Underactuated finger and underactuated multi-finger hand grasping system

Abstract

The present application discloses an underactuated finger and an underactuated multi-finger hand grasping system, belonging to the technical field of underactuated fingers. It comprises a finger base, the finger base is provided with a first driving mechanism, the first driving mechanism drives the middle finger joint connected thereto, and drives the middle finger joint to rotate along the width direction of the finger base; a transmission mechanism is provided in the middle finger joint, the first driving mechanism drives the end finger connected to the transmission mechanism through the transmission mechanism, and drives the end finger to rotate along the width direction of the middle finger joint. The compact structural design of the underactuated finger in a small space is realized, the accuracy and reliability are improved, and the grasping effect is good; the underactuated fingers are all connected to the upper plate thread through the finger rotating shaft, which reduces the complexity of the structure, and the electrical signal lines are connected between the modules through the wire holes of the finger base and the finger rotating shaft. The problem existing in the prior art that "the transmission mechanism is difficult to pre-tighten in real time, the rigidity is poor, the actual grasping effect is poor, and it is difficult to complete high-quality grasping" is solved.

Description

Technical Field

[0001] The present application relates to the technical field of underactuated fingers, and in particular to an underactuated finger and an underactuated multi-finger hand grasping system. Background Art

[0002] The statements herein merely provide background art related to the present application and do not necessarily constitute prior art.

[0003] When the number of drive units is less than the number of degrees of freedom, this drive mode is called under-actuation. Although the number of drive units is less than the number of degrees of freedom, the mechanism can still work normally under the action of some constraints. Multi-fingered hands generally have multiple fingers and each finger has multiple joints. If a full drive mode is used, a drive unit must be installed on each active joint, which will not only make the robot bulky but also complex to control.

[0004] The under-actuated multi-fingered hand is a universal end effector with similar structure and function to the human hand. It adopts a mechanical design in which the number of actuators is less than the joint degrees of freedom, which reduces the control difficulty and the size and mass of the hand while maintaining good performance and a high degree of anthropomorphism. It can flexibly manipulate objects of various shapes and complete complex tasks.

[0005] At present, under-actuated fingers generally use wire rope transmission, rope transmission, synchronous toothed belt transmission, etc. The transmission mechanism is difficult to pre-tighten in real time, has poor rigidity, and the actual grasping effect is poor, making it difficult to complete high-quality grasping. Summary of the invention

[0006] In view of the shortcomings of the prior art, the embodiments of the present application adopt an under-actuated approach, reasonably design the finger mechanism, and constrain it in a certain way to provide an under-actuated finger and under-actuated multi-finger hand system with a simple structure, good transmission rigidity, and good grasping effect.

[0007] In a first aspect, the present application provides an underactuated finger:

[0008] An underactuated finger comprises a finger base, wherein a first driving mechanism is arranged on the finger base, and the first driving mechanism drives a middle finger joint connected thereto to drive the middle finger joint to rotate along a width direction of the finger base;

[0009] A transmission mechanism is arranged in the middle knuckle, and the first driving mechanism drives the end finger connected to the transmission mechanism through the transmission mechanism, and drives the end finger to rotate along the width direction of the middle knuckle.

[0010] By adopting the above technical solution, a compact structure design in a small space is achieved, the lightweight of the equipment is ensured, and a multi-stage transmission is designed in a small space. The normal operation of the under-actuated finger can be achieved with only a few drive units. The transmission mechanism has a small gap and good rigidity, which improves the grasping accuracy and reliability of the under-actuated finger.

[0011] Further, the first driving mechanism includes a first motor, a first bevel gear, a first fixed shaft, a first gear and a second bevel gear;

[0012] The first motor is horizontally arranged on the finger base along the length direction of the finger base, and the first bevel gear is arranged on the extension shaft of the first motor;

[0013] The first fixed shaft is fixed to the middle finger joint along the width direction of the middle finger joint, the first fixed shaft is located at the connection part between the middle finger joint and the finger base, and a first gear is fixed to one end of the first fixed shaft;

[0014] The second bevel gear is fixed to the middle finger joint, and the second bevel gear is loosely sleeved on the other end of the first fixed shaft;

[0015] The first bevel gear is meshed with the second bevel gear.

