Soft finger and mechanical paw

Abstract

The invention belongs to the technical field of mechanical equipment, and particularly relates to a soft finger and a mechanical gripper, the soft finger comprises an actuator, the actuator is of a cylindrical structure and is provided with a closed end and an open end, the actuator is made of an elastic material, and a strain limiting layer is arranged on one side of the side wall of the actuator; one end of the air cylinder is open and is connected with the open end of the actuator; the piston is sleeved in the air cylinder; and a particulate matter filled between the piston and the closed end of the actuator, the particulate matter being capable of being compressed when the piston moves toward the closed end of the actuator, the particulate matter being converted from fluidity to solid characteristics, and the actuator being bent toward the strain limiting layer side. The mechanical gripper comprises a plurality of the soft fingers and further comprises a hollow main shaft and a driving assembly, the soft fingers are evenly distributed in the circumferential direction of the hollow main shaft, and the driving assembly is used for driving the soft fingers to be close to or away from one another. High sealing performance is not needed, and the control precision, stability and flexibility of the soft fingers are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical equipment and relates to a soft finger and a mechanical gripper. Background Art

[0002] In mine rescue operations, a robotic gripper must precisely grasp, move, and safely capture trapped personnel and objects. This places high demands on its control accuracy, stability, and safety. The robotic grippers currently used in mine rescue equipment are primarily soft grippers. Their structural design is primarily based on flexible materials, bionic principles, and novel drive technologies, achieving adaptability, safe interaction, and multifunctional gripping.

[0003] The core of a soft gripper lies in its driving mechanism, and the most common driving methods are pneumatic drive and hydraulic drive. Conventional pneumatic drives mainly include pneumatic networks, bellows structures, and vacuum drives. The pneumatic network consists of multiple interconnected air chambers. When inflated, the air chambers expand, causing bending deformation due to differences in material thickness. For example, the PneuNet gripper developed by Harvard University achieves directional bending through asymmetric distribution of air chambers. The bellows structure adopts a corrugated chamber design, which expands axially after inflation. It is suitable for linear motion or combination into multi-degree-of-freedom grippers. Vacuum drive shrinks the soft structure by vacuuming it to fit the target surface to be grasped, and is suitable for grasping fragile objects. Hydraulic drive uses incompressible fluid to transmit pressure to provide greater grasping force, and is commonly used in scenarios requiring high loads, such as industrial grasping.

[0004] The soft fingers of the soft gripper are mainly cavities made of silicone. Under both pneumatic and hydraulic drive modes, the volume of gas and liquid entering the cavity needs to be changed in order to achieve the purpose of bending the soft fingers. Therefore, both drive modes require the cavity to have high sealing properties.

[0005] However, due to the complexity and uncertainty of the mine environment, factors such as collision and weathering of the robotic claw during actual operation will cause the sealing of the cavity to decrease, resulting in a decrease in the control accuracy and insufficient stability of the soft finger. Summary of the Invention

[0006] The present invention provides a soft finger and a robotic gripper, aiming to address the deficiencies in the prior art. It uses particulate matter as the driving medium of the actuator, eliminating the need for high sealing, thereby improving the control accuracy and stability of the soft finger. At the same time, the soft finger's stiffness can vary over a wide range, resulting in greater flexibility.

[0007] To achieve the above objectives, the specific technical solutions provided by the present invention are as follows: A soft finger, comprising: An actuator having a cylindrical structure and a closed end and an open end, wherein the actuator is made of an elastic material and a strain limiting layer is provided on one side of a side wall of the actuator; a cylinder having an open end and connected to the open end of the actuator; a piston, mounted in the cylinder; Particles are filled between the piston and the closed end of the actuator. When the piston moves toward the closed end of the actuator, the particles are compressed, the particles are transformed from fluidity to solid properties, and the actuator is bent toward the strain limiting layer.

[0008] Furthermore, the outer contour surface of the actuator includes an arcuate surface and a plane connected end to end in sequence, the strain limiting layer is arranged on the plane, and an elastic layer is attached to the arcuate surface.

[0009] Furthermore, the strain limiting layer includes a plurality of glass fibers interwoven in a horizontal and vertical direction.

[0010] Furthermore, the elastic layer and the strain limiting layer are coated with a silicone layer.

[0011] Furthermore, the elastic material is rubber.

[0012] Furthermore, the particles are glass balls, and the diameter of the glass balls is 1.8 mm to 2.2 mm.

