Self-adaptive variable-stiffness fin and working method thereof

Abstract

The invention discloses a self-adaptive variable-stiffness fin and a working method thereof. The fin comprises an active swing mechanism, the active swing mechanism comprises a motor and an active swing part, and the active swing part is connected with an output shaft of the motor; the driven fin is rotationally connected with the driving swinging part; the two ends of the torsional spring are connected to the driving swing part and the driven fin respectively; the variable stiffness assembly comprises a shifting block and two spring sets, the shifting block is connected with the passive fin, the two spring sets are arranged on the two sides of the shifting block respectively, the end of the shifting block can make contact with the spring sets, and each spring set comprises a plurality of springs. Two elastic pieces, namely the torsional spring and the spring set, are arranged, so that the torsional spring provides rigidity for the fin when a shifting block in the passive fin does not make contact with the spring set; when the shifting block in the passive fish fin is in contact with the spring set, the torsional spring and the spring set jointly provide rigidity for the fish fin. Therefore, the rigidity of the fin can change along with the change of the swing amplitude. The invention relates to the technical field of bionics.

Description

Technical Field

[0001] The present application relates to the technical field of bionics, and in particular to an adaptive variable stiffness fish fin and a working method thereof. Background Art

[0002] Underwater robots play an important role in ocean exploration, environmental monitoring, military and engineering. In particular, the development of bionic fish robots has brought new directions to underwater propulsion. Compared with traditional propeller propulsion, bionic fish fin propulsion is quieter, more flexible and can adapt to complex and changing water flow environments.

[0003] However, existing bionic fish fin thrusters usually have limitations in stiffness adjustment, and it is difficult to adaptively maintain efficient and flexible propulsion under different fluid environments and a wide range of driving frequencies. In order to optimize the stiffness adjustment of fish fins, existing technologies have tried a variety of solutions, including torsion spring systems, motor-driven springs, and hydraulic drive methods. Although these methods can improve propulsion efficiency under certain circumstances, they still face problems such as high energy consumption, complex systems, and insufficient adaptability.

[0004] Therefore, there is an urgent need for a bionic fin mechanism that can change the stiffness of the fin according to actual conditions, and can reduce the complexity of the mechanism and reduce energy consumption. Summary of the invention

[0005] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes an adaptive variable stiffness fish fin, which can improve the adaptability of the bionic fish fin and reduce system complexity and energy consumption.

[0006] The present application also proposes a working method for the above-mentioned adaptive variable stiffness fish fin.

[0007] According to the first aspect of the present application, the adaptive variable stiffness fish fin includes:

[0008] An active swing mechanism, comprising a motor and an active swing member, wherein the active swing member is connected to an output shaft of the motor, and the motor drives the active swing member to swing back and forth;

[0009] A passive fish fin, which is rotatably connected to the active swinging member;

[0010] A torsion spring, two ends of which are respectively connected to the active swinging member and the passive fin;

[0011] A variable stiffness component includes a toggle block and a spring group, wherein the toggle block is connected to the passive fin and swings therewith, there are two spring groups and they are respectively arranged on both sides of the toggle block, the end of the toggle block can contact the spring group, each of the spring groups contains a plurality of springs, and part of the kinetic energy of the swing of the toggle block can be converted into the elastic potential energy of the spring.

[0012] According to the adaptive variable stiffness fish fin of the embodiment of the present application, at least the following beneficial effects are achieved: by providing two elastic parts, a torsion spring and a spring group, when the toggle block in the passive fish fin does not contact the spring group, the torsion spring provides the stiffness of the fish fin; when the toggle block in the passive fish fin contacts the spring group, the torsion spring and the spring group jointly provide the stiffness of the fish fin. Thus, the stiffness of the fish fin can change with the change of the swing amplitude, and the system complexity and energy consumption are lower than those of the traditional mechanism.

[0013] According to some embodiments of the present application, the variable stiffness assembly also includes a first contact block and a second contact block, the first contact block is arranged at the end of the toggle block, and a contact surface is arranged on the side of the first contact block; the second contact block is arranged at the end of the spring group, and a roller is installed on the second contact block, and the roller can roll in contact with the contact surface.