[0016] Preferably, the transmission mechanism comprises a second fixed shaft, a third fixed shaft and a fourth gear;

[0017] The second fixed shaft is horizontally arranged on the middle finger joint along the width direction of the middle finger joint, a second gear is arranged at one end of the second fixed shaft, the second gear is loosely sleeved on the second fixed shaft, and the second gear is meshed with the first gear;

[0018] The third fixed shaft is horizontally arranged on the middle finger joint along the width direction of the middle finger joint, a third gear is arranged at one end of the third fixed shaft, the third gear is loosely sleeved on the third fixed shaft, and the third gear is meshed with the second gear;

[0019] The fourth gear is disposed on one side of the end finger along the width direction, and the fourth gear is meshed with the third gear.

[0020] By adopting the above technical solution, the first bevel gear on the extended shaft of the first motor is used as a power source to drive the second bevel gear to rotate, and then drive the middle finger joint to rotate. The middle finger joint is used as a secondary power source to drive the fixed shaft on the middle finger joint, thereby realizing a multi-stage gear transmission with an empty sleeve on the fixed shaft, thereby driving the end finger to realize the grasping action, and realizing a compact structural design in a narrow space.

[0021] Further, the intermediate bracket is a U-shaped structure, and the end finger includes a fingertip, a fingertip axis and a tactile sensor;

[0022] An angle sensor is arranged at one end of the middle knuckle, and the fingertip axis passes through an inner hole of the angle sensor and is arranged at one end of the middle knuckle;

[0023] One end of the fingertip is arranged at the middle knuckle, and the touch sensor is arranged at the fingertip.

[0024] By adopting the above technical solution, the fingertip working surface is provided with a tactile sensor, which can sense the contact force and sliding trend changes in a small area. A single under-actuated finger can be easily combined into a two-finger, three-finger or other multi-finger grasping system, which can realize the grasping operation of fragile, weak and easily damaged objects.

[0025] Furthermore, one end of the finger base is a U-shaped structure, which is rotatably connected to one end of the middle knuckle; the middle knuckle is a U-shaped structure, and the other end of the middle knuckle is rotatably connected to the terminal finger.

[0026] By adopting the above technical solution, the finger base has high structural strength, which can meet the needs of grasping the middle knuckles and the end fingers; the gap between the finger joints is reduced to reduce the motion error caused by the mechanical gap.

[0027] In a second aspect, the present application provides an underactuated multi-finger hand grasping system based on the above underactuated fingers;

[0028] An under-actuated multi-finger hand grasping system based on the above under-actuated finger comprises a base, on which a two-finger rotation drive device, a first under-actuated finger, a second under-actuated finger and a third under-actuated finger are arranged;

[0029] The connecting line of the mounting points of the first under-actuated finger, the second under-actuated finger and the third under-actuated finger is located on a straight line passing through the center of the upper plate of the base, and the mounting point of the two-finger rotation driving device is located on another straight line passing through the center of the upper plate of the base and is perpendicular to the connecting line of the mounting points of the first under-actuated finger, the second under-actuated finger and the third under-actuated finger;

[0030] The two-finger rotation driving device drives the first under-actuated finger and the third under-actuated finger to rotate along an axis direction perpendicular to their installation points respectively.

[0031] By adopting the above technical solution, each finger is modularly designed with a simple structure, good transmission rigidity, high precision, strong reliability and good grasping effect. It can grasp cylindrical, circular and other irregular types of target objects, with more grasping types and a wider grasping range.

[0032] Furthermore, the first under-actuated finger, the second under-actuated finger, and the third under-actuated finger have the same structure; a finger rotation shaft is vertically arranged at the other end of the finger base, the top end of the finger rotation shaft is connected to the finger base, the finger rotation shaft passes through the upper plate of the base, and is rotationally connected to the upper plate through a standard fine thread arranged on the outer surface of the middle part of the finger rotation shaft.

[0033] By adopting the above technical solution, the three finger modules are all threadedly connected to the upper plate through the finger rotating shaft, replacing the complexity of rotating mechanisms such as bearings and slewing supports.

[0034] Furthermore, a second wire passing hole penetrating the finger rotation axis is vertically arranged in the middle of the finger rotation axis, and the second wire passing hole is used for accommodating the electrical signal line.

[0035] Preferably, one end of the finger rotation axis of the first under-actuated finger and the third under-actuated finger is respectively provided with a steel wire single groove wheel, and the steel wire single groove wheel is located below the upper plate of the base;

[0036] The double-finger rotation drive device comprises a second motor and a steel wire double-groove wheel, the output shaft of the second motor passes through the upper plate of the base, the steel wire double-groove wheel is arranged on the output shaft of the motor, and the steel wire double-groove wheel is located below the upper plate;

[0037] The double-grooved wire wheel and the single-grooved wire wheel of the first under-actuated finger form a same-direction wire transmission mechanism, i.e., their movement directions are the same; the double-grooved wire wheel and the single-grooved wire wheel of the second under-actuated finger form a reverse wire transmission mechanism, i.e., their movement directions are reversed;

[0038] Furthermore, the range of motion is 0-180°.