[0013] A robotic gripper comprises a plurality of the above-mentioned soft fingers, a hollow main shaft and a drive assembly, wherein the plurality of soft fingers are evenly distributed around the circumference of the hollow main shaft, and the drive assembly is used to drive the plurality of soft fingers to move closer to or away from each other.

[0014] Furthermore, the driving assembly includes: a rotary drive member, the output shaft of which is connected to the hollow main shaft; A first connector, a second connector, and an end connector are sequentially arranged and respectively sleeved on the hollow main shaft, wherein the second connector is threadedly connected to the hollow main shaft, the first connector and the end connector are respectively sleeved and fixed to the hollow main shaft via bearings, and the housing of the rotary drive member is fixed to the first connector; Multiple force transmission components are evenly distributed around the circumference of the hollow main shaft, and each force transmission component corresponds to a soft finger. The force transmission components include: a push-pull rod, a connecting rod 1, a triangular bracket and a connecting rod 2, wherein the push-pull rod is passed through the cylinder, one end of the push-pull rod is fixed to the piston, and the other end is hinged to the connecting rod 1 and the connecting rod 2 respectively, the connecting rod 2 is hinged to the second connector, the connecting rod 1 is hinged to one end of the triangular bracket, and the other end of the triangular bracket is hinged to the first connector.

[0015] Compared with the prior art, the soft finger and robotic gripper of the present invention have the following advantages: The actuator cavity is filled with particles, which does not require overly strict sealing. The particles are less sensitive to the environment and pressure, making them more suitable for harsh environments. In addition, when grasping the target, due to the fluidity of the particles, when contacting the target, it is a flexible contact and will not produce a hard collision with the target. The particles can play a shock-absorbing role during the transmission process and protect the structure of mechanical parts. At the same time, the shape of the actuator will be adjusted according to the target surface, thereby increasing the contact area with the grasped target. Moreover, when the actuator grasps the target, by pushing the particles in the cavity into the actuator, the particles in the actuator produce a "blocking effect", which can achieve a large stiffness change with a small volume change, so the stability can be guaranteed. Therefore, compared with traditional mechanical claws, it has higher precision, stability and safety, strong practicality, and is worthy of promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The overall structure of the present invention is shown in FIG. Figure 1 .

[0017] Figure 2 It is a schematic diagram of the local structure of the present invention Figure 2 .

[0018] Figure 3 The state diagram of the local structure of the present invention is shown as follows Figure 1 .

[0019] Figure 4 The state diagram of the local structure of the present invention is shown as follows Figure 2 . DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the technical solution of the present invention will be clearly and fully described below with reference to the accompanying drawings.

[0021] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship 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 device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0022] In addition, it should be further explained that in the description of the embodiments of the present invention, unless otherwise specified, " / " means or, for example, A / B can mean A or B: "and / or" in the text is merely a description of the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present invention, "multiple" refers to two or more than two.

[0023] The terms "first," "second," "third," and "fourth" below are used for descriptive purposes only and should not be understood to imply or suggest relative importance or implicitly indicate the number of the technical features indicated. Thus, features qualified as "first," "second," "third," and "fourth" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0024] The present invention provides soft fingers and mechanical grippers, such as Figures 1 to 4 As shown, the soft finger includes an actuator 13, a cylinder 7, a piston 15, a strain limiting layer 17 and particles 16. Figure 3 and Figure 4 As shown, the actuator 13 is a barrel structure with a closed end and an open end. The actuator 13 is made of elastic material. A strain limiting layer 17 is provided on one side of the side wall of the actuator 13. One end of the cylinder 7 is open and connected to the open end of the actuator 13 to form the main structure of the soft finger. The piston 15 is mounted in the cylinder 7, so that a cavity is formed between the piston 15 and the closed end of the actuator 13, and the particulate matter 16 is filled in the cavity. When the piston 15 moves toward the closed end of the actuator 13, it can compress the particulate matter 16, so that the particulate matter 16 is converted from fluidity to solid properties, and the actuator 13 is deformed and bent toward the strain limiting layer 17 side.

[0025] Specifically, as a further optimization solution of the embodiment, the elastic material is rubber.

[0026] Specifically, an opening at one end of the cylinder 7 is connected to an open end of the actuator 13 via a connector 8 to form an integral structure, and a cavity for storing the particles 16 is formed between the piston 15 and the closed end of the actuator 13 .

