Flexible optical waveguide soft hand and die for underwater application

Abstract

The utility model relates to the technical field of soft manipulators, in particular to a flexible optical waveguide soft manipulator for underwater application and a die. The flexible optical waveguide soft hand comprises a soft actuator body, a connecting seat and a flexible optical waveguide sensor, a soft hand cabin is arranged in the soft actuator body, and the soft actuator body can be bent after the soft hand cabin is inflated or filled with liquid; two flexible optical waveguide sensors are arranged on the two sides of the soft actuator body respectively and used for sensing bending of the soft actuator body. The connecting base is arranged at the rear end of the soft actuator body and used for being connected with external equipment. The flexible optical waveguide soft hand can sense the bending of the fingers, and the efficiency of the soft hand for executing the operation task in the underwater complex environment is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of soft manipulators, in particular to a flexible optical waveguide soft manipulator and a mold for underwater applications. Background Art

[0002] Underwater manipulators are a typical tool for performing diverse tasks in underwater environments. After years of development, numerous research achievements have been made in underwater manipulator technology, both domestically and internationally, playing a vital role in the development and exploration of underwater resources. Currently, based on the demands of actual operational tasks, underwater manipulators have evolved from their initial single-degree-of-freedom rigid counterparts to highly flexible flexible manipulators.

[0003] In the early days, single-degree-of-freedom (DOF) manipulators were commonly used for underwater operations. Schilling, for example, developed various types of clamp-type manipulators. While their appearance and structure varied, they all had only one degree of freedom: open / close. This limited grasping style and the inability to achieve closed gripping made them more suitable for large, hard objects like rocks. Consequently, the tasks that these manipulators could perform were relatively limited. To increase the degrees of freedom of underwater manipulators, thereby enhancing finger dexterity and enabling a wider range of underwater operations, considerable research has been conducted both domestically and internationally.

[0004] When performing underwater operations, it's essential for manipulators to integrate multiple sensor units to sense their own posture and the external environment, thereby improving underwater operation efficiency. However, due to the extremely complex underwater environment, both rigid and soft underwater manipulators face significant challenges in terms of perception. Traditional underwater grasping tasks rely on remote control of underwater manipulators using visual feedback. Underwater manipulators are typically controlled in an open-loop manner, with little or no closed-loop feedback based on their own sensory information. Utility Model Content

[0005] In response to the above problems, the purpose of the present utility model is to provide a flexible optical waveguide soft hand and mold for underwater applications. The flexible optical waveguide soft hand can sense the bending of the fingers and improve the efficiency of the soft hand in performing work tasks in complex underwater environments.

[0006] In order to achieve the above purpose, the utility model adopts the following technical means:

[0007] On the one hand, the utility model provides a flexible optical waveguide soft hand for underwater applications, comprising a soft actuator body, a connecting seat and a flexible optical waveguide sensor, wherein a soft hand cabin is provided in the soft actuator body, and the soft actuator body can bend after the soft hand cabin is inflated with air or liquid; two flexible optical waveguide sensors are respectively provided on both sides of the soft actuator body, and the flexible optical waveguide sensors are used to sense the bending of the soft actuator body; the connecting seat is arranged at the rear end of the soft actuator body for connecting to external equipment.

[0008] The body of the soft actuator is a pressure bag made of silicone with a rectangular waveguide structure. When filled with gas or liquid medium, the pressure bag expands and bends.

[0009] The soft actuator body includes a fingertip, a deformation section and a finger fixing section arranged in sequence from front to back, wherein the deformation section includes a holding cabin and a bending cabin. The holding cabin is close to the finger fixing section and produces a small curvature while maintaining the driving force; the bending cabin is close to the fingertip, and the top of the bending cabin is a rectangular corrugated structure, which can provide a large curvature.

[0010] The flexible optical waveguide sensor includes an optical waveguide soft shell and a light emitting device and a photosensitive device arranged at both ends of the optical waveguide soft shell. An optical waveguide core is arranged in the optical waveguide soft shell, and the light emitted by the light emitting device is transmitted to the photosensitive device through the optical waveguide core.

