Hybrid power bionic robotic fish and control method thereof

Abstract

The invention provides a hybrid power bionic robotic fish and a control method thereof, and relates to the technical field of bionic robots. The two pectoral fins comprise pectoral fin motors and pectoral fin plates, the pectoral fin plates comprise a plurality of rigid plates, flexible plates and a plurality of limiting mechanisms, the flexible plates are connected with the rigid plates respectively, and each limiting mechanism is arranged between every two adjacent rigid plates, so that the pectoral fin plates cannot be bent when swinging backwards and can be bent when swinging forwards; the tail fin is driven by the tail fin motor to rotate; the controller controls the two pectoral fin motors and the tail fin motor to rotate through a CPG control network, the CPG control network is composed of three oscillator units, and output angles of the three oscillator units correspond to rotation angle changes of the two pectoral fin motors and the tail fin motor respectively. The method has the beneficial effects that the CPG control network is used for controlling coupling cooperative movement of the two pectoral fins and the tail fin, random switching between pectoral fin propelling and tail fin propelling can be achieved, and hybrid driving of pectoral fin propelling and tail fin propelling can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of bionic robots, and in particular to a hybrid power bionic robot fish and a control method thereof. Background Art

[0002] According to the different parts that generate the main propulsion force, bionic robot fish can be divided into two categories: robot fish with body and tail fin propulsion mode (BCF) and robot fish with median fin to fin propulsion mode (MPF). Among them, robot fish with body and tail fin propulsion mode (BCF) have excellent maneuverability, while robot fish with median fin to fin propulsion mode (MPF) have high stability. Current intelligent bionic robot fish usually only use a single propulsion method, either pectoral fin propulsion or tail fin propulsion, and often cannot switch the propulsion method.

[0003] Secondly, the middle fin propulsion mode has wave motion and vibration motion, among which the vibration motion is divided into wing, flapping and rowing motion according to the rotation axis of the pectoral fin. In the rowing motion, the pectoral fin uses a rigid pectoral fin. The fin beat cycle includes a power stroke, in which the pectoral fin beats toward the rear of the robot and obtains thrust through the induced drag on the fin, and a recovery stroke, in which the pectoral fin beats toward the front of the body to prepare for the next cycle. During the recovery stroke, the fluid will produce resistance on the pectoral fin, reducing the net thrust generated by the pectoral fin. Summary of the invention

[0004] In view of this, in order to solve the above-mentioned problems existing in the current bionic robotic fish movement, an embodiment of the present invention provides a hybrid bionic robotic fish and a control method thereof.

[0005] An embodiment of the present invention provides a hybrid bionic robotic fish, comprising:

[0006] Fish body;

[0007] Two pectoral fins are symmetrically arranged on both sides of the fish body, the pectoral fins include a pectoral fin motor and a pectoral fin plate connected to the output end of the pectoral fin motor, the pectoral fin plate includes a plurality of rigid plates, a flexible plate and a plurality of limiting mechanisms, all rigid plates are sequentially arranged at intervals on the front side of the flexible plate, the flexible plates are respectively connected to the rigid plates, each limiting mechanism is arranged between two adjacent rigid plates, the pectoral fin plate swings backward to form a power stroke and swings forward to form a recovery stroke, and the limiting mechanism and the flexible plate cooperate to make the pectoral fin plate unable to bend when swinging backward and able to bend when swinging forward;

[0008] A tail fin is arranged at the rear end of the fish body, and the tail fin is driven by a tail fin motor to rotate;

[0009] And a controller, which is respectively connected to the two pectoral fin motors and the caudal fin motor, and the controller controls the rotation of the two pectoral fin motors and the caudal fin motor through a CPG control network, thereby controlling the coupled coordinated movement of the two pectoral fins and the caudal fin; wherein the CPG control network is composed of three oscillator units, and the output angles of the three oscillator units correspond to the rotation angle changes of the two pectoral fin motors and the caudal fin motor, respectively, and the control algorithm model of the CPG control network is as follows:

[0010]

[0011] θ i =d i +z i cos(φ i )

[0012] Where i and j represent the motor numbers, f i is the frequency, β i is the time asymmetry coefficient, k i is the frequency transition coefficient, T i is the oscillation period, z i is the amplitude, p z is the amplitude gain, Z i is the expected amplitude, d i is the bias, p d is the bias gain, D i is the desired bias, φ i is the phase, ω ij is the coupling weight, is the desired phase difference, θ i is the output angle.

