An underwater bionic fish pectoral fin bistable electromagnetic braking mechanism

Abstract

The present invention belongs to the technical field of underwater robots, and particularly relates to a bistable electromagnetic braking mechanism for the pectoral fins of an underwater biomimetic fish. It can achieve the braking and non-braking of the motor output shaft, with a compact structure and a simple control method. It includes a brake base fixed on the internal frame of the fish body; the brake base, a fixed connecting rod, a pressing rod, and a horizontal moving connecting rod form a four-bar linkage mechanism; the first half shaft and ceramic bearings, the second half shaft and ceramic bearings are installed at the rotation center of the linkage mechanism, so that the pressing rod swings reciprocally with the half shaft as the rotation center, and the horizontal moving connecting rod rotates relative to the pressing rod; the brake base is connected to the limiting mechanism frame; a pulling-back electromagnet is installed on the brake base, and a pushing-out electromagnet is installed on the limiting mechanism frame; a return spring I and a return spring II are installed between the pressing rod and the base.

Description

Technical Field

[0001] The invention belongs to the technical field of underwater robots, and particularly relates to a bistable electromagnetic braking mechanism for the pectoral fins of an underwater biomimetic fish. Background Art

[0002] The biomimetic fish has important application values both in the military and civilian fields. The main functions of the pectoral fins in the biomimetic fish are to make the body move forward, control the direction, or "brake" during movement. When the caudal fin is not moving, the pectoral fins open to both sides of the fish body. When swinging back and forth, the fish body moves forward. When one pectoral fin swings, the fish body turns to the side where the fin does not move. Therefore, accurately controlling the pectoral fin angle for a long time plays an important role. Currently, most of the pectoral fins of biomimetic fish use servo motors or electromagnetic brake devices to complete the braking link, and continuous power supply to the mechanism is required to maintain a specific pectoral fin rotation axis angle, which consumes a large amount of electric energy and greatly reduces the endurance of the biomimetic fish. In addition, the installation space in the cavity of the biomimetic fish is narrow, and the braking mechanism is required to be structurally compact. Therefore, it is particularly important to design a braking mechanism with low energy consumption and compact structure for the pectoral fins of biomimetic fish. Summary of the Invention

[0003] Aiming at the defects existing in the prior art, the invention provides a bistable electromagnetic braking mechanism with a simple structure. Through the combined action of an electromagnet, a spring, and a mechanical limiting device, the braking and non-braking of the motor output shaft can be realized. The structure is compact, the control method is simple, and power is only consumed at the moment of switching between the braking state and the non-braking state, and no power is consumed in other stable states.

[0004] To achieve the above object, the invention adopts the following technical solutions, including a brake base (13) fixed on the internal frame of the fish body; characterized in that, the brake base (13), a fixed connecting rod (11), a pressure rod (5), and a horizontal moving connecting rod (3) form a four-bar linkage;

[0005] The first half shaft (9), a ceramic bearing (10), the second half shaft (2), and a ceramic bearing (1) are installed at the rotation center of the linkage mechanism, so that the pressure rod (5) swings reciprocally with the first half shaft (9) as the rotation center, and the horizontal moving connecting rod (3) rotates relative to the pressure rod (5);

[0006] The brake base is connected to the limit mechanism frame; a pull-back electromagnet is installed on the brake base, and a push-out electromagnet is installed on the limit mechanism frame; a return spring I (4) and a return spring II (8) are installed between the pressure rod (5) and the base (13). The friction block (7) is fixedly connected to the pressure rod (5); the pull-back electromagnet (15) and its output shaft (14) are connected to the pressure rod connecting plate (12) through a hinge connecting block (6), and the pressure rod connecting plate (12) is connected to the pressure rod (5); the round rod (27) is connected to the horizontal moving link (3) and can move horizontally in the guide groove of the limit mechanism frame (28).

[0007] On the inner side of the limit mechanism frame (28), a rotating shaft I (25), a rotating shaft II (26), a limit shaft I (23), and a limit shaft II (24) are installed; the limit flap I (29) and the limit flap II (30) can rotate around the rotating shaft I (25) and the rotating shaft II (26), the spring (22) is connected to the limit flap I (29) and the limit flap II (30), and the wedge block I (20) and the wedge block II (21) are connected to the limit flap I (29) and the limit flap II (30).

