Under-actuated eagle claw imitating mechanical grab bucket

Abstract

The invention belongs to the field of grab buckets, and relates to an under-actuated eagle claw imitating mechanical grab bucket which can grab objects of various shapes and sizes through few power sources. The technical scheme comprises a base, a power piece and a grab bucket. The power piece is fixed to the base and comprises a piston which moves in a reciprocating mode in the first direction. The grab bucket is arranged on the side, away from the base, of the power piece, and the grab bucket is connected with the piston. The grab bucket comprises grippers, each gripper comprises a flexible ball, the four grippers are distributed around the center line of the piston, one end of each gripper is hinged to the piston, the middle of each gripper is connected with the base, and the grippers have the tendency of rotating around the connecting points of the grippers and the base. The center points of the flexible balls are all located in the space formed by folding the four tongs.

Description

Technical Field

[0001] The present invention belongs to the field of grab buckets and relates to an underactuated eagle-claw-like mechanical grab bucket. Background Art

[0002] In the fields of modern industry and technology, mechanical grab bucket devices play a crucial role. Due to its advantages such as simple structure, low cost, and high reliability, the underactuated system has gradually attracted attention. An underactuated system refers to a system in which the number of independent control inputs is less than the number of degrees of freedom of the system. In the field of mechanical grab buckets, the application of underactuated technology can enable the grab bucket to achieve various grasping actions with fewer control inputs, improving the adaptability and flexibility of the grab bucket. In addition, the biological structures and movement patterns in nature often inspire human technological innovation. As an efficient grasping organ, the eagle's claw has a unique structure and grasping mechanism. The eagle's claw can accurately grasp prey during high-speed flight, with large grasping force, high stability, and flexible movements. Studying the structure and grasping principle of the eagle's claw can provide useful references for designing new mechanical grab bucket devices.

[0003] Currently, traditional mechanical grab buckets often have problems such as a cumbersome drive system that requires multiple power sources to control each grasping part, high control difficulty, and inflexible operation; complex structure, consisting of multiple parts with large volume and weight; and limited adaptability to objects of different shapes, sizes, and materials, requiring adjustment or replacement for specific types of objects. With the continuous progress of technology, people's performance requirements for mechanical grab buckets are getting higher and higher. In view of the problems existing in the existing mechanical grab buckets, the present invention overcomes the above defects. By adopting an underactuated design, it can achieve the control of each grasping part with fewer power sources, with flexible operation; and by simulating the physiological structure of the eagle's claw, it has a simple and compact structure, better flexibility and adaptability; at the same time, it can adaptively grasp objects of various shapes and sizes like the eagle's claw, and has stronger grasping ability for irregular objects and objects with smooth surfaces. Summary of the Invention

[0004] To overcome the defects in the above related technologies, the present invention proposes an underactuated eagle-claw-like mechanical grab bucket, which can complete the grasping of objects of various shapes and sizes with fewer power sources.

[0005] To achieve the above technical objectives, the underactuated eagle-claw-like mechanical grab bucket described in the present invention includes: a base, a power member, and a grab bucket. The power member is fixed on the base, and the power member includes a piston that reciprocates along a first direction. The grab bucket is arranged on the side of the power member away from the base, and the grab bucket is connected to the piston.

[0006] Among them, the grab includes a gripper, the gripper includes a flexible ball, four grippers are distributed around the central line of the piston, one end of the gripper is hinged to the piston, the middle of the gripper is connected to the base, the gripper has a tendency to rotate around the connection point with the base, and the center points of the flexible balls are all located within the space where the four grippers are closed.

