Highly adaptive variable stiffness flexible manipulator and grasping method

Abstract

The application discloses a high-adaptability variable-rigidity flexible manipulator and a grabbing method thereof, and relates to the technical field of robot end execution. The manipulator comprises a plurality of rope-driven flexible grabbing fingers connected to a high-adaptability attaching transmission structure. The rope-driven flexible grabbing finger comprises a multi-joint movable rigid phalanx, a flexible adaptable contact layer and a special-shaped channel air bag. The high-adaptability attaching transmission structure comprises a transmission cavity formed by connecting a flexible attaching silica gel sleeve and a fixed bottom plate seat, and a plurality of connecting rods and a plurality of soft springs are arranged in the transmission cavity. The contact surface of the manipulator and an object is made of flexible material, so that flexible contact can be realized. The high-adaptability attaching transmission structure can well attach to the grabbed object, the attaching degree of grabbing is increased, the adaptability of grabbing is improved, and under the influence of the air bag and the variable-rigidity structure, the rigidity can be changed during the bearing process, so that the bearing capacity of the manipulator is increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of robot end execution technology, and particularly relates to a high-adaptability variable stiffness flexible manipulator and a grasping method thereof. BACKGROUND

[0002] At present, traditional rigid manipulators have high strength and high precision when grasping objects. Their structure is stable, and they can maintain accurate positioning and motion control in repeated operations, especially suitable for repetitive tasks on industrial production lines. However, they generally lack flexibility and adaptability. For irregularly shaped or easily damaged objects, rigid manipulators cannot grasp them gently, risking damage to the objects or ineffective grasping. In addition, they may pose a safety hazard in environments where they work with humans, as hard materials can cause injury when colliding with people.

[0003] With the development of manipulator technology, soft manipulators exhibit different advantages in grasping operations due to the use of flexible materials. Soft manipulators can gently wrap and grasp irregular or fragile objects, reducing damage to the objects. Their adaptability makes them excel at handling irregularly shaped and fragile objects.

[0004] Invention patent application with publication number CN 111791247 A proposes a variable stiffness linear drive flexible gripper based on layer interference technology and its variable stiffness control method. The flexible gripper is driven by a motor to rotate the tendon, causing the fingers to bend. The stiffness change of the gripper is controlled by an external negative pressure pump. However, due to the fact that most of the overall structure is made of flexible materials and the grasping part has no rigid structural support, the stiffness change is limited, and it cannot provide greater load capacity and grasping stability.

[0005] Utility model patent with publication number CN 218082707 U proposes a driving device for a flexible variable stiffness manipulator. The manipulator changes the overall grasping stiffness of the manipulator through an extension tendon driver, and adjusts the grasping force of the manipulator through a bending tendon driver to complete the grasping of the manipulator. However, due to the complexity of its drive, the excessive number of required drive motors leads to control difficulties.

[0006] Invention patent application with publication number CN 110788881 A proposes a pneumatic soft gripper with vacuum adsorption type locking joints. The pneumatic soft gripper increases the flexible suction disc spine in the soft fingers to realize a variable stiffness full flexible gripper. Although it improves the carrying capacity, it still has the problems of insufficient stability in grasping objects and weak carrying capacity, especially on objects with complex shapes. SUMMARY

[0007] The present application aims to provide a high-adaptability variable-rigidity flexible manipulator and a grasping method thereof, which can perform high-adaptability coating grasping, has the advantages of simple driving, good adaptability, strong bearing capacity, high grasping stability and the like.

[0008] To achieve the above-mentioned object, the technical scheme of the present application is as follows: a high-adaptability variable-rigidity flexible manipulator, comprising a plurality of rope-driven flexible grasping fingers connected to a high-adaptability adhering transmission structure.

[0009] The rope-driven flexible grasping finger comprises a multi-joint movable rigid phalanx, a flexible adaptable contact layer and a special-shaped channel air bag, the flexible adaptable contact layer is fixed to the inner side of the multi-joint movable rigid phalanx, and the special-shaped channel air bag is fixed to the outer side of the multi-joint movable rigid phalanx.

[0010] The high-adaptability adhering transmission structure comprises a transmission cavity formed by the flexible adhering silica gel sleeve and the fixed base plate seat, a plurality of connecting rods and a plurality of soft springs are arranged in the transmission cavity, the connecting rods pass through the flexible adhering silica gel sleeve and are connected to the upper part of a spherical sleeve, the spherical sleeve is connected to a suction disc in a nested manner, the upper end of the soft spring is fixed to the reserved hole of the fixed base plate seat, and the lower end of the soft spring is nested in the hollow groove of the connecting rod.