[0014] According to some embodiments of the present application, the spring group includes at least two springs, the second contact block is mounted to an end of each of the springs, and the roller is disposed between two adjacent springs.

[0015] According to some embodiments of the present application, the contact surface is a curved surface.

[0016] According to some embodiments of the present application, along the direction of the rotation axis of the roller, the contact surface is in an involute shape around the rotation axis of the roller.

[0017] According to some embodiments of the present application, the toggle block contacts the roller and applies a force, and the spring is stretched under the force of the toggle block.

[0018] According to some embodiments of the present application, the installation position of the first contact block on the toggle block can be adjusted to change the distance between the first contact block and the rotation axis of the passive fin.

[0019] According to some embodiments of the present application, a tail fin is installed at the end of the passive fin.

[0020] According to some embodiments of the present application, the adaptive variable stiffness fin further includes a connecting member, the passive fin is rotatably connected to the active swinging member via the connecting member, and the passive fin is detachably connected to the connecting member.

[0021] According to the working method of the second aspect of the present application, based on the above-mentioned adaptive variable stiffness fish fin, it includes a small swing mode and a large swing mode, wherein:

[0022] The small swing modes include:

[0023] The motor is started, and the active swinging member swings under the drive of the motor;

[0024] The passive fin swings along with the active swinging member, and the torsion spring is compressed;

[0025] Before the toggle block contacts the spring group, the kinetic energy of the passive fin is completely converted into the elastic potential energy of the torsion spring;

[0026] The torsion spring releases elastic potential energy to the passive fish fin to restore the passive fish fin to an initial state;

[0027] The above steps are repeated cyclically, and the passive fins provide driving force for the bionic fish to swim;

[0028] The large swing patterns include:

[0029] The motor is started, and the active swinging member swings under the drive of the motor;

[0030] The passive fin swings along with the active swinging member, and the torsion spring is compressed;

[0031] The toggle block contacts the spring group, and the kinetic energy of the passive fin is completely converted into the elastic potential energy of the torsion spring and the spring group;

[0032] The torsion spring and the spring group jointly release elastic potential energy to the passive fish fin to restore the passive fish fin to an initial state;

[0033] The above steps are repeated cyclically, and the passive fins provide driving force for the bionic fish to swim.

[0034] According to the working method of the embodiment of the present application, at least the following beneficial effects are achieved: when the toggle block in the passive fish fin does not contact the spring group, the torsion spring provides the stiffness of the fish fin, and the fish fin swings slightly; when the toggle block in the passive fish fin contacts the spring group, the torsion spring and the spring group jointly provide the stiffness of the fish fin, and the fish fin swings greatly. By providing two elastic parts, the torsion spring and the spring group, the characteristics of different rigidities of the fish fin under different swing amplitudes can be achieved.

[0035] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings are used to provide further understanding of the technical solution disclosed in the present application and constitute a part of the specification. Together with the embodiments disclosed in the present application, they are used to explain the technical solution disclosed in the present application and do not constitute a limitation on the technical solution disclosed in the present application.

[0037] Figure 1 A three-dimensional diagram of an adaptive variable stiffness fish fin according to an embodiment of the first aspect of the present application;

[0038] Figure 2 A side view of an adaptive variable stiffness fish fin according to an embodiment of the first aspect of the present application;

[0039] Figure 3 for Figure 2 Sectional view at AA in the middle;

[0040] Figure 4 This is a cross-sectional view of the adaptive variable stiffness fish fin when swinging according to the first aspect of the present application;

[0041] Figure 5 for Figure 4 A partial enlarged view of point B in the middle.

[0042] Figure numerals: 100 - active swing mechanism, 110 - motor, 120 - active swing member, 200 - passive fin, 210 - tail fin, 300 - torsion spring, 410 - toggle block, 420 - spring group, 421 - spring, 430 - first contact block, 431 - contact surface, 440 - second contact block, 441 - roller, 500 - connecting member. DETAILED DESCRIPTION

[0043] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0044] In the description of the present application, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0045] In the description of this application, "several" means more than one, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0046] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0047] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0048] Underwater robots play an important role in ocean exploration, environmental monitoring, military and engineering. In particular, the development of bionic fish robots has brought new directions to underwater propulsion. Compared with traditional propeller propulsion, bionic fish fin propulsion is quieter, more flexible and can adapt to complex and changing water flow environments.

