A variable-rigidity soft finger hinge mechanism, soft manipulator and working method thereof

Abstract

The present application discloses a variable-rigidity soft finger hinge mechanism, a soft manipulator and a working method thereof, wherein the variable-rigidity soft finger hinge mechanism comprises a first hinged member, which is provided with a first hinge plate; a second hinged member, which is provided with a second hinge plate, wherein the first hinge plate and the second hinge plate are staggered and stacked; a hollow hinge shaft, which passes through each of the first hinge plate and the second hinge plate, and an opening is provided in the middle of the hollow hinge shaft, and the opening is connected to a channel inside the hollow hinge shaft; there are two extrusion plates, which can be slidably mounted to both ends of the hollow hinge shaft; a first rope, one end of which is connected to the extrusion plate, and the other end passes through the channel and passes out at the opening. The first hinge and the second hinge can be bent in both directions; by tightening the first rope, the extrusion plate can be pressed against the first hinge plate and the second hinge plate, thereby increasing the friction resistance between the two to change the rigidity. The present application relates to the field of manipulator technology.

Description

Technical Field

[0001] The present application relates to the technical field of manipulators, and in particular to a variable-rigidity soft finger hinge mechanism, a soft manipulator and a working method thereof. Background Art

[0002] Compared with traditional rigid robots, soft robots are made of flexible materials and have the advantages of light weight, safety and environmental protection, high flexibility, low control complexity, and low cost. They show great development potential in human-machine interaction, non-destructive grasping, and special operations. Soft fingers, as the end effectors of soft robots, can be classified into fluid drive (gas or liquid), tendon drive, and intelligent material drive according to the driving mode. However, no matter what driving mode is used, due to the inherent softness of flexible materials, the load capacity of soft fingers is insufficient, which restricts their grasping of large and heavy objects.

[0003] In this regard, researchers have proposed various variable stiffness mechanisms, including antagonistic mechanisms, blocking mechanisms, and smart material variable molecular property mechanisms. Among them, the blocking mechanism mainly applies negative pressure to make the blocking media (including granular media, layer media, fiber media, etc.) in the variable stiffness unit squeeze each other, increase their shear stress, and thus increase the stiffness of the overall structure.

[0004] However, limited by the short development time and the incompleteness of technology, the current variable stiffness soft fingers based on the blocking principle face three major limitations: 1. Both finger movement and stiffness changes rely on gas-driven strategies (generally speaking, fingers are driven by positive pressure, while variable stiffness is activated by negative pressure). The introduction of the air pump makes the entire gripper system extremely bulky and noisy during operation. It is also more dependent on external power and gas sources. 2. Currently, the design of variable stiffness soft fingers based on the blocking principle generally adopts the method of directly attaching the variable stiffness unit to the surface of the soft finger. This not only increases the complexity of the structure, but also inevitably poses a certain degree of hindrance to the flexible movement of the fingers. 3. The current variable stiffness fingers can generally only achieve one-way bending, which greatly restricts their adaptability in changing environments and the flexibility of task execution. Summary of the invention

[0005] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a variable stiffness soft finger hinge mechanism, which can grasp objects in a bidirectional bending manner and can change the stiffness to increase the stability of the clamping.

[0006] The present application also proposes a soft manipulator including the above-mentioned variable stiffness soft finger hinge mechanism, and a working method of the soft manipulator.

[0007] According to the first aspect of the present application, the variable stiffness soft finger hinge mechanism includes:

[0008] A first hinge member provided with at least two first hinge plates;

[0009] A second hinged member is provided with at least two second hinged plates, wherein the first hinged plates and the second hinged plates are alternately stacked;

[0010] A hollow hinge shaft, which passes through each of the first hinge plate and the second hinge plate, and an opening is formed in the middle of the hollow hinge shaft, and the opening is connected to a channel inside the hollow hinge shaft;

[0011] There are two extrusion plates, which are slidably mounted on both ends of the hollow hinge shaft;

[0012] a first rope, one end of which is connected to the extrusion plate, the other end of which passes through the passage and out of the opening;

[0013] The first hinge member and the second hinge member can be bent bidirectionally around the hollow hinge shaft, and tightening the first rope can cause the extrusion plate to press against the first hinge plate and the second hinge plate to increase the friction resistance therebetween.

[0014] The variable stiffness soft finger hinge mechanism according to the embodiment of the present application has at least the following beneficial effects: the first hinge and the second hinge can be bent in two directions, and have a larger range of motion compared to the traditional unidirectional bending manipulator; by tightening the first rope, the extrusion plate can be pressed toward the first hinge plate and the second hinge plate, thereby increasing the friction resistance between the two and increasing the stability of the hinge mechanism.

