Lockable array needle type mechanical finger for grabbing closely arranged objects

Abstract

The invention discloses a lockable array needle type mechanical finger used for grabbing closely arranged objects. Comprising a base and further comprises mechanical fingers movably arranged on the base. The mechanical finger comprises a shell, a flexible cavity, a movable needle and blocking particles, the movable needle is connected to the shell in a sliding mode, the shell is provided with a gas connector, the flexible cavity is arranged in the shell, the interior of the shell is divided into a blocking cavity and a gas cavity which are not communicated with each other through the flexible cavity, the gas cavity is communicated with the gas connector, and the blocking particles are arranged in the blocking cavity. The end of the movable needle is located in the blocking cavity, and the blocking particles are arranged in the blocking cavity. According to the lockable array needle type mechanical finger for grabbing the closely arranged objects, under the condition that the objects are closely arranged, the mechanical finger can effectively solve the problem that grabbing is difficult due to the fact that the shape of a traditional mechanical finger is fixed, smooth sliding of the movable needles can be guaranteed, and the mechanical finger can be used for grabbing the closely arranged objects. And unstable grabbing caused by an overlarge gap between the movable needles is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical hand production, in particular to a lockable array needle type mechanical hand finger for closely arranged object grabbing. BACKGROUND

[0002] Robot grasping technology is one of the core topics in the field of robot research, and its main goal is to achieve reliable operation of objects with different shapes and sizes in different environments.

[0003] According to the invention patent application with publication number CN111571626A and publication date of August 25, 2020, a mechanical finger and a mechanical hand are disclosed. Among them, the mechanical finger includes a finger body assembly, a matching assembly and a driving assembly; wherein the matching assembly includes an assembly body, an elastic element, a variable magnetic assembly and a limiting connecting piece; the finger body assembly is connected to the assembly body through the limiting connecting piece; and the first surface corresponds to the assembly body; the elastic element is located between the assembly body and the finger body assembly, and the elastic element is in a compressed state, thereby forming an elastic pre-stress; one of the variable magnetic part and the first magnetic matching part is arranged on the assembly body, and the other is arranged on the finger body assembly; when the first magnetic attraction force is generated between the variable magnetic part and the first magnetic matching part, the first magnetic attraction force overcomes the elastic pre-stress, and the finger body assembly is close to the assembly body. The main technical effect is that the mechanical finger can quickly release the target object.

[0004] In the prior art, when closely arranged objects are grabbed, suction cup type, customized fingers, magnetic fingers, etc. can be used. Integrated suction cups or vacuum suction cups are used to grab objects, and the end effector realizes non-contact grabbing by using Bernoulli effect in fluid mechanics. It cannot grab porous, breathable, ultra-thin or irregularly shaped objects. According to the gap, the cost of the customized mechanical finger is high, and in order to adapt to the gap, the thickness of the parallel finger will be designed according to the gap width, which affects the structural strength. The magnetic finger can only grab ferromagnetic objects. Therefore, a lockable array needle type mechanical hand finger for closely arranged object grabbing is proposed to solve the problem that the prior art cannot efficiently and conveniently grab closely arranged objects. SUMMARY

[0005] The purpose of the present application is to provide a lockable array needle type mechanical hand finger for closely arranged object grabbing, which aims to solve the problem that the prior art cannot efficiently and conveniently grab closely arranged objects.

[0006] In order to achieve the above purpose, the present application provides the following technical scheme: A lockable array needle type mechanical hand finger for closely arranged object grabbing, comprising a base, further comprising a mechanical hand finger movably arranged on the base; The mechanical finger comprises a shell, a flexible cavity, a movable needle and a blocking particle, the movable needle is slidingly connected to the shell, the shell is provided with a gas interface, the flexible cavity is arranged inside the shell, the inside of the shell is divided into a blocking cavity and a gas cavity which are not communicated with each other by the flexible cavity, the gas cavity is communicated with the gas interface, the end of the movable needle is located inside the blocking cavity, and the blocking particle is arranged in the blocking cavity.

[0007] Preferably, the shell comprises a positioning cavity and a forming cavity, the positioning cavity is connected with the forming cavity, and the flexible cavity is arranged in the forming cavity.

[0008] Preferably, the end of the movable needle is provided with a needle set sleeve, an elastic unit is arranged between the needle set sleeve and the positioning cavity, and the elastic unit is sleeved on the movable needle.

[0009] Preferably, the number of the movable needles is several, and the several movable needles are arranged in an array.

