Configurable underwater anti-stiction soft gripper and grasping method

Abstract

The application discloses a variable-configuration underwater anti-sticking soft gripper and a grabbing method. The underwater anti-sticking soft gripper comprises a finger fixing table, one end of which is fixedly connected with an underwater mechanical arm through a flange; four finger supports, which are uniformly and spacedly arranged along the circumference of the finger fixing table, one end of each of the four finger supports being fixedly installed on the other end of the finger fixing table; four finger grabbing mechanisms, one end of each of the four finger grabbing mechanisms being movably installed on the other end of the corresponding finger support; and a telescopic driving mechanism, which is arranged between the four finger grabbing mechanisms and is hingedly connected with the upper parts of the four finger grabbing mechanisms. The grabbing method is performed according to a cross-configuration grabbing mode and a side-by-side configuration grabbing mode. The underwater anti-sticking soft gripper has the two configuration grabbing modes of the side-by-side configuration and the cross-configuration, realizes grabbing of underwater grabbing objects of different types, and has high anti-sticking property under water.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of underwater soft robots, in particular to a configuration-variable underwater anti-stickiness soft gripper and a grabbing method. BACKGROUND

[0002] The ocean covers more than two-thirds of the Earth's surface and contains abundant and yet to be fully developed resources. In recent years, with the rapid development of underwater facility construction and deep-sea exploration technology, the demand for intelligent operation and maintenance of underwater operations has increased significantly. However, due to safety risks, environmental complexity, and high training costs for divers, traditional underwater operation relying on manpower has been unable to meet the needs of modern efficient operations. Therefore, underwater robots equipped with mechanical hands have emerged as the times require, providing a new solution for the development and protection of marine resources. Traditional rigid underwater mechanical hands perform well in terms of gripping force and anti-interference ability, but when faced with soft and smooth marine organisms, they often fail to grasp due to uneven force distribution or overly harsh movements, and even cause damage to the organisms themselves. In contrast, soft grippers, with their superior adaptability and agility, have a clear advantage in handling complex and delicate grasping tasks.

[0003] However, due to a series of obstacles caused by the underwater environment and the complexity of marine organisms, the reliability and flexibility of current underwater soft grippers are still very limited. The technical challenge that needs to be addressed urgently is how to reduce the stickiness of flowing water that causes poor stability of soft grippers, and how to improve the flexibility and adaptability of underwater soft grippers to adapt to complex and diverse underwater grasping objects. In the prior art, rigid support skeletons are used to prevent soft parts from shaking due to water stickiness during grasping, but the external rigid support skeletons reduce the softness and service life of the soft gripper. In the prior art, to increase the flexibility of the soft gripper, a slide rail structure is provided at the end of each finger, and the soft hand can adjust the position of a single finger to adapt to different sizes of grasping objects. However, this type of soft gripper does not have the ability to change configuration and cannot adapt to the optimal grasping method according to the shape of the grasping object. SUMMARY

[0004] To solve the problems in the background art, the present application provides a configuration-variable underwater anti-stickiness soft gripper and a grabbing method to solve the technical problem of grasping task failure of underwater soft grippers in the prior art due to the effects of water stickiness and complex grasping objects.

[0005] The technical solution adopted by the present application is:

[0006] I. A configuration-variable underwater anti-stickiness soft gripper

[0007] The finger fixing table is fixedly connected with the underwater mechanical arm through a flange at one end; four finger supports are uniformly and spacedly arranged along the circumference of the finger fixing table, and one end of each finger support is fixedly installed on the other end of the finger fixing table; four finger grabbing mechanisms are movably installed at the other end of the corresponding finger support at one end of each finger grabbing mechanism; a telescopic driving mechanism is arranged between the four finger grabbing mechanisms, and the telescopic driving mechanism comprises a hydraulic cavity assembly and a connecting assembly, the connecting assembly is fixedly connected with the hydraulic cavity assembly, and the connecting assembly is further hingedly connected with the upper part of each of the four finger grabbing mechanisms, so that the four finger grabbing mechanisms are driven to rotate by the telescopic driving mechanism to form different configurations.

[0008] The anti-sticking is the ability of the soft gripper to resist the frictional resistance of the liquid during the grabbing operation in the liquid.

[0009] Each finger grabbing mechanism comprises a finger connecting assembly movably installed at the other end of the corresponding finger support at one end, and a single finger assembly fixedly installed at the other end of the finger connecting assembly.

[0010] The finger connecting assembly comprises a second finger fixing base provided with a small hole at one end, a rotary bearing arranged in the small hole, an outer ring of the rotary bearing being interference-fitted in the small hole, and an inner ring of the rotary bearing being interference-fitted with the other end of the finger support, so that the second finger fixing base is movably installed on the corresponding finger support; a first pin hole seat fixedly installed on the second finger fixing base; a first finger fixing base adhesively nested in the other end of the second finger fixing base at one end, the first finger fixing base being fixedly connected with the second finger fixing base through a base connecting bolt, the other end of the first finger fixing base being provided with a convex- concave interlocking structure, and a hole one being further formed in the first finger fixing base.

[0011] The single finger assembly comprises: a soft hand outer shell provided with a concave-convex interlocking structure and fixedly connected with the concave-convex interlocking structure of the first finger fixed base, the soft hand outer shell is further provided with a plurality of convex blocks one connected in the in-plane direction, and a hole two and a hole three are respectively formed on the convex blocks one close to the first finger fixed base; a soft hand inner shell, the overall shape of the soft hand inner shell is consistent with that of the soft hand outer shell, the soft hand outer shell is sleeved outside the soft hand inner shell, the soft hand inner shell is provided with a plurality of convex block groups connected in the in-plane direction, the overall shape of each convex block group is consistent with that of the corresponding convex block one in the soft hand outer shell, each convex block group is sleeved with the corresponding convex block one in the soft hand outer shell, each convex block group is provided with a plurality of convex blocks two in the out-of-plane direction, and a hole four is further formed on the convex blocks two close to the first finger fixed base; a finger base, which is sealingly bonded to the bottom of the soft hand inner shell, forms a soft hand inner shell sealed cavity with the inner surface of the soft hand inner shell, and is sealingly bonded with the soft hand outer shell, the finger base, the outer surface of the soft hand inner shell and the inner surface of the soft hand outer shell form a soft hand outer shell sealed cavity; a soft hand outer shell flow connector, one end of which is in communication with the hole two of the soft hand outer shell, so that the soft hand outer shell flow connector is in communication with the soft hand outer shell sealed cavity; a soft hand inner shell flow connector, one end of which passes through the hole one and the hole three and is in communication with the hole four, so that the soft hand inner shell flow connector is in communication with the soft hand inner shell sealed cavity; an outer finger assembly hydraulic pump connected with the other end of the soft hand outer shell flow connector; an inner finger assembly hydraulic pump connected with the other end of the soft hand inner shell flow connector.