[0013] Furthermore, the controller is used to adjust the time asymmetry coefficient β i The time ratio of the power stroke and the recovery stroke is adjusted to make the power stroke time faster and the recovery stroke time slower, thereby increasing the net thrust of the pectoral fin.

[0014] Furthermore, the pectoral fin also includes a driving rod, one end of which is connected to the output end of the pectoral fin motor, and the other end of which is connected to the rigid plate located at the inner edge.

[0015] Furthermore, the limiting mechanism includes two U-shaped limiting blocks, which are respectively fixed on two adjacent rigid plates, and the openings of the two limiting blocks are arranged opposite to each other, and avoidance gaps are provided at the two ends of one side of the limiting block opening relative to the gap between the two rigid plates.

[0016] Furthermore, the tail fin includes the tail fin motor, a flexible joint and a tail fin plate, the output end of the tail fin motor is connected to the flexible joint, and the flexible joint is connected to the tail fin plate.

[0017] In addition, an embodiment of the present invention further provides a control method for a hybrid bionic robotic fish, which is applied to the above-mentioned hybrid bionic robotic fish and includes the following steps:

[0018] The swing relationship between the pectoral fin and the caudal fin during the coordinated propulsion process is adjusted by adjusting the swing period, amplitude, offset and phase difference of the pectoral fin and the caudal fin during the swing.

[0019] Furthermore, it also includes:

[0020] Adjusting the swing amplitude of the tail fin to 0 and the swing amplitude of the two pectoral fins to non-zero, so that the two pectoral fins swing synchronously and the tail fin does not swing;

[0021] Adjust the time asymmetry coefficient β i The time ratio of the power stroke and the recovery stroke is adjusted to make the power stroke time faster and the recovery stroke time slower, thereby increasing the net thrust of the pectoral fin.

[0022] Furthermore, it also includes: adjusting the swing amplitude of the two pectoral fins to 0 and the swing amplitude of the caudal fin to non-zero, so that the caudal fin swings and the pectoral fin does not swing.

[0023] Furthermore, it also includes: adjusting the swing amplitude of the two pectoral fins to be non-zero, the swing amplitude of the caudal fin to be non-zero, the phase difference between one pectoral fin and the caudal fin to be 0, and the phase difference between the other pectoral fin and the caudal fin to be -π, so that the movement laws of the pectoral fin and the caudal fin on one side are the same, and the movement laws of the pectoral fin and the caudal fin on the other side are opposite.

[0024] Furthermore, it also includes: adjusting the swing amplitude of one of the pectoral fins to 0, the swing amplitude of the other pectoral fin to non-0, and the swing amplitude of the caudal fin to non-0, and adjusting the caudal fin offset so that the caudal fin is offset toward the side of the pectoral fin with a swing amplitude of 0, thereby causing the hybrid bionic robotic fish to deflect toward the side where the pectoral fin with a swing amplitude of 0 is located.

[0025] The beneficial effects brought about by the technical solution provided by the embodiment of the present invention are:

[0026] 1. A hybrid bionic robot fish and a control method thereof of the present invention controls the rotation of the two pectoral fin motors and the caudal fin motor through a CPG control network, thereby controlling the coupled coordinated movement of the two pectoral fins and the caudal fin, and can switch arbitrarily between pectoral fin propulsion and caudal fin propulsion, and can also realize a hybrid drive of pectoral fin propulsion and caudal fin propulsion.

[0027] 2. A hybrid bionic robotic fish and a control method thereof of the present invention adopts a flexible passive joint for the pectoral fins, and the rigid plates are flexibly connected, so that the pectoral fins maintain a straight backward movement during the power stroke. At the same time, during the recovery stroke, the rigid plates rotate relatively to each other, and the pectoral fins bend adaptively, thereby reducing the resistance caused by fluid interaction. The time ratio of the power stroke and the recovery stroke is controlled by CPG, so that the power stroke time is faster and the recovery stroke time is slower, so as to minimize the resistance on the pectoral fins and maximize the net thrust generated by the pectoral fins.

