Pneumatic soft gripper for picking fruits and vegetables

Abstract

The invention relates to the technical field of manipulators, and discloses a pneumatic soft gripper for picking fruits and vegetables, which comprises a soft finger, and the outer arc surface of the soft finger is provided with a bionic bending cavity I and a bionic reverse bending cavity II. A blade is connected to the upper surface of the soft finger, a blade bending limiting ring is arranged on the outer arc surface of the first bionic bending cavity, a first winding line is wound around the inner surface of the first bionic bending cavity, an isolation layer is arranged between the first bionic bending cavity and the second bionic reverse bending cavity, and a soft wrist is connected to the lower surface of the soft finger. The soft wrist comprises telescopic soft body drivers, the upper surfaces of the three sets of telescopic soft body drivers are connected with the lower surface of the connecting piece, and the lower surfaces of the three sets of telescopic soft body drivers are fixedly connected with a base. The soft fingers can be turned outwards to be opened and folded inwards to be grasped tightly to adapt to fruits and vegetables of different sizes and shapes, and the blades are arranged at the tail ends of the fingers, so that fruit and vegetable pedicles can be cut.

Description

Technical Field

[0001] The invention relates to the technical field of manipulators, and in particular to a pneumatic soft gripper for picking fruits and vegetables. Background Art

[0002] The grasping, picking and placing of fruits and vegetables usually require a manipulator. Traditional rigid manipulators have poor flexibility and are easy to damage objects with soft surfaces. Soft mechanical grippers are made of flexible materials. By reducing the impact force between the gripper and the grasped object during the grasping process, they can achieve flexible grasping of the grasped object and have good application prospects.

[0003] In order to achieve non-destructive picking of fragile items such as fruits and vegetables, scholars have developed a rigid-flexible coupling mechanical claw. The invention patent with application number CN201820945613.6 discloses an adjustable pneumatic soft gripper, which consists of three pneumatic fingers, and can adjust the relative installation position of the flexible single finger according to the shape and size of the object. The arc-shaped slider is connected to the single finger by a buckle, which can be quickly installed and disassembled, facilitating the maintenance and replacement of the flexible gripper. However, the grasping performance is poor and the grasping objects are limited. The pneumatic soft manipulator with application number CN201810217240.5 adds a chassis composed of rigid components, and realizes the axial and radial movement of the fingers through the motor screw and slider, thereby increasing the range of motion of the fingers. The mechanism structure of this soft manipulator is relatively complex, requires more parts, and has a high manufacturing cost, which cannot meet the large demand for soft manipulators at the terminal of manufacturing equipment. The invention patent with application number CN201811582621.X introduces a soft actuator that contracts under negative pressure and has the characteristics of large driving compliance. However, a fiber tube is provided in the elastomer of the actuator, which makes the preparation of the actuator more difficult. In addition, the soft actuator does not have an elongation function.

[0004] In order to reduce the damage of fruits and vegetables by rigid parts during the picking process, scholars have developed a flexible mechanical claw made entirely of flexible materials. The invention patent with application number CN201810371643.5 includes three pneumatic soft fingers distributed in a circle, which realizes the flexible grasping of soft objects such as fruits and vegetables, but the volume of a single drive cavity limits the large eversion deformation of the fingers. In addition, this type of manipulator cannot yet realize the flipping and rotation of the fingers, so the posture cannot be adjusted when grasping and placing objects, and the grasping range is limited. Application number 202211235397.3 discloses a pneumatic tea picking soft manipulator that imitates handle picking. The pneumatic soft gripper adopts pneumatic picking. When picking, the pneumatic gripper presses the cut-off part and pulls the tea leaves apart through torsional force to realize the function of tea picking. The invention patent with application number CN202310377075.0 discloses a variable-length flexible pneumatic software gripper that can flexibly adjust the finger length according to the size of the grasped object to achieve the best grasping posture, and the fingers have the characteristic of low cost. However, the gripper cannot pick fruits and vegetables that need to shorten the stems, such as strawberries.