[0012] The in-plane direction is the parallel plane of the plane where the finger base is located; and the out-of-plane direction is the parallel plane of the plane where the side surface of the soft hand outer shell is located.

[0013] The hydraulic cavity assembly comprises: a telescopic driving base, which is a hollow cylinder with open ends, and a hole five is formed in the side surface of the telescopic driving base; two soft telescopic sealed cavities, one end of each soft telescopic sealed cavity is in communication with the two ends of the telescopic driving base respectively, and the other end of each soft telescopic sealed cavity is sealed, the telescopic driving base and the two soft telescopic sealed cavities form a telescopic hollow cavity; a telescopic driving mechanism flow connector, one end of which is in communication with the hole five of the telescopic driving base, so that the telescopic driving mechanism flow connector is in communication with the telescopic hollow cavity; a telescopic mechanism hydraulic pump, the other end of the telescopic driving mechanism flow connector is in communication with the telescopic mechanism hydraulic pump.

[0014] The connecting assembly comprises two fixed plates fixedly installed at one end of the two soft expansion sealing cavities respectively, four second pin hole seats, one end of two second pin hole seats fixedly installed on the corresponding one fixed plate vertically side by side respectively, one end of the other two second pin hole seats fixedly installed on the other fixed plate vertically side by side respectively, four pin hole seat connecting rods, one end of each pin hole seat connecting rod hingedly connected with the other end of the corresponding second pin hole seat, the other end of each pin hole seat connecting rod hingedly connected with the first pin hole seat on the corresponding second finger fixed base, and each pin hole seat connecting rod drives the finger connecting assembly to rotate along the circumferential plane of the finger fixing table through the first pin hole seat.

[0015] The underwater anti-sticking soft gripper further comprises:

[0016] A control system is electrically connected with the four outer finger assembly hydraulic pumps, the four inner finger assembly hydraulic pumps and the expansion mechanism hydraulic pump respectively.

[0017] II. A gripping method of the underwater anti-sticking soft gripper

[0018] The gripping method is performed according to a cross configuration gripping mode and a side-by-side configuration gripping mode respectively. The cross configuration gripping mode is to first empty the liquid in the soft expansion sealing cavity to make the finger bases of the four finger gripping mechanisms arranged in a cross configuration, then adjust the liquid in the soft inner shell sealing cavity to adjust the rigidity of the side of the single finger assembly, and finally fill the liquid into the soft outer shell sealing cavity to achieve gripping, which is used for gripping irregular spherical objects.

[0019] The side-by-side configuration gripping mode is to first fill the liquid into the soft expansion sealing cavity to make the finger bases of the four finger gripping mechanisms arranged in a side-by-side configuration, then adjust the liquid in the soft inner shell sealing cavity to adjust the rigidity of the side of the single finger assembly, and finally fill the liquid into the soft outer shell sealing cavity to achieve gripping, which is used for gripping irregular cylindrical or flat objects.

[0020] The cross configuration arrangement is that the faces where the opposite two finger bases of the four finger bases are located are parallel to each other, and the faces where the adjacent two finger bases are located are perpendicular to each other; the side-by-side configuration arrangement is that the face where each finger base is located is in the same plane as the face where one adjacent finger base is located, and is parallel to the face where the other adjacent finger base is located.

[0021] The rigidity is the ability of the single finger assembly to resist deformation under the action of the liquid viscous force.

[0022] The cross configuration gripping mode specifically comprises:

[0023] Before the underwater anti-sticking soft gripper performs the gripping operation, the expansion hollow cavity, the soft inner shell sealing cavity and the soft outer shell sealing cavity are filled with liquid.

[0024] The telescopic mechanism hydraulic pump continuously extracts liquid through the telescopic driving mechanism flow joint, the soft telescopic sealing cavity is contracted to drive the rotation of each finger grabbing mechanism, until the telescopic hollow cavity is completely contracted, so that the four finger grabbing mechanisms form a cross-shaped arrangement.

[0025] The inner finger assembly hydraulic pump fills and extracts liquid into the soft hand inner shell sealing cavity through the soft hand inner shell flow joint, so as to adjust the rigidity of the side of the single finger assembly.

[0026] The outer finger assembly hydraulic pump fills liquid into the soft hand outer shell sealing cavity through the soft hand outer shell flow joint, so that the single finger assembly is bent to realize grabbing, and is used for grabbing irregular objects similar to balls.

[0027] The side-by-side arrangement grabbing mode is specifically:

[0028] Before the underwater anti-sticking soft gripper performs the grabbing operation, the telescopic hollow cavity, the soft hand inner shell sealing cavity and the soft hand outer shell sealing cavity are filled with liquid.

[0029] The telescopic mechanism hydraulic pump continuously fills liquid inward through the telescopic driving mechanism flow joint, the soft telescopic sealing cavity is expanded to drive the rotation of each finger grabbing mechanism, until the telescopic hollow cavity is completely expanded, so that the four finger grabbing mechanisms form a side-by-side arrangement.

[0030] The inner finger assembly hydraulic pump fills and extracts liquid into the soft hand inner shell sealing cavity through the soft hand inner shell flow joint, so as to adjust the rigidity of the side of the single finger assembly.

[0031] The outer finger assembly hydraulic pump fills liquid into the soft hand outer shell sealing cavity through the soft hand outer shell flow joint, so that the single finger assembly is bent to realize grabbing, and is used for grabbing irregular objects similar to cylinders or flat objects.