[0028] 3. A hybrid bionic robotic fish and a control method thereof of the present invention can achieve coordinated propulsion between the pectoral fin and the tail fin when turning, so that the robotic fish can have a faster turning speed and a smaller turning radius. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram of a hybrid bionic robotic fish of the present invention;

[0030] Figure 2 This is a schematic diagram of the rear side of the pectoral fin plate;

[0031] Figure 3 This is a diagram of the internal structure of a hybrid bionic robotic fish of the present invention;

[0032] Figure 4 This is a schematic diagram of the front side of the pectoral fin plate;

[0033] Figure 5 yes Figure 4 A partial enlarged view of the middle A;

[0034] Figure 6 It is a motion diagram of the pectoral fin power stroke;

[0035] Figure 7 It is a schematic diagram of the motion of the pectoral fin recovery stroke;

[0036] Figure 8 It is a schematic diagram of the CPG control network;

[0037] Fig. 9 This is a motion schematic diagram of a hybrid bionic robotic fish pectoral fin propulsion mode of the present invention;

[0038] Fig.10 It is a motion schematic diagram of a hybrid bionic machine in a tail fin propulsion mode of the present invention;

[0039] Fig.11 This is a motion schematic diagram of a hybrid bionic robot fish in a pectoral fin and caudal fin coordinated propulsion mode according to the present invention;

[0040] Fig.12 This is a motion schematic diagram of a hybrid bionic robotic fish in a left turn mode according to the present invention;

[0041] Fig.13 It is a motion schematic diagram of a hybrid power bionic robot fish in a right turn mode according to the present invention.

[0042] In the figure: 1. fish body; 2. pectoral fin; 3. caudal fin; 4. controller; 5. pectoral fin motor; 6. pectoral fin plate; 7. driving rod; 8. caudal fin motor; 9. caudal fin plate; 10. flexible joint; 11. rigid plate; 12. limiting mechanism; 13. flexible plate; 14. limiting block; 15. avoidance gap; 16. gap. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the present invention clearer, the following will further describe the embodiments of the present invention in conjunction with the accompanying drawings. The following is a preferred embodiment of the present invention, which is intended to provide a basic understanding of the present invention, but is not intended to confirm the key or decisive elements of the present invention or to limit the scope of protection.

[0044] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0045] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0046] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in the subsequent drawings. At the same time, it should be understood that for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0047] It should be noted that, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] Please refer to Figure 1 and 2 An embodiment of the present invention provides a hybrid bionic robotic fish, comprising a fish body 1, two pectoral fins 2, a caudal fin 3 and a controller 4.

[0049] The shape of the fish body 1 is similar to that of a real fish in nature. For example, in this embodiment, the fish body 1 is approximately spindle-shaped. It is understandable that the fish body 1 can also be set to other shapes. The interior of the fish body 1 is hollow, and the internal space of the fish body 1 is used to arrange components such as the controller 4.

[0050] The two pectoral fins 2 are symmetrically arranged on both sides of the fish body 1, and the pectoral fins 2 include a pectoral fin motor 5 and a pectoral fin plate 6 connected to the output end of the pectoral fin motor 5. The two pectoral fin motors 5 are installed side by side inside the fish body 1, located at the front of the fish body 1.

[0051] like Figure 3 and 4 As shown, the overall shape of the pectoral fin plate 6 can be set to be approximately the same as the shape of the pectoral fin of a real fish in nature. The pectoral fin plate 6 includes a plurality of rigid plates 11, a flexible plate 13 and a plurality of limiting mechanisms 12, all rigid plates 11 are sequentially arranged at intervals on the front side of the flexible plates 13, there is a gap 16 between two adjacent rigid plates 11, all rigid plates 11 are located on the same plane, the front side of the flexible plate 13 is attached to and fixedly connected with the rear side of each rigid plate 11, so that the flexible plate 13 is respectively connected to each rigid plate 11. The flexible plate 13 can be selected as a rubber plate, which can produce adaptive deformation according to the movement of the rigid plate 11.

[0052] In some embodiments, the pectoral fin 2 also includes a driving rod 7, which is L-shaped, with one end of the driving rod 7 extending into the fish body 1 and connected to the output end of the pectoral fin motor 5, and the other end extending to one side of the fish body 1 and connected to the rigid plate 11 located on the inner edge.

[0053] Combination Figure 6 and 7 As shown, each of the limiting mechanisms 12 is arranged between two adjacent rigid plates 11, and the pectoral fin plate 6 swings backward to form a power stroke and swings forward to form a recovery stroke. The limiting mechanism 12 and the flexible plate 13 cooperate to make the pectoral fin plate 6 unable to bend when swinging backward and able to bend when swinging forward.

