knuckle shell 29, a tip knuckle shell 30, a strain gauge 1 31 and a strain gauge 2 32.

[0020] Combination Figure 1As shown, the base 1 is used as the root connection part of the robot finger, and its bottom is provided with a mounting hole for easy installation and fixation with the palm assembly. Its top extends forward and is provided with a connecting ear at the front end for connecting the lower swing rod 16, and a through hole is transversely provided at the rear end of the top for installing the root joint shaft 18. The bottom of the lower swing rod 16 and the connecting ear at the front end of the top of the base 1 are hinged through the root pin shaft 2 to form a rotating pair, and the top of the lower swing rod 16 is transversely fixed with an intermediate connecting pin 6 for connecting the intermediate finger joint shell 29, and the sleeve 19 is slidably sleeved on the lower swing rod 16 to form a moving pair, and a positioning shaft 5 is integrally provided on the side of the bottom of the outer wall of the sleeve 19 for connecting the arc connecting rod 4. The root joint shaft 18 is rotatably inserted into the through hole at the rear end of the top of the base 1, the driving wheel 14 is coaxially connected and fixed with the root joint shaft 18, an eccentric shaft is integrally arranged at the rear end of the wheel surface on the same side of the driving wheel 14 and the positioning shaft 5, the two ends of the arc connecting rod 4 are processed with shaft holes and are respectively hinged with the eccentric shaft of the driving wheel 14 and the positioning shaft 5 of the sleeve 19 to form a rotating pair, the top of the circumference of the driving wheel 14 is processed with a winding groove and its rear end is connected and fixed with one end of the tendon rope 13, the other end of the tendon rope 13 passes through the winding groove and is led downward from the front end of the driving wheel 14 to transmit the motion and force output by the winding motor, the tendon rope 13 controls the rotation of the driving wheel 14 and transmits it to the sleeve 19 through the arc connecting rod 4, so as to realize the sliding of the sleeve 19 and the forward swing of the lower swing rod 16. The transfer connecting rod 20 is arranged obliquely in the front-to-back direction at the front end adjacent to the lower swing rod 16, and its front end is provided with a connecting ear for connecting the upper swing rod 9, and its rear end is transversely provided with a through hole for the installation of the intermediate joint shaft 23. The connecting ear at the bottom of the upper swing rod 9 and the front end of the transfer link 20 is hinged through the intermediate pin 7 to form a rotating pair. The top connecting pin 10 is fixed horizontally on the top of the upper swing rod 9 for connecting the tip knuckle shell 30. The motion and force are transmitted through the transfer link 20. At the same time, the upper swing rod 9 and the lower swing rod 16 are staggered so that the working spaces of the two are not in the same plane to avoid mutual interference of the structures when the grasping action is realized. The intermediate joint shaft 23 is rotatably inserted into the through hole at the rear end of the transfer link 20. The torsion spring 22 is installed on the intermediate joint shaft 23 and connected and positioned with the intermediate knuckle shell 29, providing the intermediate joint shaft 23 with a torque opposite to the grasping motion direction to realize under-actuated grasping and automatic reset after grasping. This under-actuated mode can realize proportional coupling motion when not grasping, and the continued motion of the tip knuckle shell 30 after the intermediate knuckle shell 29 contacts the grasped object. The top joint shaft 26 is arranged transversely at a position adjacent to the front end above the upper swing rod 9, and the sensor communication module 12 is arranged at a position adjacent to the top joint shaft 26 to realize communication of the sensor unit.

[0021] The sensing unit includes a root angle sensor 17, a top angle sensor 25 and a proximity sensor 27. The root angle sensor 17 is installed on the root joint shaft 18 to measure the rotational position information of the driving wheel 14 relative to the root end finger joint shell 28, the top angle sensor 25 is installed on the top joint shaft 26 to measure the rotational position information of the tip finger joint shell 30 relative to the top joint shaft 26, and the proximity sensor 27 is installed on the front end surface of the sensing communication module 12 to measure the proximity information between the tip finger joint shell 30 and the grasped object.

[0022] In addition, in order to realize the connection between the root joint shaft 18, the intermediate joint shaft 23 and the top joint shaft 26 and the root end finger joint shell 28, the intermediate finger joint shell 29 and the tip finger joint shell 30 respectively, a root bearing 1 3 and a root bearing 2 15 are respectively arranged at both ends of the root joint shaft 18, an intermediate bearing 1 8 and an intermediate bearing 2 21 are respectively arranged at both ends of the intermediate joint shaft 23, and a top bearing 11 and a top bearing 2 24 are respectively arranged at both ends of the top joint shaft 26.