[0032] The present application has the beneficial effects that:

[0033] 1、The single finger assembly of the present application is entirely made of high-elastic flexible material, which prevents rigid components from damaging underwater complex types of grabbed objects under the premise of ensuring greater grabbing force.

[0034] 2、The present application adopts hydraulic driving, can generate greater grabbing force, and can self-adaptively adjust the internal pressure according to the underwater environment to balance the water pressure.

[0035] 3、The telescopic driving mechanism designed in the application makes the finger grabbing mechanism have two configurations, the rotation of the single finger assembly is driven by the finger connecting assembly, the free switching between the side-by-side configuration and the cross configuration is realized, the bending direction of the single finger assembly has the maximum grabbing force, when facing different types of underwater grabbing objects, selecting the appropriate configuration can make the bending direction of the single finger assembly perpendicular to the contact surface of the grabbing object, so as to generate greater grabbing force and more accurate grabbing direction, thereby improving the grabbing accuracy and stability.

[0036] 4、The single finger assembly of the application comprises two sealed cavities, a soft hand inner shell sealed cavity and a soft hand outer shell sealed cavity; the soft hand outer shell sealed cavity is pressurized to realize the bending of the single finger, and the soft hand inner shell sealed cavity forms uniform size, opposite direction and perpendicular to the soft gripper grabbing force direction internal force after being pressurized, thereby improving the out-of-plane stiffness of the single finger and the ability of the soft gripper to resist water body viscous force.

[0037] 5、The single finger assembly of the application has low grabbing force in a small degree of bending state, the soft hand inner shell sealed cavity is connected with high water pressure, which does not change the bending degree of the soft gripper, but the overall stiffness of the finger is improved, so that the grabbing force can be higher. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is a three-dimensional schematic view of the application without a hydraulic pump;

[0039] Figure 2 is a structure schematic view of the application before and after the change of two configurations without a hydraulic pump;

[0040] Figure 3 is a top view of the telescopic driving assembly before and after the change of two configurations of the application;

[0041] Figure 4 is a structure schematic view of the telescopic driving mechanism of the application without a hydraulic pump;

[0042] Figure 5 is an exploded schematic view of the single finger assembly and the finger connecting assembly of the application without a hydraulic pump;

[0043] Figure 6 is a structure schematic view of the finger connecting assembly of the application;

[0044] Figure 7 (a) is a structure schematic view of the soft hand outer shell of the application; Figure 7 (b) is a structure schematic view of the soft hand inner shell of the application; Figure 7 (c) is a cross-sectional structure schematic view of the soft hand outer shell and the soft hand inner shell after assembly;

[0045] Figure 8is a single finger assembly fingertip lateral force with soft hand shell sealed cavity hydraulic changes in experimental results figure;

[0046] Figure 9 is a single finger assembly fingertip force with soft hand shell sealed cavity hydraulic changes in experimental results figure.

[0047] In the figure: 1, the finger fixed table; 2, the finger support; 3, the finger connecting assembly; 31, the first finger fixed base; 32, the second finger fixed base; 33, the base connecting bolt; 34, the first pin hole seat; 4, the telescopic drive mechanism; 41, the fixed plate; 42, the soft telescopic sealed cavity; 43, the telescopic drive base; 44, the second pin hole seat; 45, the pin hole seat connecting rod; 46, the pin hole seat connecting bolt; 5, the single finger assembly; 51, the soft hand shell flow joint; 52, the soft hand shell; 53, the soft hand inner shell; 54, the finger base; 55, the soft hand inner shell flow joint; 56, the soft hand inner shell sealed cavity; 57, the soft hand shell sealed cavity; 6, the telescopic drive mechanism flow joint. DETAILED DESCRIPTION

[0048] The application will be described in greater detail with reference to the drawings and embodiments, but the application is not limited thereto. Those skilled in the art can make several improvements and refinements without departing from the principles of the application, and these improvements and refinements are also considered to be within the scope of protection of the application. The contents not described in detail in the specification belong to the prior art known to those skilled in the art.

[0049] As shown in Figure 1 and Figure 2 , the configuration variable underwater anti-sticking soft gripper of the embodiment is a four-jaw structure, and the overall height is about 300mm. The underwater anti-sticking soft gripper of the embodiment comprises:

[0050] The finger fixed table 1 is detachably fixedly connected with the underwater mechanical arm through a flange at one end, and a through hole with a diameter of 10mm is further arranged in the middle of the finger fixed table 1. The finger fixed table 1 is in the shape of a two-layer stepped cylinder, and the overall material is stainless steel, which is manufactured by injection molding.

[0051] The four finger supports 2 are uniformly and circumferentially arranged along the finger fixed table 1, and the circle formed by the circumferential uniform and interval arrangement of the four finger supports 2 has a diameter of 150mm. One end of each finger support 2 is welded and fixedly installed on the other end of the finger fixed table 1. Each finger support 2 is a curved cylinder with a diameter of 5mm, and the material is stainless steel, which is manufactured by injection molding.

[0052] Four finger grasping mechanisms, each of which is vertically arranged, one end of each of the finger grasping mechanisms is movably installed at the other end of the corresponding finger support 2; each of the finger grasping mechanisms can rotate around the other end of the corresponding finger support 2, so as to change the configuration of the underwater anti-sticky soft gripper.

[0053] The telescopic driving mechanism 4 is arranged between the four finger grasping mechanisms, and is located at the middle of the side close to the connection between the finger support 2 and the finger fixing table 1. One end of the telescopic driving mechanism 4 penetrates through the through hole of the finger fixing table 1. The telescopic driving mechanism 4 includes a hydraulic cavity assembly and a connecting assembly. The connecting assembly is fixedly connected with the hydraulic cavity assembly, and is further hingedly connected with the upper parts of the four finger grasping mechanisms.

[0054] The anti-stickiness refers to the ability of the soft gripper to resist the frictional resistance generated by the liquid during the grasping operation in the liquid.

[0055] As shown in Figure 1 , Figure 2 and Figure 5 Each of the finger grasping mechanisms includes:

[0056] The finger connecting assembly 3 is movably installed at the other end of the corresponding finger support 2. The finger connecting assembly 3 is at the same height as the telescopic driving mechanism 4. The four finger connecting assemblies 3 and the telescopic driving mechanism 4 are centrally symmetrically arranged.

