Pneumatic soft hand robot

Abstract

The invention belongs to the technical field of rehabilitation robots, and particularly relates to a pneumatic soft hand robot. Comprising a main bending module, a middle air pipe connecting layer and a reverse bending module which are sequentially connected from top to bottom, the main bending module is provided with two or three sets of independent upper cavity structures protruding upwards, the reverse bending module is provided with a lower cavity structure protruding downwards, and the middle air pipe connecting layer is used for connecting the main bending module and the reverse bending module. And air pressure is provided for the lower cavity structure and the upper cavity structures, so that the bending and stretching actions of the pneumatic soft hand robot are realized. Different finger joints are ventilated so as to assist the finger with the injured hand in stretching and bending, various rehabilitation postures and auxiliary grabbing tasks are completed, and the purpose of helping a patient with the injured hand to recover better is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of rehabilitation robots, and in particular relates to a pneumatic soft hand robot. Background Art

[0002] Stroke is the third leading cause of death and disability worldwide. As the number of stroke patients increases, approximately 75% of stroke survivors experience impaired motor function, and 55% to 75% of stroke patients face persistent motor dysfunction in the upper limbs and hands. Hands play a vital role in the physical interaction between humans and the environment. However, stroke patients often have difficulty completing prescribed movements, which seriously affects their quality of life and ability to perform daily activities and reduces their ability to take care of themselves. Therefore, hand rehabilitation after stroke is essential to restore a functionally independent lifestyle. Studies have shown that robot-assisted repetitive task training can effectively help restore hand function.

[0003] In order to overcome the limitations of traditional robots, soft hand rehabilitation robots use soft actuators to achieve finger rehabilitation and assisted movement. Among them, pneumatically driven soft rehabilitation robots are light, flexible, and safe, and are suitable for hand assistance and rehabilitation. However, most of the current pneumatic soft hand rehabilitation robots can only achieve unidirectional bending of fingers. Therefore, designing a bidirectionally bending pneumatic soft hand rehabilitation robot can better meet the rehabilitation training needs of patients with hand injuries. Summary of the invention

[0004] In response to the above problems, the purpose of the present invention is to provide a pneumatic soft hand robot with a bidirectional bending actuator. By ventilating different finger joints, it can help the fingers extend and flex, complete a variety of rehabilitation postures and assist grasping tasks, and achieve the purpose of helping patients with hand injuries recover better.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a pneumatic soft hand robot, comprising a main bending module, an intermediate air pipe connecting layer and a reverse bending module which are connected in sequence from top to bottom, wherein the main bending module is provided with two or three groups of upwardly protruding and independent upper cavity structures, the reverse bending module is provided with a downwardly protruding lower cavity structure, the intermediate air pipe connecting layer is used to connect the main bending module and the reverse bending module, and provide air pressure for the lower cavity structure and each upper cavity structure, so as to realize the bending and stretching movements of the pneumatic soft hand robot.

[0007] The upper cavity structure of the main bending module includes a plurality of semicircular cross-section air cavities arranged in sequence, and each group of two adjacent semicircular cross-section air cavities is connected through the main bending module gas channel. After gas is introduced into each semicircular cross-section air cavity, the main bending module can realize the main bending function of the soft hand robot.

[0008] After the upper cavity structure of the main bending module is pressurized, the end fingertips can reach a bending angle of 180°.

[0009] The lower cavity structure of the reverse bending module includes a plurality of trapezoidal cross-section air cavities arranged in parallel, and two adjacent trapezoidal cross-section air cavities are connected through the reverse bending module gas channel. After gas is introduced into each trapezoidal cross-section air cavity, the reverse bending module can realize reverse bending of the soft hand robot.

[0010] After the lower cavity structure of the reverse bending module is pressurized, the end fingertip can reach a bending angle of 70°.

[0011] The fingertip force of reverse bending of the reverse bending module is smaller than the fingertip force of main bending of the main bending module.

[0012] The intermediate air pipe connection layer includes a connecting plate and a plurality of air pipes arranged on the connecting plate. Both sides of the connecting plate are sealed and connected to the main bending module and the reverse bending module respectively. The plurality of air pipes supply air to the upper cavity structures of the main bending module and the lower cavity structures of the reverse bending module respectively.

[0013] The upper side surface of the connecting plate is provided with a plurality of main bending module ventilation holes respectively connected with the upper cavity structures; the lower side surface of the connecting plate is provided with reverse bending module ventilation holes connected with the lower cavity structure.

[0014] By controlling the air pressure in each upper cavity structure of the main bending module, various bending forms of the pneumatic soft hand robot can be achieved.