[0008] Furthermore, the push-out electromagnet (18) is installed on the push-out electromagnet mounting bracket (17), the pull-back electromagnet (15) is installed on the pull-back electromagnet mounting bracket (16), the pull-back electromagnet mounting bracket (16) is connected to the brake base (13), and the push-out electromagnet mounting bracket (17) is connected to the limit mechanism frame (28).

[0009] Furthermore, after the pull-back electromagnet (15) is powered on, the output shaft (14) drives the pressure rod (5) to swing towards the base (13) through the hinge connecting block (6) and the pressure rod connecting plate (12). The pressure rod (5) drives the horizontal moving link (3) and the round rod (27) to move towards the base (13) in the groove of the limit frame (28). The round rod (27) pushes open the wedge-shaped end face of the flap (29, 30) to make it flip by a certain angle. The round rod (27) moves inside the two wedge blocks of the limit flap (29, 30). The pull-back electromagnet (15) stops power supply. Under the action of the return springs (4, 8), the pressure rod (5) pulls the horizontal moving link (3) to move away from the base (13). At the same time, the round rod (27) contacts the vertical surfaces of the wedge blocks of the limit flap I (29) and the limit flap II (30). The limit flap I (29) and the limit flap II (30) contact the limit shaft I (23) and the limit shaft II (24) under the pulling force of the spring (22), realizing the limiting and holding effect on the round rod (27) and the pressure rod (5). In this state, the friction block (7) is in a non-contact state with the pectoral fin output shaft, that is, a non-braking holding state.

[0010] Further, after the push electromagnet (18) is powered on, the output shaft (19) extends and pushes open the wedge-shaped blocks I (20) and II (21) of the limit flap I (29) and the limit flap II (30), causing the limit flap I (29) and the limit flap II (30) to overcome the tension of the spring (22) and rotate by a certain angle around the rotating shafts I (25) and II (26). The limiting effect of the limit flap I (29) and the limit flap II (30) on the round bar (27) disappears. Under the action of the return spring I (4) and the return spring II (8), the pressure rod (5) pulls the horizontal moving link (3) away from the base (13). At the same time, the round bar (27) moves along the guide groove to the outside of the limit flap I (29) and the limit flap II (30). Under the elastic force of the return spring I (4) and the return spring II (8), the pressure rod (5) makes the friction block (7) contact the pectoral fin output shaft and enters the braking and holding state. The push electromagnet (18) can stop power supply immediately after being powered on instantaneously. The pressing force of the pressure rod (5) and the friction block (7) on the output shaft is always provided by the return spring.

[0011] Further, braking is achieved by the contact between the friction block (7) and the output shaft. The magnitude of the braking force is related to the friction block material, the surface structure and shape of the friction block, the elastic force generated by the return spring, etc., and can be adjusted according to the actual braking force magnitude requirements.

[0012] Further, mechanical limiting is achieved by the interaction force between the round bar (27) and the wedge-shaped surfaces of the limit flap I (29) and the limit flap II (30), causing rotation. As the round bar (27) moves, when the interaction force between the wedge-shaped surfaces of the limit flap I (29) and the limit flap II (30) and the round bar (27) disappears, the limit flap I (29) and the limit flap II (30) contact the limit shafts I (23) and II (24) under the tension of the spring (22), and the limit flap I (29) and the limit flap II (30) close. In the closed state, the minimum distance between the top surfaces of the wedge-shaped blocks of the two limit flaps I (29) and II (30) is less than the diameter of the round bar (27). At this time, the round bar (27) can only move between the two wedge-shaped blocks on the limit flap and cannot move out of the limit flap I (29) and the limit flap II (30), realizing the limiting effect.

[0013] Advantages of the present invention compared with the prior art.

[0014] The bistable electromagnetic brake of the present invention can realize the switching between the braking state and the non-braking state by the transient action of the electromagnet, and utilize the mechanical limiting structure. Moreover, neither the braking state nor the non-braking state requires long-term power supply, which can effectively reduce energy consumption and thus improve the underwater endurance time of the bionic fish. Description of the Drawings

[0015] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The protection scope of the present invention is not limited to the description of the following content.

[0016] Figure 1 Three-dimensional structural schematic diagram of the bionic fish pectoral fin electromagnetic brake of the present invention;

[0017] Figure 2 Schematic diagram of the action of the limiting mechanism when the brake of the present invention is converted from the braking state to the non-braking state;

[0018] Figure 3 Schematic diagram of the brake of the present invention working in the non-braking state;

[0019] Figure 4 Schematic diagram of the action when the brake of the present invention is converted from the non-braking state to the braking state;

[0020] Figure 5 Schematic diagram of the limiting mechanism when the brake of the present invention works in the braking state.