[0007] Preferably, the gripper includes: a first connecting rod, a second connecting rod, a third connecting rod, a torsion spring, a driving motor and a pulling rope. The first connecting rod is a straight rod, and one end of the first connecting rod is hinged to the piston. The middle of the second connecting rod is connected to the base, and the second connecting rod has a tendency to rotate around the center point of the connection position with the base. One end of the second connecting rod is hinged to the other end of the first connecting rod, and a flexible ball is also fixed at a position away from one end of the second connecting rod at the center point of the connection position between the second connecting rod and the base. The third connecting rod is hinged to the other end of the second connecting rod. The torsion spring is sleeved on the hinged rod of the second connecting rod and the third connecting rod, and one end of the torsion spring is fixedly connected to the second connecting rod, and the other end of the torsion spring is fixedly connected to the third connecting rod. The driving motor is fixedly connected to the piston. One end of the pulling rope is fixedly connected to the output shaft of the driving motor. When the output shaft of the driving motor rotates, the pulling rope is wound around the output shaft. The other end of the pulling rope bypasses the hinge between the second connecting rod and the third connecting rod and is fixedly connected to the outside of the third connecting rod. The pulling rope drives the third connecting rod to rotate in a direction away from the space where the four grippers are closed.

[0008] Preferably, the flexible ball includes: a hollow sphere, a flexible bladder, an electromagnetic coil, a storage bladder and a magnetorheological fluid. The hollow sphere includes a spherical shell. A through groove is provided on the hollow sphere, and the through groove penetrates the spherical shell and is isolated from the internal space of the hollow sphere. The second connecting rod passes through the through groove and is fixed. A flexible bladder is fixed on the surface of the hollow sphere away from the through groove side, and the flexible bladder is a curved surface adapted to the outer surface of the spherical shell. An electromagnetic coil is fixed between the flexible bladder and the outer surface of the spherical shell. The storage bladder is arranged in the internal space of the hollow sphere. The storage bladder communicates with the flexible bladder through the spherical shell, and the outside of the internal space of the hollow sphere is sealed. The magnetorheological fluid is filled into the storage bladder and the flexible bladder, and the filling volume of the magnetorheological fluid is 70% - 90% of the internal space of the storage bladder and the flexible bladder.

[0009] Preferably, a plurality of grooves are provided on the surface of the flexible ball on the side close to the space where the four grippers are closed.

[0010] Preferably, the driving motor is fixed to the piston end, and the center line of the output shaft of the driving motor is collinear with the center line of the piston. The second connecting rod includes: two rods with the same structure and a connecting column. The two rods with the same structure are arranged in parallel, and a plurality of connecting columns are arranged between the two rods with the same structure. The pulling rope is fixedly connected to the outside of the third connecting rod through the connecting column in sequence.

[0011] Preferably, the base includes: a connecting seat and a T-shaped member. The upper end of the connecting seat is provided with a connecting flange for the equipment, and a power member is fixed to the lower end of the connecting seat. The T-shaped member is a block structure as a whole. The upper end of the T-shaped member is fixedly connected to the connecting seat, and the lower end of the T-shaped member is hinged to the middle of the second connecting rod.

[0012] Preferably, a wire passing hole is further provided at the lower end of the T-shaped member, and the other end of the pulling rope passes through the wire passing hole and is fixedly connected to the corresponding third connecting rod through the connecting column.

[0013] Preferably, the grab further includes a guide coil. The guide coil is arranged on one side of the output shaft of the driving motor and at the same height, and the guide coil is fixedly connected to the driving motor. One ends of the plurality of pulling ropes pass through the guide coil and are fixedly connected to the output shaft of the driving motor.

[0014] Preferably, the four grippers include one first gripper and three second grippers. The widths of the second connecting rod and the third connecting rod of the first gripper are greater than those of the second connecting rod and the third connecting rod of the first gripper. The included angle between adjacent second grippers among the three second grippers is 60°, and the three second grippers and the first gripper are all symmetrical about a center line.

[0015] The beneficial effects of the present invention are as follows: The flexible ball of the present invention simulates the physiological structure of the eagle's claw. In particular, the toe pads on the eagle's claw are simulated by flexible balls, which can improve the adaptability to objects with different structures and sizes, as well as enhance the friction on the object surface. In addition, the flexible ball has a certain protection function for fragile objects.

[0016] The arrangement of the four grippers of the present invention simulates the unequal toe type of the eagle's claw, which can improve the grasping adaptability, specifically, improve the grasping adaptability and grasping strength for objects with a larger volume.

