High-degree-of-freedom soft hand device with controllable posture and size and working method of high-degree-of-freedom soft hand device

Abstract

The technical scheme of the invention discloses a posture and size controllable high-degree-of-freedom soft hand device and a working method thereof, and the posture and size controllable high-degree-of-freedom soft hand device is characterized by comprising a mounting disc; the base, at least three finger assemblies, a first displacement mechanism, a connecting piece, a second displacement mechanism, a steering engine, a soft finger rotating mechanism, a soft finger and a limiting sleeve penetrate through the soft finger rotating mechanism, one end of the limiting sleeve is connected with the steering engine, and when the steering engine works, the soft finger rotating mechanism is controlled to rotate, and switching of working modes of the soft finger is achieved; and the background controller is electrically connected with and controls the first displacement mechanism, the second displacement mechanism, the steering engine and the pneumatic assembly to enable the three soft fingers to stretch, open, close, rotate and grab. According to the finger assembly, the posture and the size of the gripper can be automatically adjusted according to the shape and the size of a grabbed object, and the purposes of soft and stable clamping and operation of objects of multiple sizes, multiple shapes and multiple materials are achieved. The soft hand is low in manufacturing and using cost, convenient to assemble and suitable for the fields of soft robots and robot learning.

Description

Technical Field

[0001] The present invention relates to the technical field of robot hands, and in particular to a high-freedom soft hand device with controllable posture and size and a working method thereof. Background Art

[0002] Dexterous manipulation has always been an important goal in the field of robotics. The dexterity of human fingers and hands enables us to handle a variety of objects, from simple grasping to complex assembly tasks. However, most robotic manipulation research is limited to using single-degree-of-freedom parallel-claw grippers or suction cup devices as end effectors. Despite recent progress in the design of dexterous robotic hands, such as Shadow Hand, Schunk Hands, and Allegro Hand, they are generally fragile and expensive. In addition, these hands are usually composed of rigid components and require force sensors to ensure safe handling of objects. Existing two-finger or multi-finger rigid grippers, such as Franka Emika and Kinova KG-3, although simple in structure and easy to control, are not suitable for complex tasks due to their limited degrees of freedom.

[0003] Rigid grippers and dexterous hands have difficulty grasping soft and fragile objects directly. To solve this problem, it is usually necessary to wrap soft materials outside the gripper or integrate force sensors on the end effector, which increases the cost of hardware and algorithms. In addition, for objects with complex surfaces, it is difficult for rigid grippers to form an effective contact surface, which often leads to grasping failures. Collisions may also occur during operation, damaging the robot hand, objects, and even threatening the safety of experimenters.

[0004] Soft robotic hands show promise in addressing these issues, especially in flexible grasping and underwater manipulation tasks. There are many types of soft grippers based on the drive mechanism and structural design, such as air-driven, liquid-driven, magnetorheological fluid, shape memory alloy, and cavity-based, tendon-driven, origami-based structures, etc. However, the application of soft robotic hands in the field of robot learning is not yet widespread. Most cutting-edge academic research focuses on the development of new materials and structures, which are difficult and expensive to manufacture, have complex structures, and have high technical barriers. On the other hand, existing commercial soft robotic hands are usually simple in structure, with limited degrees of freedom and flexibility, and do not show obvious advantages over rigid hands in daily manipulation tasks. Summary of the invention

[0005] The purpose of the present invention is to address the limitations of existing soft robotic hands and provide a high degree of freedom soft hand device with controllable posture and size. This is a low-cost, highly flexible soft robotic hand designed for robotic learning research. The finger assembly has an innovative motion structure that significantly enhances adaptability and versatility. Its reconfigurable design of length, opening and closing degree and grasping mode improves the success rate of grasping objects of different sizes. The soft hand is capable of performing a variety of tasks and grasping objects of various sizes and materials. It is composed of off-the-shelf components, is low-cost and easy to assemble.

[0006] In order to solve the above technical problems, the technical solution of the present invention provides a high-degree-of-freedom soft hand device with controllable posture and size, wherein the soft hand device comprises:

[0007] Installation disk;

[0008] A base, connected to the mounting plate;

[0009] At least three finger assemblies are connected below the base in a centrally symmetrical structure, and the finger assemblies include:

[0010] A first displacement mechanism connected to the base;

[0011] A connecting member, movably connected to the first displacement mechanism;

[0012] a second displacement mechanism, connected to the connecting member and in a perpendicular state to the first displacement mechanism, and moving back and forth in a first direction when the first displacement mechanism is in operation;

[0013] A steering gear, fixed to the connecting member;

[0014] a soft finger rotation mechanism connected to the second displacement mechanism and moving back and forth in the second direction when the second displacement mechanism is in operation;

[0015] A soft finger is connected to the soft finger rotating mechanism and moves together with the soft finger rotating mechanism;

[0016] A limiting sleeve passes through the soft finger rotating mechanism and one end of which is connected to the steering gear. When the steering gear is working, the limiting sleeve controls the soft finger rotating mechanism to rotate and realizes the switching of the working mode of the soft finger; and

[0017] The backend controller is electrically connected to and controls the first displacement mechanism, the second displacement mechanism and the steering gear to make the three soft fingers perform extension, opening and closing, rotation and grasping actions.