[0010] Preferably, the number of the mechanical fingers is several, and the several mechanical fingers are arranged on the base in an array.

[0011] Preferably, the base is provided with a gas pump, and the gas pump is communicated with the gas interface.

[0012] In the above technical solution, the present application provides a lockable array needle type mechanical finger for closely arranged object grabbing, which has the following beneficial effects: Firstly, by changing the gas pressure in the gas cavity, the locking and releasing of the movable needle can be flexibly controlled, so that the mechanical finger can adaptively grab different objects according to their shapes, greatly enhancing the flexibility and adaptability of grabbing. Especially in the case of closely arranged objects, this adaptive grabbing ability is particularly important, which can effectively avoid the problem of difficult grabbing caused by the fixed shape of traditional mechanical fingers.

[0013] Secondly, the mechanical finger structure is designed ingeniously, the blocking particle is aggregated and locked by the deformation of the flexible cavity, which is stable and reliable, and ensures the accurate execution of the grabbing action. At the same time, the gap design between the movable needle and the inner wall of the blocking cavity ensures the smooth sliding of the movable needle, and avoids the problem of unstable grabbing caused by the too large gap between the movable needles. BRIEF DESCRIPTION OF DRAWINGS

[0014] In order to make the technical scheme of the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments will be briefly introduced. Obviously, the accompanying drawings in the following description only aim to explain some embodiments of the present application, and other drawings can also be obtained by those skilled in the art based on these drawings.

[0015] Figure 1 The overall structural schematic diagram provided by the embodiment of the present application is shown in the figure. Figure 2 The three-dimensional structural schematic diagram of the mechanical finger provided by the embodiment of the present application is shown in the figure. Figure 3 The planar structural schematic diagram of the mechanical finger provided by the embodiment of the present application is shown in the figure. Figure 4 The schematic diagram of the mechanical finger grabbing closely arranged objects provided by the embodiment of the present application is shown in the figure.

[0016] Explanation of the reference signs: 1, base; 2, mechanical finger; 21, outer shell; 211, positioning cavity; 212, shaped cavity; 213, cover plate; 214, fixing plate; 215, cavity positioning piece; 22, flexible cavity; 23, movable needle; 24, movable particle; 25, gas interface; 26, blocking cavity; 27, gas cavity; 28, needle group sleeve; 29, elastic unit. DETAILED DESCRIPTION

[0017] In order to make those skilled in the art better understand the technical scheme of the present application, the present application will be further described in detail below with reference to the accompanying drawings.

[0018] Please refer to Figure 1 — Figure 4 A lockable array needle type mechanical finger for grabbing closely arranged objects, comprising a base 1, further comprising a mechanical finger movably arranged on the base 1. The mechanical finger 2 comprises an outer shell 21, a flexible cavity 22, a movable needle 23 and a blocking particle 24. The movable needle 23 is slidably connected to the outer shell 21. The outer shell 21 is provided with a gas interface 25. The flexible cavity 22 is arranged inside the outer shell 21. The inside of the outer shell 21 is divided into a blocking cavity 26 and a gas cavity 27 which are not connected to each other by the flexible cavity 22. The gas cavity 27 is connected to the gas interface 25. The end of the movable needle 23 is located inside the blocking cavity 26. The blocking particle 24 is arranged inside the blocking cavity 26.

[0019] As an embodiment provided by the present application, the shell 21 comprises a positioning cavity 211 and a shaped cavity 212, the positioning cavity 211 is connected with the shaped cavity 212, a cover plate 213 is fixedly installed on the outer wall of one side of the shaped cavity 212, the flexible cavity 22 is arranged inside the shaped cavity 212, the inside of the shaped cavity 212 is divided into the blocking cavity 26 and the gas cavity 27 which are not communicated with each other by the flexible cavity 22, the gas cavity 27 is communicated with the gas interface 25 arranged on the shell 21, the flexible cavity 22 is located inside the shaped cavity 212, and the shaped cavity 212 is closed by the cover plate 213, so that the flexible cavity 22 can be fixed in the shaped cavity 212.