[0057] The single finger assembly 5 is fixedly installed at the other end of the finger connecting assembly 3.

[0058] As shown in Figure 5 and Figure 6 The finger connecting assembly 3 includes:

[0059] The second finger fixing base 32 is provided with a small hole at one end. A rotary bearing is arranged in the small hole. The outer ring of the rotary bearing is interference-fitted in the small hole. The inner ring of the rotary bearing is interference-fitted with the other end of the finger support 2. The second finger fixing base 32 is movably installed on the corresponding finger support 2, so as to realize the free rotation of the finger connecting assembly 3 around the finger support 2.

[0060] The first pin hole seat 34 is fixedly installed on the second finger fixing base 32.

[0061] The first finger fixing base 31 is adhesively nested in the other end of the second finger fixing base 32 at one end. The first finger fixing base 31 is fixedly connected with the second finger fixing base 32 through the base connecting bolt 33. The other end of the first finger fixing base 31 is provided with a concave-convex interlocking structure. A hole one is further formed in the first finger fixing base 31.

[0062] The first finger fixing base 31, the second finger fixing base 32 and the first pin hole seat 34 are all made of photosensitive resin and are manufactured by using a light-cured 3D printing process.

[0063] As shown in Figure 1 , Figure 2 and Figure 5 , the single finger assembly 5 comprises:

[0064] As shown in Figure 7 (a), the soft hand outer shell 52 is provided with a concave-convex interlocking structure and is detachably fixedly connected with the concave-convex interlocking structure of the first finger fixing base 31. In order to further improve the fixing strength, strong glue can be filled in the concave-convex interlocking structure to improve the reliability of the concave-convex interlocking structure. The soft hand outer shell 52 is also provided with a plurality of convex blocks one connected in the in-plane direction, and the convex blocks one near the first finger fixing base 31 are respectively provided with hole two and hole three.

[0065] As shown in Figure 7 (b), the soft hand inner shell 53, the overall shape of the soft hand inner shell 53 is consistent with that of the soft hand outer shell 52, as shown in Figure 7 (c), the soft hand outer shell 52 is fitted and wrapped outside the soft hand inner shell 53. The soft hand inner shell 53 is provided with a plurality of convex block groups connected in the in-plane direction. The overall shape of each convex block group is consistent with that of the corresponding convex block one in the soft hand outer shell 52. Each convex block group is fitted and wrapped with the corresponding convex block one in the soft hand outer shell 52. Each convex block group is provided with a plurality of convex blocks two in the out-of-plane direction, and one of the convex blocks two near the first finger fixing base 31 is also provided with hole four.

[0066] The finger base 54 is sealingly bonded to the bottom of the soft hand inner shell 53. The finger base 54 and the inner surface of the soft hand inner shell 53 form a soft hand inner shell sealing cavity 56. The finger base 54 is also sealingly bonded to the soft hand outer shell 52. The outer surface of the finger base 54, the outer surface of the soft hand inner shell 53 and the inner surface of the soft hand outer shell 52 form a soft hand outer shell sealing cavity 57.

[0067] The soft hand outer shell flow connector 51 is in communication with the hole two of the soft hand outer shell 52 at one end, so that the soft hand outer shell flow connector 51 is in communication with the soft hand outer shell sealing cavity 57.

[0068] The soft hand inner shell flow connector 55 is in communication with the hole four after passing through the hole one and the hole three at one end, so that the soft hand inner shell flow connector 55 is in communication with the soft hand inner shell sealing cavity 56.

[0069] The outer finger assembly hydraulic pump is connected with the other end of the soft hand outer shell flow connector 51.

[0070] The inner finger assembly hydraulic pump is connected with the other end of the soft hand inner shell flow connector 55.

[0071] The in-plane direction is the parallel direction of the plane where the finger base 54 is located; the out-of-plane direction is the parallel direction of the plane where the soft hand shell 52 side is located.

[0072] The soft hand shell 52 side is the side of the convex block one of the soft hand shell 52.

[0073] In the specific implementation, the soft hand shell 52 is 200 mm long, 50 mm wide, and 30 mm high, and the wall thickness is 2 mm at the groove formed between adjacent convex blocks one, and the wall thickness is 5 mm at the rest, the finger base 54 has the same width of 50 mm, a length of 180 mm, and a thickness of 5 mm, so that the finger base 54 can be perfectly aligned with the bottom of the soft hand shell 52 and sealed and bonded by underwater insulating sealant, the soft hand inner shell 53 is 160 mm long, 40 mm wide, and 20 mm high, each group of convex blocks has three convex blocks two in the out-of-plane direction, the groove formed between adjacent convex blocks two is 2 mm wide, the groove wall thickness is 1.5 mm, and the rest of the wall thickness is 3.5 mm, the bottom of the soft hand inner shell 53 is sealed and bonded with the finger base 54 by underwater insulating sealant, because the width of the soft hand inner shell 53 is equal to the width of the soft hand shell 52 excluding the wall thickness, the soft hand inner shell 53 can be nested in the soft hand shell 52, and the soft hand inner shell 53 side wall is attached to the soft hand shell 52 inner side wall. The soft hand shell 52, the soft hand inner shell 53, and the finger base 54 are all made of high-elasticity silicone rubber material inverted mold, which is soft as a whole, and the soft hand shell runner joint 51 and the soft hand inner shell runner joint 55 are made of polyvinyl chloride resin extrusion molding, and the above materials all have excellent corrosion resistance and good softness.

[0074] When the outer finger assembly hydraulic pump pumps liquid into the inside of the soft hand shell sealed cavity 57 through the soft hand shell runner joint 51, the hydraulic pressure in the soft hand shell sealed cavity 57 increases, the in-plane direction groove expands first due to the thin wall thickness, and the single finger assembly 5 is bent by mutual extrusion; when the inner finger assembly hydraulic pump pumps liquid into the inside of the soft hand inner shell sealed cavity 56 through the soft hand inner shell runner joint 55, the hydraulic pressure in the soft hand inner shell sealed cavity 56 increases, the out-of-plane direction groove expands first due to the thin wall thickness, and the equal and opposite forces are generated by mutual extrusion and act on the soft hand shell 52 inner side wall, and the in-plane direction groove cannot be extruded due to the large distance and thick wall thickness, so the soft hand inner shell sealed cavity 56 does not affect the bending degree of the single finger assembly 5.