[0018] Optionally, the mounting plate has a first mounting plate hole, a second mounting plate hole and a mounting plate wire outlet hole, and the base has a base wire outlet hole, a first base hole and a second base hole; the mounting plate and the base are connected by installing fasteners between the second mounting plate hole and the first base hole, the mounting plate wire outlet hole and the base wire outlet hole are used to control the passage of cables, the first mounting plate hole is used to connect the soft hand device to an external robotic arm, and the second base hole is used to connect the first displacement mechanism via fasteners.

[0019] Optionally, the first displacement mechanism comprises:

[0020] a first slide connected to the base;

[0021] A first screw rod, both ends of which are fixed in the first slide;

[0022] A first sliding block is meshedly connected with the first screw rod; and

[0023] A first motor is connected to one end of the first slide and is connected to the first screw rod through a motor shaft;

[0024] The connecting member is connected to the first sliding block.

[0025] Optionally, the second displacement mechanism comprises:

[0026] A second slide, connected to the connecting member;

[0027] A second screw rod, both ends of which are fixed in the second slide and are perpendicular to each other on the same plane as the first screw rod;

[0028] a second slider, meshingly connected with the second screw rod, and

[0029] A second motor is connected to one end of the second slide and is connected to the second lead screw through a motor shaft.

[0030] Optionally, the soft finger rotation mechanism comprises:

[0031] Outer ring;

[0032] The inner ring is concentrically connected to the inner ring of the outer ring through a retaining spring and a bearing, and can rotate around the axis of the outer ring;

[0033] The inner ring is provided with an inner ring air passage that passes through in the up-down direction, and the upper surface and the lower surface of the inner ring are connected to an air pipe and a connector respectively at the inner ring air passage, and the air pipe is connected to a backstage controller and an air pressure source through a main air pipe;

[0034] A first gap and a second gap are formed between the inner ring and the outer ring;

[0035] The soft finger is connected to the connecting head.

[0036] Optionally, the clamping spring includes a first clamping spring and a second clamping spring;

[0037] The inner ring is connected to the bearing through a first clamping spring, and an inner ring convex portion and an inner ring concave portion are formed on the outer side of the inner ring. The first clamping spring is arranged in the inner ring concave portion and clamps the bearing on the outer side of the inner ring with the inner ring convex portion.

[0038] The bearing is fixed to the outer ring by a pair of second retaining springs, a pair of outer ring recesses for accommodating the pair of second retaining springs are formed on the inner side of the outer ring, and the outer ring is also provided with outer ring screw holes, which are connected to the second slider by installing fasteners in the outer ring screw holes;

[0039] The outer ring is in a circular ring structure, and the inner ring is in a structure with cutouts formed on two sides, and the first gap and the second gap are formed between the two cutouts of the inner ring and the inner circle of the outer ring.

[0040] Optionally, the first retaining spring is formed with a first retaining spring recess and a first retaining spring protrusion respectively located at both ends of the first retaining spring recess, the two first retaining spring protrusions bite the inner ring with each other, the first retaining spring protrusion is immersed in the inner ring recess, and the second gap is formed between the first retaining spring recess, the inner ring of the outer ring and the cutout of the inner ring.

[0041] Optionally, one end of the limiting sleeve is connected to the servo through a wheel disc, and the other end is formed with a first side of the limiting sleeve and a second side of the limiting sleeve, and the first side of the limiting sleeve and the second side of the limiting sleeve respectively pass through the first gap and the second gap to be connected to the soft finger rotation mechanism.

[0042] Optionally, the soft finger is a hollow structure composed of multiple interconnected air chamber units. When the air pressure source delivers positive pressure, the soft finger contracts in the positive direction; when the air pressure source delivers negative pressure, the soft finger contracts in the reverse direction; when the air pressure source delivers atmospheric pressure, the soft finger is in a natural non-contracted state.