[0011] The optical waveguide soft shell is made of opaque silicone material with a low refractive index; the optical waveguide core is made of transparent polyurethane material with a high refractive index and is filled in the optical waveguide soft shell.

[0012] On the other hand, the present invention provides a mold for preparing the flexible optical waveguide soft hand for underwater application as described above, comprising a wax core mold and a soft actuator mold;

[0013] The wax core mold is used to make the wax core; the wax core is set in the soft actuator mold, and the soft actuator body is prepared by injecting silicone into the soft actuator mold.

[0014] The wax core mold includes a left baffle, a wax chamber, a front baffle, a right baffle and a top cover, wherein the left baffle, the wax chamber and the right baffle are placed in sequence from left to right and the front ends are connected by the front baffle, the tops of the left baffle, the wax chamber and the right baffle are sealed and connected by the top cover, the wax chamber has a plurality of concave molds arranged in sequence along the length direction, the top cover is provided with a flat groove covering the plurality of concave molds on the wax chamber, and the rear end of the top cover is provided with a material injection groove, through which the flat groove of the top cover and the plurality of concave molds of the wax chamber are filled with molten wax, the wax solidifies, and a wax core with a plurality of spaced-apart convex structures is obtained.

[0015] The soft actuator mold includes a base plate, an air cabin plate and an upper baffle. The base plate, the air cabin plate and the upper baffle are sequentially molded from bottom to top to form a mold cavity. A wax core is arranged in the mold cavity. An injection cavity is formed between the outer surface of the wax core and the inner wall of the mold cavity. Silicone is injected into the injection cavity. After solidification, an injection body containing the wax core is formed. After the wax core is melted, a soft actuator body with a soft hand cabin is obtained.

[0016] The advantages and beneficial effects of the present invention are as follows: the present invention provides a flexible optical waveguide soft hand for underwater applications, in which the soft fingers are designed as bellows-type flexible structures, and the fingers are bent and deformed by applying pressure through the internal channels of the fingers, so as to grasp underwater objects; the bending of the fingers is sensed by a flexible optical waveguide sensor, and the soft hand and the optical waveguide sensor are combined to improve the efficiency of the soft hand in performing work tasks in complex underwater environments, and the flexible optical wave sensor can be used to feedback the status of the soft hand itself and environmental information.

[0017] The utility model adopts a flexible optical waveguide sensor to detect small changes and subtle signals, and has strong resistance to electromagnetic interference and environmental noise. It has the characteristics of fast response and can detect and respond to changes in real time. At the same time, the optical waveguide sensor can detect without contact with the target object.

[0018] The bending perception of the soft actuator of the present invention has the characteristics of high linearity, sensitivity and low hysteresis, and embedding sensors on both sides of the soft actuator not only has little effect on its bending performance, but also can reduce the hysteresis during pressure relief. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is an axonometric diagram of a flexible optical waveguide soft hand for underwater applications according to the present invention;

[0020] Figure 2 This is an exploded view of a flexible optical waveguide soft hand for underwater applications in the utility model;

[0021] Figure 3 This is an axonometric view of the software actuator body in the present utility model;

[0022] Figure 4 This is a cross-sectional view of the body of the software actuator in the present invention;

[0023] Figure 5 This is an axonometric diagram of the flexible optical waveguide sensor in the present utility model;

[0024] Figure 6 This is a schematic structural diagram of the wax core mold in the utility model;

[0025] Figure 7 This is an axonometric drawing of the wax core in the present invention;

[0026] Figure 8 This is one of the axonometric drawings of the soft actuator mold in the present utility model;

[0027] Figure 9 This is the second axonometric drawing of the soft actuator mold in the present utility model;

[0028] Figure 10 This is the conversion circuit diagram of the utility model.