[0039] By adopting the above technical solution, the steel wire double groove wheel is directly driven by the second motor and is divided into two transmission paths, one is an ∞-shaped transmission, and the other is a synchronous belt parallel transmission, which is used to drive the first under-actuated finger and the third under-actuated finger to rotate in the opposite direction at the same time, and the movement range does not exceed 180; all groove wheels have the same diameter, and 1:1 transmission can be achieved.

[0040] Further, it also includes a palm mounting plate;

[0041] The palm mounting plate is disposed above the base through a connecting plate, and the palm mounting plate is located in the middle portion surrounded by the first under-actuated finger, the second under-actuated finger, and the third under-actuated finger;

[0042] The first underactuated finger, the second underactuated finger, and the third underactuated finger are height-adjustable between the palm mounting plate and the upper plate of the base.

[0043] By adopting the above technical solution, the height of the three under-actuated fingers can be adjusted between the upper plate and the palm mounting plate, and the height between the three fingers and the upper plate can also be adjusted. It has a certain adaptability, can further expand the grasping space, and adapt to the grasping operations of more types of objects.

[0044] Preferably, it also includes a palm tactile sensor;

[0045] The palm tactile sensor is arranged on the palm mounting plate;

[0046] Furthermore, the first under-actuated finger, the second under-actuated finger and the third under-actuated finger are respectively provided with a control unit, and the control unit is used to obtain tactile data and rotation angle data;

[0047] A main controller is arranged in the base, and the main controller is used to realize coordinated control of the first under-actuated finger, the second under-actuated finger and the third under-actuated finger according to the tactile data and the rotation angle data.

[0048] By adopting the above technical solution, the joint angle and tactile data can be collected and wirelessly transmitted to the main control system in the palm, which saves signal data lines, reduces the burden on the main controller and improves the comprehensive control performance.

[0049] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0050] 1. This application designs an underactuated finger, and designs a multi-stage gear transmission in a narrow space. The first bevel gear on the extended shaft of the first motor is used as a power source to drive the second bevel gear to rotate, and then drive the middle finger joint to rotate. The middle finger joint is used as a secondary power source to drive the fixed shaft on the middle finger joint, so as to realize the multi-stage gear transmission on the fixed shaft, thereby driving the end finger to realize the grasping action, realizing a compact structural design in a narrow space, and the transmission mechanism has small clearance, good rigidity, high precision and high reliability;

[0051] 2. The underactuated finger designed in this application has a tactile sensor on the fingertip working surface, which can sense the contact force and sliding trend changes in a small area. A single underactuated finger can be easily combined into a two-finger, three-finger or other multi-finger grasping system, which can realize the grasping operation of fragile, weak and vulnerable objects;

[0052] 3. The underactuated multi-finger hand grasping system designed in this application has three underactuated fingers connected to the upper plate through a finger rotation axis, replacing the complexity of a rotating mechanism such as a bearing and a slewing support. The height can be adjusted between the upper plate and the palm mounting plate, and has a certain degree of adaptability, which can further expand the grasping space and adapt to the grasping operation of more types of objects;

[0053] 4. The under-actuated multi-finger grasping system designed in this application realizes the reverse rotation movement of the modular fingers on both sides, and can grasp cylindrical, circular, and other irregular types of target objects, with more grasping types and a wider grasping range, thereby improving the overall control performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The drawings in the specification, which constitute a part of the present application, are used to provide further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0055] Figure 1 is a schematic diagram of the structure of an under-actuated finger provided in an embodiment of the present application;

[0056] Figure 2 It is a structural schematic diagram of a finger base and a finger rotation axis provided in an embodiment of the present application;

[0057] Figure 3 is a schematic diagram of the structure of an under-actuated multi-finger hand grasping system provided in an embodiment of the present application;

[0058] Figure 4 It is a schematic diagram of the structure of the upper plate provided in the embodiment of the present application;

[0059] Figure 5 is a structural schematic diagram of another angle of the under-actuated multi-finger hand grasping system provided in an embodiment of the present application;

[0060] Figure 6 This is a control connection diagram of the underactuated multi-finger hand grasping system provided in the embodiment of the present application.