[0015] According to some embodiments of the present application, there are two first ropes, and the two first ropes are connected to the two extrusion plates in a one-to-one correspondence, and both of the two first ropes pass through the opening.

[0016] According to some embodiments of the present application, the variable-rigidity soft finger hinge mechanism also includes a driver, which is connected to the first rope and is used to pull the first rope.

[0017] According to some embodiments of the present application, the driver includes a first motor and a steering wheel, the steering wheel is mounted on an output shaft of the first motor, the first rope is connected to the steering wheel, and the rotation of the steering wheel can pull the first rope.

[0018] According to some embodiments of the present application, the variable-rigidity soft finger hinge mechanism further includes a shell, the driver is enclosed in the shell, and the shell is provided with a hole for the first rope to pass through.

[0019] According to some embodiments of the present application, the variable stiffness soft finger hinge mechanism further comprises a protection rod, which spans across the outer sides of each of the first hinge plates and the second hinge plates and is used to prevent external objects from entering the gap between the first hinge plates and the second hinge plates.

[0020] According to the second aspect of the present application, the soft manipulator comprises finger phalanges, a finger drive assembly and the above-mentioned variable stiffness soft finger hinge mechanism, wherein adjacent finger phalanges are hinged via the variable stiffness soft finger hinge mechanism, and the finger drive assembly drives each of the finger phalanges to bend relative to each other.

[0021] The soft manipulator according to the embodiment of the present application has at least the following beneficial effects: the variable stiffness soft finger hinge mechanism does not affect the normal bending of the finger bones while changing its stiffness, so that the manipulator can perform grasping tasks without interference.

[0022] According to some embodiments of the present application, the finger drive assembly includes a second motor and a second rope, the output shaft of the second motor is equipped with a pulley, the second rope is wound around the pulley, the end of the second rope passes through each of the finger phalanges and is connected to the endmost finger phalange, and the second motor pulling the second rope can drive each of the finger phalanges to bend.

[0023] According to some embodiments of the present application, the finger phalanges, the finger drive assembly and the variable-rigidity soft finger hinge mechanism connected in series form a finger group, and the soft manipulator also includes a gripper base. The number of the finger groups is at least two and both are mounted to the gripper base.

[0024] According to the working method of the third aspect of the present application, based on the above-mentioned soft manipulator, the method comprises the following steps:

[0025] The second motor pulls the second rope, and the second rope drives each of the phalanges of the fingers to bend;

[0026] The finger phalanges of two adjacent finger groups are moved closer to each other to complete the gripping of the object; or the finger phalanges of two adjacent finger groups are moved away from each other to complete the opening of the soft manipulator;

[0027] In each of the variable-rigidity soft finger hinge mechanisms, the first rope pulls the extrusion plate so that the extrusion plate is pressed toward the first hinge plate and the second hinge plate;

[0028] The first hinge plate and the second hinge plate contact each other so that the mutual friction force increases, thereby preventing the first hinge plate and the second hinge plate from rotating.

[0029] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to provide further understanding of the technical solution disclosed in the present application and constitute a part of the specification. Together with the embodiments disclosed in the present application, they are used to explain the technical solution disclosed in the present application and do not constitute a limitation on the technical solution disclosed in the present application.

[0031] Figure 1 A three-dimensional diagram of a variable stiffness soft finger hinge mechanism according to an embodiment of the first aspect of the present application;

[0032] Figure 2 A three-dimensional diagram of a first hinge and a second hinge in a variable stiffness soft finger hinge mechanism according to an embodiment of the first aspect of the present application;

[0033] Figure 3 A cross-sectional view of a variable stiffness soft finger hinge mechanism according to an embodiment of the first aspect of the present application;

[0034] Figure 4 This is a driving schematic diagram of a driver in a variable stiffness soft finger hinge mechanism according to an embodiment of the first aspect of the present application;

[0035] Figure 5 This is a three-dimensional diagram of the variable stiffness soft finger hinge mechanism after the housing is installed in the embodiment of the first aspect of the present application;

[0036] Figure 6 A three-dimensional diagram of a soft manipulator according to an embodiment of the second aspect of the present application;

[0037] Figure 7 A schematic diagram of the inward bending of a finger group of a soft manipulator according to the second aspect of the present application;

[0038] Figure 8 This is a schematic diagram of the outward bending of the finger group of the soft robot arm according to the second embodiment of the present application.