[0075] In the embodiment of the present application, the soft hand shell 52 is provided with convex blocks one in the direction of the single finger assembly 5, i.e. in the in-plane direction. When the outer finger assembly hydraulic pump fills water into the soft hand shell sealed cavity 57 through the soft hand shell flow joint 51 to increase the pressure, the in-plane recesses formed between the adjacent convex blocks one expand first due to the thin wall thickness, thereby realizing the bending of the single finger assembly 5. Each group of convex blocks of the soft hand inner shell 53 is provided with convex blocks two perpendicular to the direction of the single finger assembly 5, i.e. in the out-of-plane direction. When the inner finger assembly hydraulic pump fills water into the soft hand inner shell sealed cavity 56 to increase the pressure, the out-of-plane recesses formed between the adjacent convex blocks two expand first due to the thin wall thickness, thereby generating equal and opposite forces and acting on the inner side wall of the soft hand shell 52, thereby enhancing the out-of-plane rigidity of the single finger assembly 5.

[0076] Rigidity refers to the ability of the single finger assembly 5 to resist deformation under the action of liquid viscous force.

[0077] As shown in Figure 3 and Figure 4 , the hydraulic cavity assembly comprises:

[0078] The telescopic driving base 43 is a hollow cylinder with open ends. The side surface of the telescopic driving base 43 is provided with a hole five.

[0079] The two soft telescopic sealed cavities 42 are respectively communicated with the two ends of the telescopic driving base 43. The other end of each soft telescopic sealed cavity 42 is sealed. The telescopic driving base 43 and the two soft telescopic sealed cavities 42 form a telescopic hollow cavity.

[0080] The telescopic driving mechanism flow joint 6 is communicated with the hole five of the telescopic driving base 43, so that the telescopic driving mechanism flow joint 6 is communicated with the telescopic hollow cavity.

[0081] The telescopic driving assembly flow joint 6 is made of polyvinyl chloride resin extrusion molding, which has good softness.

[0082] The telescopic mechanism hydraulic pump is communicated with the telescopic driving mechanism flow joint 6 through the through hole of the finger fixing table 1.

[0083] As shown in Figure 3 and Figure 4 , the connecting assembly comprises:

[0084] The two fixed plates 41 are respectively fixedly installed at the sealed end of the two soft telescopic sealed cavities 42.

[0085] The four second pin hole seats 44 are respectively and vertically fixedly installed on the corresponding one of the two fixed plates 41.

[0086] Four pin hole seat connecting rods 45, one end of each pin hole seat connecting rod 45 is respectively hinged with the other end of the corresponding second pin hole seat 44 through a pin hole seat connecting bolt 46, the other end of each pin hole seat connecting rod 45 is respectively hinged with the first pin hole seat 34 on the corresponding second finger fixing base 32, each pin hole seat connecting rod 45 drives the finger connecting assembly 3 to rotate along the plane where the finger fixing table 1 is located in the circumference through the first pin hole seat 34.

[0087] The fixed plate 41, the telescopic driving base 43, the second pin hole seat 44 and the pin hole seat connecting rod 45 are all made of photosensitive resin material and are made by 3D printing process, the soft telescopic sealing cavity 42 is made of high-elasticity silicone rubber material by reverse molding, the whole is soft, the telescopic driving mechanism flow joint 6 is made of polyvinyl chloride resin by extrusion molding and has excellent chemical stability and good softness; the above materials all have high corrosion resistance in water environment, so they can be used for a long time, the telescopic hollow cavity is initially completely filled with water, when the telescopic mechanism hydraulic pump continuously fills water into the telescopic hollow cavity or pumps water out of the telescopic hollow cavity through the telescopic driving mechanism flow joint 6, because the water pressure inside the telescopic hollow cavity is greater than or less than the external water pressure, the telescopic hollow cavity expands and elongates or contracts and shortens, thereby dragging the second pin hole seat and the pin hole seat connecting rod to move outward or inward, so as to drive each finger connecting assembly 3 and the single finger assembly 5 to rotate, so as to realize the configuration change of the soft gripper.

[0088] The viscous force of the soft gripper in the liquid is that when the soft gripper performs the grabbing operation in the liquid, it drives the mutual movement between each layer of liquid to generate a tangential friction force, the friction force is opposite to the relative motion direction, hinders the flow of the liquid, and then hinders the soft gripper to perform the grabbing operation in the liquid.

[0089] As shown in Figure 8 the experimental result graph of the lateral force of the fingertip of the single finger assembly 5 of the underwater anti-viscous soft gripper changing with the water pressure of the soft hand outer shell sealing cavity 57 in the soft hand inner shell sealing cavity 56. The experimental results show that the greater the water pressure in the soft hand inner shell sealing cavity 56, the higher the out-of-plane rigidity of the single finger assembly 5, the smaller the out-of-plane bending of the single finger assembly 5 caused by the viscous force of the water body, and the higher the anti-viscous effect.

[0090] In this embodiment, the force applied to the lateral side of the single finger assembly 5 is used instead of the influence of the water viscosity force. The experimental scheme is as follows: the single finger assembly 5 is placed horizontally on the lateral side and the internal pressure is consistent with the ambient pressure, a force sensor is placed on the lateral side of the single finger assembly 5, the force sensor is located above the vertical moving stage support, different sizes of water pressure are introduced into the soft hand inner shell sealed cavity 56 and the soft hand outer shell sealed cavity 57 of the single finger assembly 5, and after stabilization, the vertical moving stage support is moved up by 15 mm to simulate the effect of water viscosity force, and the output change of the force sensor is recorded.

