A variable stiffness integral soft finger and finger trainer

Abstract

The present invention discloses a variable stiffness integral soft finger and a finger trainer. The variable stiffness integral soft finger includes a base structure, a through hole, a variable stiffness structure and a fingertip structure. One end of the base structure is connected to the through hole, one end of the variable stiffness structure is connected to the other end of the base structure, and the fingertip structure is connected to the other end of the variable stiffness structure. A cavity structure is formed between the through hole, the base structure, the variable stiffness structure and the fingertip structure. The structure of the present invention has a high degree of anthropomorphism. When a load is applied, it can achieve different bending profiles with variable stiffness. Its internal stress distribution is uniform, stress concentration is small, deformation is coordinated, and the service life is long. It adopts an integral molding structure, which fits the fingers well and can adapt to the hand sizes of different people.

Description

Technical Field

[0001] The present invention relates to the technical field of bionic flexible fingers, in particular to a variable-rigidity integral soft finger and a finger trainer. Background Art

[0002] Motor dysfunction is a common problem in society today, manifesting as superficial motor impairments following neurological diseases (e.g., stroke) or injuries (e.g., post-traumatic arthritis). With impaired motor function, individuals lose the ability to perform activities of daily living (ADLs). To improve hand mobility, patients with hand dysfunction require continuous passive motion exercises that include repetitive tasks such as grasping and oppositional movements.

[0003] The flexible finger structure in the existing technology cannot achieve different bending profiles with variable stiffness when load is applied. The stress distribution inside the structure will be uneven, and there will be local stress concentration, which will shorten the service life of the flexible finger. There will also be radial expansion, which will reduce the bending conversion efficiency. At the same time, the manufacturing process is complicated, and it cannot be formed as a whole. It is also difficult to adapt to the hand sizes of different people. Therefore, improvement is urgently needed. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a variable stiffness integral soft finger and finger trainer, which is used to solve the problem that the flexible finger structure in the prior art cannot achieve different bending profiles with variable stiffness when load is applied, and the stress distribution inside the structure is uneven, and there is local stress concentration, which shortens the service life of the flexible finger. There is radial expansion, which reduces the bending conversion efficiency. At the same time, the manufacturing process is complicated, it cannot be formed as a whole, and it is difficult to adapt to the hand sizes of different people.

[0005] To achieve the above-mentioned and other related objectives, the present invention provides a variable stiffness integral soft finger, the variable stiffness integral soft finger comprising:

[0006] a base structure having one end connected to the through hole;

[0007] a variable stiffness structure, one end of which is connected to the other end of the base structure;

[0008] a fingertip structure connected to the other end of the variable stiffness structure;

[0009] A cavity structure is formed among the through hole, the base structure, the variable stiffness structure and the fingertip structure.

[0010] In one embodiment of the present invention, the variable stiffness structure comprises:

[0011] a first joint structure, one end of which is connected to the base structure, and the other end of which is connected to one end of the first knuckle structure;

[0012] a second joint structure, one end of which is connected to the other end of the first knuckle structure, and the other end of the second joint structure is connected to one end of the second knuckle structure;

[0013] One end of the third joint structure is connected to the other end of the second finger joint structure, and the other end of the third joint structure is connected to the fingertip structure.

[0014] In one embodiment of the present invention, the variable stiffness structure comprises:

[0015] a first joint structure, one end of which is connected to the base structure, and the other end of which is connected to one end of the first knuckle structure;

[0016] One end of the second joint structure is connected to the other end of the first finger joint structure, and the other end of the second joint structure is connected to the fingertip structure.

[0017] In one embodiment of the present invention, the first joint structure and the second joint structure are wavy non-rotating structures, the top surfaces of the first joint structure, the second joint structure and the third joint structure are corrugated structures, and the corrugated structures include a plurality of alternatingly connected crest structures and trough structures; the first finger joint structure and the second finger joint structure are flat structures.

[0018] In one embodiment of the present invention, the cross-sectional structure of the crest structure in the radial direction includes:

[0019] a plurality of first arcs, wherein the plurality of first arcs are tangent to each other;

[0020] The first bottom edge line is arranged between the first arc lines on both sides of the bottom.

[0021] In one embodiment of the present invention, the cross-sectional structure of the trough structure in the radial direction includes:

[0022] a plurality of second arcs, wherein the plurality of second arcs are tangent to each other;

[0023] The second bottom edge line is arranged between the second arc lines on both sides of the bottom.