[0061] In the figure: 1, first motor; 2, motor mounting plate; 3, finger base; 4, first bevel gear; 5, second bevel gear; 6, first intermediate connecting rod; 7, second fixed shaft; 8, bottom plate; 9, third fixed shaft; 10, fingertip; 11, angle sensor; 12, tactile sensor; 13, fingertip shaft; 14, fourth gear; 15, third gear; 16, second intermediate connecting rod; 17, second gear; 18, first gear; 19, first fixed shaft; 20, first thread hole; 21, first thread hole; 22, second thread hole; 23, second thread hole; 24, threaded portion; 25, Groove wheel mounting column; 26, upper plate; 27, second motor; 28, single-groove wire wheel; 29, ∞-shaped steel wire; 30, lower plate; 31, main control board; 32, double-groove wire wheel; 33, parallel steel wire; 34, first under-actuated finger; 35, second under-actuated finger; 36, third under-actuated finger; 37, first control unit; 38, second control unit; 39, third control unit; 40, multi-way switch; 41, DC power supply line; 42, threaded hole in upper plate; 43, motor mounting hole; 44, palm tactile sensor; 45, palm mounting plate; 46, connecting plate; 47, upper plate.

[0062] In order to show the positions of various parts, the distances or sizes between them are exaggerated and the schematic diagram is for reference only. DETAILED DESCRIPTION

[0063] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present application have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0064] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless otherwise explicitly stated in the present application, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "include" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or their combinations;

[0065] For the convenience of description, if the words "up", "down", "left" and "right" appear in this application, they only indicate that they are consistent with the up, down, left and right directions of the drawings themselves, and do not limit the structure. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on this application.

[0066] Terminology explanation section: The terms "install", "connect", "connect", "fixed", etc. in this application should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; it can be an internal connection between two elements, or an interaction relationship between two elements. For ordinary technicians in this field, the specific meaning of the terms in this application can be understood according to the specific circumstances.

[0067] Embodiment 1

[0068] As introduced in the background technology, the rigidity and actual grasping effect of the under-actuated fingers in the prior art are very poor, and it is difficult to achieve high-quality grasping. In order to solve the above technical problems, the present application proposes an under-actuated finger, which adopts an under-actuated method, reasonably designs the finger mechanism, constrains it in a certain way, and uses very few drive units to achieve the normal operation of the manipulator.

[0069] In order to improve the movement speed and control accuracy of the underactuated hand, the weight of the hand should be reduced as much as possible in terms of structure and material while ensuring that the fingers have sufficient strength and rigidity. It is required to use high-strength lightweight materials and the gap between the finger joints should be as small as possible to reduce the movement error caused by mechanical clearance.

[0070] like Figure 1-Figure 2 As shown, this embodiment records an under-actuated multi-fingered hand, including a finger base 3, on which a first driving mechanism is installed, the first driving mechanism drives the middle finger joints connected thereto, and drives the middle finger joints to rotate along the width direction of the finger base 3; a transmission mechanism is installed in the middle finger joints, and the first driving mechanism drives the terminal fingers connected to the transmission mechanism through the transmission mechanism, and drives the terminal fingers to rotate along the width direction of the middle finger joints.

[0071] One end of the finger base 3 is a U-shaped structure, and the other end of the finger base 3 is a horizontally arranged mounting plate. A motor mounting plate 2 is vertically installed on one side of the U-shaped structure of the finger base 3 close to the mounting plate; the middle finger joint includes a first middle connecting rod 6, a second middle connecting rod 16 and a bottom plate 8, and the first middle connecting rod 6 and the second middle connecting rod 16 are respectively vertically installed at both ends of the bottom plate 8 along the width direction and fastened by screws to form a U-shaped structure with an accommodating space; the end finger includes a fingertip 10, a fingertip axis 13 and a tactile sensor 12, and the tactile sensor 12 is installed on the working surface of the fingertip 10.

