Double-joint flexible robotic fish driven by torsional spring

Abstract

The invention discloses a double-joint flexible robotic fish driven by a torsional spring. The robot fish comprises a robot fish shell, a control system and a driving system, the robot fish shell comprises a fish body upper portion, a fish body middle portion, a fish body lower portion and a fish tail portion, and inner cavities of the fish body upper portion, the fish body middle portion and the fish body lower portion communicate with one another; the two joint fish tails are connected through a torsion spring to realize flexibility; the driving system comprises a motor for realizing active driving and a torsional spring for realizing passive driving; the control system is installed in an inner cavity in the middle of the fish body and controls the driving system by remotely receiving signals output by an external controller, and therefore movement of the robotic fish is controlled. The robot fish is convenient to mount and dismount, the movement of the robot fish can be remotely controlled, the cost is greatly reduced, and the structure is simpler.

Description

Technical Field

[0001] The present invention relates to a robotic fish technology, and in particular to a dual-joint flexible robotic fish driven by a torsion spring. Background Art

[0002] With the overexploitation of land resources, the ocean's rich resources have become a new target for human exploration. A safe and effective way to explore the unfathomable depths and complex and ever-changing deep sea environment is through the use of unmanned underwater vehicles (UAVs). Robotic fish, as a type of AUV, can play a vital role in underwater environments, potentially replacing manual labor in underwater tasks such as marine environmental monitoring and marine life research. They hold significant research value and application prospects.

[0003] Traditional unmanned underwater vehicles primarily use propellers to generate propulsion, which has the disadvantages of high noise, high energy consumption, and a compromise between maneuverability and propulsion efficiency. Because fish swimming offers advantages such as flexibility, high propulsion efficiency, and strong adaptability, many researchers have turned to research based on the morphology and mechanisms of fish. Double-jointed robotic fish can better simulate fish swimming and improve swimming efficiency. Traditional double-jointed robotic fish use two servos to drive them, which is costly and complex. Summary of the Invention

[0004] The purpose of the present invention is to provide a dual-joint flexible robotic fish driven by a torsion spring. The flexibility of the dual-joint robotic fish can be achieved by combining a single servo and a torsion spring.

[0005] The technical solution for achieving the purpose of the present invention is: a dual-joint flexible robotic fish driven by a torsion spring, comprising a robotic fish housing, a control system, and a drive system, wherein: The robotic fish housing includes an upper portion of the fish body, a middle portion of the fish body, a lower portion of the fish body, a first joint of the fish tail, and a second joint of the fish tail, wherein the internal cavities of the upper portion of the fish body, the middle portion of the fish body, and the lower portion of the fish body are interconnected; the first joint of the fish tail and the second joint of the fish tail are connected by two joint connectors, one end of the first joint connector is connected to the first joint of the fish tail, and the other end is buckled with the second joint connector, and the other end of the second joint connector is connected to the second joint of the fish tail; The drive system includes a servo and two torsion springs, wherein the servo is used to realize active control of the first joint of the fish tail, is fixed to the end groove in the middle of the fish body, and is connected to the first joint of the fish tail through the servo connector; the two torsion springs are used to realize passive control of the second joint of the fish tail, and both of the torsion springs have one end fixed at the connection between the first joint connector and the first joint of the fish tail, and the other end fixed at the connection between the second joint connector and the second joint of the fish tail; The control system includes a microcontroller, a Bluetooth module and a battery. The microcontroller is connected to the servo via a DuPont cable and is placed on a partition in the cavity in the middle of the fish body together with the Bluetooth module. The battery is placed in the lower part of the fish body to power the microcontroller and Bluetooth module while lowering the overall center of gravity of the robotic fish.

[0006] Furthermore, the upper part, the middle part and the lower part of the fish body are connected by screws, and waterproof sealant is added between the gaps at the connection between the upper part and the middle part, and the middle part and the lower part of the fish body to achieve sealing.

[0007] Furthermore, the groove at the middle end of the fish body is provided with a screw hole for fixing the servo, and the servo is fixed to the middle end of the fish body by screws.

[0008] Furthermore, the two torsion springs are both made of stainless steel, with a wire diameter of 0.5 mm, an outer diameter of 5 mm, 3 turns, and an angle of 180°.

[0009] Furthermore, a counterweight is placed in the inner cavity of the lower part of the fish body to lower the center of gravity of the robotic fish and keep the robotic fish balanced in the water.