[0011] As a preferred scheme of the present application, a follow-up rod is arranged in the transmission cavity, the upper end of the follow-up rod passes through the fixed base plate seat and a hollow fixed seat and is connected to a pulley assembly, a wire rope is wound around the pulley assembly, the wire rope passes through the fixed base plate seat and is connected to the rope-driven flexible grasping finger, and the hollow fixed seat is connected to the upper surface of the fixed base plate.

[0012] As a preferred scheme of the present application, a gear is arranged between each joint of the multi-joint movable rigid phalanx, the gear is fixed to the multi-joint movable rigid phalanx through a gear shaft, the wire rope passes around the gear to connect the rope-driven flexible grasping finger and the high-adaptability adhering transmission structure together, and the wire rope provides driving for the rope-driven flexible grasping finger.

[0013] As a preferred scheme of the present application, spherical granular materials are filled in the interlayer of the flexible adhering silica gel sleeve, and the flexible adhering silica gel sleeve is connected to an external air source.

[0014] As a preferred scheme of the present application, a plurality of downward extending plates are arranged on the fixed base plate seat, and each downward extending plate is rotationally connected to a corresponding rope-driven flexible grasping finger.

[0015] As a preferred scheme of the present application, a groove for limiting the connecting rod is formed in the flexible adhering silica gel sleeve.

[0016] As a preferred scheme of the present application, the flexible adhering silica gel sleeve top is provided with an upward extending positioning plate which is arranged in the fixed bottom plate seat.

[0017] As a preferred scheme of the present application, the hemispherical part of the spherical sleeve is embedded in the upper part of the suction cup to achieve rotary sliding connection.

[0018] As a preferred scheme of the present application, the central axis of the follow-up rod is collinear with the central axis of the reserved hole in the center of the fixed bottom plate seat.

[0019] The present application also provides a grasping method of the high adaptability variable stiffness flexible manipulator, comprising the following steps:

[0020] S1, the high adaptability adhering transmission structure is longitudinally moved with the plurality of rope driven flexible grasping fingers, when the suction cup contacts the grasped object, the soft spring provides pressure which is transmitted to the spherical sleeve through the connecting rod, the suction cup rotates on the hemispherical part of the spherical sleeve to adjust the adsorption angle, so that the suction cup is tightly attached to the surface of the grasped object;

[0021] S2, after the high adaptability adhering transmission structure is tightly adhered to the grasped object, the special-shaped channel air bag is inflated to gradually expand, the flexible adhering silica gel sleeve is pumped to shrink the interlayer, and the spherical granular material in the interlayer increases in interference stiffness;

[0022] S3, after the special-shaped channel air bag is completely inflated and the interlayer of the flexible adhering silica gel sleeve is completely shrunk, the high adaptability adhering transmission structure and the plurality of rope driven flexible grasping fingers continue to move longitudinally, the suction cup is tightly attached to the grasped object, the force of the object on the suction cup is transmitted to the follow-up rod through the spherical sleeve and the connecting rod, the follow-up rod rises to drive the wire rope to shrink, and then drive the rope driven flexible grasping fingers to bend inward at the same time, so as to complete the grasping and covering action.

[0023] The present application can achieve the following technical effects due to the above technical scheme:

[0024] 1. The high adaptability variable stiffness flexible manipulator provided by the present application connects the rope driven flexible grasping fingers and the high adaptability adhering transmission structure together through the wire rope around the gear assembly to provide driving for the rope driven flexible grasping fingers, which can simplify the driving and realize synchronous movement of the high adaptability adhering transmission structure and the rope driven flexible grasping fingers, so that the grasping is more stable and the carrying capacity is improved.

[0025] 2. The high-adaptability variable-rigidity flexible manipulator provided by the application has a high-adaptability attached transmission structure, and flexible attached silica gel sleeves, suction cups, connecting rods, spherical sleeves and soft springs are reasonably arranged under the pressure provided by the soft springs, so that the suction cups are closely attached to the surface of the object being gripped, and the spherical sleeves enable the suction cups to self-adapt to the slight ups and downs of the surface of the object, thereby improving the adaptability of the manipulator.