[0015] The main bending module, the intermediate air pipe connecting layer and the reverse bending module are all made of silicone material.

[0016] The advantages and beneficial effects of the present invention compared with the prior art are:

[0017] Conforms to human hand bionics: The pneumatic soft hand robot provided by the present invention has a structural design that conforms to the bending and stretching forms of the human hand, and the reverse bending module can better fit the movement of the fingers.

[0018] Good safety: The present invention drives the soft hand robot by pneumatic drive, and can realize the rehabilitation movement of fingers under safe air pressure. It has been verified by experiments that the reverse bending fingertip force is smaller than the main bending fingertip force, thus ensuring safety.

[0019] Large finger bending angle: The main bending module of the present invention adopts a twelve-cavity structure, and the fingertips can reach a bending angle of 180° after pressurization. The fingertips of the reverse bending module can reach a bending angle of 70°, meeting the requirements of finger bending.

[0020] Multiple rehabilitation gestures: The present invention can achieve multiple bending shapes of fingers by controlling different joints of the soft hand robot, and can assist the fingers in completing stretching movements, ultimately meeting the needs of multiple rehabilitation training.

[0021] Auxiliary function: After testing, the maximum load capacity of a single finger of the present invention is 260g under 130Kpa, which can assist patients with hand injuries to grasp objects of appropriate weight. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is an axonometric diagram of a pneumatic soft hand robot of the present invention;

[0023] Figure 2 This is an axonometric diagram of the composition structure of a pneumatic soft hand robot of the present invention;

[0024] Figure 3 One of the axonometric views of the main bending module in the present invention;

[0025] Figure 4 This is the second axonometric drawing of the main bending module in the present invention;

[0026] Figure 5 This is one of the axonometric views of the intermediate air pipe connection layer in the present invention;

[0027] Figure 6 This is the second axonometric view of the intermediate air pipe connection layer in the present invention;

[0028] Figure 7 One of the axonometric views of the reverse bending module of the present invention;

[0029] Figure 8 This is the second axonometric view of the reverse bending module in the present invention;

[0030] Fig. 9 It is a structural schematic diagram of a middle finger mold in one embodiment of the present invention;

[0031] Fig.10 Schematic diagram of the structure of a thumb mold in another embodiment of the present invention.

[0032] In the figure: 101-semicircular cross-section air cavity, 102-main bending module gas channel, 103-trachea, 104-main bending module ventilation hole, 105-reverse bending module ventilation hole, 106-trapezoidal cross-section air cavity, 107-reverse bending module gas channel, 108-main bending module, 109-intermediate trachea connecting layer, 110-reverse bending module, 111-connecting plate;

[0033] 201-main bending module lower part mold Ⅰ, 202-main bending module upper part mold Ⅰ, 203-intermediate tracheal layer main bending surface mold Ⅰ, 204-intermediate tracheal layer reverse bending surface mold Ⅰ, 205-reverse bending module upper part mold Ⅰ, 206-reverse bending module lower part mold Ⅰ, 207-main bending module lower part mold Ⅱ, 208-main bending module upper part mold Ⅱ, 209-intermediate tracheal layer main bending surface mold Ⅱ, 210-intermediate tracheal layer reverse bending surface mold Ⅱ, 211-reverse bending module lower part mold Ⅱ, 212-reverse bending module upper part mold Ⅱ. DETAILED DESCRIPTION

[0034] In order to have a further understanding of the features, purposes and functions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0035] See also Figure 1 , Figure 2 As shown, the present invention provides a pneumatic soft hand robot, including a main bending module 108, an intermediate air pipe connecting layer 109 and a reverse bending module 110 connected in sequence from top to bottom, wherein the main bending module 108 is provided with two or three groups of upwardly protruding and independent upper cavity structures, the reverse bending module 110 is provided with a downwardly protruding lower cavity structure, the intermediate air pipe connecting layer 109 is used to connect the main bending module 108 and the reverse bending module 110, and provide air pressure for the lower cavity structure and each upper cavity structure, so as to realize the bending and stretching movements of the pneumatic soft hand robot.

[0036] See also Figure 3 , Figure 4 As shown, in an embodiment of the present invention, the upper cavity structure of the main bending module 108 includes a plurality of semicircular cross-section air cavities 101 arranged in sequence, and each group of two adjacent semicircular cross-section air cavities 101 are connected through a main bending module gas channel 102. After gas is introduced into each semicircular cross-section air cavity 101, the main bending module 108 can realize the main bending function of the soft hand robot.