[0010] Furthermore, the outer shell of the robotic fish, which is composed of the upper, middle and lower parts of the robotic fish body, is covered with a silicone film to achieve waterproof sealing, and is sealed at the servo connector with a margin to allow the servo connector to swing normally.

[0011] Furthermore, the servo and the servo connector are fixed by screws, the servo connector and the first joint of the fishtail are fixed by screws, the first joint of the fishtail and one end of the first joint connector are fixed by screws, the other end of the first joint connector and one end of the second joint connector are connected by a snap-fit structure, the other end of the second joint connector and the second joint of the fishtail are fixed by screws, and the two torsion springs are symmetrically fixed on the left and right sides of the first joint connector and the second joint connector by screws.

[0012] Furthermore, the working principle is as follows: the Bluetooth module remotely receives the signal transmitted by the external controller, causing the microcontroller to generate a signal to control the rotation of the servo. The first joint of the fish tail swings with the rotation of the servo. At the same time, the second joint of the fish tail swings under the restriction of two torsion springs, thereby realizing the flexibility of the swinging of the robot fish's tail.

[0013] Furthermore, by controlling the angle and frequency of the servo rotation, the robotic fish can achieve different movement modes. Its movement modes are as follows: Stationary: The servos do not rotate and the robotic fish maintains a balanced state in the water.

[0014] Straight travel: The servo rotates in a sinusoidal wave with equal amplitudes in the positive and negative half-cycles. The higher the frequency, the faster the robot fish swims. Turn left: The servo rotates with a half-cycle amplitude on the right side greater than that on the left side. The higher the frequency, the faster the robot fish turns. Turn right: Opposite of turn left.

[0015] Furthermore, with the left side of the fishtail as the negative direction and the right side as the positive direction, when going straight, the servo rotation angle range is -30°~30°; when turning left, the servo rotation angle range is -15°~30°; when turning right, the servo rotation angle range is -30°~15°.

[0016] Compared with the prior art, the present invention has the following significant advantages: 1. The fish body adopts modular design, which is easy to install and disassemble.

[0017] 2. The control system uses a wireless transmission module to remotely control the movement of the robotic fish.

[0018] 3. The flexibility of the dual joints at the tail of the robotic fish is achieved through the combination of a servo and two torsion springs. Compared with the dual-servo drive solution, the cost is greatly reduced and the structure is simpler. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a front view of a double-jointed robotic fish structure of the present invention.

[0020] Figure 2 This is a cross-sectional view of a double-jointed robotic fish structure of the present invention.

[0021] Figure 3 This is a schematic structural diagram of a servo connector for a dual-joint robotic fish according to the present invention.

[0022] Figure 4 This is a schematic structural diagram of the first and second joint connecting parts of the fishtail of a double-jointed robotic fish of the present invention.

[0023] Explanation of reference numerals: 1. Upper part of fish body; 2. Middle part of fish body; 3. Lower part of fish body; 4. Servo connector; 5. First joint of fish tail; 6. Joint connector; 7. Joint connector; 8. Second joint of fish tail; 9. Torsion spring; 10. Servo; 11. Partition; 12. Internal cavity of lower part of fish body DETAILED DESCRIPTION

[0024] The present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application.

[0025] The present application provides a dual-joint robotic fish, comprising a robotic fish housing, a control system, and a drive system.

[0026] The robot fish housing includes an upper fish body portion 1, a middle fish body portion 2, a lower fish body portion 3, a first fish tail joint 5, and a second fish tail joint 8, wherein: The internal cavities of the upper part 1, the middle part 2 and the lower part 3 of the fish body are connected to each other; the first joint 5 of the fish tail and the second joint 8 of the fish tail are connected through the first joint connector 6 and the second joint connector 7, one end of the first joint connector 6 is connected to the first joint 5 of the fish tail, and the other end is buckled with the second joint connector 7, and the other end of the second joint connector 7 is connected to the second joint 8 of the fish tail.

[0027] The driving system includes a steering gear 10 and two torsion springs 9, wherein the steering gear 10 is used to realize active control of the first joint 5 of the fish tail, is fixed in the end groove of the middle part 2 of the fish body, and is connected to the first joint 5 of the fish tail through the steering gear connector 4; the two torsion springs 9 are used to realize passive control of the second joint 8 of the fish tail, and both of the torsion springs 9 have one end fixed at the connection between the first joint connector 6 and the first joint (5) of the fish tail, and the other end fixed at the connection between the second joint connector 7 and the second joint (8) of the fish tail, wherein one torsion spring is fixed on the left side of the second joint connector, and the other is fixed on the right side of the first joint connector.