[0023] Combination Figure 2 As shown, the root knuckle housing 28, the middle knuckle housing 29 and the tip knuckle housing 30 are respectively mounted on the lower swing bar 16, the upper swing bar 9 and the sensor communication module 12. Bearing holes are provided on both sides of the bottom of the root knuckle housing 28 for mounting the root bearing 1 3 and the root bearing 2 15 to form a revolute pair. In addition, a mounting position is provided on the inner wall of the root knuckle housing 28 to mount and fix the root angle sensor 17. Bearing holes are opened on both sides of the bottom of the middle knuckle shell 29 for the installation of the middle bearing 1 8 and the middle bearing 2 21 to form a rotating pair. At the same time, pin holes are opened on both sides of the bottom of the middle knuckle shell 29 at positions corresponding to the middle connecting pin 6. The top of the lower swing rod 16 is plug-connected with the pin holes on both sides of the bottom of the middle knuckle shell 29 through the middle connecting pin 6 to form a rotating pair, which transmits the movement and force of the lower swing rod 16 to the middle knuckle shell 29, thereby pushing the middle knuckle shell 29 to rotate around the middle joint axis 23. In addition, an installation position is set on the inner wall of the middle knuckle shell 29 to install and fix the torsion spring 22. Bearing holes are opened on both sides of the bottom of the tip knuckle shell 30 for installing the top bearing 11 and the top bearing 2 24 to form a revolving pair. At the same time, pin holes are opened on both sides of the bottom of the tip knuckle shell 30 at positions corresponding to the top connecting pin 10. The top of the upper swing rod 9 is plug-connected with the pin holes on both sides of the bottom of the tip knuckle shell 30 through the top connecting pin 10 to form a revolving pair, which transmits the movement and force of the upper swing rod 9 to the tip knuckle shell 30, thereby pushing the tip knuckle shell 30 to rotate around the top joint axis 26. In addition, an installation position is set on the inner wall of the tip knuckle shell 30 to install and fix the sensor communication module 12 and the top angle sensor 25, and a window is opened at the front end of the tip knuckle shell 30 to expose the proximity sensor 27 to the outside.

[0024] In addition, a positioning beam can be set on the top of the middle finger joint shell 29, and a nesting hole is horizontally set on the top of the positioning beam to be rotatably connected to the top joint shaft 26. Strain gauge 1 31 and strain gauge 2 32 are respectively fixed on the side and front end of the positioning beam and connected to the sensor communication module 12. When grasping, the reaction force of the grasped object is applied, and the force condition of the positioning beam can be measured by the strain gauge 1 31 and the strain gauge 2 32.

[0025] Compared with a single rope drive or connecting rod rotation, this hybrid transmission mechanism of connecting rod and tendon rope mechanism combines the characteristics of tendon rope drive such as freedom of mode and spatial guidance with the characteristics of high connecting rod stiffness and determined motion trajectory, thereby realizing free grasping of robot fingers.

[0026] Combination Figure 3 As shown, based on the finger structure as a modular finger, each modular finger has three knuckles and three rotational joints. Taking the humanoid robot dexterous hand and medical rehabilitation prosthesis as the application background, a lightweight, under-actuated humanoid five-finger dexterous hand is designed. The whole hand is composed of a palm frame and five modular fingers. The five modular fingers are fixed to the corresponding positions of the palm frame through the mounting holes at the bottom of the base 1. The tendons 13 extending from the five modular fingers are independently driven by the matching little finger winding motor 33, ring finger winding motor 34, middle finger winding motor 35, index finger winding motor 36 and thumb winding motor 37. The bending of the corresponding modular finger is completed by winding and pulling the tendon rope 13 to realize the grasping action. In addition, for the thumb, an additional rotary joint 39 independently driven by the thumb linear motor 38 can be matched. Through extension and rotation, the modular finger corresponding to the thumb has the grasping action of swinging and bending two degrees of freedom.

[0027] 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.