[0005] Although the current soft gripper has better flexibility, the fingers cannot realize the finger-like cutting function, and the gripper cannot be opened, which limits the grasping range; the driver has no extension and contraction functions, resulting in poor picking stability. In order to improve the grasping range and efficiency, realize pulling and easy-to-control operations, and improve the stability of the picking process, it is necessary to develop a new type of soft gripper to meet actual needs. Summary of the invention

[0006] In view of the defects existing in the above-mentioned prior art, the purpose of the present invention is to propose a pneumatic soft gripper for picking fruits and vegetables, which solves the problems that the fingers of the prior art cannot cut at the picking point, cannot grasp and pull within a large range, and is difficult to achieve large deformation inward grasping and outward eversion.

[0007] In order to achieve the above-mentioned objectives, the present invention adopts the following technical scheme: a pneumatic soft gripper for picking fruits and vegetables, comprising a soft finger, the outer arc surface of the soft finger is fixedly connected to a connecting piece, the outer arc surface of the soft finger is provided with a bionic bending cavity 1, the outer arc surface of the soft finger is provided with a bionic reverse bending cavity 2, the upper surface of the soft finger is connected with a blade, the inner surface of the bionic bending cavity 1 is wound with a winding wire 1, an isolation layer is arranged between the bionic bending cavity 1 and the bionic reverse bending cavity 2, the outer arc surface of the bionic bending cavity 1 is provided with a blade bending limit ring, the inner surface of the blade bending limit ring is connected to the outer arc surface of the soft finger, the bionic bending cavity 1 is connected to a pneumatic mechanism through a conduit and a cavity conduit 2, and the bionic reverse bending cavity 2 is connected to the pneumatic mechanism through a conduit and a cavity conduit 1.

[0008] Furthermore, the lower surface of the soft finger is connected to a soft wrist, and the soft wrist includes a telescopic soft driver. Three groups of the telescopic soft drivers are provided, and the upper surfaces of the three groups of the telescopic soft drivers are connected to the lower surface of the connecting piece, and the lower surfaces of the three groups of the telescopic soft drivers are fixedly connected to a base, and the cross-sections of the three groups of the telescopic soft drivers are located in the same plane. The outer surface of the telescopic soft driver is wound with a winding wire 2, and the outer surface of the telescopic soft driver is sleeved with a ring, and the telescopic soft driver is connected to the pneumatic mechanism through a wrist-like catheter.

[0009] Furthermore, the telescopic soft actuators are all cylindrical cavities, and the front end is a curved surface feature connected to the soft finger.

[0010] Furthermore, one group of the telescopic soft drives and the other two groups of the telescopic soft drives are not bonded to each other.

[0011] Furthermore, a restriction layer is provided on the outer arc surface of the soft finger, and the restriction layer is made of a non-stretchable material.

[0012] Furthermore, the lower surface of the soft finger is connected to the connecting piece and communicated with the catheter and the second cavity catheter.

[0013] The outstanding effects of the present invention are:

[0014] 1. The soft fingers can be opened outward and closed inward to grasp, which can adapt to fruits and vegetables of different sizes and shapes. There are blades at the end of the fingers to cut the stems of fruits and vegetables.

[0015] 2. The three telescopic actuators of the soft wrist can realize the grasping process through positive pressure stretching, and the pressure relief and negative pressure contraction process, and cooperate with the finger movements to achieve stable and lossless picking. The wrist can be opened and closed to adapt to the shapes of different fruits and vegetables.

[0016] 3. The pneumatic soft manipulator of the present invention performs the entire picking process through pneumatic regulation, which can achieve non-destructive and stable picking of fruits and vegetables, and the grasping process is easy to control. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the three-dimensional structure of an embodiment of the present invention.

[0018] Figure 2 Schematic diagram of a longitudinal section of a soft finger in an embodiment of the present invention.