[0027] Specifically, as a further optimization solution of the embodiment, the material of the head of the piston 15 is soft rubber and the outer dimensions match the inner diameter of the cylinder 7 .

[0028] It should be noted that the cross-section of the actuator 13 is semicircular, and the outer contour surface includes an arc surface and a plane connected in sequence from end to end. The strain limiting layer 17 is attached to the plane of the actuator 13, and the elastic layer 14 is attached to the arc surface of the actuator 13. The elastic layer 14 is made of elastic rubber and has a certain degree of stretchability.

[0029] Specifically, the strain limiting layer 17 includes a plurality of glass fibers interwoven horizontally and vertically.

[0030] The elastic layer 14 and the strain limiting layer 17 are coated with a silicone layer. Specifically, after the elastic layer 14 and the strain limiting layer 17 are attached to the surface of the actuator 13, a double-strand Kevlar wire is wrapped around the actuator 13 and a layer of silicone is molded using a mold to form a silicone layer on the surface of the actuator 13.

[0031] Specifically, the diameter of the glass ball is 1.8mm~2.2mm.

[0032] As the preferred embodiment described above, the diameter of the glass ball is 2 mm.

[0033] The present invention also provides a mechanical gripper, such as Figure 1 and Figure 2 As shown, the robotic gripper includes a hollow main shaft 1, a drive assembly and a plurality of soft fingers as described above. The plurality of soft fingers are evenly distributed around the circumference of the hollow main shaft 1, constituting an actuator for grasping the grasped target. The drive assembly is used to drive the plurality of soft fingers to move closer to or away from each other.

[0034] As a further optimization scheme of the embodiment, the driving assembly includes a rotating driving part, a triangular bracket 2, a connecting rod 1 3, a connecting rod 2 4, a push-pull rod 5, a triangular support plate 6, a first connector 10, a second connector 11 and an end connector 12.

[0035] The output shaft of the rotary drive member is connected to the hollow main shaft 1. The first connector 10, the second connector 11 and the end connector 12 are arranged in sequence and are respectively mounted on the hollow main shaft 1. The second connector 11 is threadedly connected to the hollow main shaft 1. The first connector 10 and the end connector 12 are respectively mounted and fixed to the hollow main shaft 1 through bearings. Multiple force transmission components are evenly distributed around the circumference of the hollow main shaft 1. Each force transmission component includes: a push-pull rod 5, a connecting rod 1 3, a triangular bracket 2 and a connecting rod 2 4. The push-pull rod 5 is inserted into the cylinder 7. One end of the push-pull rod 5 is fixed to the piston 15, and the other end is hinged to the connecting rod 1 3 and the connecting rod 2 4 respectively. The connecting rod 2 4 is hinged to the second connector 11. The connecting rod 1 3 is hinged to one end of the triangular bracket 2. The other end of the triangular bracket 2 is hinged to the first connector 10.

[0036] Specifically, the push-pull rod 5 and the piston 15 are fixedly connected to form a force transmission path, and the push-pull rod 5 is inserted into the end surface of the cylinder 7 and can slide relatively.

[0037] The hollow spindle 1 is provided with a first connector 10, a second connector 11, and an end connector 12, arranged sequentially from top to bottom. The end of the hollow spindle 1 closest to the first connector 10 is connected to a rotary drive member, and the second connector 11 is threadedly connected to the hollow spindle 1. Furthermore, the first connector 10 and the end connector 12 are each cylindrical structures, and are respectively secured to the hollow spindle 1 via bearings. The housing of the rotary drive member is secured to the first connector 10, constraining its motion and position. The bearings are preferably ball bearings, which provide support for the first connector 10 and the end connector 12 while also isolating their motion.

[0038] In addition, the end connector 12 is a cylindrical structure with a circular appearance. Three triangular support plates 6 are arranged circumferentially around the end connector 12. One end of the triangular support plate 6 is fixedly connected to the end connector 12, and the other end is connected to the cylinder 7 through a first hinged connection seat, thereby realizing the hinged connection between the cylinder 7 and the triangular support plate 6.

[0039] As a further optimization scheme of the embodiment, the outer shapes of the first connector 10 and the second connector 11 are regular hexagons, and a second articulated connection seat is provided at the center of the three spacing surfaces of the first connector 10, and a third articulated connection seat is provided at the center of the three spacing surfaces of the second connector 11, and the center planes of the first articulated connection seat, the second articulated connection seat and the third articulated connection seat are all located on the same plane.