[0054] The limiting mechanism 12 can be selected from various stopper limiting structures. Figure 5As shown, in this embodiment, the limiting mechanism 12 includes two U-shaped limiting blocks 14, which are respectively fixed on two adjacent rigid plates 11, and the openings of the two limiting blocks 14 are arranged opposite to each other, and the two ends of one side of the opening of the limiting block 14 are arranged at positions opposite to the gap 16 between the two rigid plates 11. In this way, for any two adjacent rigid plates 11, when the pectoral fin plate 6 swings backward, the two limiting blocks 14 are pressed tightly and cannot rotate relative to each other, even if the pectoral fin plate 6 cannot bend, a large thrust can be generated; when the pectoral fin plate 6 swings forward, the two limiting blocks 14 can produce a certain angle of relative rotation under the action of the avoidance, even if the pectoral fin plate 6 bends, reducing the resistance caused by fluid interaction.

[0055] In some embodiments, any two adjacent rigid plates 11 may be connected by a plurality of limiting mechanisms 12, and each limiting mechanism 12 is arranged at intervals along the length direction of the gap 16 between the two rigid plates 11, so that the rigid plates 11 can be limited in a predetermined direction more stably.

[0056] The tail fin 3 is arranged at the rear end of the fish body 1, and the tail fin 3 is driven to rotate by the tail fin motor 8. Specifically, the tail fin 3 includes the tail fin motor 8, a flexible joint 10 and a tail fin plate 9, the output end of the tail fin motor 8 is connected to the flexible joint 10, the flexible joint 10 is connected to the tail fin plate 9, and the tail fin plate 9 swings left and right under the drive of the tail fin motor 8. The overall shape of the tail fin plate 9 can be set to be approximately the same as the shape of a real fish tail fin in nature, such as generally set to a crescent shape.

[0057] The pectoral fin motor 5 and the caudal fin motor 8 can flexibly select various servo motors according to actual application scenarios. As described in this embodiment, the pectoral fin motor 5 and the caudal fin motor 8 are both waterproof steering gears, and it can be understood that the pectoral fin motor 5 and the caudal fin motor 8 can also select other types of servo motors.

[0058] The controller 4 is connected to the two pectoral fin motors 5 and the caudal fin motor 8 respectively, and the controller 4 controls the rotation of the two pectoral fin motors 5 and the caudal fin motor 8 through the CPG control network, thereby controlling the coupling and coordinated movement of the two pectoral fins 2 and the caudal fin 3. Figure 8 As shown, since the hybrid bionic robot fish has three degrees of freedom, namely the swinging of the two pectoral fin plates 6 and the swinging of the caudal fin plate 9, the controller 4 in this embodiment forms a CPG control network through three oscillator units, and the output angles of the three oscillator units correspond to the rotation angle changes of the two pectoral fin motors 5 and the caudal fin motor 8 respectively.

[0059] The CPG control network adopts a phase oscillator model to perform bionic control of the hybrid bionic robotic fish. The control algorithm model of the CPG control network mainly includes a continuity transition equation, an amplitude equation, a bias equation, a phase equation and an output equation, which are as follows:

[0060]

[0061] θ i =d i +z i cos(φ i )

[0062] Where i and j represent the motor numbers, f i is the frequency, β i is the time asymmetry coefficient, k i is the frequency transition coefficient, T i is the oscillation period, z i is the amplitude, p z is the amplitude gain, Z i is the expected amplitude, d i is the bias, p d is the bias gain, D i is the desired bias, φ i is the phase, ω ij is the coupling weight, is the desired phase difference, θ i is the output angle.

[0063] In this way, the swing period, amplitude, offset and phase difference can be adjusted by the controller 4, so as to adjust the swing relationship between the two pectoral fins 2 and the caudal fin 3 in the process of coordinated propulsion, and realize the coupled coordinated motion of the two pectoral fins 2 and the caudal fin 3. It should be noted that the controller 4 adjusts the time asymmetry coefficient β i That is, the time ratio between the power stroke and the recovery stroke of the pectoral fin 2 can be controlled so that the power stroke time of the pectoral fin 2 is faster and the recovery stroke time is slower, thereby increasing the net thrust of the pectoral fin 2 .