[0017] The present invention uses a driving motor and a pulling rope, which can reduce the power source, lower the cost and control difficulty, and at the same time reduce the equipment failure rate. Description of the Drawings

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the related art, the following will briefly introduce the drawings required for the description of the embodiments or the related art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 Structural diagram of the present invention; Figure 2 Structural diagram of the present invention in another direction; Figure 3 Structural diagram of the gripper of the present invention; Figure 4 Structural diagram of the flexible ball of the present invention; Figure 5 Three - view drawings of the T - shaped part of the present invention; Figure 6 Structural diagram of the T - shaped part of the present invention. Detailed implementation manners

[0020] To make the above - mentioned objects, features, and advantages of the present invention more obvious and understandable, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0021] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is 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 operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0022] The terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0023] Such as Figures 1 to 6As shown in the figure, the underactuated eagle-claw mechanical grab 3 according to some embodiments of the present invention includes: a base 1, a power member 2, and a grab 3. The power member 2 is fixed on the base 1, and the power member 2 includes a piston that reciprocates in a first direction. The grab 3 is disposed on a side of the power member 2 away from the base 1, and the grab 3 is connected to the piston.

[0024] Wherein, the grab 3 includes a gripper, the gripper includes a flexible ball 31, four grippers are distributed around the center line of the piston, one end of the gripper is hinged to the piston, the middle of the gripper is connected to the base 1, the gripper has a tendency to rotate around the connection point with the base 1, and the center points of the flexible balls 31 are all located within the space where the four grippers are closed.

[0025] In some examples, the power member 2 can adopt a cylinder 21, and the outer shell of the cylinder 21 is vertically fixed on the base 1, that is, the cylinder 21 reciprocates in a first direction (vertical direction). The grab 3 is fixed to the base 1 and hinged to the piston of the cylinder 21. When the piston reciprocates, the grab 3 is driven to operate.

[0026] The grab 3 of the present application simulates the eagle-claw structure, that is, the grab 3 includes four grippers, and a flexible ball 31 is arranged on each gripper. The flexible ball 31 can be made of rubber material, and the diameter can be, for example, 3 - 5 cm. The center point of the flexible ball 31 is located inside the grab 3. When the grab 3 closes inward, the flexible ball 31 is squeezed by the object inside the grab 3 and can form a resultant force with the gripper, which is suitable for grasping small fixed-volume items.

[0027] In some embodiments, the gripper includes: a first link 321, a second link 322, a third link 323, a torsion spring, a drive motor 325, and a pulling rope. The first link 321 is a straight rod, and one end of the first link 321 is hinged to the piston. The middle of the second link 322 is connected to the base 1, and the second link 322 has a tendency to rotate around the center point of the connection position with the base 1. One end of the second link 322 is hinged to the other end of the first link 321. A flexible ball 31 is also fixed at a position of the center point of the connection position between the second link 322 and the base 1 that is away from one end of the second link 322. The third link 323 is hinged to the other end of the second link 322. The torsion spring is sleeved on the hinged rod of the second link 322 and the third link 323, and one end of the torsion spring is fixedly connected to the second link 322, and the other end of the torsion spring is fixedly connected to the third link 323. The drive motor 325 is fixedly connected to the piston. One end of the pulling rope is fixedly connected to the output shaft of the drive motor 325. When the output shaft of the drive motor 325 rotates, the pulling rope is wound around the output shaft. The other end of the pulling rope bypasses the hinge between the second link 322 and the third link 323 and is fixedly connected to the outside of the third link 323. The pulling rope drives the third link 323 to rotate in a direction away from the space where the four grippers close together.

[0028] In some examples, the first link 321 is a straight rod. According to the distribution mode of the four grippers, a plurality of first links 321 are distributed around the piston, and the first link 321 is hinged to the piston.

[0029] The second link 322 can be a two-section structure: a first-section link 3221 and a second-section link 3222. The first-section link 3221 is a straight rod, and the second-section link 3222 is an arc-shaped rod. The first-section link 3221 and the second-section link 3222 are fixedly connected. The connection position between the first-section link 3221 and the second-section link 3222 is hinged to the base 1, so that the second link 322 can rotate around the hinge of the base 1. One end of the first-section link 3221 is also hinged to the first link 321. The flexible ball 31 is fixed in the middle of the second-section link 3222.