[0049] However, existing bionic fish fin thrusters usually have limitations in stiffness adjustment, and it is difficult to adaptively maintain efficient and flexible propulsion under different fluid environments and a wide range of driving frequencies. In order to optimize the stiffness adjustment of fish fins, existing technologies have tried a variety of solutions, including torsion spring systems, motor-driven springs, and hydraulic drive methods. Although these methods can improve propulsion efficiency under certain circumstances, they still face problems such as high energy consumption, complex systems, and insufficient adaptability.

[0050] In this regard, the present application proposes an adaptive variable stiffness fish fin, which provides two elastic parts, a torsion spring 300 and a spring group 420. When the toggle block 410 in the passive fish fin 200 does not contact the spring group 420, the torsion spring 300 provides the stiffness of the fish fin; when the toggle block 410 in the passive fish fin 200 contacts the spring group 420, the torsion spring 300 and the spring group 420 jointly provide the stiffness of the fish fin. Thus, the stiffness of the fish fin can change with the change of the swing amplitude, and the system complexity and energy consumption are lower than those of the traditional mechanism.

[0051] In addition, the present application also proposes a working method for the above-mentioned adaptive variable stiffness fish fin. When the toggle block 410 in the passive fish fin 200 does not contact the spring group 420, the torsion spring 300 provides the stiffness of the fish fin, and the fish fin swings slightly at this time; when the toggle block 410 in the passive fish fin contacts the spring group 420, the torsion spring 300 and the spring group 420 jointly provide the stiffness of the fish fin, and the fish fin swings greatly at this time. By providing two elastic parts, the torsion spring 300 and the spring group 420, the characteristics of different stiffness under different swing amplitudes of the fish fin can be achieved.

[0052] Reference Figure 1 The working method of the adaptive variable stiffness fish fin in the embodiment of the first aspect of the present application comprises an active swing mechanism 100, a passive fish fin 200, a torsion spring 300 and a variable stiffness assembly. Among them, the active swing mechanism 100 is a driving part of the adaptive variable stiffness fish fin, which is used to provide a force for the swinging of the fish fin. The passive fish fin 200 is connected to the active swing mechanism 100 and swings accordingly, thereby simulating the push of the fish fin on the surrounding water when the fish swims. The torsion spring 300 is used to drive the passive fish fin 200 to return to the center. The variable stiffness assembly is used to provide additional force to quickly return the passive fish fin 200 to the center when the passive fish fin 200 swings greatly, so as to achieve the effect of changing the stiffness of the fish fin according to the swing amplitude of the passive fish fin.

[0053] Specifically, refer to Figure 2 The active swing mechanism 100 includes a motor 110 and an active swing member 120. The active swing member 120 is connected to the output shaft of the motor 110, and the motor 110 drives the active swing member 120 to swing back and forth. The passive fin 200 is rotatably connected to the active swing member 120, and the two ends of the torsion spring 300 are respectively connected to the active swing member 120 and the passive fin 200, so that the passive fin 200 can swing with the swing of the active swing member 120, and the torsion spring 300 can provide a force to return the passive fin 200 to the normal position.

[0054] Reference Figure 3 The variable stiffness assembly includes a toggle block 410 and a spring group 420. The toggle block 410 is connected to the passive fin 200 and swings therewith. There are two spring groups 420, which are respectively arranged on both sides of the toggle block 410. The end of the toggle block 410 can contact the spring group 420. Each spring group 420 contains a plurality of springs 421. Part of the kinetic energy of the swing of the toggle block 410 can be converted into the elastic potential energy of the spring 421.

[0055] The working principle of the adaptive variable stiffness fish fin is as follows: when the passive fish fin 200 swings slightly, the toggle block 410 swings to the limit and does not contact the spring group 420. At this time, only the torsion spring 300 provides the force to drive the passive fish fin 200 to return to the correct position. When the passive fish fin 200 swings greatly, the toggle block 410 is provided with a force to return to the correct position by the torsion spring 300 before contacting the spring group 420. After the toggle block 410 contacts the spring group 420, the spring group 420 joins and drives the passive fish fin 200 to return to the correct position together with the torsion spring 300. Therefore, the adaptive variable stiffness fish fin has different stiffnesses at different swing amplitudes, can adapt to different fish fin swing conditions, has better environmental adaptability, and has a simple structure. The energy consumption is also lower than that of the traditional variable stiffness fish fin mechanism.