[0021] In the figure, 1, ceramic bearing; 2, half shaft; 3, horizontal moving connecting rod; 4, return spring I; 5, pressure rod; 6, hinge connecting block; 7, friction block; 8, return spring II; 9, half shaft; 10, ceramic bearing; 11, fixed connecting rod; 12, pressure rod connecting plate; 13, base; 14, pull-back electromagnet output shaft; 15, pull-back electromagnet; 16, pull-back electromagnet mounting bracket; 17, push-out electromagnet mounting bracket; 18, push-out electromagnet; 19, push-out electromagnet output shaft; 20, wedge block I; 21, wedge block II; 22, spring; 23, limiting shaft I; 24, limiting shaft II; 25, rotating shaft I; 26, rotating shaft II; 27, round rod; 28, limiting mechanism frame; 29, limiting flap I; 30, limiting flap II; 31, guiding rod I; 32, guiding rod II. Specific embodiments

[0022] As Figure 1 shown, the underwater bionic fish pectoral fin electromagnetic braking mechanism of this specific embodiment is composed of a base 13, a fixed connecting rod 11, a pressure rod 5 and a horizontal moving connecting rod 3 to form a four-bar linkage mechanism. The half shafts 9 and ceramic bearings 10 are installed at the center of rotation of the connecting rod, and the half shaft 2 and ceramic bearing 1 are installed, so that the pressure rod 5 can swing reciprocally with the half shaft 9 as the center of rotation, and the horizontal moving connecting rod 3 rotates relative to the pressure rod 5. The base 13 is fixedly connected to the internal frame of the fish body.

[0023] The pull-back electromagnet 15 is connected to the base 13 through the mounting bracket 16. The output shaft 14 of the electromagnet 15 passes through the inner hole of the base 13 and is connected to the pressure rod connecting plate 12 and the pressure rod 5 through the hinge connecting block 6. The friction block 7 is fixedly connected to the pressure rod 5. Return springs 4 and 8 are installed between the pressure rod 5 and the base 13, and the return springs reciprocate along the guiding rods 31 and 32.

[0024] The limiting mechanism frame 28 is connected to the base 13. The rotating shafts 25 and 26, the limiting flap plates 29 and 30, and the limiting shafts 24 and 25 are installed inside the limiting frame. Wedge-shaped blocks 20 and 21 are installed at the other ends of the limiting flap plates 29 and 30. The limiting flap plates 29 and 30 can rotate around the rotating shafts 25 and 26, and the flipping angles of the limiting flap plates 29 and 30 are controlled by the springs 22 and the limiting shafts 23 and 24. The pushing electromagnet 18 is connected to one end of the limiting mechanism frame 28 through the pushing electromagnet mounting bracket 17. One end of the horizontal moving connecting rod 3 is installed with a round rod 27, so that it makes a reciprocating linear motion in the guiding groove of the limiting frame 28.

[0025] Combined with Figures 1 - 3 , when the pulling-back electromagnet 15 is powered on, the output shaft 14 of the pulling-back electromagnet pulls the pressing rod 5 and the friction block 7 through the hinge connecting block 6 and the pressing rod connecting plate 12. The pressing rod 5 overcomes the elastic forces of the return springs 4 and 8 and moves closer to the base 13 around the half shaft 9. The pressing rod 5 drives the horizontal moving connecting rod 3 and the round rod 27 to make a horizontal movement in the guiding groove of the limiting mechanism frame 28 towards the base 13.

[0026] After the round rod 27 pushes open the limiting flap plates 29 and 30 and moves between the wedge-shaped blocks of the flap plates themselves and the installed wedge-shaped blocks 20 and 21, the flap plates 29 and 30 are reset to contact the limiting shafts 23 and 24 under the pulling force of the spring 22. After the pulling-back electromagnet 15 stops being powered on and the pulling force disappears, under the action of the return springs 4 and 8, the pressing rod 5, the horizontal moving connecting rod 3 and the round rod 27 make the round rod 27 contact the vertical surface of the wedge-shaped block of the flap plate itself, restricting its freedom of movement in the horizontal direction and realizing the limiting function. In this state, the friction block 7 is in a non-contact state with the pectoral fin output shaft, and can maintain the non-braking state without consuming electric energy.