[0091] As shown in Figure 8 , the experimental results prove that when there is no water pressure in the soft hand inner shell sealed cavity 56, the force received by the lateral side of the single finger assembly 5 continuously increases with the continuous increase of the water pressure in the soft hand outer shell sealed cavity 57, which indicates that when the single finger assembly 5 is bent, the rigidity of the single finger assembly 5 gradually increases due to the increase of the pressure in the soft hand outer shell sealed cavity 57, and the resistance to water viscosity force is enhanced. When 10 kPa water pressure is introduced into the soft hand inner shell sealed cavity 56, the anti-viscosity ability of the single finger assembly 5 when not bent increases from 0.76 N to 1.01 N, and when the water pressure in the soft hand outer shell sealed cavity 57 continuously increases, the force received by the lateral side of the single finger assembly 5 continuously increases, and when the water pressure is 60 kPa, it stabilizes at 1.57 N, and the anti-viscosity effect is significantly improved. When 20 kPa water pressure is introduced into the soft hand inner shell sealed cavity 56, the anti-viscosity effect of the single finger assembly 5 is improved to a greater extent. The above results prove that the nested double-layer sealed cavity design has excellent improvement on the water body viscosity resistance ability of the underwater soft gripper.

[0092] In this embodiment, the force applied to the lateral side of the single finger assembly 5 is used instead of the influence of the water viscosity force. The experimental scheme is as follows: the single finger assembly 5 is placed horizontally on the lateral side and the internal pressure is consistent with the ambient pressure, a force sensor is placed on the lateral side of the single finger assembly 5, the force sensor is located above the vertical moving stage support, different sizes of water pressure are introduced into the soft hand inner shell sealed cavity 56 and the soft hand outer shell sealed cavity 57 of the single finger assembly 5, and after stabilization, the vertical moving stage support is moved up by 15 mm to simulate the effect of water viscosity force, and the output change of the force sensor is recorded.

[0093] As shown in Figure 9As shown, the experimental results prove that when there is no water pressure in the soft inner shell sealing cavity 56, the force received by the fingertips of the single finger assembly 5 continuously increases with the continuous increase of the water pressure in the soft outer shell sealing cavity 57, which indicates that when the single finger assembly 5 is bent, the gripping force of the single finger assembly 5 gradually increases due to the increase of the pressure in the soft outer shell sealing cavity 57. When the water pressure in the soft inner shell sealing cavity 56 is 10 kPa, the force received by the fingertips of the single finger assembly 5 is obviously improved when the water pressure in the soft outer shell sealing cavity 57 increases from 0 to 20 kPa. When the water pressure in the soft outer shell sealing cavity 57 increases to 60 kPa, the force received by the fingertips of the single finger assembly 5 is almost the same as that when there is no water pressure in the soft inner shell sealing cavity 56, which indicates that the gripping force of the single finger assembly 5 at a low bending degree is significantly improved. When the water pressure in the soft inner shell sealing cavity 56 is 20 kPa, the gripping force of the single finger assembly 5 at a low bending degree is further improved. The above results prove that the nested double-layer sealing cavity design can significantly improve the gripping force of the underwater soft gripper at a low bending degree.

[0094] The underwater anti-sticking soft gripper with variable configuration of the embodiment further comprises a control system electrically connected with the four outer finger assembly hydraulic pumps, the four inner finger assembly hydraulic pumps and the telescopic mechanism hydraulic pump, respectively.

[0095] The embodiment performs gripping according to the gripping method of the underwater anti-sticking soft gripper.

[0096] The gripping method is performed according to the cross configuration gripping mode and the side-by-side configuration gripping mode, respectively.

[0097] The cross configuration gripping mode is to first empty the liquid in the soft telescopic sealing cavity 42 to make the finger bases 54 of the four finger gripping mechanisms arranged in a cross configuration, then adjust the liquid in the soft inner shell sealing cavity 56 to adjust the rigidity of the side of the single finger assembly 5, and finally fill the liquid into the soft outer shell sealing cavity 57 to achieve gripping, which is used for gripping irregular objects such as spheres.

[0098] The side-by-side configuration gripping mode is to first fill the liquid into the soft telescopic sealing cavity 42 to make the finger bases 54 of the four finger gripping mechanisms arranged in a side-by-side configuration, then adjust the liquid in the soft inner shell sealing cavity 56 to adjust the rigidity of the side of the single finger assembly 5, and finally fill the liquid into the soft outer shell sealing cavity 57 to achieve gripping, which is used for gripping irregular objects such as cylinders or flat objects.

[0099] The cross-shaped arrangement is arranged such that the two opposite finger bases 54 are parallel to each other, and the two adjacent finger bases 54 are perpendicular to each other; the side-by-side arrangement is arranged such that the plane of each finger base 54 is parallel to the plane of one adjacent finger base 54, and perpendicular to the plane of the other adjacent finger base 54. In the cross-shaped arrangement, one set of two opposite finger gripping mechanisms is rotated by 45 degrees in one direction, and the other set of two opposite finger gripping mechanisms is rotated by 45 degrees in the opposite direction, to form the side-by-side arrangement.

[0100] The cross-shaped arrangement can achieve close contact with the object to be gripped when the object is a spherical irregular object, so that the gripping force is maximally utilized, and the gripping accuracy, stability and accuracy are improved, for example, the object to be gripped includes but is not limited to stones, sea urchins and snails in the ocean; the side-by-side arrangement can achieve close contact with the object to be gripped when the object is a cylindrical or flat irregular object, so that the gripping force is maximally utilized, and the gripping accuracy, stability and accuracy are improved, for example, the object to be gripped includes but is not limited to various fish, sea cucumbers and shells in the ocean.

[0101] The cross-shaped gripping method is specifically as follows:

[0102] Before the underwater anti-sticking soft gripper performs the gripping operation, the telescopic hollow cavity, the soft hand inner shell sealed cavity 56 and the soft hand outer shell sealed cavity 57 are filled with liquid.

[0103] The telescopic mechanism hydraulic pump continuously extracts liquid outside through the telescopic drive mechanism flow joint 6, the soft telescopic sealed cavity 42 is contracted to drive the rotation of each finger gripping mechanism, until the telescopic hollow cavity is completely contracted, so that the four finger gripping mechanisms form a cross-shaped arrangement.

[0104] The inner finger assembly hydraulic pump fills and extracts liquid into the soft hand inner shell sealed cavity 56 through the soft hand inner shell flow joint 55, so as to adjust the rigidity of the side surface of the single finger assembly 5.