[0043] In order to solve the above technical problems, the technical solution of the present invention further provides a working method of a high-degree-of-freedom soft hand device with controllable posture and size according to any one of the above items, wherein the working method is as follows:

[0044] When the soft finger needs to bend inward, the background controller controls the air pressure source to deliver positive pressure;

[0045] When the soft finger needs to bend outward, the background controller controls the air pressure source to deliver negative pressure;

[0046] When the natural state of the soft finger is required, the background controller controls the air pressure source to deliver atmospheric pressure;

[0047] When the soft finger needs to change the working mode, the background controller controls the steering gear to rotate, the steering gear drives the limiting sleeve to rotate, and the limiting sleeve drives the soft finger rotating mechanism to rotate so that the soft finger rotates and changes the working mode.

[0048] The beneficial effects of the technical solution of the present invention are:

[0049] The finger assembly of the present invention can autonomously adjust the posture and size of the gripper according to the shape and size of the grasped object, so as to achieve the purpose of soft and stable gripping and operation of objects of multiple sizes, shapes and materials. The soft hand has low manufacturing and use costs, is easy to assemble, and is suitable for the fields of soft robots and machine learning. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 is a three-dimensional diagram of a soft hand device according to an embodiment of the present invention;

[0051] Figure 2 is a three-dimensional diagram of a finger assembly in an embodiment of the present invention;

[0052] Figure 3 is a three-dimensional diagram of a mounting plate in an embodiment of the present invention;

[0053] Figure 4 is a three-dimensional diagram of a base in an embodiment of the present invention;

[0054] Figure 5 A three-dimensional diagram of a soft finger rotation mechanism in an embodiment of the present invention;

[0055] Figure 6 is a top view of the soft finger rotation mechanism in an embodiment of the present invention;

[0056] Figure 7 for Figure 6 Middle AA section view;

[0057] Figure 8 is a stereogram of the inner ring in an embodiment of the present invention;

[0058] Fig. 9 is a stereogram of the outer ring in an embodiment of the present invention;

[0059] Fig.10 A three-dimensional diagram of a first clip spring in an embodiment of the present invention;

[0060] Fig.11 is a three-dimensional diagram of a second clip spring in an embodiment of the present invention;

[0061] Fig.12 is a three-dimensional diagram of a connecting member in an embodiment of the present invention;

[0062] Fig.13 is a three-dimensional diagram of a first displacement mechanism in an embodiment of the present invention;

[0063] Fig.14 is a three-dimensional diagram of a second displacement mechanism in an embodiment of the present invention;

[0064] Fig.15 A three-dimensional diagram of a restriction sleeve in an embodiment of the present invention;

[0065] Fig.16 A three-dimensional diagram of a soft finger in an embodiment of the present invention;

[0066] Fig.17 FIG. 4 is an exploded view of a soft hand device according to an embodiment of the present invention.

[0067] In the accompanying drawings: 1. mounting plate, 11. first mounting plate hole, 12. mounting plate outlet hole, 13. second mounting plate hole, 2. base, 21. base outlet hole, 22. first base hole, 23. second base hole, 3. finger assembly, 31. servo, 311. servo gear, 312. wheel, 32. first displacement mechanism, 321. first displacement mechanism screw hole, 322. first motor, 323. first slider, 324. first screw rod, 325. first slide, 33. connector, 331. first connector hole, 332. second connector hole, 333. third connector hole, 34. second displacement mechanism, 341. second displacement mechanism screw hole, 342. second motor, 343. second slider, 344. second screw rod, 345. second slider Table, 35, soft finger rotation mechanism, 351, inner ring, 3511, inner ring airway, 3512, connector, 3513, inner ring convex portion, 3514, inner ring concave portion, 352, outer ring, 3521, outer ring screw hole, 3522, outer ring concave portion, 353, air pipe, 354, first retaining spring, 3541, first retaining spring convex portion, 3542, first retaining spring concave portion, 355, bearing, 356, second retaining spring, 357, first gap, 358, second gap, 36, limiting sleeve, 361, limiting sleeve concave portion, 362, limiting sleeve screw hole, 363, limiting sleeve second side, 364, limiting sleeve first side, 37, soft finger, 371, soft finger fingertip, 372, air chamber unit, 373, soft finger air port, 374, contact surface, 38, incision. DETAILED DESCRIPTION