[0024] In one embodiment of the present invention, the minimum cross-sectional area of ​​the cavity of the trough structure in the radial direction is times the maximum cross-sectional area of ​​the cavity of the peak structure in the radial direction. times to 1 times, and in the axial middle section, the cavity height corresponding to the trough structure is the cavity height corresponding to the peak structure To 1 times.

[0025] In one embodiment of the present invention, the stiffness of the first joint structure and the second joint structure is greater than the stiffness of the first joint structure, the second joint structure, and the third joint structure; in the axial section of the variable stiffness integral soft finger, the corresponding distance between the crest structure and the trough structure of the first joint structure and the second joint structure is smaller than the corresponding distance between the crest structure and the trough structure of the first joint structure, the second joint structure, and the third joint structure.

[0026] In one embodiment of the present invention, grooves are provided on the corrugated structure of the wavy non-rotating structure, and in the corrugated structure on the top surface near the bottom surface, the groove depth between the peak structure and the trough structure decreases as the distance from the bottom surface decreases.

[0027] The present invention also provides a finger trainer, comprising:

[0028] At least one variable stiffness integral soft finger, the variable stiffness integral soft finger being used for finger training, the variable stiffness integral soft finger comprising:

[0029] a base structure having one end connected to the through hole;

[0030] a variable stiffness structure, one end of which is connected to the other end of the base structure;

[0031] a fingertip structure connected to the other end of the variable stiffness structure;

[0032] A cavity structure is formed between the through hole, the base structure, the variable stiffness structure and the fingertip structure;

[0033] The through hole is used for passing fluid;

[0034] The variable stiffness integral soft finger contacts the finger surface or the glove.

[0035] As described above, the variable stiffness integral soft finger and finger trainer of the present invention have the following beneficial effects:

[0036] The variable-rigidity, integral soft finger of the present invention comprises a base structure, a variable-rigidity structure, a fingertip structure, and through-holes. The structure of the present invention resembles a finger, demonstrating a high degree of anthropomorphism. When a load is applied, the present invention can achieve different bending profiles with variable stiffness. It exhibits uniform internal stress distribution, minimal stress concentration, and coordinated deformation, resulting in a long service life. Its simple manufacturing process and integral molding structure ensure a good fit with the finger, adapting to different hand sizes.

[0037] The variable-rigidity integral soft finger of the present invention can distinguish the length and position of the knuckle joints of different people.

[0038] The variable stiffness integral soft finger of the present invention is an integral soft finger with variable stiffness. Different stiffness can be produced by adjusting the structure of different positions of the integral soft finger, thereby realizing different hand movements required in various physical therapies.

[0039] The stiffness of the knuckle structure of the variable stiffness integral soft finger of the present invention is greater than the stiffness of the joint structure, so that different bending contours can be achieved according to the bending degrees of different knuckle joints of the human finger.

[0040] The groove depth set in the variable stiffness structure of the present invention changes with the circumferential position, which can ensure that the bending deformation in the up and down directions is easy, the bending deformation is coordinated, and the stress distribution is uniform. At the same time, the stiffness in the left and right directions is large, the supporting capacity is improved, and the deformation of the variable stiffness soft finger in the left and right directions is limited, so that the deformation of the integral soft finger is more in line with the human finger movement.

[0041] The variable stiffness integral soft finger of the present invention can be used in two application modes, including an assistive application mode and a rehabilitation application mode. In the assistive application mode, it can perform daily life activities such as grasping and pinching. In the rehabilitation application mode, it can perform different repetitive tasks to achieve continuous passive movement.

[0042] The deformation of the variable stiffness integral soft finger of the present invention is mainly caused by the angle change of the adjacent angles of the wave peaks, rather than by the expansion and extrusion deformation of the sides of the wave peaks. Moreover, the cross-sectional contour lines of the wave peaks and troughs of the present invention are arcs, so the pressure resistance is better.

[0043] The variable-rigidity integral soft finger of the present invention can ensure that the knuckles of the soft finger fit more naturally with the human finger, thereby ensuring the performance of the structure and the comfort of fitting.

[0044] The variable stiffness integral soft finger of the present invention is made of elastic material. When used as the finger part of a hand rehabilitation device, the hand can be bent and stretched to different degrees by adjusting the pressure of the fluid. At the same time, the finger can be properly hyperextension-rehabilitation-produced without generating rigid constraints and compression on the blood vessels and muscles of the hand, and there will be no discomfort when used for a long time.