[0027] Combined with Figures 4 - 5 , when the pushing electromagnet 18 is powered on, the output shaft 19 of the pushing electromagnet 18 extends and pushes open the wedge-shaped blocks 20 and 21, so that the limiting flap plates 29 and 30 overcome the pulling force of the spring 22 and rotate a certain angle around the rotating shafts 24 and 25. The limiting effect of the fixed wedge-shaped blocks of the limiting flap plates 29 and 30 disappears. The pressing rod 4, the horizontal moving connecting rod 3 and the round rod 27 move away from the base 13 under the elastic forces of the return springs 4 and 8, and keep in contact with the pectoral fin output shaft, and can maintain the braking state without consuming electric energy.

[0028] Specifically, the electromagnet is installed on the electromagnet mounting bracket. The electromagnet generates a pulling force or a pushing force after being powered on. The pulling-back electromagnet 15 and the pushing electromagnet 18 are fixed on the brake base through the mounting bracket. The brake base is fixedly connected to the fish body. The electromagnet cooperates with the horizontal moving connecting rod, the round rod 27 and the mechanical limiting mechanism to realize the pulling-back, pushing-out and holding processes. The pressing rod 5 and the friction block 7 are connected in a form of bolt assembly.

[0029] The pull-back electromagnet mounting bracket 16 is mounted on the brake base. When the pull-back electromagnet 15 is energized, the pulling force provided by the electromagnet causes the pressure rod 5 and the connecting base to move towards the brake base, and at the same time drives the horizontal moving link and the round rod 27 to move in the guiding groove of the limit frame. When the round rod 27 moves, the limit flap is pushed open and flipped by a certain angle. When the round rod 27 moves inside the two wedge-shaped blocks of the limit flap, the pull-back electromagnet 15 can stop power supply. Under the action of the return spring, the round rod 27 contacts and is limited by the wedge-shaped block of the limit flap, so that the friction block 7 is separated from the motor output shaft, realizing the non-braking holding state.

[0030] When the push-out electromagnet 18 is energized, the output shaft of the electromagnet extends and pushes open the wedge-shaped block. At the same time, the limit flap flips by a certain angle, so that the limiting effect on the horizontal moving link and the round rod 27 disappears. The pressure rod 5, the horizontal moving link and the round rod 27 quickly reset by the spring force. Under the elastic force of the return spring, the pressure rod 5 makes the friction block 7 contact the motor output shaft, realizing the braking and holding state. The braking force is related to the spring force, the material of the friction block 7 and the shape of the contact surface. Thus, the braking energy comes from the spring force and there is no need for continuous power consumption.

[0031] The underwater bionic fish pectoral fin braking mechanism of the present invention utilizes the mutual cooperation of an electromagnet, a return spring, a mechanical limiting mechanism, etc. Only by short-time power supply of the electromagnet can the braking or non-braking state be maintained, without long-time power consumption, thereby ensuring the endurance of the underwater bionic fish robot.

[0032] It can be understood that the above specific description of the present invention is only for explaining the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those of ordinary skill in the art should understand that the present invention can still be modified or equivalently replaced to achieve the same technical effects; as long as the use requirements are met, they are all within the protection scope of the present invention.

Claims

1. An underwater bionic fish pectoral fin bistable electromagnetic braking mechanism, comprising a brake base (13) fixed on the inner frame of the fish body; characterized in that: The brake base (13), the fixed connecting rod (11), the pressure rod (5), and the horizontal moving connecting rod (3) form a four-bar linkage mechanism; The rotating centers of the four-bar linkage mechanism are installed with the first half shaft (9), the ceramic bearing (10), the second half shaft (2), and the ceramic bearing (1), so that the pressure rod (5) swings reciprocally with the first half shaft (9) as the rotating center, and the horizontal moving connecting rod (3) rotates relatively with the pressure rod (5); The brake base is connected to the limit mechanism frame; a pull-back electromagnet is installed on the brake base, and a push-out electromagnet is installed on the limit mechanism frame; a return spring I (4) and a return spring II (8) are installed between the pressure rod (5) and the base (13); The friction block (7) is fixedly connected to the pressure rod (5); the pull-back electromagnet (15) and its pull-back electromagnet output shaft (14) are connected to the pressure rod connecting plate (12) through a hinge connecting block (6), and the pressure rod connecting plate (12) is connected to the pressure rod (5); the round rod (27) is connected to the horizontal moving connecting rod (3) and can move horizontally in the guide groove of the limit mechanism frame (28); Inside the limit mechanism frame (28), a rotating shaft I (25), a rotating shaft II (26), a limit shaft I (23), and a limit shaft II (24) are installed; the limit flap I (29) and the limit flap II (30) can rotate around the rotating shaft I (25) and the rotating shaft II (26), the spring (22) is connected to the limit flap I (29) and the limit flap II (30), and the wedge block I (20) and the wedge block II (21) are connected to the limit flap I (29) and the limit flap II (30).