[0020] The flexible cavity 22 is fixedly installed in the shaped cavity 212, so as to ensure the stability of the flexible cavity 22 in the shaped cavity 212. The end of the movable needle 23 extends into the blocking cavity 26 and keeps a certain gap with the inner wall of the blocking cavity 26, so as to facilitate the sliding of the movable needle 23 in the blocking cavity 26. The blocking particles 24 are filled in the blocking cavity 26 and are in contact with the inner wall of the blocking cavity 26 and the end of the movable needle 23. When the gas pressure in the gas cavity 27 changes, the flexible cavity 22 will deform, so as to push the flexible cavity 22 to deform and extrude the blocking particles 24, the blocking particles 24 are gathered and abut against the end of the movable needle 23, the movable needle 23 is locked, and the shape adaptation of the grasped object is realized. Then the plurality of mechanical fingers 2 arranged on the base 1 keep moving towards each other to grasp the object.

[0021] The present application has the following beneficial effects: Firstly, the locking and releasing of the movable needle 23 can be flexibly controlled through the change of the gas pressure in the gas cavity 27, so that the mechanical fingers 2 can adaptively grasp different objects according to the shapes of the objects, and the flexibility and adaptability of grasping are greatly enhanced. Especially in the case that the objects are closely arranged, the adaptive grasping ability is particularly important, which can effectively avoid the grasping difficulty problem caused by the fixed shape of the traditional mechanical fingers.

[0022] Secondly, the mechanical fingers 2 are designed ingeniously, the blocking particles 24 are gathered and locked by the deformation of the flexible cavity 22 to push the movable needle 23, the process is stable and reliable, and the accurate execution of the grasping action is ensured. At the same time, the gap between the movable needle 23 and the inner wall of the blocking cavity 26 is designed, which not only ensures the smooth sliding of the movable needle 23, but also avoids the unstable grasping problem caused by the too large gap between the movable needles 23.

[0023] As an embodiment provided by the present invention, the positioning cavity 211 is connected to the molding cavity 212, the flexible cavity 22 is arranged in the molding cavity 212, and the movable needle 23 is slidably connected to the positioning cavity 211. Specifically, a cover plate 213 installed on the molding cavity 212 is provided with a plurality of through holes, and the end of the movable needle 23 passes through the through holes and can maintain free sliding in the through holes.

[0024] A fixing plate 214 is fixedly installed on the outer wall of the positioning cavity 211, and a cavity positioning piece 215 is provided between the fixing plate 214 and the cover plate 213. The molding cavity 212, the cover plate 213, the fixing plate 214 and the positioning cavity 211 are connected to the cavity positioning piece 215 by bolts.

[0025] The needle assembly sleeve 28 and the movable needle 23 are both located in the fixed plate 214, which can prevent foreign matter from entering the movable needle 23 during use and extend the service life. Figure 1 As shown, one side of the fixing plate 214 is designed to be open, so as to facilitate clamping of objects.

[0026] Preferably, both the positioning cavity 211 and the fixing plate 214 are provided with through holes for passing the movable needles 23 , and the number and distribution positions of the through holes are adapted to the number and distribution positions of the movable needles 23 .

[0027] As an embodiment provided by the present invention, Figure 2 As shown, there are several movable pins 23 , and the movable pins 23 are distributed in a rectangular array. The movable pins 23 distributed in a matrix array can adapt to more working conditions.

[0028] It should be noted that the arrangement of the movable pins 23 is not limited to a rectangular array, but can also be a circular array, a triangular matrix or other special-shaped matrices to adapt to different working conditions.

[0029] Further, such as Figure 3 As shown, a needle assembly sleeve 28 is sleeved on the outer wall of the end of the movable needle 23, and an elastic unit 29 is provided between the needle assembly sleeve 28 and the housing 21. Specifically, the elastic unit 29 is a compression spring, and the elasticity of the compression spring drives the needle assembly sleeve 28 to be positioned at the end of the movable needle 23. Preferably, a protrusion is provided on the end of the movable needle 32 to prevent the needle assembly sleeve 28 from falling out.

[0030] Assuming that the diameter of the end of the movable needle 23 of the robotic finger 2 is d mm, it can be embedded in a narrow gap with a minimum width of d+0.3 mm and can fully grasp objects with a gap width of 1.5d or more.

[0031] When the mechanical finger 2 is in the process of grabbing, since the movable needle 23 is in the active state at this time, and the end of the movable needle 23 can be driven by the elastic unit 29 to always be located outside the positioning cavity 211, when the movable needle 23 touches the object to be grabbed, the movable needle 23 is pressed, the elastic unit 29 is extruded, and the elastic unit 29 is contracted, at this time, one end of the movable needle 23 moves towards the flexible cavity 22, that is, one end of the movable needle 23 moves inside the blocking cavity 26, through the abutment of a plurality of arrayed movable needles 23 and the outer wall of the target object, the movable needle 23 can adapt to the shape of the object to be grabbed, then, the gas in the gas interface 25 is filled into the gas cavity 27 through the gas pump arranged on the base 1, the gas cavity 27 is isolated from the blocking cavity 26 through the flexible cavity 22, and the gas cavity 27 is in the inflated state, so the filled gas will extrude the flexible cavity 22, so that the flexible cavity 22 deforms towards the blocking cavity 26, and then the inner wall of the flexible cavity 22 extrudes the blocking particles 24, finally the blocking particles 24 fix the end of the movable needle 23 inside the blocking cavity 26, realizing the shape-adaptive locking of the object.