[0068] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0069] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0070] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0071] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0072] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0073] See also Figure 1 , Figure 2 and Fig.17FIG. 1 shows a high-degree-of-freedom soft hand device with controllable posture and size according to an embodiment, wherein the soft hand device comprises a mounting plate 1; a base 2 connected to the mounting plate 1; at least three finger assemblies 3 connected below the base 2 in a centrally symmetrical structure, and the finger assemblies 3 comprise a first displacement mechanism 32 connected to the base 2; a connecting member 33 movably connected to the first displacement mechanism 31; a second displacement mechanism 34 connected to the connecting member 33 and in a mutually perpendicular state to the first displacement mechanism 32, and when the first displacement mechanism 32 is working, the finger assemblies 3 are moved in a first direction B (such as Figure 2 servo 31, fixed to the connecting member 33; soft finger rotation mechanism 35, connected to the second displacement mechanism 34, when the second displacement mechanism 34 is working, in the second direction C (as shown); Figure 2 The soft finger 37 is connected to the soft finger rotating mechanism 35 and moves together with the soft finger rotating mechanism 35; the limiting sleeve 36 passes through the soft finger rotating mechanism 35 and one end is connected to the steering gear 31. When the steering gear 31 is working, the soft finger rotating mechanism 35 is controlled to rotate and the working mode of the soft finger 37 is switched; and the background controller (not shown) is electrically connected to and controls the first displacement mechanism 32, the second displacement mechanism 34 and the steering gear 31 to make the three soft fingers 37 extend, open and close, rotate and grasp.

[0074] In this embodiment, Figure 3 and Figure 4 As shown, the mounting plate 1 has a first mounting plate hole 11, a second mounting plate hole 13 and a mounting plate wire outlet hole 12, and the base 2 has a base wire outlet hole 21, a first base hole 22 and a second base hole 23; the mounting plate 1 and the base 2 are connected by installing fasteners (not shown) between the second mounting plate hole 13 and the first base hole 22, the mounting plate wire outlet hole 12 and the base wire outlet hole 21 are used to control the passage of cables (not shown), the first mounting plate hole 11 is used to connect the soft hand device to an external robotic arm (not shown), and the second base hole 23 is used to connect the first displacement mechanism 32 through fasteners (not shown).

[0075] In this embodiment, Fig.13 As shown, the first displacement mechanism 32 includes a first slide 325 connected to the base 2; a first screw rod 324, both ends of which are fixed in the first slide 325; a first slider 323, meshingly connected to the first screw rod 324; and a first motor 322, which is connected to one end of the first slide 325 and connected to the first screw rod 324 through a motor shaft; wherein the connecting member 33 is connected to the first slider 323.

[0076] In this embodiment, Fig.14As shown, the second displacement mechanism 34 includes a second slide 345, which is connected to the connecting member 33; a second screw rod 344, both ends of which are fixed in the second slide 345 and are perpendicular to the first screw rod 324 on the same plane; a second slider 343, which is meshed and connected to the second screw rod 344, and a second motor 342, which is connected to one end of the second slide 343 and connected to the second screw rod 344 through a motor shaft.

[0077] In this embodiment, Figure 5 , Figure 6 and Figure 7 As shown, the soft finger rotating mechanism 35 includes an outer ring 352; an inner ring 351, which is concentrically connected to the inner ring of the outer ring 352 through a retaining ring and a bearing 355, and can rotate around the axis of the outer ring 352; wherein the interior of the inner ring 351 is provided with an inner ring airway 3511 which passes through in the up and down directions, and the upper surface and the lower surface of the inner ring 351 are respectively connected to the air pipe 353 and the connector 3512 at the inner ring airway 3511, and the air pipe 353 is connected to the background controller and the air pressure source through the main air pipe (not shown); a first gap 357 and a second gap 358 are formed between the inner ring 351 and the outer ring 352; the soft finger 37 is connected to the connector 3512.

[0078] In this embodiment, Figure 5 , Figure 6 , Figure 7 , Figure 8 , Fig. 9 , Fig.10 and Fig.11 As shown, the retaining spring includes a first retaining spring 354 and a second retaining spring 356; the inner ring 351 is connected to the bearing 355 through the first retaining spring 354, and the outer side of the inner ring 351 is formed with an inner ring convex portion 3513 and an inner ring concave portion 3514, the first retaining spring 354 is arranged in the inner ring concave portion 3514 and clamps the bearing 355 outside the inner ring 351 with the inner ring convex portion 3513; the bearing 355 is fixed to the outer ring 352 through a pair of second retaining springs 356, and the inner ring 352 is fixed to the outer ring 352. A pair of outer ring recesses 3522 for accommodating a pair of second retaining springs 356 are formed on the side, and the outer ring 352 is also provided with an outer ring screw hole 3521, which is connected to the second slider 343 by installing fasteners (not shown) in the outer ring screw hole 3521; the outer ring 352 is a circular ring structure, and the inner ring 351 is a structure with cutouts 38 formed on both sides, and a first gap 357 and a second gap 358 are formed between the two cutouts 38 of the inner ring 351 and the inner circle of the outer ring 352.