[0037] In this embodiment, each upper cavity structure is provided with four semicircular cross-section air cavities 101, and the upper cavity structure of the main bending module 108 can achieve a bending angle of 180° at the distal fingertips after pressurization.

[0038] See also Figure 7 , Figure 8 As shown, in an embodiment of the present invention, the lower cavity structure of the reverse bending module 110 includes a plurality of trapezoidal cross-section air cavities 106 arranged in parallel, and two adjacent trapezoidal cross-section air cavities 106 are connected through a reverse bending module gas channel 107. After gas is introduced into each trapezoidal cross-section air cavity 106, the reverse bending module 110 can realize reverse bending of the soft hand robot.

[0039] Furthermore, after the lower cavity structure of the reverse bending module 110 is pressurized, the end fingertip can reach a bending angle of 70°. The fingertip force of the reverse bending module 110 is smaller than the main bending fingertip force of the main bending module 108 .

[0040] See also Figure 5 , Figure 6 As shown, in an embodiment of the present invention, the intermediate air pipe connecting layer 109 includes a connecting plate 111 and a plurality of air pipes 103 arranged on the connecting plate 111, and the two sides of the connecting plate 111 are respectively sealed and connected to the main bending module 108 and the reverse bending module 110, and the plurality of air pipes 103 respectively supply air to the upper cavity structures of the main bending module 108 and the lower cavity structures of the reverse bending module 110.

[0041] Furthermore, the upper side of the connecting plate 111 is provided with a plurality of main bending module ventilation holes 104 respectively connected to the upper cavity structures; the lower side of the connecting plate 111 is provided with a reverse bending module ventilation hole 105 connected to the lower cavity structure. The reverse bending module ventilation hole 105 and each main bending module ventilation hole 104 are respectively connected to an air pipe 103. In this embodiment, there are four air pipes 103. By controlling the air pressure in each upper cavity structure of the main bending module 108, a variety of bending forms of the pneumatic soft hand robot can be achieved.

[0042] Specifically, the main bending module 108 is the upper layer of the finger, which is mainly responsible for the flexion movement of the finger. It is a three-level cavity structure designed to simulate the three joints of the finger. Each joint has four semicircular cross-section air cavities 101. The cross-sectional shape of the semicircular cross-section air cavity 101 is a semicircle, which has better bending performance. The reverse bending module 110 is the lower layer of the finger, which is mainly responsible for the extension movement of the finger. The cross-sectional design is trapezoidal. Under the condition of not affecting the main bending and safety of the finger, the cross-sectional shape of the trapezoidal cross-section air cavity 106 adopts a trapezoidal shape, which can provide a sufficiently large reverse bending force. The intermediate tracheal connection layer 109 is an intermediate layer, the purpose of which is to place the trachea 103, and to transport air to the main bending module 108 and the reverse bending module 110 through the main bending module ventilation holes 104 and the reverse bending module ventilation holes 105, respectively, and will play a connecting role.

[0043] In the embodiment of the present invention, the main bending module 108, the intermediate air tube connection layer 109 and the reverse bending module 110 are all made of silicone material. When the main bending module 108 is provided with three groups of upwardly protruding and independent upper cavity structures, a middle finger is formed with twelve semicircular cross-sectional air cavities 101; when the main bending module 108 is provided with two groups of upwardly protruding and independent upper cavity structures, a thumb is formed with eight semicircular cross-sectional air cavities 101.

[0044] Specifically, the middle finger is prepared using a middle finger mold. Fig. 9 As shown, the middle finger mold consists of six parts: the lower part mold Ⅰ201 of the main bending module, the upper part mold Ⅰ202 of the main bending module, the main bending surface mold Ⅰ203 of the intermediate air tube layer, the reverse bending surface mold Ⅰ204 of the intermediate air tube layer, the upper part mold Ⅰ205 of the reverse bending module and the lower part mold Ⅰ206 of the reverse bending module. Fig. 9 As shown in (A), the main bending module lower part mold Ⅰ201 and the main bending module upper part mold Ⅰ202 are used to prepare the main bending module 108 of the middle finger; see Fig. 9 As shown in (B), the intermediate tracheal layer main curved surface mold Ⅰ203 and the intermediate tracheal layer reverse curved surface mold Ⅰ204 are used to prepare the intermediate tracheal connecting layer 109 of the middle finger; see Fig. 9 As shown in (C), the reverse bending module upper part mold I 205 and the reverse bending module lower part mold I 206 are used to prepare the reverse bending module 110 of the middle finger.