[0028] The control system includes a microcontroller, a Bluetooth module and a battery. The microcontroller is connected to the servo 10 via a DuPont cable and is placed together with the Bluetooth module on a partition 11 in the cavity in the middle part 2 of the fish body. The partition is perforated to save material and facilitate internal wiring. The battery is placed in the lower part 3 of the fish body to power the microcontroller and Bluetooth module while lowering the overall center of gravity of the robotic fish.

[0029] The upper, middle, and lower parts of the fish body (1, 2, and 3) are connected by screws, and waterproof sealant is added to the gaps between the upper and middle parts (2, 3) and the middle and lower parts (3). The robotic fish's housing is manufactured using 3D printing, which is cost-effective and provides a good seal. It is also streamlined to mimic the shape of a fish, enhancing swimming efficiency.

[0030] A counterweight is placed in the inner cavity 12 at the lower part of the fish body to lower the center of gravity of the robotic fish and keep the robotic fish balanced in the water.

[0031] The servo 10 and the servo connector 4 are fixed by screws. The four holes on the servo steering wheel are aligned with the four holes on the servo connector, and the screws are tightened to fix them. The servo connector 4 and the first joint 5 of the fishtail are fixed by screws. The first joint 5 of the fishtail and the first joint connector 6 are fixed by screws. The second joint connector 7 and the first joint connector 6 are connected by a snap-fit structure. The second joint connector 7 and the second joint 8 of the fishtail are fixed by screws. The two torsion springs 9 are symmetrically fixed between the first joint 5 of the fishtail and the second joint 8 of the fishtail by screws. The above connectors and components are all matched with the help of screws by punching, which is convenient for disassembly and assembly. The first joint 5 of the fishtail is driven by a steering gear 10 to swing. The first joint 5 of the fishtail is connected to the steering gear 10 via a steering gear connector 4. The steering gear connector 4 is designed with a mechanism that can match the steering gear steering wheel. The second joint 8 of the fishtail is connected to the first joint 5 of the fishtail via a first joint connector 6 and a second joint connector 7, and is driven by two torsion springs 9. After the steering gear drives the first joint to swing, the left torsion spring is compressed (stretched) and the right torsion spring is stretched (compressed), thereby driving the second joint to swing, thereby achieving flexibility.

[0032] The outer portion of the robotic fish shell, which is composed of the upper portion 1, the middle portion 2 and the lower portion 3 of the robotic fish body, is covered with a silicone membrane. The silicone membrane is closed at the servo connector 4, while leaving a margin so that the servo can drive the joints to swing normally, thereby achieving overall waterproof sealing.

[0033] The present invention uses a torsion spring-driven dual-joint flexible robotic fish. By controlling the angle and frequency of the servo's swing, the robotic fish can achieve different motion modes. Its motion modes are as follows: Stationary: The servos do not swing and the robotic fish maintains balance in the water.

[0034] Straight travel: The servo performs sinusoidal oscillations with equal amplitudes in the positive and negative half-cycles. The higher the frequency, the faster the robot fish swims.

[0035] Turn left: The servo swings with a half-cycle amplitude on the right side that is greater than that on the left side. The higher the frequency, the faster the robot fish turns.

[0036] Turn right: Opposite of turn left.

[0037] In one embodiment, the robotic fish can swim at a speed of 7.9 cm / s in still water.

[0038] The present invention reduces costs by using a torsion spring to drive the second joint of the fish tail. At the same time, a control system is designed to enable remote control of the robotic fish to achieve three movement modes: straight ahead, left turn, and right turn.

