Multi-mode mixed motion bionic fish based on piezoelectric bimorph assembly and control method thereof

Abstract

The invention provides a multi-mode mixed motion bionic fish based on a piezoelectric bimorph assembly and a control method of the multi-mode mixed motion bionic fish. The bionic fish comprises a bionic fish head, a plurality of motion plates, the piezoelectric bimorph assembly, a plurality of bionic fish shells, a bionic fish tail plate and a fish head cylindrical pin. The bionic fish skeleton comprises a bionic fish head, a bionic fishplate, a plurality of moving plates and piezoelectric crystal plates which are symmetrically adhered to the bionic fish head, the bionic fishplate and the plurality of moving plates, and the bionic fish head, the plurality of moving plates and the bionic fishplate can rotate relatively; according to the bionic fish position closed-loop control method, a bionic fish skeleton is changed into a driving part formed by hinging four sections of motion plates bonded with piezoelectric bimorphs, and the motion posture and the swimming speed of the bionic fish are controlled by controlling the excitation voltage and the excitation frequency applied to the piezoelectric bimorphs; precise control over the position of the bionic fish is achieved, and the bionic fish has the advantages of being high in control precision, adaptability and propelling efficiency, good in expansibility, easy to assemble and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater biomimetic robotic fish, and more specifically, particularly relates to a multi-modal hybrid motion biomimetic fish based on a piezoelectric bimorph component and a control method thereof. Background Art

[0002] With the proposal of the "Marine Power Strategy" in recent years, humans have always paid high attention to the exploration, development, and utilization of marine resources. Compared with traditional underwater submersibles, underwater biomimetic robotic fish have prominent advantages such as low resistance, high propulsion efficiency, and high flexibility, and are currently widely used in fields such as marine resource exploration, water quality detection, and military.

[0003] The published text of the Chinese patent application with the publication number CN119190317A discloses a multi-functional underwater submersible, which uses multiple thrusters to jointly control the motion state of the submersible. Although this design can achieve functions such as rotation, acceleration, and uniform speed of the submersible by independently or combinatorially controlling the thrusters, and improves the problem of insufficient submersible function of traditional submersibles, it cannot solve the defects of low propulsion efficiency, poor flexibility, and poor expandability of traditional submersibles.

[0004] The published text of the Chinese patent application with the publication number CN119460038A discloses a structure of a parallel biomimetic robotic fish, which uses three motors to drive multiple driving components, and then adjusts the angle of the pectoral fin to achieve the ascent or descent of the biomimetic fish; then adjusts the angle of the dorsal fin to achieve the attitude adjustment of the biomimetic fish; and then adjusts the swing of the caudal fin to achieve the control of the swimming speed and motion mode of the biomimetic fish. Although this design can make the biomimetic fish simulate different swimming modes and improve the flexibility of the biomimetic fish underwater, it cannot solve the problems of insufficient steering torque and low steering efficiency when the dorsal fin turns, and the structure of this invention is relatively complex. Summary of the Invention

[0005] Aiming at the deficiencies in the prior art, the present invention provides a biomimetic fish motion control method based on a piezoelectric bimorph component. By changing the biomimetic fish skeleton into a driving part composed of three motion plates bonded with piezoelectric bimorphs and controlling the excitation voltage and excitation frequency applied to each piezoelectric bimorph, the motion attitude and swimming speed of the biomimetic fish are controlled, and with the biomimetic fish position closed-loop control method proposed by the present invention, precise control of the position of the biomimetic fish is achieved, which has the advantages of high control accuracy, strong adaptability, high propulsion efficiency, good expandability, and simple assembly.

[0006] In order to achieve the above-mentioned objectives, the present invention provides a bionic fish based on piezoelectric dual-chip regulation, including a bionic fish head, several moving plates (a first moving plate, a second moving plate, a third moving plate), a piezoelectric dual-chip assembly (a first lower piezoelectric chip, a first upper piezoelectric chip, a second lower piezoelectric chip, a second upper piezoelectric chip, a third lower piezoelectric chip, a third upper piezoelectric chip, a fourth lower piezoelectric chip, a fourth upper piezoelectric chip), several bionic fish shells (a first bionic fish shell, a second bionic fish shell, a third bionic fish shell), a bionic fish tail plate, and a fish head cylindrical pin.

[0007] The skeleton of the bionic fish includes several moving plates and piezoelectric chips symmetrically bonded thereon; the bionic fish head is hinged to the first moving plate, the second moving plate, the third moving plate and the bionic fish tail plate in sequence through the structure above, and the bionic fish head, the moving plates and the bionic fish tail plate can all rotate relative to each other.