[0064] In addition, an embodiment of the present invention further provides a control method for a hybrid bionic robot fish, which is applied to the hybrid bionic robot fish, and by adjusting the swing period, amplitude, offset and phase difference of the pectoral fin 2 and the caudal fin 3 when they swing, and adjusting the swing relationship of the pectoral fin 2 and the caudal fin 3 during the coordinated propulsion process, the pectoral fin propulsion, caudal fin propulsion, pectoral fin and caudal fin coordinated propulsion, and left and right turns of the hybrid bionic robot fish can be achieved. The details are as follows:

[0065] In this embodiment, motor numbers 1, 2, and 3 represent the pectoral fin motor 5 of the left pectoral fin 2, the pectoral fin motors 5 of the left and right pectoral fins 2, and the tail fin motor 8, respectively.

[0066] Pectoral fin propulsion: adjust the swing amplitude of the tail fin 3 to 0 and the swing amplitude of the two pectoral fins 2 to non-zero, so that the two pectoral fins 2 swing synchronously and the tail fin 3 does not swing. Since the tail fin 3 does not move, there is no need to care about the phase difference between the pectoral fin 2 and the tail fin 3. Other parameters of the control algorithm model of the CPG control network can be flexibly set according to the actual propulsion needs of the hybrid bionic robot fish. Fig. 9 As shown, in this embodiment, the following settings are made: Z 1 =Z 2 =20°, Z 3 =0°, β 1 =β 2 =0.75, β 3 =0, T i =1,D i =0, In this way, the two pectoral fin motors drive the two pectoral fins 2 to swing, thereby driving the hybrid bionic robotic fish to move.

[0067] In addition, the time asymmetry coefficient β can also be adjusted i The time ratio of the power stroke and the recovery stroke is adjusted to make the power stroke time faster and the recovery stroke time slower, thereby increasing the net thrust of the pectoral fins 2 and achieving efficient propulsion. Since the two pectoral fins 2 swing symmetrically, the head of the hybrid bionic robotic fish shakes very little and has strong head stability.

[0068] Tail fin propulsion mode: adjust the swing amplitude of the two pectoral fins 2 to 0 and the swing amplitude of the tail fin 3 to non-zero, so that the tail fin 3 swings and the pectoral fin 2 does not swing. Other parameters of the control algorithm model of the CPG control network can be flexibly set according to the actual propulsion needs of the hybrid bionic robot fish. Fig.10 As shown, in this embodiment, the following settings are made: Z 1 =Z 2 =0°, Z 3 =30°, β 1 =β 2 =0,β 3 =0.5, T i =1,D i =0, The tail fin 3 swings in this way to propel the hybrid bionic robot fish to move, and the robot fish has high-speed swimming performance.

[0069] Pectoral fin and caudal fin coordinated propulsion mode: adjust the swing amplitude of the two pectoral fins 2 to non-zero, the swing amplitude of the caudal fin 3 to non-zero, the phase difference between one pectoral fin 2 and the caudal fin 3 is 0, and the phase difference between the other pectoral fin 2 and the caudal fin 3 is -π, so that the movement law of the pectoral fin 2 and the caudal fin 3 on one side is the same, and the movement law of the pectoral fin 2 and the caudal fin 3 on the other side is opposite. Even if the pectoral fin 2 and the caudal fin 3 on one side swing to the maximum angle and the minimum angle at the same time, the time for the pectoral fin 2 and the caudal fin 3 on the other side to swing to the maximum angle and the minimum angle is opposite. In this embodiment, the phase difference between the pectoral fin 2 and the caudal fin 3 on the left side is 0, and the phase difference between the pectoral fin 2 and the caudal fin 3 on the right side is π.

[0070] Other parameters of the control algorithm model of the CPG control network can be flexibly set according to the actual propulsion needs of the hybrid bionic robotic fish. Fig.11 As shown, in this embodiment, the following settings are made: Z 1 =Z 2 =20°, Z 3 =30°, β 1 =β 2 =0.75, β 3 =0.5, T i =1,D i =0,

[0071] In this way, the two pectoral fins 2 and the caudal fin 3 swing together to generate propulsion, which propels the hybrid bionic robot fish to move, so that the hybrid bionic robot fish has a more efficient swimming performance. In addition, the shaking of the fish head caused by the swing of the caudal fin 3 will cause yaw, while the coordination of the pectoral fins 2 can reduce the yaw phenomenon, so that this mode can have better stability.