[0105] The outer finger assembly hydraulic pump fills liquid into the soft hand outer shell sealed cavity 57 through the soft hand outer shell flow joint 51, so that the single finger assembly 5 is bent to achieve gripping, which is used for gripping a spherical irregular object.

[0106] The side-by-side gripping method is specifically as follows:

[0107] Before the underwater anti-sticking soft gripper performs the gripping operation, the telescopic hollow cavity, the soft hand inner shell sealed cavity 56 and the soft hand outer shell sealed cavity 57 are filled with liquid.

[0108] The telescopic mechanism hydraulic pump continuously fills liquid into the telescopic drive mechanism flow channel joint 6, the soft telescopic sealing cavity 42 expands to drive the rotation of each finger grabbing mechanism, until the telescopic hollow cavity is fully expanded, so that the four finger grabbing mechanisms are arranged in a side-by-side configuration.

[0109] The inner finger assembly hydraulic pump fills and extracts liquid into the soft inner hand shell sealing cavity 56 through the soft inner hand shell flow channel joint 55, so as to adjust the rigidity of the side of the single finger assembly 5.

[0110] The outer finger assembly hydraulic pump fills liquid into the soft outer hand shell sealing cavity 57 through the soft outer hand shell flow channel joint 51, so that the single finger assembly 5 bends to achieve grabbing, for grabbing cylindrical or flat irregular objects.

[0111] By controlling the pressure of the liquid in the soft outer hand shell sealing cavity 57, the degree of finger bending and the grabbing force are changed under different water pressure conditions to grab different objects in different environments; the greater the water pressure in the soft inner hand shell sealing cavity 56, the higher the out-of-plane rigidity of the single finger assembly 5, the higher the grabbing force, and the smaller the out-of-plane bending of the single finger assembly 5 caused by water body viscosity, the higher the anti-viscosity effect.

[0112] In the embodiment of the present application, the cavities inside the underwater anti-viscosity soft body gripper are filled with liquid, generally pure water, and are driven by hydraulic pressure. Several hydraulic pumps adjust the liquid pressure in the soft body gripper cavity in real time according to the underwater environment pressure of the soft body gripper to balance the external water pressure. In addition, by controlling the liquid pressure in the cavity of the underwater anti-viscosity soft body gripper, the degree of finger bending and the grabbing force can be changed under different water pressure conditions to stably grab different objects in different environments.

[0113] The present application has two configurations of side-by-side and cross-shaped grabbing modes, which realizes grabbing of different types of underwater grabbing objects, and has high anti-viscosity in water.

[0114] The above specific embodiments are used to explain and illustrate the present application, rather than limit the present application. Any modifications, equivalent replacements, changes, etc. made to the present application within the spirit and protection scope of the claims fall within the protection scope of the present application.

Claims

1. A variable configuration underwater anti-stiction soft gripper, comprising: The utility model relates to a kind of underwater mechanical arm fingered gripper, including: Finger fixing platform (1), one end is fixedly connected with underwater mechanical arm by flange; Four finger supports (2) are evenly spaced along the circumference of finger fixing platform (1), and one end of each finger support (2) is fixedly installed on the other end of finger fixing platform (1); Four finger gripping mechanisms, one end of each finger gripping mechanism is movably installed on the other end of the corresponding finger support (2) respectively; Each finger gripping mechanism includes a finger connecting assembly (3), and the finger connecting assembly (3) includes a second finger fixing base (32); A telescopic drive mechanism (4) is arranged between the four finger gripping mechanisms, and the telescopic drive mechanism (4) includes a hydraulic cavity assembly and a connecting assembly, the connecting assembly is fixedly connected with the hydraulic cavity assembly, and the connecting assembly is also hingedly connected with the upper parts of the four finger gripping mechanisms respectively, so that the four finger gripping mechanisms are driven to rotate by the telescopic drive mechanism (4) to form different configurations; The hydraulic cavity assembly includes: A telescopic drive base (43) is a hollow cylinder with open ends, and a hole five is formed in the side surface of the telescopic drive base (43); Two soft telescopic sealing cavities (42) are in communication with the two ends of the telescopic drive base (43) respectively, and the other end of each soft telescopic sealing cavity (42) is sealed, so that the telescopic drive base (43) and the two soft telescopic sealing cavities (42) form a telescopic hollow cavity; A telescopic drive mechanism flow connector (6) is in communication with the hole five of the telescopic drive base (43), so that the telescopic drive mechanism flow connector (6) is in communication with the telescopic hollow cavity; A telescopic mechanism hydraulic pump is in communication with the other end of the telescopic drive mechanism flow connector (6); The connecting assembly includes: Two fixed plates (41) are fixedly installed at the sealed ends of the two soft telescopic sealing cavities (42) respectively; Four second pin hole seats (44) are fixedly installed on the corresponding one of the two fixed plates (41) respectively, and the other two second pin hole seats (44) are fixedly installed on the other fixed plate (41) respectively; 2. A variable configuration underwater anti-stiction soft gripper according to claim 1, wherein, Four pin hole seat connecting rods (45) are hingedly connected with the other ends of the corresponding second pin hole seats (44) respectively, and the other ends of the four pin hole seat connecting rods (45) are hingedly connected with the first pin hole seats (34) on the corresponding second finger fixing bases (32) respectively, so that each pin hole seat connecting rod (45) drives the finger connecting assembly (3) to rotate along the plane in which the finger fixing platform (1) is located. Each finger gripping mechanism includes: A finger connecting assembly (3) is movably installed at the other end of the corresponding finger support (2); 3. A variable configuration underwater anti-stiction soft gripper according to claim 2, wherein, A single finger assembly (5) is fixedly installed at the other end of the finger connecting assembly (3). The finger connecting assembly (3) includes: The second finger fixing base (32) is provided with a small hole at one end, a rotary bearing is arranged in the small hole, the outer ring of the rotary bearing is interference fitted in the small hole, and the inner ring of the rotary bearing is interference fitted with the other end of the finger support (2), so that the second finger fixing base (32) is movably arranged on the corresponding finger support (2); The first pin hole seat (34) is fixedly arranged on the second finger fixing base (32); The first finger fixing base (31) is adhesively nested in the other end of the second finger fixing base (32), the first finger fixing base (31) is fixedly connected with the second finger fixing base (32) through the base connecting bolt (33), the other end of the first finger fixing base (31) is provided with a convex-concave interlocking structure, and the first finger fixing base (31) is further provided with a hole one.