[0029] In the figure: 1-left baffle, 2-left wax cabin, 3-right wax cabin, 4-front baffle, 5-right baffle, 6-top cover, 7-wax mold, 8-left air cabin plate, 9-right air cabin plate, 10-left bottom plate, 11-right bottom plate, 12-upper baffle, 13-soft actuator body, 131-finger tip, 132-deformation section, 1321-holding cabin, 1322-bending cabin, 133-finger fixing section, 14-flexible optical waveguide sensor, 1401-optical waveguide soft shell, 1402-light-emitting device, 1403-photosensitive device, 1404-optical waveguide core, 15-connecting seat, 16-pagoda connector. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0031] See also Figure 1 、 Figure 2 As shown, an embodiment of the present invention provides a flexible optical waveguide soft hand for underwater applications, including a soft actuator body 13, a connecting seat 15 and a flexible optical waveguide sensor 14, wherein a soft hand cabin is provided in the soft actuator body 13, and the soft actuator body 13 can bend after the soft hand cabin is inflated with air or liquid; two flexible optical waveguide sensors 14 are respectively provided on both sides of the soft actuator body 13, and the flexible optical waveguide sensors 14 are used to sense the bending of the soft actuator body 13; the connecting seat 15 is provided at the rear end of the soft actuator body 13 for connecting to external equipment.

[0032] See also Figure 3 、 Figure 4 As shown, in this embodiment of the present invention, the soft actuator body 13 is a pressure bladder made of silicone (30A hardness) with a rectangular waveguide structure. When filled with gas or liquid, the pressure bladder expands, causing the finger to bend. The hardness of the soft actuator body 13 material is very close to that of the sensor body, minimizing any inconsistencies in their deformation.

[0033] Specifically, the soft actuator body 13 includes a fingertip 131, a deformation section 132, and a finger fixing section 133, arranged in sequence from front to back. The deformation section 132 includes a holding chamber 1321 and a bending chamber 1322. The holding chamber 1321 and the bending chamber 1322 form a composite cavity structure. The holding chamber 1321 is close to the finger fixing section 133, generating a small degree of curvature while maintaining the driving force. The bending chamber 1322 is close to the fingertip 131. The upper surface of the bending chamber 1322 is a rectangular corrugated structure that can provide a large degree of curvature, exerting force on the object, so that the soft hand can generate sufficient grasping force while maintaining an appropriate degree of curvature. All cavities are connected, and the driving fluid flows from the rear channel into each cavity through a sealed tube, so that the internal pressure of the soft actuator quickly reaches the same level, improving the response speed of the soft actuator.

[0034] See also Figure 5 As shown, in an embodiment of the present invention, the flexible optical waveguide sensor 14 includes an optical waveguide soft shell 1404 and a light emitting device 1402 and a photosensitive device 1403 arranged at both ends of the optical waveguide soft shell 1404. An optical waveguide core 1404 is provided in the optical waveguide soft shell 1404, and the light emitted by the light emitting device 1402 is transmitted to the photosensitive device 1403 through the optical waveguide core 1404.

[0035] Specifically, the optical waveguide soft shell 1404 is made of a low-refractive-index and opaque silicone material; the optical waveguide core 1404 is made of a high-refractive-index and transparent polyurethane material filled in the optical waveguide soft shell 1404 .

[0036] To ensure total internal reflection of light within the waveguide, the waveguide soft shell 1404 is made of a low-refractive-index, opaque silicone material (Dragon Skin 20A / B, refractive index 1.41, Smooth-On Inc.), while the waveguide core 1404 is made of a high-refractive-index, transparent polyurethane material (Clear Flex 30A / B, refractive index 1.48, Smooth-On Inc.). These two materials have similar tensile properties, ensuring consistent sensor deformation. Furthermore, to minimize the effects of visible light, an infrared light-emitting diode with a wavelength of 940 nm was selected as the light source, and a corresponding photodiode was used as the photoelectric detection device.

[0037] The entire manufacturing process of the flexible optical waveguide sensor 14 mainly includes two steps:

[0038] The first step is to make the optical waveguide soft shell 1401:

[0039] A small amount of black dye (Silc Pig, Smooth-On Inc.) was added to the Dragon Skin 20A / B solution (20A hardness silicone solution) in a 1:1 ratio, poured into the shell mold, and then taken out when it was cured.