[0039] Figure numerals: 100 - first hinge, 110 - first hinge plate, 200 - second hinge, 210 - second hinge plate, 300 - hollow hinge shaft, 310 - channel, 320 - opening, 400 - extrusion plate, 500 - first rope, 510 - knot, 600 - drive, 610 - first motor, 620 - steering wheel, 700 - housing, 800 - protection rod, 900 - finger drive assembly, 910 - second motor, 911 - wheel disc, 920 - second rope, 1000 - gripper base. DETAILED DESCRIPTION

[0040] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0041] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply 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 understood as a limitation on the present application.

[0042] In the description of this application, "several" means more than one, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0043] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0044] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0045] Compared with traditional rigid robots, soft robots are made of flexible materials and have the advantages of light weight, safety and environmental protection, high flexibility, low control complexity, and low cost. They show great development potential in human-machine interaction, non-destructive grasping, and special operations. Soft fingers, as the end effectors of soft robots, can be classified into fluid drive (gas or liquid), tendon drive, and intelligent material drive according to the driving mode. However, no matter what driving mode is used, due to the inherent softness of flexible materials, the load capacity of soft fingers is insufficient, which restricts their grasping of large and heavy objects.

[0046] In this regard, researchers have proposed various variable stiffness mechanisms, including antagonistic mechanisms, blocking mechanisms, and smart material variable molecular property mechanisms. Among them, the blocking mechanism mainly applies negative pressure to make the blocking media (including granular media, layer media, fiber media, etc.) in the variable stiffness unit squeeze each other, increase their shear stress, and thus increase the stiffness of the overall structure.

[0047] However, limited by the short development time and the incompleteness of technology, the current variable stiffness soft fingers based on the blocking principle face three major limitations: 1. Both finger movement and stiffness changes rely on gas-driven strategies (generally speaking, fingers are driven by positive pressure, while variable stiffness is activated by negative pressure). The introduction of the air pump makes the entire gripper system extremely bulky and noisy during operation. It is also more dependent on external power or gas sources. 2. Currently, the design of variable stiffness soft fingers based on the blocking principle generally adopts the method of directly attaching the variable stiffness unit to the surface of the soft finger. This not only increases the complexity of the structure, but also inevitably poses a certain degree of hindrance to the flexible movement of the fingers. 3. The current variable stiffness fingers can generally only achieve one-way bending, which greatly restricts their adaptability in changing environments and the flexibility of task execution.

[0048] In this regard, the present application proposes a variable stiffness soft finger hinge mechanism, in which the first hinge 100 and the second hinge 200 can be bent in two directions, and have a larger range of motion compared to traditional unidirectional bending manipulators; by tightening the first rope 500, the extrusion plate 400 can be pressed toward the first hinge plate 110 and the second hinge plate 210, thereby increasing the friction resistance therebetween and increasing the stability of the hinge mechanism.

[0049] In addition, the present application also proposes a soft manipulator including the above-mentioned variable stiffness soft finger hinge mechanism, and its working method. The variable stiffness soft finger hinge mechanism does not affect the normal bending of the finger bones while changing the stiffness, so that the manipulator can perform grasping tasks without interference.

[0050] Reference Figure 1 The variable stiffness soft finger hinge mechanism in the embodiment of the first aspect of the present application comprises a first hinge 100, a second hinge 200, a hollow hinge shaft 300, a squeeze plate 400 and a first rope 500. The first hinge 100 and the second hinge 200 together constitute the main structure of the variable stiffness soft finger hinge mechanism, and the two are hinged to each other through the hollow hinge shaft 300. The first rope 500 is used to pull the squeeze plate 400, so that the squeeze plate 400 applies a force to the first hinge 100 and the second hinge 200, thereby increasing the friction resistance between the two, thereby improving the stiffness of the variable stiffness soft finger hinge mechanism, and being able to grasp heavier objects.

[0051] Specifically, refer to Figure 2 The first hinge 100 is provided with at least two first hinge plates 110, and the second hinge 200 is provided with at least two second hinge plates 210. The first hinge plates 110 and the second hinge plates 210 are stacked alternately, and a gap is left between the first hinge plates 110 and the second hinge plates 210. During normal rotation, since there is a gap between the first hinge plates 110 and the second hinge plates 210, there is no contact between the two, so the friction resistance during rotation is low; when the first hinge plates 110 and the second hinge plates 210 are approached to each other by an external force, the two come into contact with each other to generate sliding friction, which can prevent the first hinge plates 110 and the second hinge plates 210 from rotating relative to each other.