[0045] The variable stiffness integral soft finger of the present invention can also be used as an industrial bionic gripper to achieve actions such as grasping, holding and pulling. The grasping force can be changed according to the weight of the target object without causing damage to the grasped object. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A schematic structural diagram of a variable stiffness integral soft finger provided in an embodiment of the present application.

[0047] Figure 2 A schematic diagram of the axial cross-sectional structure of a variable stiffness integral soft finger provided in one embodiment of the present application.

[0048] Figure 3 A schematic diagram of the axial cross-sectional structure of a variable stiffness integral soft finger provided in yet another embodiment of the present application.

[0049] Figure 4 A schematic cross-sectional view of the wave crest structure of a variable stiffness integral soft finger provided in an embodiment of the present application.

[0050] Figure 5 A schematic cross-sectional view of the trough structure of a variable stiffness integral soft finger provided in an embodiment of the present application.

[0051] Figure 6 A schematic diagram of the bending state of a variable stiffness integral soft finger provided in an embodiment of the present application.

[0052] Figure 7 A schematic diagram of an application of a variable stiffness integral soft finger provided in one embodiment of the present application.

[0053] Figure 8 A schematic diagram of an application of a variable stiffness integral soft finger provided in yet another embodiment of the present application.

[0054] Figure 9 A schematic diagram of an application of a variable stiffness integral soft finger provided in yet another embodiment of the present application.

[0055] Component number description

[0056] 1 Fingertip structure

[0057] 2 Peak structure

[0058] 3 trough structure

[0059] 4 Structure of the first phalanx

[0060] 5The bottom surface corresponding to the peak

[0061] 6 Concave arc surface corresponding to the trough

[0062] 7 Basic Structure

[0063] 8 through holes

[0064] 9 Raised structure

[0065] 10 fingers

[0066] 11 elastic straps

[0067] 12First joint structure

[0068] 13 Second phalanx structure

[0069] 14 Second joint structure

[0070] 15Third joint structure

[0071] 21 First Arc

[0072] 22 first bottom line

[0073] 31 Second Arc

[0074] 32 second bottom line DETAILED DESCRIPTION

[0075] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other unless they conflict.

[0076] It should be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0077] See also Figure 1 、 Figure 2 、 Figure 3 , Figure 1 A schematic structural diagram of a variable stiffness integral soft finger provided in an embodiment of the present application. Figure 2 A schematic diagram of the axial cross-sectional structure of a variable stiffness integral soft finger provided in one embodiment of the present application. Figure 3A schematic diagram of the axial cross-sectional structure of a variable stiffness integral soft finger is provided as another embodiment of the present application. The present invention provides a variable stiffness integral soft finger, the structure of the entire variable stiffness integral soft finger is an integrally formed structure, and the variable stiffness integral soft finger is an axially asymmetric structure up and down, and an axially symmetrical structure left and right. The material of the variable stiffness integral soft finger can be, but is not limited to, an elastic material, and can also be made of other materials, and can be configured according to specific needs. The variable stiffness integral soft finger includes, but is not limited to, a base structure 7, a through hole 8, a variable stiffness structure, and a fingertip structure 1. One end of the base structure 7 is connected to the through hole 8. One end of the variable stiffness structure is connected to the other end of the base structure 7. The fingertip structure 1 is connected to the other end of the variable stiffness structure. A cavity structure is formed between the through hole 8, the base structure 7, the variable stiffness structure, and the fingertip structure 1. The structure of the fingertip structure 1 can be a solid structure or a closed cavity structure.