[0026] 3. The high-adaptability variable-rigidity flexible manipulator provided by the application has a flexible attached silica gel sleeve interlayer filled with spherical particles, and the particles form negative pressure through air extraction during gripping, so as to realize rigidity improvement and increase the stability and carrying capacity of gripping.

[0027] 4. The high-adaptability variable-rigidity flexible manipulator provided by the application has a flexible attached silica gel sleeve, which ensures that the particles and other structures do not interfere with each other during work, and enables the particles to be concentrated and distributed, thereby facilitating rigidity change. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0029] Figure 1 Fig. 1 is a structural schematic diagram of the high-adaptability variable-rigidity flexible manipulator;

[0030] Figure 2 Fig. 2 is a structural schematic diagram of the rope-driven flexible gripping finger;

[0031] Figure 3 Fig. 3 is a half-sectional view of the high-adaptability attached transmission structure;

[0032] Figure 4 Fig. 4 is a structural schematic diagram of the flexible attached silica gel sleeve;

[0033] Figure 5 Fig. 5 is a structural schematic diagram of the spherical sleeve;

[0034] Figure 6 Fig. 6 is a schematic diagram of the high-adaptability variable-rigidity flexible manipulator in a gripping state;

[0035] Figure 7 Fig. 7 is a schematic diagram of the multi-joint movable rigid phalanx structure.

[0036] The figure sequence description: 1, rope-driven flexible gripper finger; 2, high adaptability attached transmission structure; 3, wire rope; 11, multi-joint movable rigid phalanx; 12, flexible adaptable contact layer; 13, special-shaped channel air bag; 141, gear shaft; 142, gear; 211, flexible attached silica gel sleeve; 212, spherical granular material; 22, suction cup; 23, connecting rod; 24, spherical sleeve; 25, soft spring; 26, fixed bottom plate seat; 27, follow-up rod; 28, hollow fixed seat; 291, pulley assembly; 292 pulley shaft. DETAILED DESCRIPTION

[0037] In order to make the technical problems, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and not to limit the present application.

[0038] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0039] In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited. The meaning of "several" is one or more, unless otherwise explicitly specified and limited.

[0040] In the description of the present application, it should be understood that the terms "center", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0041] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. Example 1

[0042] AsFigure 1 As shown in the figure, this embodiment provides a highly adaptable variable stiffness flexible manipulator, which includes rope-driven flexible grasping fingers 1 (four are shown in the figure, but can be adjusted according to actual conditions), a highly adaptable attachment transmission structure 2, and a rope 3, wherein the rope 3 provides drive for the rope-driven flexible grasping fingers.

[0043] like Figure 2 As shown, the rope-driven flexible grasping finger 1 includes a multi-joint movable rigid phalanx 11, a flexible and adaptable contact layer 12, and an irregularly shaped channel airbag 13. The flexible and adaptable contact layer 12 is fixed to the inner side of the multi-joint movable rigid phalanx 11 by adhesive bonding. The irregularly shaped channel airbag 13 is fixed to the outer side of the multi-joint movable rigid phalanx 11 by adhesive bonding. There are gears 142 between each joint of the multi-joint movable rigid phalanx 11. The gears 142 are fixed to the multi-joint movable rigid phalanx 11 by gear shaft 141. The rope 3 passes around all the gears 14 and is fixed to the limiting post of the arc-shaped joint at the tail. One end of the irregularly shaped channel airbag 13 is connected to an external air source through a universal interface.

[0044] like Figure 3 As shown, the highly adaptable adhesive transmission structure 2 includes a flexible adhesive silicone sleeve 211, a suction cup 22, a connecting rod 23, a spherical sleeve 24, a soft spring 25, a fixed base plate 26, a follower rod 27, a hollow fixed base 28, a pulley assembly 291, and a pulley shaft 292. The positioning plate extending upward from the flexible adhesive silicone sleeve 211 is placed inside the fixed base plate 26, and the flexible adhesive silicone sleeve 211 and the fixed base plate 26 are connected and fixed by fastening bolts around the perimeter. The connecting rod 23 is threaded to the upper part of the spherical sleeve 24. The suction cup 22 is nested to the hemispherical part of the spherical sleeve 24. The connecting rod 23 is fixed by a groove on the flexible silicone sleeve 211. The upper end of the soft spring 25 is fixed in the reserved hole of the fixed base plate 26, and the lower end of the soft spring 25 is nested in the hollow groove of the central connecting rod 23. The upper end of the follower rod 27 passes through the central reserved hole of the fixed base plate 26 and the hollow fixed seat 28 and is connected to the pulley assembly 291. The lower end of the follower rod 27 is nested in the connecting rod 23. Inside the hollow groove, the hollow fixed seat 28 is threadedly connected to the fixed base plate 26, and the limiting part of the follower rod 27 is located above the fixed base plate 26; the pulley assembly 291 includes symmetrically arranged transverse pulleys and symmetrically arranged longitudinal pulleys, and the transverse pulleys and longitudinal pulleys are both mounted on the follower rod through pulley shafts 292; a rope 3 is wound around the pulley 291, one end of the rope is fixed to the fixed column inside the fixed base plate, and the other end passes through the fixed base plate 26 and is connected to the rope-driven flexible gripping finger 1.