[0032] The mechanical finger 2 can be integrated into the clamping jaw system of a mechanical hand, that is, the base 1 can be a mechanical clamping jaw, and a grabbing system with double-side cooperative clamping capacity can be constructed by connecting the mechanical finger 2 to the output end of the mechanical clamping jaw.

[0033] For the mechanical finger 2, a gas pump, a gas conveying hose and a valve are needed, thereby constructing a clamping system with active locking function.

[0034] The passive deformation mechanism of the arrayed movable needles 23 adapts to complex gap geometry and object contour; after shape adaptation, the gas pump drives the flexible cavity 22 to deform and fix the spatial pose of the movable needle 23, ensuring the stability of the grabbing process; effectively overcoming the mechanical coupling problem existing in the traditional elastic mechanism, specifically, the spring element of the spring clamping jaw structure in the prior art will generate an elastic restoring force opposite to the direction of the grabbing force when it is pressed and deformed, and this reaction force will significantly weaken the effective grabbing force. The gas locking mechanism provided by the application can completely eliminate the negative influence of such parasitic force on the grabbing performance.

[0035] The self-driven finger in the prior art is required to be simple in structure and small in size in order to adapt to narrow gap grabbing objects, which is contradictory to the self-driven structure, and thus is difficult to realize, while the mechanical finger 2 provided by the embodiment of the application adopts a passive structure, and can realize the grabbing of objects arranged in narrow gaps by using thinner needles.

[0036] In actual use, the grabbing process can be summarized as the following three main stages: I. Approach the target object: This stage aims to move the base 1 as a whole to the vicinity of the target object through robot motion control, and try to align the center of the base 1 with the center of mass or geometric center of the object as much as possible, laying the foundation for subsequent accurate grasping.

[0037] II. Linear insertion and realization of gap self-adaptation: In this stage, the manipulator drives the base 1 to perform linear insertion along the set direction, usually the vertical direction. As shown in Figure 4 , during the process, the manipulator finger 2 with the structure of an array of movable needles 23 can be self-adapted according to the local contact condition, and the needle group embedded in the gap area will remain its initial state to penetrate the target position, while the needle group in contact with the obstacle will be deformed through passive sliding or compression, thereby realizing adaptive insertion into the narrow gap between the stacked objects, and then completing the contact positioning of the target object. As shown in Figure 4 , where the black arrow is the gas input direction, the white arrow is the motion direction of the manipulator finger 2, and the black small arrow is the expansion direction of the flexible cavity 22.

[0038] III. Clamping and extraction: When the manipulator finger 2 successfully inserts and completes the enveloping of the target object, the base 1 performs the clamping action, that is, the two center-directed synchronous folding, thereby realizing the stable clamping of the target object. Subsequently, the manipulator performs the extraction motion in the vertical direction or the preset path, reliably separating the target object from the stacked environment.

[0039] This three-stage operation process fully combines the structural adaptability and task planning strategy, and is particularly suitable for realizing accurate and efficient grasping of the target object in a complex stacked environment.

[0040] Working principle: In the assembly, first, the tail of the movable needle 23 is completely passed through the hole of the cover plate 213 until the head of the movable needle 23 and the cover plate 213 coincide; then the elastic unit 29 is sleeved on the tail of the movable needle 23 at the cover plate 213, and the needle group sleeve 28 is sleeved on the tail end of the movable needle 23, and the sleeved length is completely through the whole needle group sleeve 28. The main purpose of this step is to enable the movable needle 23 to move vertically along the hole of the fixed plate 201, and at the same time, a plurality of movable needles 23 can be in the same horizontal plane. The purpose of the elastic unit 29 is to control the vertical movement of the needle group, and to keep the shape of the needle group, so that it can better adapt to the surface shape of the object and realize grabbing in the narrow gap. When the movable needle 23 group is subjected to external downward pressure and begins to contact the grabbing environment, part of the needles will retract upward in the vertical direction after touching the target object or other obstacles; and those embedded in the gap and not under stress remain in place, thereby achieving effective fitting and stable support of objects in narrow gaps. Each needle in the needle group structure realizes independent displacement response through the elastic unit 29, and has good adaptive ability. However, if the needle group with elastic unit 29 is directly exposed to the external environment, dust, debris and other impurities are easy to enter the spring area, thereby affecting the motion performance of the structure, and even causing mechanical damage. Therefore, a positioning cavity 211 is arranged on the periphery of the needle group to assist in positioning the movable needle 23 and isolate external interference and improve the robustness and service life of the overall structure.