[0028] 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. An underactuated robot finger based on a hybrid transmission of a connecting rod and a tendon mechanism, characterized in that: The invention comprises a base (1), an arc-shaped connecting rod (4), an upper swing rod (9), a tendon rope (13), a driving wheel (14), a lower swing rod (16), a root joint shaft (18), a sleeve (19), a transfer connecting rod (20), an intermediate joint shaft (23), a top joint shaft (26), a root end finger joint shell (28), an intermediate finger joint shell (29) and a tip end finger joint shell (30), wherein a connecting ear is arranged at the top front end of the base (1) and is hinged to the bottom of the lower swing rod (16), an intermediate connecting pin (6) is transversely fixed to the top of the lower swing rod (16), and the sleeve (19) is slidably sleeved. A positioning shaft (5) is integrally arranged on the lower swing rod (16) and the side of the bottom of the outer wall of the sleeve (19); the root joint shaft (18) is rotatably connected to the through hole at the rear end of the top of the base (1); the driving wheel (14) is coaxially connected and fixed to the root joint shaft (18); a winding groove is processed on the top of the circumference of the driving wheel (14) and its rear end is connected and fixed to the tendon rope (13); the tendon rope (13) is led out from the front end of the driving wheel (14); an eccentric shaft is integrally arranged on the rear end of the wheel surface on the same side of the driving wheel (14) and the positioning shaft (5); shaft holes are processed at both ends of the arc-shaped connecting rod (4) and are respectively connected to the eccentric shaft. The spindle and the positioning shaft (5) are hinged, the transfer link (20) is arranged obliquely in the front-to-back direction at a position adjacent to the front end of the lower swing rod (16), the front end of the transfer link (20) is provided with a connecting ear and is hinged to the bottom of the upper swing rod (9), the top of the upper swing rod (9) is transversely fixed with a top connecting pin (10), the intermediate joint shaft (23) is rotatably connected to the through hole at the rear end of the transfer link (20), the top joint shaft (26) is transversely arranged at a position adjacent to the front end of the upper swing rod (9), and the bottom sides of the root end knuckle shell (28) are respectively connected to the root joint shaft (18) through bearings. ) is rotatably connected, the bottom sides of the middle knuckle shell (29) are rotatably connected to the middle joint shaft (23) through bearings, the two ends of the middle connecting pin (6) are respectively plug-connected to the pin holes opened at corresponding positions of the middle knuckle shell (29), a torsion spring (22) is installed between the middle joint shaft (23) and the middle knuckle shell (29) to provide a reverse torque, the bottom sides of the tip knuckle shell (30) are respectively rotatably connected to the top joint shaft (26) through bearings, and the two ends of the top connecting pin (10) are respectively plug-connected to the pin holes opened at corresponding positions of the tip knuckle shell (30).

2. The underactuated robot finger based on hybrid transmission of connecting rod and tendon mechanism according to claim 1, characterized in that: A sensing communication module (12) is fixedly installed inside the tip knuckle shell (30), and a proximity sensor (27) is connected and installed on the front surface of the sensing communication module (12). The proximity sensor (27) is exposed to the outside through a window provided at the front end of the tip knuckle shell (30) and is used to measure proximity information between the tip knuckle shell (30) and the grasped object.

3. The underactuated robot finger based on hybrid transmission of connecting rod and tendon mechanism according to claim 2 is characterized in that: The sensing communication module (12) is connected to a root angle sensor (17) and a top angle sensor (25); the root angle sensor (17) is fixedly mounted on the inner wall of a root end knuckle shell (28) and sleeved on the root joint shaft (18) for measuring the rotational position information of the driving wheel (14) relative to the root end knuckle shell (28); the top angle sensor (25) is fixedly mounted on the inner wall of a tip knuckle shell (30) and sleeved on the top joint shaft (26) for measuring the rotational position information of the tip knuckle shell (30) relative to the top joint shaft (26).

4. The underactuated robot finger based on hybrid transmission of connecting rod and tendon mechanism according to claim 2 or 3, characterized in that: A positioning beam is arranged on the top of the middle finger joint shell (29), a nesting hole is arranged transversely on the top of the positioning beam and is rotatably connected to the top joint shaft (26), the sensing communication module (12) is connected to a strain gauge 1 (31) and a strain gauge 2 (32), the strain gauge 1 (31) and the strain gauge 2 (32) are respectively fixed on the side and the front end of the positioning beam, and are used to measure the force condition of the positioning beam.

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