[0030] The third link 323 is an arc-shaped rod member, which is hinged to the second-section link 3222. A torsion spring is arranged at the connection position between the third link 323 and the second-section link 3222. Under the action of the torsion spring, the third link 323 has a tendency to move inside the grab bucket 3.

[0031] The driving motor 325 is fixed to the lower end of the piston of the air cylinder 21. Each gripper is equipped with a pulling rope. One end of the pulling rope is fixedly connected to the output shaft of the driving motor 325, and the other end of the pulling rope is fixedly connected to the outer side of the third connecting rod 323 through one end of the second-stage connecting rod 3222. When the driving motor 325 operates, the pulling rope is tightened to cause the third connecting rod 323 to turn outward.

[0032] In some embodiments, the flexible ball 31 includes: a hollow sphere 311, a flexible bladder 312, an electromagnetic coil 313, a storage bladder 314, and a magnetorheological fluid. The hollow sphere 311 includes a spherical shell. A through groove is provided on the hollow sphere 311, and the through groove penetrates the spherical shell and is isolated from the internal space of the hollow sphere 311. The second connecting rod 322 passes through the through groove and is fixed. A flexible bladder 312 is fixed to the surface of the hollow sphere 311 away from the through groove, and the flexible bladder 312 is a curved surface adapted to the outer surface of the spherical shell. An electromagnetic coil 313 is fixed between the flexible bladder 312 and the outer surface of the spherical shell. The storage bladder 314 is arranged in the internal space of the hollow sphere 311. The storage bladder 314 communicates with the flexible bladder 312 through the spherical shell, and the internal space of the hollow sphere 311 is hermetically sealed to the outside. The magnetorheological fluid is filled into the storage bladder 314 and the flexible bladder 312, and the filling volume of the magnetorheological fluid is 70% - 90% of the internal space of the storage bladder 314 and the flexible bladder 312.

[0033] In some examples, the hollow sphere 311 is an elastic rubber sphere with a volume of 3 - 5 cm³. A cavity is provided inside the hollow sphere 311, and the side wall thickness of the hollow sphere 311 is 2 - 3 cm. A through groove is provided on the side wall of the flexible ball 31, and the through groove has an interference fit with the second-stage connecting rod 3222, that is, when the flexible ball 31 is inserted into the second-stage connecting rod, they remain relatively fixed. In addition, the inner cavity of the flexible ball 31 communicates with the through groove, and when the flexible ball 31 is squeezed, the air in the inner cavity can be discharged, and when the flexible ball 31 is not squeezed, it can recover autonomously.

[0034] The flexible bladder 312 and the storage bladder 314 can be elastic rubber air bladders. Herein, the internal space of the storage bladder 314 and the flexible bladder 312 refers to: the internal space when the storage bladder 314 and the flexible bladder 312 are filled with gas and the cortex of the elastic rubber air bladder does not undergo elastic deformation.

[0035] The wire of the electromagnetic coil can penetrate the inside of the hollow sphere 311, be arranged side by side with the pulling rope, and be guided to the driving motor 325.

[0036] In some embodiments, a plurality of grooves are provided on the surface of the flexible ball 31 near the space where the four grippers are closed. In some examples, the grooves can be circular grooves or hexagonal grooves with a diameter of 0.5 and a depth of 2 mm. The plurality of grooves are closely arranged. The grooves can increase the friction of the flexible ball 31, or the grooves can press against the smooth object surface to achieve adsorption on the object surface, generally improving the grasping ability of the object.

[0037] In some embodiments, the drive motor 325 is fixed to the piston end, and the center line of the output shaft of the drive motor 325 is collinear with the center line of the piston. The second link 322 includes: two rods with the same structure and connecting columns. The two rods with the same structure are arranged in parallel, and a plurality of connecting columns are provided between the two rods with the same structure. The pulling rope passes through the connecting columns in sequence and is fixedly connected to the outside of the third link 323.

[0038] The base 1 includes: a connecting seat 11 and a T-shaped member 12. The upper end of the connecting seat 11 is provided with a connecting flange for the device, and a power member 2 is fixed to the lower end of the connecting seat 11. The T-shaped member 12 is an overall block structure. The upper end of the T-shaped member 12 is fixedly connected to the connecting seat 11, and the lower end of the T-shaped member 12 is hinged to the middle of the second link 322.