[0019] Figure 3 Schematic diagram of the structure of the soft finger in an embodiment of the present invention.

[0020] Figure 4 Schematic diagram of the structure of the telescopic driver in the embodiment of the present invention.

[0021] Figure 5 Schematic diagram of a longitudinal section of a telescopic actuator in an embodiment of the present invention.

[0022] Figure 6 It is a schematic diagram of the telescopic actuator in the extended, natural and shortened states according to the embodiment of the present invention.

[0023] Figure 7 Schematic diagram of a cross section of a soft finger in an embodiment of the present invention.

[0024] Figure 8 Schematic diagram of the cross-sectional structure of a wrist in an embodiment of the present invention.

[0025] Among them, 1. soft fingers; 2. soft wrist; 3. blade; 4. connector; 5. base; 6. isolation layer; 7. blade bending limit ring; 8. winding wire one; 9. bionic bending cavity one; 10. bionic reverse bending cavity two; 11. cavity catheter two; 12. cavity catheter one; 13. restriction layer; 14. winding wire two; 15. wrist catheter; 16. telescopic soft drive; 17. ring. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0027] Example

[0028] like Figure 1-4 As shown, a pneumatic soft gripper for picking fruits and vegetables in this embodiment includes three soft fingers 1 and a soft wrist 2, and the soft finger 1 is connected to one end of a first connecting member 4, and is characterized in that: the soft finger 1 includes a bionic bending cavity 1 9 and a reverse bionic reverse bending cavity 2 10 which are sequentially fitted and connected, the bionic bending cavity 1 9 and the bionic reverse bending cavity 2 10 are separated by an isolation layer 6, and the outer surface of the soft finger 1 is provided with a winding wire 1 8 for limiting the radial deformation of the soft finger 1, and the two side surfaces of the bionic bending cavity 1 9 and the reverse bionic reverse bending cavity 2 10 for fitting are respectively provided with a limiting layer for limiting the axial deformation of the soft finger 1, and the bionic bending cavity 1 9 and the reverse bionic reverse bending cavity 2 10 are respectively connected to the pneumatic mechanism through a conduit 15 and a cavity conduit 2.

[0029] One end of the soft finger 1 in this embodiment is connected to the bottom end of the connector 4. The soft finger 1 includes a bionic bending cavity 1 9, a bionic reverse bending cavity 2 10 and a blade 3 which are sequentially connected. The bionic bending cavity 1 9 is used to realize the conventional grasping action of the soft finger 1, and the bionic reverse bending cavity 2 10 is used to realize the eversion action of the soft finger 1. The restriction layer 13 can limit the axial deformation of both sides of the bionic bending cavity 1 9 and the bionic reverse bending cavity 2 10. The blade 3 is connected to the bionic bending cavity 1 9. When the bionic bending cavity 1 9 is bent, the blade 3 bends and closes at the limiting ring to shorten the fruit stem, thereby realizing the picking and grasping of the fruit.

[0030] The lower surface of the soft finger 1 is connected to a soft wrist 2, which includes three cylindrical telescopic soft actuators 16 parallel to each other and a connector 4 and a base 5 respectively connected to both ends of the three telescopic soft actuators 16. The cross-sections of the three telescopic soft actuators 16 are located in a plane. Figure 3 As shown, the outer surface of the telescopic soft drive 16 is provided with a spiral guide groove, a winding wire 14 is wound in the guide groove, and the outer surface of the telescopic soft drive 16 is provided with a ring 17 with a radius of 12. Figure 1 As shown, the telescopic soft driver 16 in the soft wrist 2 needs to perform regular combined pressurization on the soft wrist 2 to realize the movement of the soft wrist 2 in different directions. When three telescopic soft drivers 16 simultaneously apply positive pressure, the wrist extends; when three telescopic soft drivers 16 simultaneously apply negative pressure, the wrist shortens.