[0072] By adjusting the swing amplitude of one of the pectoral fins 2 to 0, the swing amplitude of the other pectoral fin 2 to non-zero, and the swing amplitude of the caudal fin 3 to non-zero, and adjusting the caudal fin offset so that the caudal fin is directed toward the side of the pectoral fin with a swing amplitude of 0, the hybrid bionic robotic fish is deflected toward the side of the pectoral fin with a swing amplitude of 0, thereby achieving left or right turn.

[0073] Turn left: adjust the swing amplitude of the pectoral fin 2 on the left side to 0, the swing amplitude of the pectoral fin 2 on the right side to non-zero, the swing amplitude of the caudal fin 3 to non-zero, and adjust the offset of the caudal fin 3 so that the caudal fin 3 is offset toward the side of the pectoral fin 2 on the left side, that is, control the swing area of ​​the caudal fin 3 to be located on the left side of the center line of the hybrid bionic robotic fish.

[0074] Other parameters of the control algorithm model of the CPG control network can be flexibly set according to the actual propulsion needs of the hybrid bionic robotic fish. Fig.12As shown, in this embodiment, the following settings are made: Z 1 =0°, Z 2 =Z 3 =30°, β 1 =0,β 2 =0.75, β 3 =0.5, T i =1,D 1 =D 2 =0,D 3 =30°,

[0075] At this time, the tail fin 3 swings back and forth around the left side of the center line of the hybrid bionic robot fish, and at the same time, the pectoral fin 2 on the right side also swings, and the pectoral fin 2 on the left side is in a stationary state. The coordinated movement of the tail fin 3 and the pectoral fin 2 on the right side generates a forward propulsion force and a left lateral force to achieve a left turn.

[0076] Turn right: adjust the swing amplitude of the pectoral fin 2 on the right side to 0, the swing amplitude of the pectoral fin 2 on the left side to non-0, the swing amplitude of the caudal fin 3 to non-0, and adjust the offset of the caudal fin 3 so that the caudal fin 3 is offset toward the side of the pectoral fin 2 on the right side, that is, control the swing area of ​​the caudal fin 3 to be located on the right side of the center line of the hybrid bionic robotic fish.

[0077] Other parameters of the control algorithm model of the CPG control network can be flexibly set according to the actual propulsion needs of the hybrid bionic robotic fish. Fig.13 As shown, in this embodiment, the following settings are made: Z 1 =Z 3 =30°, Z 2 =0°, β 1 =0.75, β 2 =0,β 3 =0.5, T i =1,D 1 =D 2 =0,D 3 =-30°,

[0078] At this time, the tail fin 3 swings back and forth around the right side of the center line of the hybrid bionic robot fish, and at the same time, the pectoral fin 2 on the left side also swings, and the pectoral fin 2 on the right side is in a stationary state. The coordinated movement of the tail fin 3 and the pectoral fin 2 on the left side generates a forward propulsion force and a left lateral force to achieve a right turn.

[0079] The hybrid bionic robot fish turns in coordination with the pectoral fin 2 and the caudal fin 3 to achieve a smaller turning radius and a faster turning speed.

[0080] In this article, the directional words such as front, back, top, and bottom involved are defined by the positions of the parts in the drawings and the positions of the parts relative to each other, just for the sake of clarity and convenience in expressing the technical solution. It should be understood that they are relative concepts and can change accordingly according to different ways of use and placement, and the use of the directional words should not limit the scope of protection claimed in this application.