[0040] The second step is to make the optical waveguide core 1404:

[0041] Mix the Clear Flex 30A / B solution in a volume ratio of 1:1 and pour it into the optical waveguide soft shell 1401 with optoelectronic devices placed at both ends. After curing, the optoelectronic devices and the polyurethane material are bonded together to prevent the light emitting device 1402, the photosensor 1403 and the optical waveguide core 1404 from separating when the sensor is deformed. The final flexible optical waveguide sensor 14 is formed. Figure 5 shown.

[0042] In the embodiment of the present invention, the overall length of the flexible optical waveguide sensor 14 is about 95 mm, the dimensions of the optical waveguide core 1404 are: length×width×height are 80×1.5×1.5 mm, and the thickness of the optical waveguide soft shell 1401 is 1 mm.

[0043] See also Figure 10 As shown, to convert the optical signal received by photosensor 1403 into an analog electrical signal, a photoconductive mode conversion circuit with high sensitivity, fast response, and low interference is used. A 68Ω resistor is connected in series with the infrared light-emitting diode for current limiting. The infrared receiving diode is connected to a 3.3V reverse bias voltage. A 0.1-1MΩ resistor is also connected in series, depending on the data collector's requirements, to ensure that the output voltage is within the analog input voltage range of the data collector. To further eliminate external interference, a commercial optoelectronic isolation voltage follower is added. A 16-bit data collector is used to collect the sensor's output voltage, with a sampling frequency of 20Hz.

[0044] The utility model provides a flexible optical waveguide soft hand for underwater applications. The soft fingers are designed as bellows-type flexible structures. Pressurization is applied to the internal channels of the fingers to achieve bending and deformation of the fingers, thereby achieving the purpose of grasping underwater objects. The bending of the fingers is sensed by a flexible optical waveguide sensor. The soft hand and the optical waveguide sensor are combined to improve the efficiency of the soft hand in performing work tasks in complex underwater environments. The flexible optical wave sensor can be used to feedback the status of the soft hand itself and environmental information.

[0045] Another embodiment of the present invention provides a preparation mold for a flexible optical waveguide soft hand for underwater application as in the above embodiment, including a wax core mold and a soft actuator mold; the wax core mold is used to make a wax core 7, see Figure 7As shown; the wax core 7 is set in the soft actuator mold, and the soft actuator body 13 is prepared by injecting silicone into the soft actuator mold.

[0046] See also Figure 6 、 Figure 7 As shown, in the embodiment of the present invention, the wax core mold includes a left baffle 1, a wax cabin, a front baffle 4, a right baffle 5 and a top cover 6, wherein the left baffle 1, the wax cabin and the right baffle 5 are placed in sequence from left to right and the front ends are connected by the front baffle 4, the tops of the left baffle 1, the wax cabin and the right baffle 5 are sealed and connected by the top cover 6, the wax cabin has a plurality of concave molds arranged in sequence along the length direction, the top cover 6 is provided with a flat groove covering the multiple concave molds on the wax cabin, and the rear end of the top cover 6 is provided with a material injection groove, through which the flat groove of the top cover 6 and the multiple concave molds of the wax cabin are filled with molten wax, the wax solidifies, and a wax core 7 with a plurality of spaced-apart convex structures is obtained, and the formed wax core 7 is prepared for the subsequent soft hand cabin.

[0047] In this embodiment, the wax chamber is a split structure including a left wax chamber 2 and a right wax chamber 3 with the same structure, so as to facilitate mold separation.

[0048] See also Figure 8 、 Figure 9 As shown, in an embodiment of the present invention, the soft actuator mold includes a base plate, an air cabin plate and an upper baffle 12. The base plate, the air cabin plate and the upper baffle 12 are sequentially molded from bottom to top to form a mold cavity. The wax core 7 is arranged in the mold cavity. An injection cavity is formed between the outer surface of the wax core 7 and the inner wall of the mold cavity. Silicone is injected into the injection cavity, and an injection body containing the wax core 7 is formed after solidification. After the wax core 7 is melted, a soft actuator body 13 with a soft hand cabin is obtained.