[0045] Specifically, the thumb is prepared using a thumb mold. Fig.10 As shown, the thumb mold consists of six parts, including the main bending module lower part mold Ⅱ207, the main bending module upper part mold Ⅱ208, the middle tracheal layer main bending surface mold Ⅱ209, the middle tracheal layer reverse bending surface mold Ⅱ210, the reverse bending module lower part mold Ⅱ211 and the reverse bending module upper part mold Ⅱ212. Fig.10 As shown in (a), the main bending module lower part mold II 207 and the main bending module upper part mold II 208 are used to prepare the main bending module 108 of the thumb; see Fig.10 As shown in (b), the middle tracheal layer main curved surface mold II 209 and the middle tracheal layer reverse curved surface mold II 210 are used to prepare the middle tracheal connecting layer 109 of the thumb; see Fig.10 As shown in (c), the reverse bending module lower part mold II 211 and the reverse bending module upper part mold II 212 are used to prepare the reverse bending module 110 of the thumb.

[0046] The present invention provides a pneumatic soft hand robot. Taking the middle finger as an example, the preparation process is as follows:

[0047] The mold material is PLA, which is printed by Bambu Lab 3D printer. The pneumatic soft hand robot is made of Ecoflex 00-50 silicone in a 1:1 ratio.

[0048] The manufacturing process of the main bending module 108 is: cover the main bending module upper part mold Ⅰ202 on the main bending module lower part mold Ⅰ201, then pour the stirred silicone compound into the mold, let it stand for three hours, and then demould.

[0049] The production process of the intermediate air tube connecting layer 109 is: first place the air tube 103 into the corresponding hole, then pour the silicone material into the intermediate air tube layer main curved surface mold Ⅰ203, and finally cover the intermediate air tube layer reverse curved surface mold Ⅰ204 on the intermediate air tube layer main curved surface mold Ⅰ203 and fix it. After standing for three hours, demold it.

[0050] The reverse bending module 110 is manufactured by an inverted casting method: first, a silicone compound is poured into the reverse bending module lower part mold Ⅰ206, and then the reverse bending module upper part mold Ⅰ205 is covered on the reverse bending module lower part mold Ⅰ206. Finally, it is inverted, with the reverse bending module lower part mold Ⅰ206 on top, and cast again, left to stand for three hours, and demoulding.

[0051] Finally, glue the three parts together to get the middle finger. The production process of the thumb is the same as that of the middle finger.

[0052] In this embodiment, the mathematical model of the main bending module 108 is

[0053] The length of the unit air cavity module is a, the expanded length of the module after inflation is b, the height is h, the bending angle is θ, the width of the module is c, and the error caused by environmental factors is E. The bending angle θ is given by the following formula:

[0054]

[0055] According to Avogadro's hypothesis, the equilibrium equation for gas volume and mass can be derived from Clapham's equation:

[0056]

[0057] Where P (Pa) is the pressure, V (m 3 ) is the volume, m(g) is the mass, μ(g / mol) is the molar mass, T(℃) is the absolute temperature, and R is a constant.

[0058] When the cavity is inflated, a single air cell can be regarded as a semi-ellipsoid. Therefore, the volume expression of a single inflated air cell is as follows:

[0059]

[0060] According to equations (1)-(3), the relationship between the output air pressure and the bending angle is obtained.

[0061]

[0062] In this embodiment, the mathematical model of the reverse bending module 110 is

[0063] In order to meet the requirements of reverse bending without affecting the finger flexion angle, the middle part is designed as an isosceles trapezoid, and the side is an irregular trapezoid with the same inclination angle. The height of the reverse bending module 110 is h1, the length of the upper base is b1, the length of the lower base is a1, the angle between the lower base and the side of the trapezoid is α1, and the width of the module is c.

[0064]

[0065] Among them, t is the hypotenuse of the trapezoid; R is the radius of the fan after expansion; ε is half of the central angle; θ is half of the bending angle.

[0066] When the cavity is expanded, a single chamber can be represented as:

[0067] V=2εR 2 c-Rtccosε+(a1+b1)h1c / 2 (6)

[0068] According to Avogadro's hypothesis, the equilibrium equation for gas volume and mass can be derived from Clapham's equation:

[0069]

[0070] Where P'(Pa) is the pressure, V(m 3 ) is the volume, m0(g) is the mass, μ0(g / mol) is the molar mass, T0(℃) is the absolute temperature, and R0 is a constant.

[0071] According to equations (5)-(7), the relationship between the output air pressure and the bending angle is obtained.