[0072] The first driving mechanism includes a first motor 1, a first bevel gear 4, a first fixed shaft 19, a first gear 18 and a second bevel gear 5; the first motor 1 is horizontally installed on the finger base 3 through the motor mounting plate 2 along the length direction of the finger base 3, and the first bevel gear 4 is fixedly installed on the extended shaft of the first motor 1; the first fixed shaft 19 is fixed in the circular holes on both sides of the finger base 3 along the width direction of the finger base 3, the first fixed shaft 19 is located at the connecting part between the middle finger joint and the finger base 3, and the first fixed shaft 19 itself does not rotate; a first gear 18 is fixed to one end of the first fixed shaft 19, the second bevel gear 5 is loosely sleeved on the other end of the first fixed shaft 19 and can rotate on the first fixed shaft 19, the second bevel gear 5 is fixed to the first intermediate connecting rod 6, and the first bevel gear 4 is meshed with the second bevel gear 5; the first bevel gear 4 cooperates with the second bevel gear 5, and the second motor 27 drives the first bevel gear 4 to rotate, thereby driving the second bevel gear 5 to rotate, and the bevel gear and the middle finger joint are integrated, thereby driving the middle finger joint to rotate around the first fixed shaft 19.

[0073] The transmission mechanism includes a second fixed shaft 7, a third fixed shaft 9 and a fourth gear 14; the second fixed shaft 7 is horizontally installed on the middle finger joint along the width direction of the middle finger joint, fixed in the mounting holes of the first middle connecting rod 6 and the second middle connecting rod 16, the second fixed shaft 7 itself does not rotate, is fixedly connected to the middle finger joint, and can rotate around the first fixed shaft 19 with the middle finger joint; a second gear 17 with an empty sleeve on the second fixed shaft 7 is installed at one end of the second fixed shaft 7, the second gear 17 can rotate around the second fixed shaft 7, the second gear 17 is meshed with the first gear 18, and the second gear 17 can rotate around the first fixed shaft 19 under load; the third fixed shaft 9 is horizontally installed on the middle finger joint along the width direction of the middle finger joint, fixed in another mounting hole of the first middle connecting rod 6 and the second middle connecting rod 16, the third fixed shaft 9 A third gear 15 is installed at one end and is loosely sleeved on the third fixed shaft 9. The third gear 15 can rotate around the third fixed shaft 9, and the third gear 15 is meshed with the second gear 17, and the third gear 15 can rotate around the first fixed shaft 19; one end of the fingertip 10 is horizontally inserted into the end of the middle knuckle away from the finger base 3, and an angle sensor 11 is installed at one end of the first intermediate connecting rod 6, and the fingertip shaft 13 passes through the inner hole of the angle sensor 11 and one end of the fingertip 10 is loosely sleeved in another mounting hole of the first intermediate connecting rod 6 and the second intermediate connecting rod 16, and the fingertip shaft 13 and the fingertip 10 are an integral structure; when the end finger rotates, the angle sensor 11 can measure the rotation angle of the end knuckle relative to the middle knuckle; the fourth gear 14 is fixed to one end of the fingertip shaft 13, and the fourth gear 14 is meshed with the third gear 15.

[0074] The middle finger joint also includes an upper plate 47, which is horizontally fixed between the first middle connecting rod 6 and the second middle connecting rod and is located above the bottom plate 8 by screws. It can protect the internal transmission mechanism and is fixed with screws. When maintenance is needed, the upper plate 47 can be removed quickly and easily.

[0075] The specific working mode of the underactuated finger provided in this embodiment is as follows:

[0076] Start the first motor 1, the output shaft of the first motor 1 rotates to drive the first bevel gear 4 to rotate, thereby driving the second bevel gear 5 to move. The second bevel gear 5 is loosely sleeved on the first fixed shaft 19 and fixed on the middle finger joint, thereby driving the rotation of the middle finger joint.

[0077] When the middle knuckle moves, since the first fixed shaft 19 and the first gear 18 are both fixed, the second gear 17 of the empty sleeve on the second fixed shaft 7 and the third gear 15 of the empty sleeve on the third fixed shaft 9 engage and rotate with each other, thereby driving the fourth gear 14 fixed on the fingertip shaft 13 to move. The fourth gear 14 and the fingertip shaft 13 are integrated, thereby driving the entire end finger to move.

[0078] During this process, the first fixed shaft 19 and the first gear 18 do not rotate, the second fixed shaft 7 and the third fixed shaft 9 are fixed relative to the middle finger joint, and the fingertip shaft 13 is fixed relative to the end finger, but the middle finger joint driven by the second bevel gear 5 can rotate around the first fixed shaft 19; when the entire middle finger joint rotates, the end finger simultaneously rotates around the two side shaft holes of the fingertip shaft 13 according to the set transmission ratio, realizing a compound movement around the first fixed shaft 19 and the fingertip shaft 13, thereby realizing a bending action similar to that of a single finger of a human.