[0039] A wire passing hole is further provided at the lower end of the T-shaped member 12. The other end of the pulling rope passes through the wire passing hole and is fixedly connected to the corresponding third link 323 through the connecting column.

[0040] The grab 3 further includes a guide coil. The guide coil is arranged on one side of the output shaft of the drive motor 325 and at the same height, and the guide coil is fixedly connected to the drive motor 325. One ends of the plurality of pulling ropes pass through the guide coil and are fixedly connected to the output shaft of the drive motor 325.

[0041] The four grippers include a first gripper and three second grippers. The widths of the second link 322 and the third link 323 of the first gripper are greater than those of the second link 322 and the third link 323 of the first gripper. The included angle between adjacent second grippers among the three second grippers is 60°, and the three second grippers and the first gripper are all symmetric about a center line.

[0042] This application further includes a cylinder 21 control solenoid valve, and the cylinder 21 control solenoid valve is connected to the air source and the cylinder 21.

[0043] This application further includes a Buck - Boost circuit and a power supply. The power supply is electrically connected to the current input end of the Buck - Boost circuit, and the electromagnetic coil 313 is electrically connected to the current output end of the Buck - Boost circuit.

[0044] This application also includes a controller, which can be a PLC or a microprocessor. The controller is electrically connected to the driving motor 325, the solenoid valve for controlling the cylinder 21, and the base of the triode in the Buck - Boost circuit. Among them, the power supply also powers the operation of the entire device.

[0045] The power supply and the controller can be installed on the cylinder housing and are electrically connected to the driving motor and the electromagnetic coil. The Buck - Boost circuit is integrated on the circuit board inside the controller.

[0046] The specific operation process of this application is as follows: When grasping an object, the air pump pumps air out of the cylinder 2121, causing the piston 211 to move upward, driving the first connecting rod 321 to move upward, thereby causing the second connecting rod 322 to rotate, and the lower end of the second connecting rod 322 expands outward. The output end of the driving motor 325 rotates, tightening the pulling rope, causing the third connecting rod 323 to rotate outward, that is, completing the purpose of opening the entire grab 3.

[0047] After that, align with the object so that the object is within the space of the grab 3. The driving motor 325 rotates in the reverse direction, the pulling rope is loosened, the third connecting rod 323 rotates inward, and the object is received into the grab 3. At this time, the piston of the cylinder 21 moves downward, the second connecting rod 322 rotates inward, and the flexible ball 31 and the third connecting rod 323 clamp the object, completing the grasping work of the object.

[0048] In addition, when the object is within the space of the grab 3, the hollow sphere 311 is deformed by the extrusion of the object, the internal space of the hollow sphere 311 decreases, and the magnetorheological fluid in the storage bladder 314 is extruded into the flexible bladder 312. The volume of the flexible bladder 312 increases, covering the surface of the object with a larger area. When the grasping action is completed, the controller controls the electromagnetic coil 313 to work, and under the action of the electromagnetic field, the magnetorheological fluid gradually solidifies, thus increasing the grasping force on the object.

[0049] When it is necessary to release the object, the piston 211 moves upward and at the same time the driving motor 325 tightens the pulling rope.

[0050] In the description of this specification, specific features, structures, materials, or characteristics can be combined in a suitable manner in any one or more embodiments or examples.

[0051] The above are only the specific implementation manners of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. An underactuated eagle claw-like mechanical grab, characterized in that: include: Base; A power member, the power member is fixed on the base, and the power member includes a piston that reciprocates along a first direction; A grab bucket, which is arranged on a side of the power member away from the base and connected to the piston; Wherein, the grab bucket includes a grabber, and the grabber includes a flexible ball. Four grabbers are distributed around the center line of the piston. One end of the grabber is hinged to the piston, and the middle part of the grabber is connected to the base. The grabber has a tendency to rotate around the connection point with the base, and the center points of the flexible balls are all located in the space where the four grabbers are closed.