[0072]

[0073] The present invention proposes a novel flexible pneumatic hand rehabilitation robot equipped with a bidirectional bending actuator, the maximum bending angle of the thumb can reach 70°, and the maximum bending angle of other fingers can reach 180°, which can meet the needs of daily activities. The main bending module 108 realizes the finger flexion function, adopts a three-level cavity structure, and is designed with a total of twelve air cavities. Each finger joint contains four air cavities to simulate human fingers. Each joint can be controlled individually or collaboratively, and such a design increases the finger training movement. The intermediate tracheal connection layer 109 is used to fix the trachea 103 and connect the main bending module 108 and the reverse bending module 110. The surface with three air holes is bonded to the main bending module 108, and the surface with one air hole is bonded to the reverse bending module 110. Without affecting the bending movement of the main bending module 108, the reverse bending module 110 uses a trapezoidal air chamber structure. This configuration conforms to the bending form of the human hand and can improve the reverse bending ability to achieve the function of assisting finger extension.

[0074] The present invention can realize the rehabilitation movement of fingers under safe air pressure. After experimental verification, the force of the reverse bending fingertips is less than the force of the main bending fingertips, which shows the safety of the fingers. The maximum weight that the fingers can grasp is 260g. This is particularly beneficial for the rehabilitation of patients with partial hand dysfunction. The present invention can not only complete a variety of hand rehabilitation postures, but also assist patients with hand injuries to grasp objects of suitable weight, which can better help the recovery of hand function.

[0075] The above description is only an embodiment of the present invention and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, expansion, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A pneumatic soft hand robot, characterized in that: The invention comprises a main bending module (108), an intermediate air pipe connection layer (109) and a reverse bending module (110) which are connected in sequence from top to bottom, wherein the main bending module (108) is provided with two or three groups of upper cavity structures which are raised upward and independent, and the reverse bending module (110) is provided with a lower cavity structure which is raised downward, and the intermediate air pipe connection layer (109) is used to connect the main bending module (108) and the reverse bending module (110) and provide air pressure for the lower cavity structure and each upper cavity structure, so as to realize the bending and stretching movements of the pneumatic soft hand robot.

2. The pneumatic soft hand robot according to claim 1, characterized in that: The upper cavity structure of the main bending module (108) comprises a plurality of semicircular cross-section air cavities (101) arranged in sequence, and each group of two adjacent semicircular cross-section air cavities (101) are connected via a main bending module gas channel (102). After gas is introduced into each semicircular cross-section air cavity (101), the main bending module (108) can realize the main bending function of the soft hand robot.

3. The pneumatic soft hand robot according to claim 2, characterized in that: After the upper cavity structure of the main bending module (108) is pressurized, the distal fingertip can reach a bending angle of 180°.

4. The pneumatic soft hand robot according to claim 1, characterized in that: The lower cavity structure of the reverse bending module (110) comprises a plurality of trapezoidal cross-section air cavities (106) arranged in parallel, and two adjacent trapezoidal cross-section air cavities (106) are connected via a reverse bending module gas channel (107). After gas is introduced into each trapezoidal cross-section air cavity (106), the reverse bending module (110) can realize reverse bending of the soft hand robot.

5. The pneumatic soft hand robot according to claim 4, characterized in that: After the lower cavity structure of the reverse bending module (110) is pressurized, the end fingertip can reach a bending angle of 70°.

6. The pneumatic soft hand robot according to claim 1, characterized in that: The fingertip force of reverse bending of the reverse bending module (110) is smaller than the fingertip force of main bending of the main bending module (108).

7. The pneumatic soft hand robot according to claim 1, characterized in that: The intermediate air pipe connection layer (109) comprises a connection plate (111) and a plurality of air pipes (103) arranged on the connection plate (111); two sides of the connection plate (111) are respectively sealedly connected to the main bending module (108) and the reverse bending module (110); and the plurality of air pipes (103) respectively supply air to the upper cavity structures of the main bending module (108) and the lower cavity structures of the reverse bending module (110).

8. The pneumatic soft hand robot according to claim 7, characterized in that: The upper side surface of the connecting plate (111) is provided with a plurality of main bending module ventilation holes (104) respectively connected to the upper cavity structures; the lower side surface of the connecting plate (111) is provided with reverse bending module ventilation holes (105) connected to the lower cavity structure.

9. The pneumatic soft hand robot according to claim 1, characterized in that: By controlling the air pressure in each upper cavity structure of the main bending module (108), various bending forms of the pneumatic soft hand robot can be achieved.

10. The pneumatic soft hand robot according to claim 1, characterized in that: The main bending module (108), the intermediate air pipe connecting layer (109) and the reverse bending module (110) are all made of silicone material.

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