[0049] Specifically, the bottom plate is a split structure, including a left bottom plate 10 and a right bottom plate of a symmetrical structure; the air cabin plate is also a split structure, including a left air cabin plate 8 and a right air cabin plate 9 of a symmetrical structure, to facilitate mold separation.

[0050] The utility model provides a preparation mold for a flexible optical waveguide soft hand for underwater applications, and a preparation method thereof, comprising the following steps:

[0051] Step S1: making a wax core 7 using a wax core mold;

[0052] Step S2: manufacturing the soft actuator body 13 using the soft actuator mold and the wax core 7;

[0053] Step S3: Assembling the flexible optical waveguide soft hand.

[0054] In an embodiment of the present invention, the process of making a wax core includes the following steps:

[0055] Spray the inner surface of the wax core mold with release agent and apply it evenly with a brush;

[0056] Assemble the wax core mold and insert two iron wires into the cavity of the wax core mold for fixing;

[0057] Pour the melted wax into the assembled wax core mold;

[0058] After cooling and solidifying at room temperature, take out the wax core 7 with two iron wires.

[0059] In an embodiment of the present invention, the process of manufacturing the software actuator body includes the following steps:

[0060] Place the formed wax core 7 into the soft actuator mold and support it with two iron wires to assemble the soft actuator mold; the location of the wax core 7 is the location of the soft hand gas chamber;

[0061] Pour a 1:1 weight ratio Dragon Skin 30 A / B silicone rubber (hardness 30A) solution into a syringe and inject it into the soft actuator mold under external pressure. Finally, seal the injection hole.

[0062] Place the mold in an oven at 45°C to accelerate the curing of the silicone. After the silicone is cured, remove the injection mold containing the wax core 7 from the mold.

[0063] Then put it into the oven at 90℃ to melt the wax core 7, and finally obtain the formed soft actuator body 13. Figure 3 shown.

[0064] In an embodiment of the present invention, the process of assembling the flexible optical waveguide soft hand includes the following steps: bonding two flexible optical waveguide sensors 14 to opposite sides of a soft actuator body 13; bonding a connector 15 to the rear end of the soft actuator body 13; and connecting the connector 15 to a pagoda connector 16. Specifically, Sil-Poxy (Smooth-On Inc.) is used for bonding.

[0065] To improve the molding efficiency of the soft actuator body 13, a lost wax method is used. Furthermore, the soft actuator body is made of silicone (Dragon Skin 30A / B, Smooth-On Inc.), which has a hardness very similar to that of the sensor body, minimizing deformation inconsistencies. Regarding the optical waveguide, the present invention utilizes a rectangular waveguide structure. This structure is highly symmetrical and exhibits excellent polarization characteristics. Furthermore, compared to a cylindrical waveguide, it is more convenient to design a mold for manufacturing.

[0066] This utility model integrates a flexible optical waveguide sensor 14 into a bellows-structured soft actuator body 13 to achieve proprioception. Two key considerations are: first, minimizing the impact of sensor embedding on the soft actuator's dynamic performance (bending angle); second, minimizing damage to the sensor while fully maximizing its sensing capabilities. Finally, after the soft actuator experiences a stress-strain condition driven by internal pressure, two sensors are embedded on either side of the soft actuator. When the soft actuator body 13 is driven, different locations experience different stresses and strains. Taking into account the dynamic performance of the soft actuator body 13 and the sensor's bending response, this utility model embeds a flexible optical waveguide sensor 14 on each side of the soft actuator body 13 to achieve proprioception. The structure of the soft actuator body 13 is modified based on its size. The leads at one end of the flexible optical waveguide sensor 14 extend through a channel at the bottom of the soft actuator body 13. The designed routing channel is 1.6 mm wide and 3.5 mm deep.

[0067] The above description is only an embodiment of the present invention and is not intended to limit the scope of protection 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 scope of protection of the present invention.