[0081] In the absence of conflict, the above embodiments and features in the embodiments may be combined with each other. The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A hybrid bionic robot fish, characterized in that: include: Fish body; Two pectoral fins are symmetrically arranged on both sides of the fish body, the pectoral fins include a pectoral fin motor and a pectoral fin plate connected to the output end of the pectoral fin motor, the pectoral fin plate includes a plurality of rigid plates, a flexible plate and a plurality of limiting mechanisms, all rigid plates are sequentially arranged at intervals on the front side of the flexible plate, the flexible plates are respectively connected to the rigid plates, each limiting mechanism is arranged between two adjacent rigid plates, the pectoral fin plate swings backward to form a power stroke and swings forward to form a recovery stroke, and the limiting mechanism and the flexible plate cooperate to make the pectoral fin plate unable to bend when swinging backward and able to bend when swinging forward; A tail fin is arranged at the rear end of the fish body, and the tail fin is driven by a tail fin motor to rotate; And a controller, which is respectively connected to the two pectoral fin motors and the caudal fin motor, and the controller controls the rotation of the two pectoral fin motors and the caudal fin motor through a CPG control network, thereby controlling the coupled coordinated movement of the two pectoral fins and the caudal fin; wherein the CPG control network is composed of three oscillator units, and the output angles of the three oscillator units correspond to the rotation angle changes of the two pectoral fin motors and the caudal fin motor, respectively, and the control algorithm model of the CPG control network is as follows: i i =d i +z i cos(φ i ) Where i and j represent the motor numbers, f i is the frequency, β i is the time asymmetry coefficient, k i is the frequency transition coefficient, T i is the oscillation period, z i is the amplitude, p z is the amplitude gain, Z i is the expected amplitude, d i is the bias, p d is the bias gain, D i is the desired bias, φ i is the phase, ω ij is the coupling weight, is the desired phase difference, θ i is the output angle.

2. A hybrid bionic robotic fish as claimed in claim 1, characterized in that: The controller is used to adjust the time asymmetry coefficient β i The time ratio of the power stroke and the recovery stroke is adjusted to make the power stroke time faster and the recovery stroke time slower, thereby increasing the net thrust of the pectoral fin.

3. A hybrid bionic robotic fish as claimed in claim 1, characterized in that: The pectoral fin also includes a driving rod, one end of which is connected to the output end of the pectoral fin motor, and the other end of which is connected to the rigid plate located at the inner edge.

4. A hybrid bionic robotic fish as claimed in claim 1, characterized in that: The limiting mechanism includes two U-shaped limiting blocks, which are respectively fixed on two adjacent rigid plates, and the openings of the two limiting blocks are arranged opposite to each other, and avoidance gaps are provided at the positions opposite to the gaps between the two rigid plates at both ends of one side of the limiting block opening.

5. The hybrid bionic robotic fish according to claim 1, characterized in that: The tail fin comprises the tail fin motor, a flexible joint and a tail fin plate. The output end of the tail fin motor is connected to the flexible joint, and the flexible joint is connected to the tail fin plate.

6. A control method for a hybrid bionic robot fish, characterized in that: A hybrid bionic robotic fish according to any one of claims 1 to 5, comprising the following steps: The swing relationship between the pectoral fin and the caudal fin during the coordinated propulsion process is adjusted by adjusting the swing period, amplitude, offset and phase difference of the pectoral fin and the caudal fin during the swing.

7. A control method for a hybrid bionic robotic fish as claimed in claim 6, characterized in that: Also includes: Adjusting the swing amplitude of the tail fin to 0 and the swing amplitude of the two pectoral fins to non-zero, so that the two pectoral fins swing synchronously and the tail fin does not swing; Adjust the time asymmetry coefficient β i The time ratio of the power stroke and the recovery stroke is adjusted to make the power stroke time faster and the recovery stroke time slower, thereby increasing the net thrust of the pectoral fin.

8. The control method of a hybrid bionic robot fish as claimed in claim 6, characterized in that: Also includes: The swing amplitude of the two pectoral fins is adjusted to 0 and the swing amplitude of the caudal fin is adjusted to non-zero, so that the caudal fin swings and the pectoral fin does not swing.

9. The control method of a hybrid bionic robotic fish as claimed in claim 6, characterized in that: Also includes: The swing amplitudes of the two pectoral fins are adjusted to be non-zero, the swing amplitude of the caudal fin is adjusted to be non-zero, the phase difference between one pectoral fin and the caudal fin is 0, and the phase difference between the other pectoral fin and the caudal fin is -π, so that the movement laws of the pectoral fin and the caudal fin on one side are the same, and the movement laws of the pectoral fin and the caudal fin on the other side are opposite.

10. The control method of a hybrid bionic robotic fish according to claim 6, characterized in that: It also includes: adjusting the swing amplitude of one of the pectoral fins to 0, the swing amplitude of the other pectoral fin to non-0, and the swing amplitude of the caudal fin to non-0, and adjusting the caudal fin offset so that the caudal fin is offset toward the side of the pectoral fin with a swing amplitude of 0, thereby causing the hybrid bionic robotic fish to deflect toward the side where the pectoral fin with a swing amplitude of 0 is located.

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