[0052] The hollow hinge shaft 300 passes through each of the first hinge plate 110 and the second hinge plate 210. Figure 3 , a passage 310 is provided in the hollow hinge shaft 300 and runs through both ends thereof, and an opening 320 connected to the passage 310 is provided in the middle of the hollow hinge shaft 300. There are two extrusion plates 400, which are slidably mounted on both ends of the hollow hinge shaft 300. One end of the first rope 500 is connected to the extrusion plate 400, and the other end of the first rope 500 passes through the passage 310 and passes out at the opening 320. Specifically, a knot 510 is provided at the end of the first rope 500, and the first rope 500 is connected to the extrusion plate 400 through the knot 510 and applies a force thereto.

[0053] The first hinge 100 and the second hinge 200 can be bent bidirectionally around the hollow hinge shaft 300, and have a larger range of motion than the conventional unidirectional bending mechanism. Tightening the first rope 500 can cause the extrusion plate 400 to press against the first hinge plate 110 and the second hinge plate 210 to increase the friction resistance therebetween, thereby improving the stiffness of the variable stiffness soft finger hinge mechanism.

[0054] Furthermore, there are two first ropes 500, which are connected to two extrusion plates 400 one by one, and both first ropes 500 pass through the opening 320. When the first ropes 500 passing through the opening 320 are tightened, a pulling force can be applied to the extrusion plate 400, thereby changing the stiffness of the variable stiffness soft finger hinge mechanism.

[0055] Further, refer to Figure 4The variable stiffness soft finger hinge mechanism also includes a driver 600, which is connected to the first rope 500, and the driver 600 is used to pull the first rope 500. In some embodiments, the driver 600 can be an electric pull rod, a hydraulic pull rod or a screw mechanism to provide a force to pull the first rope 500. In this embodiment, the driver 600 includes a first motor 610 and a steering wheel 620, the steering wheel 620 is installed on the output shaft of the first motor 610, the first rope 500 is connected to the steering wheel 620, and the steering wheel 620 rotates to pull the first rope 500. It is easy to understand that other forms of drivers 600 can also be used to generate forces, which will not be repeated here.

[0056] Reference Figure 5 The variable stiffness soft finger hinge mechanism further includes a housing 700, in which the driver 600 is enclosed, and a hole is provided in the housing 700 for the first rope 500 to pass through. The housing 700 is used to protect the driver 600.

[0057] Furthermore, the variable stiffness soft finger hinge mechanism further includes a protection rod 800, which spans the outer sides of each of the first hinge plate 110 and the second hinge plate 210, and is used to prevent external objects from entering the gap between the first hinge plate 110 and the second hinge plate 210, so as to avoid damage to the hinge plates due to debris between the first hinge plate 110 and the second hinge plate 210 when the first rope 500 is tightened.

[0058] Reference Figure 6 A soft manipulator in an embodiment of the second aspect of the present application includes finger phalanges, a finger drive assembly 900, and the above-mentioned variable stiffness soft finger hinge mechanism. Adjacent finger phalanges are hinged by the variable stiffness soft finger hinge mechanism, and the finger drive assembly 900 drives each finger phalange to bend relative to each other. Specifically, the finger drive assembly 900 includes a second motor 910 and a second rope 920, the output shaft of the second motor 910 is equipped with a wheel 911, the second rope 920 is wound around the wheel 911, and the end of the second rope 920 passes through each finger phalange and is connected to the endmost finger phalange. When the second motor 910 is started, the wheel 911 pulls the second rope 920 to drive each finger phalange to bend, thereby completing the control of each finger phalange.

[0059] Specifically, there are two second ropes 920, each of which passes through the through hole of each finger phalanx, and the two ends of the second rope 920 are respectively connected to one side of the last finger phalanx and the wheel 911, and the two second ropes 920 are respectively connected to the two symmetrical sides of the finger phalanx. When the wheel 911 rotates, one of the second ropes 920 can apply tension to the finger phalanx and drive it to bend to one side; when the wheel 911 rotates in the opposite direction, the other second rope 920 can apply tension to the finger phalanx and drive it to bend to the other side, thereby achieving the effect of bidirectional bending of the finger phalanx.

[0060] Furthermore, the finger phalanges, the finger driving assembly 900 and the variable stiffness soft finger hinge mechanism connected in series form a finger group. The soft manipulator also includes a gripper base 1000, and the number of finger groups is at least two and both are mounted to the gripper base 1000.