2. The underactuated eagle claw mechanical grab according to claim 1, characterized in that: The gripper comprises: A first connecting rod, wherein the first connecting rod is a straight rod, and one end of the first connecting rod is hinged to the piston; A second connecting rod, wherein the middle portion of the second connecting rod is connected to the base, and the second connecting rod has a tendency to rotate around a center point of a connection position with the base, one end of the second connecting rod is hinged to the other end of the first connecting rod, and a flexible ball is fixed at a position away from one end of the second connecting rod at a center point of a connection position between the second connecting rod and the base; a third connecting rod, the third connecting rod being hinged to the other end of the second connecting rod; A torsion spring, wherein the torsion spring is sleeved onto the hinge rod of the second connecting rod and the third connecting rod, and one end of the torsion spring is fixedly connected to the second connecting rod, and the other end of the torsion spring is fixedly connected to the third connecting rod; A driving motor, wherein the driving motor is fixedly connected to the piston; A pull rope, one end of which is fixedly connected to the output shaft of the drive motor. When the output shaft of the drive motor rotates, the pull rope is wound around the output shaft. The other end of the pull rope passes around the hinge between the second link and the third link and is fixedly connected to the outside of the third link. The pull rope drives the third link to rotate in a direction away from the space where the four grippers are closed.

3. The underactuated eagle claw mechanical grab according to claim 2, characterized in that: The flexible ball comprises: A hollow sphere, wherein the hollow sphere comprises a spherical shell, a through groove is arranged on the hollow sphere, and the through groove penetrates the spherical shell and is isolated from the inner space of the hollow sphere, and the second connecting rod is fixed after passing through the through groove; A flexible capsule is fixed on the surface of the hollow sphere away from the through groove, and the flexible capsule is a curved surface adapted to the outer surface of the spherical shell; An electromagnetic coil is fixed between the flexible capsule and the outer surface of the spherical shell; A storage capsule, wherein the storage capsule is arranged in the inner space of the hollow sphere, the storage capsule is connected with the flexible capsule through the spherical shell, and the inner space of the hollow sphere is sealed from the outside; The magnetorheological fluid is filled into the storage capsule and the flexible capsule, and the filling volume of the magnetorheological fluid is 70% to 90% of the internal space of the storage capsule and the flexible capsule.

4. The underactuated eagle claw mechanical grab according to claim 3, characterized in that: A plurality of grooves are arranged on the surface of the flexible ball on one side of the space where the four grippers are closed.

5. The underactuated eagle claw mechanical grab according to claim 4, characterized in that: The drive motor is fixed on the end of the piston, and the center line of the output shaft of the drive motor is collinear with the center line of the piston; The second connecting rod comprises: two rods with the same structure and a connecting column, the two rods with the same structure are arranged in parallel, and a plurality of connecting columns are arranged between the two rods with the same structure; The pull rope is fixedly connected to the outer side of the third connecting rod through the connecting column in sequence.

6. The underactuated eagle claw mechanical grab according to claim 5, characterized in that: The base comprises: A connecting seat, the upper end of which is arranged on a flange connected to the equipment, and a power piece is fixed on the lower end of the connecting seat; The T-shaped piece is a block-shaped structure as a whole, the upper end of the T-shaped piece is fixedly connected to the connecting seat, and the lower end of the T-shaped piece is hinged to the middle part of the second connecting rod.

7. The underactuated eagle claw mechanical grab according to claim 6, characterized in that: The lower end of the T-shaped piece is also provided with a threading hole, and the other end of the pull rope passes through the threading hole and then passes through the connecting column to be fixedly connected with the corresponding third connecting rod.

8. The underactuated eagle claw mechanical grab according to claim 7, characterized in that: The grab bucket further includes a conductive coil, which is arranged on one side of the output shaft of the drive motor and is at the same height, and the conductive coil is fixedly connected to the drive motor; One end of each of the pull ropes is fixedly connected to the output shaft of the drive motor through a conductor coil.

9. The underactuated eagle claw mechanical grab according to claim 8, characterized in that: The four grippers include a first gripper and three second grippers, and the widths of the second connecting rod and the third connecting rod of the first gripper are greater than the widths of the second connecting rod and the third connecting rod of the first gripper; The included angle between adjacent second grippers among the three second grippers is 60°, and the three second grippers and the first gripper are symmetrical about a center line.

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