[0056] Further, refer to Figure 4 and Figure 5 , the variable stiffness assembly also includes a first contact block 430 and a second contact block 440. The first contact block 430 is arranged at the end of the toggle block 410, and a contact surface 431 is arranged on the side of the first contact block 430. The second contact block 440 is arranged at the end of the spring group 420, and a roller 441 is installed on the second contact block 440, and the roller 441 can roll and contact with the contact surface 431. Therefore, when the toggle block 410 swings, it contacts the roller 441 on the second contact block 440 through the contact surface 431 on the first contact block 430, thereby driving the spring group 420 to stretch or compress, and converting the kinetic energy on the toggle block 410 into the elastic potential energy of each spring 421 in the spring group 420. Similarly, the elastic potential energy of the subsequent spring 421 is transmitted to the toggle block 410 through the second contact block 440 and the first contact block 430, and finally converted into the kinetic energy of the passive fish fin 200. The cycle is repeated to complete the repeated swinging of the passive fish fin 200.

[0057] Optionally, the spring group 420 includes at least two springs 421. The second contact block 440 is mounted to the end of each spring 421, and the roller 441 is disposed between two adjacent springs 421. By increasing or decreasing the number of springs 421 in the spring group 420, the stiffness of the passive fin 200 when swinging greatly can be adjusted.

[0058] Furthermore, the contact surface 431 is an arc-shaped surface, and the roller 441 can roll more smoothly on the arc-shaped contact surface 431. Specifically, along the rotation axis direction of the roller 441, the contact surface 431 is in an involute shape around the rotation axis of the roller 441, thereby ensuring that when the roller 441 contacts the contact surface 431, the stretching or compression direction of the spring 421 is perpendicular to the contact surface 431.

[0059] Specifically, in this embodiment, the toggle block 410 contacts the roller 441 and applies a force, and the spring 421 is stretched under the force of the toggle block 410 .

[0060] Furthermore, the installation position of the first contact block 430 on the toggle block 410 can be adjusted to change the distance between the first contact block 430 and the rotation axis of the passive fin 200. Specifically, the first contact block 430 can be fixed and limited with the toggle block 410 by bolt connection, snap connection or pin connection.

[0061] Furthermore, a tail fin 210 is installed at the end of the passive fin 200, which is used to increase the contact area between the passive fin 200 and the surrounding water area and exert a force on the surrounding water area when the passive fin 200 swings.

[0062] Furthermore, the adaptive variable stiffness fish fin also includes a connecting member 500, and the passive fish fin 200 is rotatably connected to the active swinging member 120 via the connecting member 500. The passive fish fin 200 and the connecting member 500 are detachably connected, so that different types of passive fish fins 200 can be replaced according to different application scenarios to achieve a more targeted effect.

[0063] Furthermore, the passive fin 200 and the connecting member 500 can be detachably connected by bolt connection, snap connection or pin connection. In this embodiment, the passive fin 200 and the connecting member 500 are connected by bolts.

[0064] Optionally, the active swing mechanism 120 and the motor 110 may also be connected in a detachable manner, and the active swing mechanism 120 and the passive fin 200 connected thereto may be removed from the motor 110 together to achieve the effect of overall replacement or installation on other drive sources.

[0065] A working method for the above-mentioned adaptive variable stiffness fish fin in the second aspect of the present application includes a small swing mode and a large swing mode, wherein:

[0066] The small swing pattern consists of the following steps:

[0067] S110. The motor 110 is started, and the active swing member 120 swings under the drive of the motor 110;

[0068] S120. The passive fin 200 swings with the active swing member 120, and the torsion spring 300 is compressed;

[0069] S130. Before the toggle block 410 contacts the spring assembly 420, the kinetic energy of the passive fin 200 is completely converted into the elastic potential energy of the torsion spring 300;

[0070] S140. The torsion spring 300 releases elastic potential energy to the passive fin 200 to restore the passive fin 200 to an initial state;

[0071] S150. The above steps are repeated in a loop, and the passive fin 200 provides a driving force for the bionic fish to swim;