[0031] like Figure 2 As shown, the outer surface of the soft finger 1 is provided with a guide groove of a symmetrical spiral structure, and the fiber line is wound around the outer surface of the soft finger 1 through the guide groove to form a winding line 8 for limiting the radial deformation of the soft finger 1. A blade bending limiting ring 7 is attached to the side of the bionic bending cavity 1 9 and the bionic reverse bending cavity 2 10 respectively to serve as the bionic bending cavity 1 9 limiting structure, and the blade bending limiting ring 7 is made of PLA material by 3D printing.

[0032] The robot body includes three soft fingers 1, one end of which is connected to the connector 4, and the cavity conduit 2 11 connected to the bionic bending cavity 1 9 and the conduit 15 connected to the reverse bionic reverse bending cavity 2 10 pass through the soft wrist 2 from both sides and are connected to the pneumatic mechanism through a three-way joint. The bionic bending cavity 1 9, the bionic reverse bending cavity 2 10, and the telescopic soft driver 16 are all made of silicone, the connector 4, the blade 3 and the base 5 are all 3D printed parts, and the above structures are bonded by silicone.

[0033] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A pneumatic soft gripper for picking fruits and vegetables, comprising soft fingers (1), characterized in that: The outer arc surface of the soft finger (1) is fixedly connected to a connecting piece (4), the outer arc surface of the soft finger (1) is provided with a bionic bending cavity 1 (9), the outer arc surface of the soft finger (1) is provided with a bionic reverse bending cavity 2 (10), the upper surface of the soft finger (1) is connected with a blade (3), the inner surface of the bionic bending cavity 1 (9) is wound with a winding wire 1 (8), an isolation layer (6) is provided between the bionic bending cavity 1 (9) and the bionic reverse bending cavity 2 (10), the outer arc surface of the bionic bending cavity 1 (9) is provided with a blade bending limit ring (7), the blade bending limit ring (7) is connected to the soft finger (1), the bionic bending cavity 1 (9) is connected to a pneumatic mechanism through a conduit (15) and a cavity conduit 2 (11), and the bionic reverse bending cavity 2 (10) is connected to the pneumatic mechanism through a conduit (15) and a cavity conduit 1 (12).

2. The pneumatic soft gripper for picking fruits and vegetables according to claim 1, characterized in that: The lower surface of the soft finger (1) is connected to a soft wrist (2), and the soft wrist (2) includes a telescopic soft driver (16). The telescopic soft driver (16) is provided in three groups, and the upper surfaces of the three groups of telescopic soft drivers (16) are connected to the lower surface of the connecting member (4). The lower surfaces of the three groups of telescopic soft drivers (16) are fixedly connected to a base (5). The cross-sections of the three groups of telescopic soft drivers (16) are located in a plane. The outer surface of the telescopic soft driver (16) is wound with a winding wire 2 (14). The outer surface of the telescopic soft driver (16) is sleeved with a ring (17). The telescopic soft driver (16) is connected to a pneumatic mechanism through a wrist-like catheter (15).

3. The pneumatic soft gripper for picking fruits and vegetables according to claim 2, characterized in that: The telescopic soft actuators (16) are all cylindrical cavities, and the front end is a curved surface feature connected to the soft finger (1).

4. The pneumatic soft gripper for picking fruits and vegetables according to claim 2, characterized in that: One group of the telescopic soft drives (16) and the other two groups of the telescopic soft drives (16) are not bonded to each other.

5. The pneumatic soft gripper for picking fruits and vegetables according to claim 1, characterized in that: The outer arc surface of the soft finger (1) is provided with a restriction layer (13), and the restriction layer (13) is made of a non-stretchable material.

6. A pneumatic soft gripper for picking fruits and vegetables according to any one of claim 1, characterized in that: The lower surface of the soft finger (1) is connected to the connecting piece (4) and is connected to the catheter (15) and the second cavity catheter (11).

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