[0078] like Figure 1 、 Figure 2 、 Figure 3 As shown, the variable stiffness structure includes a joint structure and a finger joint structure, the joint structure includes but is not limited to a first joint structure 12, a second joint structure 14 and a third joint structure 15, and the finger joint structure includes but is not limited to a first finger joint structure 4 and a second finger joint structure 13. One end of the first joint structure 12 is connected to the base structure 7, the other end of the first joint structure 12 is connected to one end of the first finger joint structure 4, one end of the second joint structure 14 is connected to the other end of the first finger joint structure 4, the other end of the second joint structure 14 is connected to one end of the second finger joint structure 13, one end of the third joint structure 15 is connected to the other end of the second finger joint structure 13, and the other end of the third joint structure 15 is connected to the fingertip structure 1. The first joint structure 12, the second joint structure 14, the third joint structure 15, the first phalanx structure 4, and the second phalanx structure 13 can be used in the index finger, the middle finger, the ring finger, and the little finger. The first joint structure 12, the second joint structure 14, and the third joint structure 15 are wavy non-rotating structures. The top surfaces of the first joint structure 12, the second joint structure 14, and the third joint structure 15 are corrugated structures, and the corrugated structures include a plurality of alternately connected crest structures 2 and trough structures 3. The first phalanx structure 4 and the second phalanx structure 13 are a plurality of alternately connected crest structures 2 and trough structures 3 or a flat structure. Grooves are provided on the corrugated structure of the wavy non-rotating structure. The grooves are the areas between the crest structures 2 and the trough structures 3. In the corrugated structure of the top surface near the bottom surface, the depth of the grooves between the crest structures 2 and the trough structures 3 decreases as the distance from the bottom surface decreases.

[0079] like Figure 1 、 Figure 2 、 Figure 3 As shown, the variable stiffness structure may also include a first joint structure 12 and a second joint structure 14, one end of the first joint structure 12 is connected to the base structure 7, the other end of the first joint structure 12 is connected to one end of the first finger joint structure 4, one end of the second joint structure 14 is connected to the other end of the first finger joint structure 4, and the other end of the second joint structure 14 is connected to the fingertip structure 1. The first joint structure 12, the second joint structure 14, and the first finger joint structure 4 can be used in the thumb. The variable stiffness structure may also include a joint structure and a finger joint structure. In the axial cross-section of the first finger joint structure 4 and the second finger joint structure 13, the upper structure of the finger joint structure is tangently connected to the trough structure 3 of the adjacent joint structure, or is tangently connected to the crest structure 2 of the adjacent joint structure. The bottom surface of the axial finger joint structure is tangent to the bottom surface corresponding to the trough, or is tangent to the bottom surface corresponding to the crest of the joint.

[0080] like Figure 1 、 Figure 2 、 Figure 3 As shown, the first joint structure 12, the second joint structure 14, and the third joint structure 15 include a plurality of alternately connected crest structures 2 and trough structures 3. The width of the crest structure 2 in the circumferential direction increases successively along the circumferential direction of the crest or remains consistent along the circumferential direction of the crest. Specifically, the variable stiffness integral soft finger has an integral variable stiffness, and different stiffnesses are generated by adjusting the structure of the knuckles and joint positions. The stiffness of the first knuckle structure 4 and the second knuckle structure 13 is greater than the stiffness of the first joint structure 12, the second joint structure 14, and the third joint structure 15. In the axial section of the variable stiffness integral soft finger, the corresponding distance between the crest structure and the trough structure of the first knuckle structure 4 and the second knuckle structure 13 is smaller than the corresponding distance between the crest structure and the trough structure of the first joint structure 12, the second joint structure 14, and the third joint structure 15, thereby enabling the realization of different hand movements required in various physical therapies.

[0081] like Figure 1 、 Figure 2 、 Figure 3 As shown, when the variable stiffness integral soft finger is filled with fluid through the through hole 8, the fluid can be gas or liquid, the distance between each wave peak increases, and the variable stiffness integral soft finger bends toward one side of the micro-corrugated surface. When the fluid is extracted from the through hole 8 connected to the fluid by the driving device, the distance between each wave peak decreases, and the entire variable stiffness integral soft finger bends toward one side of the wave peak and trough.

[0082] like Figure 1 、 Figure 2 、 Figure 3 As shown, the internal cavity structure of the base structure 7 is trumpet-shaped, one side of the joint structure of the variable stiffness integral soft finger is a corrugated surface including crests and troughs, and the other side of the joint structure is a micro-corrugated surface. The top surfaces of the first joint structure 12, the second joint structure 14, and the third joint structure 15 are corrugated structures, and the corrugated structure includes a plurality of alternately connected crest structures 2 and trough structures 3. The joint structure may include an inner concave arc surface 6 corresponding to the trough, or may include a bottom surface 5 corresponding to the crest. The base structure 7, the finger joint structure, the joint structure, and the fingertip structure 1 are interconnected and connected to the finger joint and joint structure to form a finger-like structure with a cavity inside, and a cavity structure is formed between each other. The upper structure of the finger joint structure in the axial direction section can be tangent to the trough of the adjacent joint structure, or it can be tangent to the crest of the adjacent joint structure. The bottom surface of the finger joint structure in the axial direction can be tangent to the inner concave arc surface 6 corresponding to the trough, or it can be tangent to the bottom surface 5 corresponding to the crest of the joint structure. The fluid communication hole 8 is connected to an external device. When the fluid communication hole 8 is connected to a driving device, a working medium can flow in and out through the fluid communication hole 8. The working medium can be, but is not limited to, gas, water, hydraulic oil and other fluids.