[0041] When the elastic unit 29 arranged outside the movable needle 23 is stretched according to the gap and the shape of the object, the compressed elastic unit 29 will generate resistance to grabbing due to deformation, which has a certain influence on the process of grabbing and releasing the object, so a lockable structure is proposed for this problem, that is, the moving needle group is locked, the purpose is to fix the needle group to keep the stability of the clamping state, and to avoid secondary interference and misoperation. Through the blocking mechanism, the flexible cavity 22 wrapped with the blocking particles 24 is pressurized by using the Pascal principle, and when the closed gas cavity 27 is inflated, the gas pressure is uniformly transmitted to all directions of the inner wall of the flexible cavity 22, forming a uniform load, extruding the wrapped blocking particles 24 and the end of the movable needle 23, and through the wrapping of small particles, the purpose of locking is achieved by using friction.

[0042] As an embodiment provided by the present application, the number of mechanical fingers 2 is several, specifically, the mechanical fingers 2 provided by the embodiment of the present application are two, and the two mechanical fingers 2 are symmetrically arranged on the base 1. Specifically, the base 1 is a mechanical hand, which can drive the mechanical fingers 2 to move towards each other to realize clamping.

[0043] As an embodiment provided by the present application, the flexible cavity 22 is made of mixed silica gel using a mold of soluble material for pouring, so as to ensure that it has a cavity inside.

[0044] The compression spring mentioned in the text has an elastic coefficient meeting the technical requirements of the technical scheme of the application.

[0045] It is understood by those skilled in the art that other similar connection modes can also implement the application. For example, welding, bonding or screwing and the like.

[0046] The above only describes certain exemplary embodiments of the application by way of illustration, and it is self-evident that those skilled in the art can modify the described embodiments in various manners without departing from the spirit and scope of the application. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the application.

Claims

1. A lockable array needle-type mechanical finger for grasping tightly arranged objects, comprising a base (1), characterized in that: It also includes a mechanical finger (2) movably arranged on the base (1); The mechanical finger (2) comprises a shell (21), a flexible cavity (22), a movable needle (23) and a blocking particle (24), wherein the movable needle (23) is slidably connected to the shell (21), the shell (21) is provided with a gas interface (25), the flexible cavity (22) is arranged inside the shell (21), and the inside of the shell (21) is divided into a blocking cavity (26) and a gas cavity (27) which are not connected to each other by the flexible cavity (22), the gas cavity (27) is connected to the gas interface (25), the end of the movable needle (23) is located inside the blocking cavity (26), and the blocking particle (24) is arranged in the blocking cavity (26).

2. The lockable array needle-type mechanical finger for grasping closely arranged objects according to claim 1, characterized in that: The housing (21) comprises a positioning cavity (211) and a molding cavity (212), the positioning cavity (211) is connected to the molding cavity (212), the flexible cavity (22) is arranged in the molding cavity (212), and the movable needle (23) is slidably connected to the positioning cavity (211).

3. The lockable array needle-type mechanical finger for grasping closely arranged objects according to claim 2, characterized in that: A needle group sleeve (28) is provided at the end of the movable needle (23), an elastic unit (29) is provided between the needle group sleeve (28) and the positioning cavity (211), and the elastic unit (29) is sleeved on the movable needle (23).

4. The lockable array needle-type robotic finger for grasping closely arranged objects according to claim 1, characterized in that: The number of the movable needles (23) is several, and the several movable needles (23) are distributed in an array.

5. The lockable array needle-type mechanical finger for grasping closely arranged objects according to claim 1, characterized in that: There are a plurality of mechanical fingers (2), and the plurality of mechanical fingers (2) are arranged in an array on the base (1).

6. The lockable array needle-type mechanical finger for grasping closely arranged objects according to claim 1, characterized in that: An air pump is provided on the base (1), and the air pump is connected to the gas interface (25).

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