4. A variable configuration underwater anti-stiction soft gripper according to claim 2, wherein, The single finger assembly (5) comprises: The soft hand outer shell (52) is provided with a convex-concave interlocking structure and is fixedly connected with the convex-concave interlocking structure of the first finger fixing base (31), the soft hand outer shell (52) is further provided with a plurality of convex blocks one connected in the in-plane direction, and the soft hand outer shell (52) is further provided with a hole two and a hole three respectively arranged on the convex blocks one close to the first finger fixing base (31); The soft hand inner shell (53) is provided with a plurality of convex block groups connected in the in-plane direction, the overall shape of each convex block group is consistent with the corresponding convex block one in the soft hand outer shell (52), each convex block group is sleeved with the corresponding convex block one in the soft hand outer shell (52), each convex block group is provided with a plurality of convex blocks two in the out-of-plane direction, and the soft hand inner shell (53) is further provided with a hole four arranged on the convex blocks two close to the first finger fixing base (31); The finger base (54) is adhesively bonded at the bottom of the soft hand inner shell (53), the finger base (54) and the inner surface of the soft hand inner shell (53) form a soft hand inner shell sealing cavity (56), and the finger base (54) is adhesively bonded with the soft hand outer shell (52); the outer surface of the soft hand inner shell (53) and the inner surface of the soft hand outer shell (52) form a soft hand outer shell sealing cavity (57); The soft hand outer shell flow connector (51) is in communication with the hole two of the soft hand outer shell (52), so that the soft hand outer shell flow connector (51) is in communication with the soft hand outer shell sealing cavity (57); The soft hand inner shell flow connector (55) is in communication with the hole four after passing through the hole one and the hole three, so that the soft hand inner shell flow connector (55) is in communication with the soft hand inner shell sealing cavity (56); The outer finger assembly hydraulic pump is connected with the other end of the soft hand outer shell flow connector (51); The inner finger assembly hydraulic pump is connected with the other end of the soft hand inner shell flow connector (55); The in-plane direction is the parallel plane of the plane where the finger base (54) is located, and the out-of-plane direction is the parallel plane of the plane where the side surface of the soft hand outer shell (52) is located.

5. The shape-changeable underwater anti-sticking soft gripper according to claim 1, characterized in that, Further comprising: The control system is electrically connected with the four outer finger assembly hydraulic pumps, the four inner finger assembly hydraulic pumps and the telescopic mechanism hydraulic pump respectively.

6. The grasping method applied to the underwater anti-sticking soft gripper of claim 4, characterized in that: the grasping method is respectively carried out in a cross-shaped configuration grasping mode and a side-by-side configuration grasping mode; the cross-shaped configuration grasping mode is to first empty the liquid in the soft stretchable sealed cavity (42) to make the finger bases (54) of the four finger grasping mechanisms form a cross-shaped configuration arrangement, then adjust the rigidity of the side of the single finger assembly (5) by adjusting the liquid in the soft inner shell sealed cavity (56), and finally realize grasping by filling the liquid into the soft outer shell sealed cavity (57), which is used for grasping irregular spherical objects; the side-by-side configuration grasping mode is to first fill the liquid into the soft stretchable sealed cavity (42) to make the finger bases (54) of the four finger grasping mechanisms form a side-by-side configuration arrangement, then adjust the rigidity of the side of the single finger assembly (5) by adjusting the liquid in the soft inner shell sealed cavity (56), and finally realize grasping by filling the liquid into the soft outer shell sealed cavity (57), which is used for grasping irregular cylindrical or flat objects; the cross-shaped configuration arrangement is that the faces where the opposite two finger bases (54) are located are parallel to each other, and the faces where the adjacent two finger bases (54) are located are perpendicular to each other; the side-by-side configuration arrangement is that the face where each finger base (54) is located is in the same plane as the face where one adjacent finger base (54) is located, and is parallel to the face where the other adjacent finger base (54) is located.

7. The method of grasping of claim 6, wherein, the cross-shaped configuration grasping mode is specifically: the underwater anti-sticking soft gripper fills the liquid into the stretchable hollow cavity, the soft inner shell sealed cavity (56) and the soft outer shell sealed cavity (57) before grasping operation; the stretchable mechanism hydraulic pump continuously extracts liquid through the stretchable driving mechanism flow joint (6), the soft stretchable sealed cavity (42) shrinks to drive the rotation of each finger grasping mechanism until the stretchable hollow cavity is completely shrunk, so that the four finger grasping mechanisms form a cross-shaped configuration arrangement; the inner finger assembly hydraulic pump fills and extracts liquid into the soft inner shell sealed cavity (56) through the soft inner shell flow joint (55), so as to adjust the rigidity of the side of the single finger assembly (5); the outer finger assembly hydraulic pump fills liquid into the soft outer shell sealed cavity (57) through the soft outer shell flow joint (51), so that the single finger assembly (5) bends to realize grasping, which is used for grasping irregular spherical objects.

8. The method of grasping of claim 7, wherein, the side-by-side configuration grasping mode is specifically: the underwater anti-sticking soft gripper fills the liquid into the stretchable hollow cavity, the soft inner shell sealed cavity (56) and the soft outer shell sealed cavity (57) before grasping operation; the stretchable mechanism hydraulic pump continuously fills liquid through the stretchable driving mechanism flow joint (6), the soft stretchable sealed cavity (42) expands to drive the rotation of each finger grasping mechanism until the stretchable hollow cavity is completely expanded, so that the four finger grasping mechanisms form a side-by-side configuration arrangement; the inner finger assembly hydraulic pump fills and extracts liquid into the soft inner shell sealed cavity (56) through the soft inner shell flow joint (55), so as to adjust the rigidity of the side of the single finger assembly (5); The hydraulic pump of the outer finger assembly fills the soft hand outer shell sealed cavity (57) through the soft hand outer shell flow channel joint (51), so that the single finger assembly (5) is bent to achieve grasping, which is used for grasping cylindrical or flat irregular objects.

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