[0079] In this embodiment, Figure 6 and Fig.10As shown, the first retaining spring 354 is formed with a first retaining spring recess 3542 and first retaining spring protrusions 3541 respectively located at both ends of the first retaining spring recess 3542, the two first retaining spring protrusions 3541 engage with each other to hold the inner ring 351, the first retaining spring protrusions 3541 are immersed in the inner ring recess 3514, and a second gap 358 is formed between the first retaining spring recess 3542, the inner ring of the outer ring 352 and the cutout 38 of the inner ring 351.

[0080] In this embodiment, Fig.15 and Fig.17 As shown, one end of the limiting sleeve 36 is connected to the servo 31 through the wheel 312, and the other end is formed with a limiting sleeve first side 364 and a limiting sleeve second side 363, which pass through the first gap 357 and the second gap 358 respectively and are connected to the soft finger rotation mechanism 35.

[0081] In this embodiment, Fig.16 As shown, the soft finger 37 is a cavity structure composed of a plurality of interconnected air chamber units 372. When the air pressure source delivers positive pressure, the soft finger 37 contracts in the positive direction. When the air pressure source delivers negative pressure, the soft finger 37 contracts in the reverse direction. When the air pressure source delivers atmospheric pressure, the soft finger 37 is in a natural non-contracted state.

[0082] In this embodiment, a working method of a high-degree-of-freedom soft hand device with controllable posture and size according to any of the above items is also provided, wherein the working method is as follows:

[0083] When the soft finger 37 is required to bend inward, the background controller controls the air pressure source to deliver positive pressure;

[0084] When the soft finger 37 is required to bend outward, the background controller controls the air pressure source to deliver negative pressure;

[0085] When the natural state of the soft finger 37 is required, the background controller controls the air pressure source to deliver atmospheric pressure;

[0086] When the soft finger 37 needs to change the working mode, the background controller controls the servo 31 to rotate, the servo 31 drives the limiting sleeve 36 to rotate, and the limiting sleeve 36 drives the soft finger rotating mechanism 35 to rotate so that the soft finger 37 rotates and changes the working mode.

[0087] The characteristics and functions of the present invention will be further understood through the following description.

[0088] The soft finger 37 of the high-degree-of-freedom soft hand device with controllable posture and size in this embodiment is a silicone gripper, which can be made of special silicone with high airtightness. This silicone material is soft and elastic and has anti-stick properties. Nitrile silicone, silicone, and polyurethane silicone are preferably used. The finger assembly 3 includes a base 2, a steering gear 31, a first slide 325, a connector 33, a second slide 345, and a soft finger 37 arranged in order from top to bottom.

[0089] During production, the soft finger 34 is first produced by the casting molding method, and the soft finger 34, the air pipe 353 and the inner ring 351 are bonded together by an adhesive; the inner ring 351, the outer ring 352 and the bearing 355 are combined together by a retaining ring; the outer ring 352 and the second slide 345, the connecting piece 33 and the first slide 325 are fixed together by screws; the servo 31, the wheel 312, the limiting sleeve 36, the connecting piece 33, the first slide 325 and the second slide 345 are combined together by screws.

[0090] Before use, the air tubes of each finger can be connected to one air tube through a multi-way piece, and then connected to the pneumatic assembly, so as to simultaneously fill each finger with gas from the same air source. This method is cheap, simple, stable and has a fast response speed. Alternatively, each finger can be connected to the pneumatic assembly through an air tube to independently fill each finger with gas.

[0091] The air source can be a pump-in-one, a "positive pressure air source + negative pressure air source" or a combination of "positive pressure air source + vacuum generator".

[0092] The air source is connected to a pneumatic triplet, a pressure regulating valve or an electrical proportional valve to adjust the air pressure in the passage.

[0093] The pneumatic components consist of relays and solenoid valves within the master controller.

[0094] The action process of the soft pneumatic gripper provided in this embodiment is as follows:

[0095] Finger component posture and size adjustment stage

[0096] According to the size, shape and material of the object, the posture and size of the finger assembly are automatically adjusted. Specifically, the screw stepper motor slide A controls the width of the soft hand, the screw stepper motor slide B controls the length of the soft hand, and the servo controls the angle of the finger around the axis to control the grasping mode and posture of the soft hand.