[0045] like Figure 4As shown, the flexible attached silica gel sleeve 211 is a sandwich structure, which is connected with external air source through general interface, and the inside of the sandwich is provided with spherical particles 212. The spherical particles 212 interfere with each other in a vacuum negative pressure mode, the overall rigidity is improved, the flexible attached silica gel sleeve 211 separates the spherical particles 212 from the soft spring 25, prevents the interference of the two, affects the working effect of the soft spring 25, and increases the aggregation degree of the spherical particles 212.

[0046] As shown in the figure, Figure 5 As shown, the hemispherical part of the spherical sleeve 24 is embedded in the upper part of the suction cup 22 to realize the rotary sliding connection.

[0047] In a preferred mode, the soft spring 25 is stably connected with the fixed bottom plate seat 26 and the connecting rod 23, the center axes of the three are collinear, and the rigidity of the soft spring 25 is appropriate.

[0048] In a preferred mode, the center axis of the follow-up rod 27 is collinear with the center axis of the center reserved hole of the fixed bottom plate seat 26.

[0049] In a preferred mode, a plurality of rope-driven flexible gripping fingers are symmetrically arranged. Embodiment 2

[0050] As shown in the figure, Figure 6 The embodiment provides a gripping method of a high-adaptability variable-rigidity flexible manipulator, which comprises the following steps:

[0051] S1, in the initial state of the gripping task, the high-adaptability variable-rigidity flexible manipulator is controlled to move longitudinally to contact the gripped object, the soft spring provides slight pressure, which is transmitted to the spherical sleeve through the connecting rod, the suction cup rotates on the hemispherical part of the spherical sleeve to adjust the adsorption angle, so that the suction cup can tightly adhere to the surface of the gripped object;

[0052] S2, after the high-adaptability attached transmission structure is tightly adsorbed to the gripped object, the external air source inflates the special-shaped channel air bag through the general interface to make it gradually expand, and the flexible attached silica gel sleeve is exhausted through the general interface to make the sandwich shrink, the spherical particles in the sandwich interfere with each other, the rigidity increases, the fixing ability to the gripped object is improved, and the stability and carrying capacity of gripping are improved;

[0053] S3, after the special-shaped channel air bag is completely inflated and the sandwich of the flexible attached silica gel sleeve is completely shrunk, the high-adaptability variable-rigidity flexible manipulator continues to move longitudinally, the suction cup tightly adheres to the gripped object, the force of the object on the suction cup is transmitted to the follow-up rod through the spherical sleeve and the connecting rod, the follow-up rod rises, the wire rope is retracted, and then the rope-driven flexible gripping finger is bent inward at the same time, the gripping and covering action is completed, and the longitudinal lifting and horizontal movement of the high-adaptability variable-rigidity flexible manipulator can complete the rotating movement.

[0054] When reaching the designated position, the external air source stops working, the air channel air bag and the flexible attached silica gel sleeve sandwich layer inside both return to atmospheric pressure, the air channel air bag returns to the initial state before grabbing, the spherical particles inside the flexible attached silica gel sleeve sandwich layer return to the initial state, the rigidity returns to the initial rigidity, the follower rod descends, the rope-driven flexible grabbing fingers open, and the object is placed.