[0079] Embodiment 2

[0080] Combination Figure 3-Figure 6The present embodiment provides an under-actuated multi-finger hand grasping system based on the above-mentioned under-actuated fingers, and the under-actuated multi-finger hand grasping system includes a base, and the base includes an upper plate 26 and a lower plate 30 arranged opposite to each other in the upper and lower directions, and the upper plate 26 and the lower plate 30 are fixed by a connecting rod; a two-finger rotation drive device, a first under-actuated finger 34, a second under-actuated finger 35 and a third under-actuated finger 36 are installed on the base; the connection line of the installation points of the first under-actuated finger 34, the second under-actuated finger 35 and the third under-actuated finger 36 is located on a straight line passing through the center of the upper plate 26, and the installation point of the two-finger rotation drive device is located at Another straight line passing through the center of the upper plate 26 is perpendicular to the line connecting the installation points of the first under-actuated finger 34, the second under-actuated finger 35 and the third under-actuated finger 36; wherein, the second under-actuated finger 35 located at the center of the upper plate 26 is a fixed finger and can only realize extension and bending movements; the other two fingers are movable fingers, each of which can independently complete extension and bending movements, and at the same time, the two fingers can also perform synchronous reverse rotational movements along the rotation axis of the upper plate 26; the two-finger rotation driving device drives the first under-actuated finger 34 and the third under-actuated finger 36 to rotate respectively along the axis direction perpendicular to their installation points.

[0081] The first under-actuated finger 34, the second under-actuated finger 35, and the third under-actuated finger 36 have the same structure; they all include a finger base 3 and a finger rotation axis; one end of the finger base 3 is a U-shaped structure, and the other end of the finger base 3 is a horizontally arranged mounting plate, a first wire passing hole 20 is provided in the middle of the mounting plate, and first threaded holes 21 are provided at the four corners; a second wire passing hole 23 is provided in the middle of the top end of the finger rotation axis, and second threaded holes 22 are provided at the four corners, the middle part of the finger rotation axis is a threaded portion 24, and the bottom end of the finger rotation axis is connected to a groove wheel mounting column 25, and the groove wheel mounting column 25 and the finger rotation axis are an integrated structure.

[0082] The upper plate 26 is provided with threaded holes according to the installation points of the first under-actuated finger 34 , the second under-actuated finger 35 and the third under-actuated finger 36 , and the upper plate 26 is provided with motor installation holes 43 according to the installation points of the double-finger rotation drive device.

[0083] The finger base 3 and the finger rotating shaft are installed in an upper and lower structure, the upper surface of the finger rotating shaft and the lower surface of the mounting plate are aligned and overlapped, the first wire hole 20 and the second wire hole 23 are aligned and overlapped, and the finger base 3 and the finger rotating shaft are fixed together by screws passing through the first threaded hole 21 and the second threaded hole 22 in sequence. The bottom end of the finger rotating shaft passes through the threaded hole of the upper plate 26, and the threaded portion 24 is threadedly connected to the upper plate 26. The outer surface of the threaded portion 24 is provided with a standard fine thread. The three under-actuated fingers are all rotatably connected to the upper plate 26 through the standard fine thread of the finger rotating shaft, replacing the complexity of the rotating mechanism such as bearings and slewing supports. The single-groove pulley 28 of the wire is installed on the groove wheel mounting column 25 of the first under-actuated finger 34 and the third under-actuated finger 36, respectively, and the single-groove pulley 28 of the wire is located below the upper plate 26.

[0084] The double-finger rotation drive device includes a second motor 27 and a steel wire double-groove wheel 32. The steel wire double-groove wheel 32 has the same diameter as the steel wire single-groove wheel 28, and can achieve 1:1 transmission; the second motor 27 is vertically installed on the upper plate 26, and the output shaft of the second motor 27 vertically passes through the motor mounting hole 43 of the upper plate 26. The steel wire double-groove wheel 32 is installed on the output shaft of the motor, and the steel wire double-groove wheel 32 is located below the upper plate 26; the steel wire double-groove wheel 32 and the steel wire single-groove wheel 28 of the first under-actuated finger 34 form a same-direction steel wire transmission mechanism through parallel steel wires 33, that is, their movement directions are in the same direction; the steel wire double-groove wheel 32 and the steel wire single-groove wheel 28 of the second under-actuated finger 35 form a reverse steel wire transmission mechanism through the ∞-shaped steel wire 29, that is, their movement directions are reversed; the movement range is 0-180°.