[0097] Finger negative pressure inhalation stage

[0098] The function of negative pressure suction of fingers is to make the fingers contract outward, thereby expanding the grasping range of the soft hand and facilitating the soft hand to approach the target object; negative pressure suction of fingers can also be used to apply grasping force from the inside of the object to grasp the object. When the relay turns on the solenoid valve of the negative pressure pipeline and cuts off the solenoid valves of the positive pressure and atmospheric pressure pipelines, the gas in the finger is sucked out and the air chamber contracts, but the length of the strain limiting layer of the finger does not change, so the finger contracts outward, which is manifested as the soft hand expanding outward.

[0099] Finger positive pressure inflation stage

[0100] The function of positive pressure inflation of fingers is to make the fingers close inwards, so as to grasp or manipulate objects. Increasing the positive pressure can improve the grasping force of the fingers. When the relay turns on the solenoid valve of the positive pressure pipeline and cuts off the solenoid valves of the negative pressure and atmospheric pressure pipelines, gas is filled into the fingers, the air chambers expand, and the air chambers squeeze each other, but the length of the strain limiting layer of the fingers does not change, so the fingers shrink inwards, which is manifested as the soft hand closing inwards.

[0101] Clamping stage

[0102] After clamping the object, the soft fingers remain inflated to hold the object stably.

[0103] Unclamping stage

[0104] After the clamping action is completed, when the clamping state needs to be released, the gas in each finger is released, or the gas in the finger is extracted using negative pressure, so that the finger assembly releases the object and the clamping operation ends.

[0105] Stress release phase

[0106] When the soft hand is finished, the pressure in the system needs to be balanced with the atmospheric pressure, which helps to extend the service life of the whole machine. When the relay connects the solenoid valve of the atmospheric pressure pipeline and cuts off the solenoid valves of the positive and negative pressure pipelines, the system is connected to the atmospheric pressure, the air pressure is released, and the fingers return to the natural non-contracted state.

[0107] The components of the soft hand device of this embodiment are further explained in detail below.

[0108] The mounting plate 1 is used to connect and fix the soft hand device to the end flange of the robot arm; the base 2 has three finger assemblies 3 symmetrically fixed along the central axis on the base 2; the finger assembly 3 is composed of a servo 31, a first displacement mechanism 32, a second displacement mechanism 34, a connecting piece 33, a soft finger rotation mechanism 35, a limiting sleeve 36 and a soft finger 37; the first displacement mechanism 31 drives the soft finger 37 to move in the horizontal direction, the second displacement mechanism drives the soft finger 37 to move in the vertical direction, the servo 31 drives the soft finger 37 to rotate along the finger axis, and the connecting piece 33 connects the first displacement mechanism 32, the second displacement mechanism 34 and the servo 31.

[0109] The first mounting plate hole 11 is used to fix the mounting plate 1 and the flange surface of the robot arm, the second mounting plate hole 13 and the first base hole 22 are used to fix the mounting plate 1 and the base 2, and the second base hole 23 is used to fix the first displacement mechanism 32 on the base 2. The wires of the first motor 322, the second motor 342 and the steering gear 31 and the main air pipe are led out through the base outlet hole 21 and the mounting plate outlet hole 12.

[0110] The soft finger rotating mechanism 35 is composed of an outer ring 352, an inner ring 351, a first retaining spring 354, a second retaining spring 356 and a bearing 355. First, the bearing 355 is placed on the inner ring convex portion 3513, and then the first retaining spring 354 is inserted into the inner ring concave portion 3514 to complete the assembly and fixation of the inner side of the bearing 355 and the inner ring 351. Then, the bearing 355 is placed between the two outer ring concave portions 3522, and the two second retaining springs 356 are inserted into the corresponding outer ring concave portions 3522 to complete the assembly and fixation of the outer side of the bearing 355 and the outer ring 352. After installation, the inner ring 351 can rotate freely relative to the outer ring 352 along the axial direction. The first retaining spring convex portion 3541 cooperates with the inner ring concave portion 3514, and the design purpose of the first retaining spring concave portion 3542 is to allow the first side 364 of the limiting sleeve and the second side 363 of the limiting sleeve to pass through the first gap 357 and the second gap 358 smoothly without interference.

[0111] The air pipe 353 is connected to the inner ring airway 3511 and sealed, and the connector 3512 is connected to the soft air port 373 (such as Fig.16 A four-way joint is used to connect the main air pipe to the three air pipes 353, and the air pressure is transmitted to the soft finger 37 via the route of "air pressure source → controller → main air pipe → air pipe → inner ring airway → soft finger".

[0112] The soft finger rotating mechanism 35 is fixed on the second sliding block 343 via the outer ring screw hole 3521 .