2. The bistable electromagnetic braking mechanism for the pectoral fin of an underwater biomimetic fish according to claim 1, characterized in that: The push-out electromagnet (18) is installed on the push-out electromagnet mounting bracket (17), the pull-back electromagnet (15) is installed on the pull-back electromagnet mounting bracket (16), the pull-back electromagnet mounting bracket (16) is connected to the brake base (13), and the push-out electromagnet mounting bracket (17) is connected to the limit mechanism frame (28).

3. The bistable electromagnetic braking mechanism for the pectoral fin of an underwater biomimetic fish according to claim 1, characterized in that: After the pull-back electromagnet (15) is energized, the pull-back electromagnet output shaft (14) pulls the pressure rod (5) to swing towards the base (13) through the hinge connecting block (6) and the pressure rod connecting plate (12). The pressure rod (5) drives the horizontal moving connecting rod (3) and the round rod (27) to move towards the base (13) in the groove of the limit mechanism frame (28). The round rod (27) pushes open the wedge-shaped end faces of the limit flap I (29) and the limit flap II (30) to make them flip by a certain angle. The round rod (27) moves into the two wedge blocks of the limit flap I (29) and the limit flap II (30). The pull-back electromagnet (I5) stops power supply. Under the action of the return spring I (4) and the return spring II (8), the pressure rod (5) pulls the horizontal moving connecting rod (3) to move away from the base (13). At the same time, the round rod (27) contacts the vertical surfaces of the wedge blocks of the limit flap I (29) and the limit flap II (30). The limit flap I (29) and the limit flap II (30) contact the limit shaft I (23) and the limit shaft II (24) under the pulling force of the spring (22), realizing the limiting and holding effect on the round rod (27) and the pressure rod (5).

4. An underwater biomimetic fish pectoral fin bistable electromagnetic braking mechanism according to claim 1, characterized in that: After the pushing electromagnet (18) is powered on, the output shaft (19) of the pushing electromagnet extends and pushes open the wedge-shaped blocks I (20) and II (21) of the limit flap I (29) and the limit flap II (30), causing the limit flap I (29) and the limit flap II (30) to overcome the tension of the spring (22) and rotate a certain angle around the rotating shafts I (25) and II (26). The limiting effect of the limit flap I (29) and the limit flap II (30) on the round bar (27) disappears. Under the action of the return spring I (4) and the return spring II (8), the pressure rod (5) pulls the horizontal moving connecting rod (3) away from the base (13). At the same time, the round bar (27) moves along the guiding groove to the outside of the limit flap I (29) and the limit flap II (30). Under the elastic force of the return spring I (4) and the return spring II (8), the pressure rod (5) makes the friction block (7) contact the pectoral fin output shaft and enters the braking and holding state. The pushing electromagnet (18) stops power supply immediately after being powered on instantaneously. The pressing force of the pressure rod (5) and the friction block (7) on the output shaft is always provided by the return spring.

5. The bistable electromagnetic braking mechanism for the pectoral fin of an underwater biomimetic fish according to claim 1, characterized in that: Mechanical limitation is achieved through the interaction force between the round bar (27) and the wedge-shaped surfaces of the limit flap I (29) and the limit flap II (30), which causes the rotation. As the round bar (27) moves, when the interaction force between the wedge-shaped surfaces of the limit flap I (29) and the limit flap II (30) and the round bar (27) disappears, the limit flap I (29) and the limit flap II (30) contact the limit shafts I (23) and II (24) under the tension of the spring (22), and the limit flap I (29) and the limit flap II (30) close. In the closed state, the minimum distance between the top surfaces of the wedge-shaped blocks of the two limit flaps I (29) and II (30) is less than the diameter of the round bar (27). At this time, the round bar (27) can only move between the two wedge-shaped blocks on the limit flap and cannot move out of the limit flap I (29) and the limit flap II (30), thus realizing the limiting effect.

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