[0085] The upper plate 26 is made of a whole piece of metal, and the overall structural strength is high. The threaded holes of the upper plate 26 are used in conjunction with the threaded portion 24 of the finger rotation axis to replace similar structures such as a slewing support structure. The threaded transmission is used as the rotation mechanism, which has high strength and reliability, and the three fingers can easily adjust the height of the under-actuated finger to the upper plate 26.

[0086] The compact and miniaturized design of the under-actuated multi-finger hand can not only ensure the lightness of the device but also provide a good grasping effect. It has natural advantages in portability and miniaturization.

[0087] Furthermore, in some embodiments, a palm mounting plate 45 is included, and the palm mounting plate 45 is an elliptical mounting plate; the palm mounting plate 45 is installed above the upper plate 26 through an L-shaped connecting plate 46, and the palm mounting plate 45 is located in the middle part (i.e., the palm) surrounded by the first under-actuated finger 34, the second under-actuated finger 35 and the third under-actuated finger 36.

[0088] A palm tactile sensor 44 is installed on the surface of the palm mounting plate 45. The elliptical platform and three modular under-actuated fingers together constitute a grasping system. The three modular under-actuated fingers can adjust their height between the upper plate 26 and the palm mounting plate 45, that is, adjust the height of the three under-actuated fingers to the palm mounting plate 45, thereby further expanding the grasping space and adapting to the grasping operation of a larger range of objects, so that the under-actuated multi-finger hand grasping system has a certain adaptability.

[0089] Furthermore, in some embodiments, a first control unit 37 is installed in the first under-actuated finger 34, a second control unit 38 is installed in the second under-actuated finger 35, and a third control unit 39 is installed in the third under-actuated finger 36 for acquiring tactile data and rotation angle data; a main control board 31 is installed on the upper surface of the lower plate 30 for realizing coordinated control of the first under-actuated finger 34, the second under-actuated finger 35 and the third under-actuated finger 36 according to the tactile data and the rotation angle data.

[0090] The DC power supply lines 41 of the first control unit 37, the second control unit 38 and the third control unit 39 are respectively passed through the first wire hole 20 of the finger base 3 and the second wire hole 23 of the finger rotation axis to be electrically connected to the main control board 31 to realize power supply; the main control board 31 is wirelessly connected with the first control unit 37, the second control unit 38 and the third control unit 39 to realize wireless data generation and reception. All electrical signal lines are connected to the main control board of the lower plate 30 through the wire holes of the finger base 3 and the finger rotation axis.

[0091] In this embodiment, the tactile sensor 12 is a thin film array tactile sensor 12, and the first control unit 37, the second control unit 38 and the third control unit 39 are all micro single-chip control boards, whose main functions are to collect data from the angle sensor 11 and the tactile sensor 12 through a multi-way switch 40 (such as model CD74HC4502), and transmit the data to the main control board 31.

[0092] The above-mentioned underactuated finger and underactuated multi-finger hand grasping system is used for robot underactuated multi-finger hand grasping and operation, and can be used as a universal end tool. It has broad application prospects in service robots, industrial robots, agricultural robots, medical surgery, human prostheses, spacecraft maintenance and other dangerous environments.

[0093] Although the above describes the specific implementation methods of the present application in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present application. Technical personnel in the relevant field should understand that on the basis of the technical solution of the present application, various modifications or deformations that can be made by technical personnel in this field without creative work are still within the scope of protection of the present application.