[0055] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A highly adaptable variable stiffness flexible manipulator, characterized by, The application relates to a high-adaptability adhesive transmission structure and a plurality of rope-driven flexible grabbing fingers connected to the high-adaptability adhesive transmission structure. The rope-driven flexible grabbing finger comprises a multi-joint movable rigid phalanx, a flexible adaptable contact layer and a special-shaped channel air bag, the flexible adaptable contact layer is fixed to the inner side of the multi-joint movable rigid phalanx, and the special-shaped channel air bag is fixed to the outer side of the multi-joint movable rigid phalanx. The high-adaptability adhesive transmission structure comprises a transmission cavity formed by connecting a flexible adhesive silica gel sleeve and a fixed base plate, a plurality of connecting rods and a plurality of soft springs are arranged in the transmission cavity, the connecting rods pass through the flexible adhesive silica gel sleeve and are connected to the upper part of a spherical sleeve, the spherical sleeve is connected to a suction disc in a nested mode, the upper end of the soft spring is fixed to a reserved hole in the fixed base plate, and the lower end of the soft spring is nested in a hollow groove in the connecting rod. A follow-up rod is arranged in the transmission cavity, the upper end of the follow-up rod passes through the fixed base plate and a hollow fixed base and is connected to a pulley assembly, a wire rope is wound around the pulley assembly, the wire rope passes through the fixed base plate and is connected to the rope-driven flexible grabbing finger, and the hollow fixed base is connected to the upper surface of the fixed base plate; the lower end of the follow-up rod is nested in the hollow groove in the connecting rod.

2. The highly adaptable variable stiffness flexible manipulator of claim 1, wherein, Gears are arranged between the joints of the multi-joint movable rigid phalanx, the gears are fixed to the multi-joint movable rigid phalanx through gear shafts, the wire rope passes around the gears to connect the rope-driven flexible grabbing finger and the high-adaptability adhesive transmission structure together, and the wire rope provides driving for the rope-driven flexible grabbing finger.

3. The highly adaptable variable stiffness flexible manipulator of claim 1, wherein, Spherical particles are filled in the interlayer of the flexible adhesive silica gel sleeve, and the flexible adhesive silica gel sleeve is connected to an external air source.

4. The highly compliant variable stiffness flexible manipulator of claim 1, wherein, A plurality of downward extending plates are arranged on the fixed base plate, and each downward extending plate is rotationally connected to a corresponding rope-driven flexible grabbing finger.

5. The highly compliant variable stiffness flexible manipulator of claim 1, wherein, A groove is formed in the flexible adhesive silica gel sleeve and used for limiting the connecting rod.

6. The highly compliant variable stiffness flexible manipulator of claim 1, wherein, A positioning plate extending upwards is arranged on the top of the flexible adhesive silica gel sleeve, and the positioning plate is arranged in the fixed base plate.

7. The highly compliant variable stiffness flexible manipulator of claim 1, wherein, The hemispherical part of the spherical sleeve is embedded in the upper part of the suction disc and is rotationally and slidably connected.

8. The highly compliant variable stiffness flexible manipulator of claim 1, wherein, The central axis of the follow-up rod is collinear with the central axis of the reserved hole in the fixed base plate.

9. A method of grasping with the high-adaptability variable-stiffness flexible manipulator according to any one of claims 1-8, characterized in that, The application further discloses a method for controlling the high-adaptability adhesive transmission structure and the plurality of rope-driven flexible grabbing fingers. S1, the high-adaptability adhesive transmission structure and the plurality of rope-driven flexible grabbing fingers are longitudinally moved, when the suction disc contacts the grabbed object, the soft spring provides pressure, the pressure is transmitted to the spherical sleeve through the connecting rod, the suction disc rotates on the hemispherical part of the spherical sleeve to adjust the suction angle, and the suction disc is tightly attached to the surface of the grabbed object; S2, after the high-adaptability adhesive transmission structure is tightly attached to the grabbed object, the special-shaped channel air bag is inflated to gradually expand, the flexible adhesive silica gel sleeve is exhausted to shrink the interlayer, and the spherical particles in the interlayer are disturbed to increase the stiffness; S3, after the special-shaped channel air bag is completely inflated and the interlayer of the flexible adhesive silica gel sleeve is completely shrunk, the high-adaptability adhesive transmission structure and the plurality of rope-driven flexible grabbing fingers continue to be longitudinally moved, the suction disc is tightly attached to the grabbed object, the force of the object on the suction disc is transmitted to the follow-up rod through the spherical sleeve and the connecting rod, the follow-up rod rises, the wire rope is shrunk, the rope-driven flexible grabbing finger is bent inwards, and the grabbing and covering action is completed.

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