[0040] Taking the driving structure of a soft finger as an example, the second hinged connection seat is connected to one end of the triangular bracket 2, and the other end is connected to one end of the connecting rod 1 3. The other end of the connecting rod 1 3 is connected to the connecting rod 2 4 and the push-pull rod 5 and can rotate relative to each other. The connecting rod 2 4 is also connected to the third hinged connection seat.

[0041] It should be noted that the three connecting rods 24 and the surrounding connection structure, while forming a force transmission path so that the push-pull rod 5 can move up and down, also form a rotation constraint on the second connector 11, so that the second connector 11 can only move up and down along the length direction of the hollow main shaft 1 when the rotary drive member rotates.

[0042] During use, when the forward and reverse rotation of the rotating drive member causes the hollow main shaft 1 to rotate forward and reverse, the second connector 11 moves up and down along the length direction of the hollow main shaft 1. When the second connector 11 moves upward, on the one hand, force is transmitted through the connecting rod 2 4 and the connecting rod 1 3 to make one end of the triangular bracket 2 rotate around the other end so that the connection end with the connecting rod 1 3 moves upward, and on the other hand, the push-pull rod 5 is synchronously driven to move upward so that the piston 15 moves toward the direction away from the closed end of the actuator 13, thereby releasing the pressure loaded on the particle 16. When the second connector 11 moves downward, on the one hand, force is transmitted through the connecting rod 2 4 and the connecting rod 1 3 to make one end of the triangular bracket 2 rotate around the other end so that the connection end with the connecting rod 1 3 moves downward, and on the other hand, the push-pull rod 5 is synchronously driven to move downward so that the piston 15 moves toward the closed end close to the actuator 13, loading pressure on the particle 16, compressing the particle 16, causing the particle 16 to change from fluidity to solid properties, and causing the actuator 13 to deform and bend toward the strain limiting layer 17 side.

[0043] Specifically, the rotary drive member is preferably a motor, and the output shaft of the motor is connected to the hollow main shaft 1 through a coupling.

[0044] The working principle of the mechanical gripper of the present invention is: Robotic claw opening action: When the forward and reverse rotation of the rotary drive member causes the second connector 11 to move upward along the hollow main shaft, force is transmitted through connecting rods 2 4 and 1 3, causing one end of the triangular bracket 2 to rotate around the other end, causing the connection end with connecting rod 1 3 to move upward. This also synchronously drives the push-pull rod 5 upward, causing the piston 15 to move away from the closed end of the actuator 13. At the same time, because the push-pull rod 5 is in contact with the end surface of the cylinder 7, the angle changes as the push-pull rod 5 moves upward, causing the cylinder 7 to open in accordance with the angle of the push-pull rod 5. The actuator 13 and the cylinder 7 are connected together by connector 8. At this time, the particles 16 in the cylinder 7 and the actuator 13 are in a flowing state, so the robot gripper is in an open state.

[0045] Robotic gripper grasping action: When the robotic gripper needs to grasp an object, the second connector 11 moves downward. On the one hand, it transmits force through connecting rods 2 4 and 1 3, causing one end of the triangular bracket 2 to rotate around the other end, causing the connection end with connecting rod 1 3 to move downward. On the other hand, it simultaneously drives the push-pull rod 5 downward, causing the piston 15 to move toward the closed end of the actuator 13, applying pressure to the particles 16, compressing the particles 16 and transforming the particles 16 from fluid to solid. At the same time, because the angles of the triangular bracket 2 and the push-pull rod 5 change as they move downward, the cylinder 7 decreases along with the angle of the push-pull rod 5. At this time, the robotic gripper contacts the grasped object. When the surface of the actuator 13 contacts the grasped object, the particles 16 in the actuator 13 are still in a fluid state. When grasping the object, they will change according to the shape of the target surface, thereby increasing the contact area and improving the stability and safety of the grasping. After sufficient contact with the grasped object, the push-pull rod 5 in the cylinder 7 pushes, causing the piston 15 to compress the particles in the cylinder 7. 16 pushes into the actuator 13. When the particles 16 in the actuator 13 are completely filled, the shape of the actuator 13 changes and bends toward the strain limiting layer 17. At the same time, based on the blocking effect of the particles 16, a larger stiffness change can be achieved with a smaller volume change. When the particles 16 in the actuator 13 are fully squeezed, the particles 16 in the actuator 13 show solid characteristics from fluidity, thereby having very large stiffness. Therefore, the robotic gripper can firmly grasp the target, and the robotic gripper is in a grasping state.