Claims

1. A flexible optical waveguide soft hand for underwater applications, characterized in that: The invention comprises a soft actuator body (13), a connecting seat (15) and a flexible optical waveguide sensor (14), wherein a soft hand chamber is provided in the soft actuator body (13), and the soft actuator body (13) can bend after the soft hand chamber is inflated with air or liquid; two flexible optical waveguide sensors (14) are respectively provided on both sides of the soft actuator body (13), and the flexible optical waveguide sensors (14) are used to sense the bending of the soft actuator body (13); and the connecting seat (15) is provided at the rear end of the soft actuator body (13) and is used to connect with external equipment.

2. The flexible optical waveguide soft hand for underwater applications according to claim 1, characterized in that: The soft actuator body (13) is a pressure bag made of silica gel and having a rectangular waveguide structure. When filled with gas or liquid medium, the pressure bag expands and achieves bending.

3. The flexible optical waveguide soft hand for underwater applications according to claim 2, characterized in that: The soft actuator body (13) comprises a finger tip (131), a deformation section (132) and a finger fixing section (133) arranged in sequence from front to back, wherein the deformation section (132) comprises a holding cabin (1321) and a bending cabin (1322), wherein the holding cabin (1321) is close to the finger fixing section (133) and generates a small curvature while maintaining a driving force; and the bending cabin (1322) is close to the finger tip (131), and the upper surface of the bending cabin (1322) is a rectangular corrugated structure, which can provide a large curvature.

4. The flexible optical waveguide soft hand for underwater applications according to claim 1, characterized in that: The flexible optical waveguide sensor (14) comprises an optical waveguide soft shell (1401) and a light emitting device (1402) and a photosensitive device (1403) arranged at both ends of the optical waveguide soft shell (1404). An optical waveguide core (1404) is arranged in the optical waveguide soft shell (1404). The light emitted by the light emitting device (1402) is transmitted to the photosensitive device (1403) through the optical waveguide core (1404).

5. The flexible optical waveguide soft hand for underwater applications according to claim 4, characterized in that: The optical waveguide soft shell (1404) is made of a low-refractive-index and opaque silicone material; the optical waveguide core (1404) is made of a high-refractive-index and transparent polyurethane material and is filled in the optical waveguide soft shell (1404).

6. A mold for preparing a flexible optical waveguide soft hand for underwater applications according to any one of claims 1 to 5, characterized in that: Including wax core mold and soft actuator mold; The wax core mold is used to make a wax core (7); the wax core (7) is set in the soft actuator mold, and the soft actuator body (13) is prepared by injecting silicone into the soft actuator mold.

7. The mold for preparing the flexible optical waveguide soft hand for underwater applications according to claim 6, characterized in that: The wax core mold comprises a left baffle (1), a wax chamber, a front baffle (4), a right baffle (5) and a top cover (6), wherein the left baffle (1), the wax chamber and the right baffle (5) are sequentially placed from left to right and the front ends are connected via the front baffle (4), the tops of the left baffle (1), the wax chamber and the right baffle (5) are sealed and connected via the top cover (6), the wax chamber is provided with a plurality of concave molds sequentially arranged at intervals along the length direction, the top cover (6) is provided with a planar groove covering the plurality of concave molds on the wax chamber, and a material injection slot is provided at the rear end of the top cover (6), and melted wax is injected into the planar groove of the top cover (6) and the plurality of concave molds of the wax chamber through the material injection slot, and the wax is solidified to obtain a wax core (7) having a plurality of spaced-apart convex structures.

8. The mold for preparing the flexible optical waveguide soft hand for underwater applications according to claim 7, characterized in that: The soft actuator mold comprises a bottom plate, an air chamber plate and an upper baffle (12); the bottom plate, the air chamber plate and the upper baffle (12) are sequentially molded from bottom to top to form a mold cavity; a wax core (7) is arranged in the mold cavity; an injection cavity is formed between the outer surface of the wax core (7) and the inner wall of the mold cavity; silica gel is injected into the injection cavity and solidified to form an injection body containing the wax core (7); and the wax core (7) is melted to obtain a soft actuator body (13) having a soft hand chamber.

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