Claims

1. An underactuated multi-finger hand grasping system, characterized in that: It comprises a base, on which a double-finger rotation driving device, a first under-actuated finger, a second under-actuated finger and a third under-actuated finger are arranged; The connecting line of the mounting points of the first under-actuated finger, the second under-actuated finger and the third under-actuated finger is located on a straight line passing through the center of the upper plate of the base, and the mounting point of the two-finger rotation driving device is located on another straight line passing through the center of the upper plate of the base and is perpendicular to the connecting line of the mounting points of the first under-actuated finger, the second under-actuated finger and the third under-actuated finger; The two-finger rotation driving device drives the first under-actuated finger and the third under-actuated finger to rotate along the axis direction perpendicular to their installation points respectively; The first under-actuated finger, the second under-actuated finger, and the third under-actuated finger have the same structure; a finger rotation shaft is vertically arranged at the other end of the finger base, the top end of the finger rotation shaft is connected to the finger base, the finger rotation shaft passes through the upper plate of the base, and is rotationally connected to the upper plate through a standard fine thread arranged on the outer surface of the middle part of the finger rotation shaft; A second wire hole penetrating the finger rotation shaft is vertically arranged in the middle of the finger rotation shaft, and the second wire hole is used for receiving the electrical signal line; One end of the finger rotation axis of the first under-actuated finger and the third under-actuated finger is respectively provided with a steel wire single groove wheel, and the steel wire single groove wheel is located below the upper plate of the base; The double-finger rotation drive device comprises a second motor and a steel wire double-groove wheel, the output shaft of the second motor passes through the upper plate of the base, the steel wire double-groove wheel is arranged on the output shaft of the motor, and the steel wire double-groove wheel is located below the upper plate; The double-grooved wire wheel and the single-grooved wire wheel of the first under-actuated finger form a same-direction wire transmission mechanism, i.e., their movement directions are the same; the double-grooved wire wheel and the single-grooved wire wheel of the second under-actuated finger form a reverse wire transmission mechanism, i.e., their movement directions are reversed; The range of motion is 0-180°; Also included is a palm mounting plate; The palm mounting plate is disposed above the base through a connecting plate, and the palm mounting plate is located in the middle portion surrounded by the first under-actuated finger, the second under-actuated finger, and the third under-actuated finger; The first underactuated finger, the second underactuated finger, and the third underactuated finger are capable of adjusting height between the palm mounting plate and an upper plate of the base.

2. The underactuated multi-finger hand grasping system according to claim 1, characterized in that: Also included are palm tactile sensors; The palm tactile sensor is arranged on the palm mounting plate; The first under-actuated finger, the second under-actuated finger and the third under-actuated finger are respectively provided with a control unit, and the control unit is used to obtain tactile data and rotation angle data; A main controller is arranged in the base, and the main controller is used to realize coordinated control of the first under-actuated finger, the second under-actuated finger and the third under-actuated finger according to the tactile data and the rotation angle data.

3. An underactuated finger of the underactuated multi-finger hand grasping system according to any one of claims 1 to 2, characterized in that: It comprises a finger base, on which a first driving mechanism is arranged, and the first driving mechanism drives the middle finger joint connected thereto to drive the middle finger joint to rotate along the width direction of the finger base; A transmission mechanism is arranged in the middle knuckle, and the first driving mechanism drives the end finger connected to the transmission mechanism through the transmission mechanism, and drives the end finger to rotate along the width direction of the middle knuckle.

4. The underactuated finger according to claim 3, wherein: The first driving mechanism includes a first motor, a first bevel gear, a first fixed shaft, a first gear and a second bevel gear; The first motor is horizontally arranged on the finger base along the length direction of the finger base, and the first bevel gear is arranged on the extension shaft of the first motor; The first fixed shaft is fixed to the finger base along the width direction of the finger base, the first fixed shaft is located at the connection part between the middle finger joint and the finger base, and a first gear is fixed to one end of the first fixed shaft; The second bevel gear is fixed to the middle finger joint, and the second bevel gear is loosely sleeved on the other end of the first fixed shaft; The first bevel gear is meshed with the second bevel gear.

5. The underactuated finger according to claim 4, wherein: The transmission mechanism includes a second fixed shaft, a third fixed shaft and a fourth gear; The second fixed shaft is horizontally arranged on the middle finger joint along the width direction of the middle finger joint, a second gear is arranged at one end of the second fixed shaft, the second gear is loosely sleeved on the second fixed shaft, and the second gear is meshed with the first gear; The third fixed shaft is horizontally arranged on the middle finger joint along the width direction of the middle finger joint, a third gear is arranged at one end of the third fixed shaft, the third gear is loosely sleeved on the third fixed shaft, and the third gear is meshed with the second gear; The fourth gear is disposed on one side of the end finger along the width direction, and the fourth gear is meshed with the third gear.

6. The underactuated finger according to claim 3, wherein: The middle finger joint is a U-shaped structure, and the end finger includes a fingertip, a fingertip axis and a tactile sensor; An angle sensor is arranged at one end of the middle knuckle, and the fingertip axis passes through an inner hole of the angle sensor and is arranged at one end of the middle knuckle; One end of the fingertip is arranged at the middle knuckle, and the touch sensor is arranged at the fingertip.

7. The underactuated finger according to claim 3, wherein: One end of the finger base is a U-shaped structure, and is rotatably connected to one end of the middle finger joint; the middle finger joint is a U-shaped structure, and the other end of the middle finger joint is rotatably connected to the terminal finger.

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