[0072] The large swing pattern consists of the following steps:

[0073] S210. The motor 110 is started, and the active swing member 120 swings under the drive of the motor 110;

[0074] S220. The passive fin 200 swings with the active swing member 120, and the torsion spring 300 is compressed;

[0075] S230. The toggle block 410 contacts the spring group 420, and the kinetic energy of the passive fin 200 is completely converted into the elastic potential energy of the torsion spring 300 and the spring group 420;

[0076] S240. The torsion spring 300 and the spring assembly 420 jointly release elastic potential energy to the passive fin 200 to restore the passive fin 200 to an initial state;

[0077] S250. The above steps are repeated in a loop, and the passive fin 200 provides the bionic fish with a driving force for swimming.

[0078] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. An adaptive variable stiffness fish fin, characterized in that: include: An active swing mechanism, comprising a motor and an active swing member, wherein the active swing member is connected to an output shaft of the motor, and the motor drives the active swing member to swing back and forth; A passive fish fin, which is rotatably connected to the active swinging member; A torsion spring, two ends of which are respectively connected to the active swinging member and the passive fin; A variable stiffness component includes a toggle block and a spring group, wherein the toggle block is connected to the passive fin and swings therewith, there are two spring groups and they are respectively arranged on both sides of the toggle block, the end of the toggle block can contact the spring group, each of the spring groups contains a plurality of springs, and part of the kinetic energy of the swing of the toggle block can be converted into the elastic potential energy of the spring.

2. The adaptive variable stiffness fish fin according to claim 1, characterized in that: The variable stiffness assembly also includes a first contact block and a second contact block, wherein the first contact block is arranged at the end of the toggle block, and a contact surface is arranged on the side of the first contact block; the second contact block is arranged at the end of the spring group, and a roller is installed on the second contact block, and the roller can roll in contact with the contact surface.

3. The adaptive variable stiffness fish fin according to claim 2, characterized in that: The spring group includes at least two springs, the second contact block is mounted to the end of each spring, and the roller is arranged between two adjacent springs.

4. The adaptive variable stiffness fish fin according to claim 3, characterized in that: The contact surface is an arc-shaped surface.

5. The adaptive variable stiffness fish fin according to claim 4, characterized in that: Along the rotation axis direction of the roller, the contact surface is in an involute shape around the rotation axis of the roller.

6. The adaptive variable stiffness fish fin according to claim 5, characterized in that: The toggle block contacts the roller and applies a force, and the spring is stretched under the force of the toggle block.

7. The adaptive variable stiffness fish fin according to claim 6, characterized in that: The installation position of the first contact block on the toggle block can be adjusted to change the distance between the first contact block and the rotation axis of the passive fin.

8. The adaptive variable stiffness fish fin according to claim 1, characterized in that: A tail fin is installed at the end of the passive fin.

9. The adaptive variable stiffness fish fin according to claim 8, characterized in that: The adaptive variable-rigidity fish fin also includes a connecting piece, through which the passive fish fin is rotationally connected to the active swinging piece, and the passive fish fin is detachably connected to the connecting piece.

10. A working method for the adaptive variable stiffness fish fin according to any one of claims 1 to 9, characterized in that: It includes small swing mode and large swing mode, among which: The small swing modes include: The motor is started, and the active swinging member swings under the drive of the motor; The passive fin swings along with the active swinging member, and the torsion spring is compressed; Before the toggle block contacts the spring group, the kinetic energy of the passive fin is completely converted into the elastic potential energy of the torsion spring; The torsion spring releases elastic potential energy to the passive fish fin to restore the passive fish fin to an initial state; The above steps are repeated cyclically, and the passive fins provide driving force for the bionic fish to swim; The large swing patterns include: The motor is started, and the active swinging member swings under the drive of the motor; The passive fin swings along with the active swinging member, and the torsion spring is compressed; The toggle block contacts the spring group, and the kinetic energy of the passive fin is completely converted into the elastic potential energy of the torsion spring and the spring group; The torsion spring and the spring group jointly release elastic potential energy to the passive fish fin to restore the passive fish fin to an initial state; The above steps are repeated cyclically, and the passive fins provide driving force for the bionic fish to swim.

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