[0113] The first displacement mechanism screw hole 321 of the first displacement mechanism 32 , the steering gear 31 and the second displacement mechanism screw hole 341 of the second displacement mechanism 34 are respectively fixedly assembled on the connecting member 33 through the first connecting member hole 331 , the second connecting member hole 332 and the third connecting member hole 333 .

[0114] The soft finger 37 is composed of a plurality of air chamber units 372 of the soft finger connected in series. When positive pressure is applied, the air chambers expand and squeeze each other, and the soft fingers bend in the direction of the contact surface; when negative pressure is applied, the air chambers contract, and the soft fingers bend in the opposite direction of the contact surface. The soft finger tip 371 is designed to be an arc shape, which is convenient for grasping small objects. The contact surface 374 is designed with anti-slip grooves.

[0115] See also Fig.17 As shown, the first displacement mechanism 32 and the second displacement mechanism 34 are both a combination of "screw guide rail slide + motor", and the motor can be a variety of motors, such as stepper motors, servo motors, etc. The principle is as follows: the second motor 342 drives the second screw 344, so that the second slider 343 moves linearly along the second screw 344, and the second slider 343 is connected to the soft finger rotation mechanism 35, so that the soft finger 37 is displaced in the vertical direction, which is macroscopically manifested as the soft finger 37 "extending and retracting"; the first motor 322 drives the first screw 324, so that the first slider 323 moves linearly along the first screw 324, and the first slider 323 is connected to the connecting member 33, so that the soft finger 37 is displaced in the horizontal direction, which is macroscopically manifested as the soft finger 37 "opening and closing".

[0116] The limiting sleeve 36 is fixed to the wheel disc 312 through the limiting sleeve screw hole 362, and the other side of the wheel disc 312 is fixedly assembled with the steering gear 311. The limiting sleeve first side 364 and the limiting sleeve second side 363 pass through the first gap 357 and the second gap 358 respectively. The limiting sleeve recess 361 is to allow the air pipe 353 to pass smoothly without being squeezed or interfered with the limiting sleeve 36.

[0117] The limiting sleeve 36 has the following functions: ① transmitting rotational force; ② limiting the deformation of the part of the soft finger 37 inside the limiting sleeve 36, so that the deformation of the soft finger 37 only occurs in the part of the soft finger 37 outside the limiting sleeve 36, which is beneficial to improving the grasping accuracy of the soft hand device; ③ providing a certain rigidity support for the soft finger 37.

[0118] The rotational motion is transmitted from the servo to the soft finger via the route of "servo → wheel → limiting sleeve → inner ring → soft finger", causing the soft finger to rotate along the finger axis, which is manifested macroscopically as the soft hand device changing different "grasping modes".

[0119] In summary, the finger assembly of the present invention can autonomously adjust the posture and size of the gripper according to the shape and size of the grasped object, so as to achieve the purpose of soft and stable gripping and operation of objects of multiple sizes, shapes and materials. The soft hand has low manufacturing and use costs, is easy to assemble, and is suitable for the fields of soft robots and robot learning.

[0120] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-degree-of-freedom soft hand device with controllable posture and size, characterized in that: The software hand device comprises: Installation disk; A base, connected to the mounting plate; At least three finger assemblies are connected below the base in a centrally symmetrical structure, and the finger assemblies include: A first displacement mechanism connected to the base; A connecting member, movably connected to the first displacement mechanism; a second displacement mechanism, connected to the connecting member and in a perpendicular state to the first displacement mechanism, and moving back and forth in a first direction when the first displacement mechanism is in operation; A steering gear, fixed to the connecting member; a soft finger rotation mechanism connected to the second displacement mechanism and moving back and forth in the second direction when the second displacement mechanism is in operation; A soft finger is connected to the soft finger rotating mechanism and moves together with the soft finger rotating mechanism; A limiting sleeve passes through the soft finger rotating mechanism and one end of which is connected to the steering gear. When the steering gear is working, the soft finger rotating mechanism is controlled to rotate and the working mode of the soft finger is switched; and The background controller is electrically connected to and controls the first displacement mechanism, the second displacement mechanism, the steering engine and the pneumatic assembly to make the three soft fingers perform extension, opening and closing, rotation and grasping actions.

2. The high-degree-of-freedom soft hand device with controllable posture and size according to claim 1, characterized in that: The mounting plate has a first mounting plate hole, a second mounting plate hole and a mounting plate wire outlet hole, and the base has a base wire outlet hole, a first base hole and a second base hole; the mounting plate and the base are connected by installing fasteners between the second mounting plate hole and the first base hole, the mounting plate wire outlet hole and the base wire outlet hole are used to control the passage of cables, the first mounting plate hole is used to connect the soft hand device to an external robotic arm, and the second base hole is used to connect the first displacement mechanism through fasteners.