[0083] See also Figure 4 、 Figure 5 , Figure 4 A schematic cross-sectional view of the wave crest structure of a variable stiffness integral soft finger provided in an embodiment of the present application. Figure 5 A schematic diagram of the cross-sectional structure of a trough structure of a variable stiffness integral soft finger provided in an embodiment of the present application. The cross-sectional structure of the crest structure 2 in the radial direction includes but is not limited to a first arc 21 and a first bottom line 22. The plurality of first arcs 21 are tangent to each other, and the first bottom line 22 is arranged between the first arcs 21 on both sides of the bottom. The cross-sectional structure of the trough structure 3 in the radial direction includes but is not limited to a plurality of second arcs 31 and a second bottom line 32. The first arc 21 includes a parabola, a quadratic curve, a fitting line, etc. The plurality of second arcs 31 are tangent to each other, and the second bottom line 32 is arranged between the second arcs 31 on both sides of the bottom. The second arc 31 includes a parabola, a quadratic curve, a fitting line, etc. The minimum cross-sectional area of ​​the cavity of the trough structure 3 in the radial direction is 1 / 4 of the maximum cross-sectional area of ​​the cavity of the crest structure 2 in the radial direction. times to 1 times, and in the axial middle section, the cavity height corresponding to the trough structure 3 is the cavity height corresponding to the peak structure 2 To 1 times, for example, the cavity height corresponding to the trough structure 3 is the cavity height corresponding to the peak structure 2 times or times.

[0084] like Figure 4 、 Figure 5 As shown, the radial cross-section of the finger joint structure can be either the contour size of the crest cross-section or the contour size of the trough cross-section. The overall contour of the trough cross-section is formed by multiple tangent arcs, and the second arcs 31 on both sides of the lower area of ​​the trough contour are tangent to the second bottom edge line 32.

[0085] See also Figure 6 , Figure 6 The following is a schematic diagram of the bending state of a variable stiffness integral soft finger provided in an embodiment of the present application. The deformation of the variable stiffness integral soft finger is mainly caused by the change in the angle of adjacent angles of the wave crests, rather than by the expansion and extrusion deformation of the sides on both sides of the wave crests. When pressure is applied, the bending at the position with the lowest stiffness will actuate the finger joints, resulting in a change in the relative joint angle. As a result, the degree of bending of the joint structure is greater than that of the knuckle structure, which is more consistent with the bending shape of the human finger. Therefore, the variable stiffness integral soft finger can achieve the different hand movements required in various physical therapies.

[0086] See also Figure 7 、 Figure 8 、 Figure 9 , Figure 7 A schematic diagram of an application of a variable stiffness integral soft finger provided in one embodiment of the present application. Figure 8 A schematic diagram of an application of a variable stiffness integral soft finger provided in yet another embodiment of the present application. Figure 9 This is a schematic diagram of an application of a variable stiffness integral soft finger provided by another embodiment of the present application. Figure 7 As shown, the variable stiffness integral soft finger can be bound to the finger 10 or the glove by providing a plurality of raised structures 9 on the bottom surface 5 corresponding to the wave crest. The raised structures 9 can be, but are not limited to, semicircular, square, or other shapes. Each raised structure 9 is provided with a tiny pore that allows the suture thread to pass through and sew with the glove, thereby playing a role in suturing and fixing. In addition, the raised structure 9 also plays a role in isolating and buffering the micro-corrugated surface and the finger 10, reducing the additional force generated when the fluid pressure is high. Figure 8 As shown, the bottom surface 5 corresponding to the crest of the variable stiffness integral soft finger can be evenly coated with special glue by gluing, and the bottom surface can be seamlessly bonded to the outer surface of each finger of the rehabilitation glove to achieve a fixing effect. Figure 9As shown, the variable stiffness integral soft finger can be fixed by binding. An elastic strap 11 is provided at the knuckle portion of the variable stiffness integral soft finger, so that the elastic strap 11 is bound to the outer surface of the finger 10 of the human body or the finger of the rehabilitation glove, which can effectively ensure that the knuckle and the finger have a good fit without affecting the performance of the variable stiffness integral soft finger.