[0046] Compared with the prior art, the present invention provides a soft finger and a mechanical gripper, in which the actuator cavity used in the structure is filled with particles, which does not require overly strict sealing, and the particles are less sensitive to the environment and pressure, making them more suitable for harsh environments. In addition, when grasping the grasped target, due to the fluidity of the particles, when contacting the target, it is a flexible contact and will not produce a hard collision with the target. The particles can play a shock-absorbing role during the transmission process and can protect the mechanical parts structure. At the same time, the shape of the actuator will be adjusted according to the target surface, thereby increasing the contact area with the grasped target. Moreover, when the actuator grasps the target, by pushing the particles in the injection cavity into the actuator, the particles in the actuator produce a "blocking effect", which can achieve a large stiffness change with a small volume change, so the stability can be guaranteed. Therefore, compared with traditional mechanical grippers, it has higher precision, stability and safety, strong practicality, and is worthy of promotion.

[0047] It will be understood that the present invention is described through some embodiments, and those skilled in the art will appreciate that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention.

[0048] Furthermore, these features and embodiments may be modified to suit specific circumstances and materials under the teachings of the present invention without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present invention are intended to be protected by the present invention.

Claims

1. A soft finger, characterized in that: include: An actuator (13) is a cylindrical structure having a closed end and an open end, the actuator (13) is made of an elastic material, and a strain limiting layer (17) is provided on one side of a side wall of the actuator (13); A cylinder (7) having an open end and connected to the open end of the actuator (13); A piston (15) is mounted in the cylinder (7); The particles (16) are filled between the piston (15) and the closed end of the actuator (13). When the piston (15) moves toward the closed end of the actuator (13), the particles (16) are compressed, the particles (16) are transformed from fluidity to solid properties, and the actuator (13) bends toward the strain limiting layer (17).

2. The soft finger according to claim 1, characterized in that: The outer contour surface of the actuator (13) comprises an arcuate surface and a plane connected end to end in sequence, the strain limiting layer (17) is arranged on the plane, and an elastic layer (14) is attached to the arcuate surface.

3. The soft finger according to claim 2, characterized in that: The strain limiting layer (17) comprises a plurality of glass fibers interwoven in a horizontal and vertical direction.

4. The soft finger according to claim 3, characterized in that: The elastic layer (14) and the strain limiting layer (17) are coated with a silicone layer.

5. The soft finger according to claim 1, characterized in that: The elastic material is rubber.

6. The soft finger according to claim 1, characterized in that: The particles (16) are glass balls, and the diameter of the glass balls is 1.8 mm to 2.2 mm.

7. A robotic gripper comprising a plurality of soft fingers according to any one of claims 1 to 6, characterized in that: It also includes a hollow main shaft (1) and a drive assembly, wherein the plurality of soft fingers are evenly distributed around the circumference of the hollow main shaft (1), and the drive assembly is used to drive the plurality of soft fingers to move closer to or farther from each other.

8. The robotic gripper according to claim 7, characterized in that: The drive assembly includes: A rotary drive member, the output shaft of which is connected to the hollow main shaft (1); A first connector (10), a second connector (11) and an end connector (12) are sequentially arranged and respectively sleeved on the hollow main shaft (1), wherein the second connector (11) is threadedly connected to the hollow main shaft (1), the first connector (10) and the end connector (12) are respectively sleeved and fixed to the hollow main shaft (1) via bearings, and the housing of the rotary drive member is fixed to the first connector (10); A plurality of force transmission components are evenly distributed around the circumference of the hollow main shaft (1), and each force transmission component corresponds to a soft finger. The force transmission components include: a push-pull rod (5), a connecting rod 1 (3), a triangular bracket (2) and a connecting rod 2 (4), wherein the push-pull rod (5) is passed through the cylinder (7), one end of the push-pull rod (5) is fixed to the piston (15), and the other end is hinged to the connecting rod 1 (3) and the connecting rod 2 (4), respectively, the connecting rod 2 (4) is hinged to the second connector (11), the connecting rod 1 (3) is hinged to one end of the triangular bracket (2), and the other end of the triangular bracket (2) is hinged to the first connector (10).

Images