3. The high-degree-of-freedom soft hand device with controllable posture and size according to claim 2, characterized in that: The first displacement mechanism comprises: a first slide connected to the base; A first screw rod, both ends of which are fixed in the first slide; A first sliding block is meshedly connected with the first screw rod; and A first motor is connected to one end of the first slide and is connected to the first screw rod through a motor shaft; The connecting member is connected to the first sliding block.

4. The high-degree-of-freedom soft hand device with controllable posture and size according to claim 3, characterized in that: The second displacement mechanism comprises: A second slide, connected to the connecting member; A second screw rod, both ends of which are fixed in the second slide and are perpendicular to each other on the same plane as the first screw rod; a second slider, meshingly connected with the second screw rod, and A second motor is connected to one end of the second slide and is connected to the second lead screw through a motor shaft.

5. The high-degree-of-freedom soft hand device with controllable posture and size according to claim 4, characterized in that: The soft finger rotation mechanism comprises: Outer ring; The inner ring is concentrically connected to the inner ring of the outer ring through a retaining spring and a bearing, and can rotate around the axis of the outer ring; The inner ring is provided with an inner ring air passage that passes through in the up-down direction, and the upper surface and the lower surface of the inner ring are connected to an air pipe and a connector respectively at the inner ring air passage, and the air pipe is connected to a backstage controller and an air pressure source through a main air pipe; A first gap and a second gap are formed between the inner ring and the outer ring; The soft finger is connected to the connecting head.

6. The high-degree-of-freedom soft hand device with controllable posture and size according to claim 5, characterized in that: The clamping spring comprises a first clamping spring and a second clamping spring; The inner ring is connected to the bearing through the first clamping spring, and an inner ring convex portion and an inner ring concave portion are formed on the outer side of the inner ring. The first clamping spring is arranged in the inner ring concave portion and clamps the bearing on the outer side of the inner ring with the inner ring convex portion. The bearing is fixed to the outer ring by a pair of the second retaining springs, a pair of outer ring recesses for accommodating the pair of the second retaining springs are formed on the inner side of the outer ring, and the outer ring is also provided with an outer ring screw hole, and is connected to the second slider by installing fasteners in the outer ring screw holes; The outer ring is in a circular ring structure, and the inner ring is in a structure with cutouts formed on two sides, and the first gap and the second gap are formed between the two cutouts of the inner ring and the inner circle of the outer ring.

7. The high-degree-of-freedom soft hand device with controllable posture and size according to claim 6, characterized in that: The first retaining spring is formed with a first retaining spring recess and first retaining spring protrusions respectively located at both ends of the first retaining spring recess, the two first retaining spring protrusions bite the inner ring with each other, the first retaining spring protrusions are immersed in the inner ring recess, and the second gap is formed between the first retaining spring recess, the inner ring of the outer ring and the cutout of the inner ring.

8. The high-degree-of-freedom soft hand device with controllable posture and size according to claim 7, characterized in that: One end of the limiting sleeve is connected to the servo through a wheel disc, and the other end is formed with a first side of the limiting sleeve and a second side of the limiting sleeve. The first side of the limiting sleeve and the second side of the limiting sleeve respectively pass through the first gap and the second gap to be connected to the soft finger rotation mechanism.

9. The high-degree-of-freedom soft hand device with controllable posture and size according to claim 8, characterized in that: The soft finger is a cavity structure composed of multiple interconnected air chamber units. When the air pressure source delivers positive pressure, the soft finger contracts in the positive direction. When the air pressure source delivers negative pressure, the soft finger contracts in the negative direction. When the air pressure source delivers atmospheric pressure, the soft finger is in a natural non-contracted state.

10. A method for operating a high-degree-of-freedom soft hand device with controllable posture and size according to any one of claims 1 to 9, characterized in that: The working method is as follows: When the soft finger is required to bend inward, the background controller controls the air pressure source to deliver positive pressure; When the soft finger needs to bend outward, the background controller controls the air pressure source to deliver negative pressure; When the natural state of the soft finger is required, the background controller controls the air pressure source to deliver atmospheric pressure; When the soft finger needs to change the working mode, the background controller controls the steering gear to rotate, the steering gear drives the limiting sleeve to rotate, and the limiting sleeve drives the soft finger rotating mechanism to rotate so that the soft finger rotates and changes the working mode.

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