[0087] like Figure 1 As shown, the present invention also provides a finger trainer, which includes at least one variable stiffness integral soft finger as mentioned above, wherein the variable stiffness integral soft finger is used for training the finger, and the through hole 8 is used for passing fluid, and the variable stiffness integral soft finger is in contact with the finger surface.

[0088] In summary, the variable-rigidity, integral soft finger of the present invention comprises a base structure 7, through-holes 8, a variable-rigidity structure, and a fingertip structure 1. When a load is applied, the present invention can achieve different bending profiles with variable stiffness. Furthermore, it has a long service life, a simple manufacturing process, and utilizes a monolithic molding structure that can accommodate different hand sizes.

[0089] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A variable stiffness integral soft finger, characterized in that: The variable stiffness integral soft finger comprises: a base structure having one end connected to the through hole; a variable stiffness structure, one end of which is connected to the other end of the base structure; a fingertip structure connected to the other end of the variable stiffness structure; A cavity structure is formed between the through hole, the base structure, the variable stiffness structure and the fingertip structure; The variable stiffness structure comprises: a first joint structure, one end of which is connected to the base structure, and the other end of which is connected to one end of the first knuckle structure; and a second joint structure, one end of which is connected to the other end of the first knuckle structure, and the other end of the second joint structure is connected to the fingertip structure; or a first joint structure, one end of which is connected to the base structure, and the other end of which is connected to one end of the first knuckle structure; a second joint structure, one end of which is connected to the other end of the first finger joint structure, and the other end of the second joint structure is connected to one end of the second finger joint structure; and a third joint structure, one end of which is connected to the other end of the second knuckle structure, and the other end of the third joint structure is connected to the fingertip structure; The first joint structure, the second joint structure and the third joint structure are wavy non-rotating body structures, and the top surface of the wavy non-rotating body structure includes a plurality of alternately connected wave crest structures and wave trough structures; the first finger joint structure and the second finger joint structure are flat structures; the width of the wave crest structure is different at different positions in the circumference thereof, and increases from top to bottom along the circumference of the wave crest structure; the bottom surface of the wavy non-rotating body structure includes a plane and an inner concave arc surface that are alternately connected in sequence, the plane is correspondingly connected to the wave crest structure, and the inner concave arc surface is correspondingly connected to the wave trough structure; A groove is formed between the crest structure and the trough structure, and the depth of the groove is the height difference between the highest point of the crest structure and the lowest point of the trough structure on the axial section. The depth of the groove is different on different axial sections along the circumference of the wavy non-rotating structure, and gradually decreases as the distance between the crest structure and the trough structure and the bottom surface decreases.

2. The variable stiffness integral soft finger according to claim 1, characterized in that: The cross-sectional structure of the crest structure in the radial direction includes: a plurality of first arcs, wherein the plurality of first arcs are tangent to each other; The first bottom edge line is arranged between the first arc lines on both sides of the bottom.

3. The variable stiffness integral soft finger according to claim 1, characterized in that: The cross-sectional structure of the trough structure in the radial direction includes: a plurality of second arcs, wherein the plurality of second arcs are tangent to each other; The second bottom edge line is arranged between the second arc lines on both sides of the bottom.

4. The variable stiffness integral soft finger according to claim 1, characterized in that: The minimum cross-sectional area of ​​the cavity of the trough structure in the radial direction is greater than the maximum cross-sectional area of ​​the cavity of the peak structure in the radial direction. times, and the minimum cross-sectional area of ​​the cavity in the radial direction of the trough structure is smaller than the maximum cross-sectional area of ​​the cavity in the radial direction of the peak structure, and in the axial middle section, the cavity height corresponding to the trough structure is greater than the cavity height corresponding to the peak structure. times, and the cavity height corresponding to the trough structure is smaller than the cavity height corresponding to the peak structure.

5. A finger trainer, characterized in that: The finger trainer comprises a variable stiffness integral soft finger as described in any one of claims 1 to 4, and the variable stiffness integral soft finger is used for training fingers.

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