[0061] The working method for the soft manipulator in the third aspect of the present application includes the following steps:

[0062] S100. The second motor 910 pulls the second rope 920, and the second rope 920 drives each finger phalanx to bend;

[0063] S200. Reference Figure 7 , the phalanges of the fingers of two adjacent finger groups approach each other to complete the grip of the object; or, refer to Figure 8 , the finger phalanges of two adjacent finger groups move away from each other, completing the opening of the soft manipulator;

[0064] S300. In each variable stiffness soft finger hinge mechanism, the first rope 500 pulls the extrusion plate 400, so that the extrusion plate 400 is pressed toward the first hinge plate 110 and the second hinge plate 210;

[0065] S400. The first hinge plate 110 and the second hinge plate 210 contact each other to increase the mutual friction force, thereby preventing the first hinge plate 110 and the second hinge plate 210 from rotating, thereby improving the structural rigidity of the soft manipulator.

[0066] Furthermore, the second rope 920 can also control a certain finger phalanx individually. The specific steps are to first use the variable stiffness soft finger hinge mechanism to lock the other finger phalanxes that do not need to be bent, tighten the first rope 500 to prevent these finger phalanxes from rotating; then pull the second rope 920 to drive only the finger phalanxes that can still move, thereby completing a specific action.

[0067] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. A variable stiffness soft finger hinge mechanism, characterized in that: include: A first hinge member provided with at least two first hinge plates; A second hinged member is provided with at least two second hinged plates, wherein the first hinged plates and the second hinged plates are alternately stacked; A hollow hinge shaft, which passes through each of the first hinge plate and the second hinge plate, and an opening is formed in the middle of the hollow hinge shaft, and the opening is connected to a channel inside the hollow hinge shaft; There are two extrusion plates, which are slidably mounted on both ends of the hollow hinge shaft; a first rope, one end of which is connected to the extrusion plate, the other end of which passes through the passage and out of the opening; The first hinge member and the second hinge member can be bent bidirectionally around the hollow hinge shaft, and tightening the first rope can cause the extrusion plate to press against the first hinge plate and the second hinge plate to increase the friction resistance therebetween.

2. The variable stiffness soft finger hinge mechanism according to claim 1, characterized in that: There are two first ropes, and the two first ropes are connected to the two extrusion plates in a one-to-one correspondence, and both of the two first ropes pass through the opening.

3. The variable stiffness soft finger hinge mechanism according to claim 1, characterized in that: The variable-rigidity soft finger hinge mechanism also includes a driver connected to the first rope, and the driver is used to pull the first rope.

4. The variable stiffness soft finger hinge mechanism according to claim 3, characterized in that: The driver includes a first motor and a steering plate. The steering plate is mounted on an output shaft of the first motor. The first rope is connected to the steering plate. The steering plate can pull the first rope when it rotates.

5. The variable stiffness soft finger hinge mechanism according to claim 4, characterized in that: The variable-rigidity soft finger hinge mechanism also includes a shell, the driver is enclosed in the shell, and the shell is provided with a hole for the first rope to pass through.

6. The variable stiffness soft finger hinge mechanism according to claim 1, characterized in that: The variable-rigidity soft finger hinge mechanism further comprises a protection bar, which spans across the outer sides of each of the first hinge plate and the second hinge plate and is used to prevent external objects from entering the gap between the first hinge plate and the second hinge plate.

7. A soft robot, characterized in that: It comprises finger phalanges, a finger drive assembly and the variable stiffness soft finger hinge mechanism described in any one of claims 1 to 6, wherein adjacent finger phalanges are hinged via the variable stiffness soft finger hinge mechanism, and the finger drive assembly drives each of the finger phalanges to bend relative to each other.

8. The soft robot according to claim 7, characterized in that: The finger drive assembly includes a second motor and a second rope, the output shaft of the second motor is equipped with a wheel, the second rope is wound around the wheel, the end of the second rope passes through each of the finger phalanges and is connected to the last finger phalange, and the second motor pulls the second rope to drive each of the finger phalanges to bend.

9. The soft robot arm according to claim 8, characterized in that: The finger phalanges, the finger drive assembly and the variable stiffness soft finger hinge mechanism connected in series form a finger group. The soft manipulator also includes a gripper base. The number of the finger groups is at least two and both are mounted to the gripper base.

10. A working method for the soft manipulator according to claim 9, characterized in that: include: The second motor pulls the second rope, and the second rope drives each of the finger phalanges to bend; The finger phalanges of two adjacent finger groups are moved closer to each other to complete the gripping of the object; or the finger phalanges of two adjacent finger groups are moved away from each other to complete the opening of the soft manipulator; In each of the variable-rigidity soft finger hinge mechanisms, the first rope pulls the extrusion plate so that the extrusion plate is pressed toward the first hinge plate and the second hinge plate; The first hinge plate and the second hinge plate contact each other so that the mutual friction force increases, thereby preventing the first hinge plate and the second hinge plate from rotating.

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