[0039] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0040] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A dual-joint flexible robotic fish driven by a torsion spring, characterized in that: It includes a robotic fish shell, a control system, and a drive system, including: The robot fish housing comprises an upper fish body (1), a middle fish body (2), a lower fish body (3), a first fish tail joint (5), and a second fish tail joint (8), wherein the internal cavities of the upper fish body (1), the middle fish body (2), and the lower fish body (3) are interconnected; the first fish tail joint (5) and the second fish tail joint (8) are connected via two joint connectors, one end of the first joint connector (6) is connected to the first fish tail joint (5), and the other end is engaged with the second joint connector (7), and the other end of the second joint connector (7) is connected to the second fish tail joint (8); The driving system comprises a steering gear (10) and two torsion springs (9), wherein the steering gear (10) is used to realize active control of the first joint (5) of the fish tail, is fixed to the end groove of the middle part of the fish body (2), and is connected to the first joint (5) of the fish tail through the steering gear connector (4); the two torsion springs (9) are used to realize passive control of the second joint (8) of the fish tail, and both of the torsion springs (9) have one end fixed to the connection between the first joint connector (6) and the first joint (5) of the fish tail, and the other end fixed to the connection between the second joint connector (7) and the second joint (8) of the fish tail; The control system includes a microcontroller, a Bluetooth module and a battery, wherein the microcontroller is connected to the servo (10) via a DuPont line and is placed together with the Bluetooth module on a partition (11) in the cavity in the middle part (2) of the fish body; the battery is placed in the lower part (3) of the fish body to power the microcontroller and the Bluetooth module while lowering the overall center of gravity of the robotic fish.

2. The double-jointed flexible robotic fish driven by a torsion spring according to claim 1, characterized in that: The upper part (1), the middle part (2) and the lower part (3) of the fish body are connected by screws, and waterproof sealant is added between the gaps at the connection between the upper part (1) and the middle part (2), and the middle part (2) and the lower part (3) of the fish body to achieve sealing.

3. The double-jointed flexible robotic fish driven by a torsion spring according to claim 1, characterized in that: The groove at the end of the middle part (2) of the fish body is provided with a screw hole for fixing the steering gear (10), and the steering gear (10) is fixed to the end of the middle part (2) of the fish body by screws.

4. The double-jointed flexible robotic fish driven by a torsion spring according to claim 1, characterized in that: The two torsion springs (9) are both made of stainless steel, with a wire diameter of 0.5 mm, an outer diameter of 5 mm, 3 turns, and an angle of 180°.

5. The double-jointed flexible robotic fish driven by a torsion spring according to claim 1, characterized in that: A counterweight is placed in the inner cavity (12) at the lower part of the fish body, which is used to lower the center of gravity of the robotic fish and keep the robotic fish balanced in the water.

6. The double-jointed flexible robotic fish driven by a torsion spring according to claim 1, characterized in that: The outer shell of the robotic fish, which is composed of the upper body (1), the middle body (2) and the lower body (3), is coated with a silicone film to achieve waterproof sealing, and is sealed at the steering gear connector (4) with a margin to allow the steering gear connector (4) to swing normally.

7. The double-jointed flexible robotic fish driven by a torsion spring according to claim 1, characterized in that: The steering gear (10) and the steering gear connecting member (4) are fixed by screws, the steering gear connecting member (4) and the first fishtail joint (5) are fixed by screws, the first fishtail joint (5) and one end of the first joint connecting member (6) are fixed by screws, the other end of the first joint connecting member (6) and one end of the second joint connecting member (7) are connected by a snap-fit structure, the other end of the second joint connecting member (7) and the second fishtail joint (8) are fixed by screws, and the two torsion springs (9) are symmetrically fixed by screws on the left and right sides of the first joint connecting member (6) and the second joint connecting member (7).

8. The double-jointed flexible robotic fish driven by a torsion spring according to claim 1, characterized in that: The working principle is as follows: the Bluetooth module remotely receives the signal transmitted by the external controller, so that the microcontroller generates a signal to control the rotation of the steering gear (10). The first joint (5) of the fish tail swings along with the rotation of the steering gear (10). At the same time, the second joint (8) of the fish tail swings under the restriction of two torsion springs (9), thereby realizing the flexibility of the swing of the fish tail of the robot fish.

9. The double-jointed flexible robotic fish driven by a torsion spring according to claim 1, characterized in that: By controlling the angle and frequency of the servo's rotation, the robotic fish can achieve different movement modes. The movement modes are as follows: Stationary: The servo does not rotate and the robot fish maintains a balanced state in the water; Straight travel: The servo rotates in a sinusoidal wave with equal amplitudes in the positive and negative half-cycles. The higher the frequency, the faster the robot fish swims. Turn left: The servo rotates with a half-cycle amplitude on the right side greater than that on the left side. The higher the frequency, the faster the robot fish turns. Turn right: Opposite of turn left.

10. The double-jointed flexible robotic fish driven by a torsion spring according to claim 9, characterized in that: With the left side of the fishtail as the negative direction and the right side as the positive direction, when going straight, the servo rotation angle range is -30°~30°; when turning left, the servo rotation angle range is -15°~30°; when turning right, the servo rotation angle range is -30°~15°.

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