[0008] The piezoelectric bimorph assembly includes a first lower piezoelectric chip, a first upper piezoelectric chip, a second lower piezoelectric chip, a second upper piezoelectric chip, a third lower piezoelectric chip, a third right upper piezoelectric chip, a fourth lower piezoelectric chip, and a fourth upper piezoelectric chip. The turning angle of the bionic fish is controlled by controlling the voltage excitation values of the lower and upper piezoelectric chips in the first, second, and third piezoelectric bimorphs; and the swimming speed of the bionic fish is controlled by controlling the voltage excitation frequencies of the lower and upper piezoelectric chips in the fourth piezoelectric bimorph.

[0009] Preferably, the bionic fish head has a trunnion at its lower end, and the first moving plate has a connecting hole at its upper end. The bionic fish head and the first moving plate are connected via the trunnion, the connecting hole, and the pinhole of the fish head cylindrical pin. In the assembled state, the bionic fish head and the fish head cylindrical pin cannot rotate relative to each other, while the first moving plate and the fish head cylindrical pin can rotate relative to each other.

[0010] Preferably, a cylindrical slide is provided at the lower end of the first moving plate, and a cylindrical ball head is provided at the upper end of the second moving plate. In the assembled state, the axes of the cylindrical slide and the cylindrical ball head coincide. The cylindrical slide is then closed along the auxiliary rolling surface of the first moving plate using an assembly process, thereby achieving connection between the first and second moving plates without affecting relative rotation of the two moving plates. The installation method and mating relationship between the second and third moving plates, and between the third and bionic fishtail plates, are identical to those between the first and second moving plates.

[0011] Preferably, strip-shaped chucks are designed on both the upper and lower sides of the first moving plate, and strip-shaped slots are correspondingly designed on the upper and lower sides inside the first bionic fish housing. In the assembled state, the axes of the strip-shaped chucks and the strip-shaped slots coincide, realizing the synchronous swing of the first moving plate and the first bionic fish housing. The installation methods and cooperation relationships between the second moving plate and the second bionic fish housing, and between the third moving plate and the third bionic fish housing are the same as those between the first moving plate and the first bionic fish housing.

[0012] Preferably, the first lower piezoelectric wafer and the first upper piezoelectric wafer are respectively bonded to the upper and lower sides of the first moving plate. The second lower piezoelectric wafer and the second upper piezoelectric wafer are respectively bonded to the upper and lower sides of the second moving plate. The third lower piezoelectric wafer and the third upper piezoelectric wafer are respectively bonded to the upper and lower sides of the third moving plate 13. The fourth lower piezoelectric wafer and the fourth upper piezoelectric wafer are respectively bonded to the upper and lower sides of the bionic fish tail plate.

[0013] Preferably, the piezoelectric bimorph and the moving plate as well as the bionic fish tail plate are fixed by epoxy resin glue.

[0014] Preferably, when the maximum driving voltage of each moving plate is U1, the swing angle is θ imax , when the swing angles of the first moving plate, the second moving plate, and the third moving plate are independently driven to be θ i , the excitation voltages of each moving plate are

[0015] Preferably, let the maximum driving voltage of the bionic fish tail plate be U1, the maximum speed of stable swimming in two bionic motion modes be v imax , the minimum speed of stable swimming be v imin , the corresponding maximum excitation frequency be f imax and the minimum excitation frequency be f imin , the body length of the bionic fish be L, and the distance between the starting point and the target point be S tra . According to Lighthill's slender body theory, when the swing amplitude of the bionic fish tail plate is constant, the swimming speed of the bionic fish can be adjusted by adjusting the frequency of the excitation voltage of the bionic fish tail plate. When the swimming speed of the bionic fish is controlled to be v, the excitation voltage of the bionic fish tail plate is U1, and the excitation frequency is

[0016] Furthermore, when the excitation voltage of the bionic fish tail plate is U1 and the excitation frequency is f, it means that the excitation voltages on the fourth lower piezoelectric wafer and the fourth upper piezoelectric wafer are both U1, the excitation voltage frequencies are both f, but the phase difference of the excitation voltages on the fourth lower piezoelectric wafer and the fourth upper piezoelectric wafer is 180°.

[0017] Preferably, this embodiment discloses a bionic fish motion control method based on a piezoelectric bimorph component. The motion control method is used to achieve the position closed-loop control of the bionic fish, and on the basis of ensuring the position control accuracy requirements of the bionic fish, the autonomous switching of the bionic motion mode is realized simultaneously to improve the response speed and flexibility of the bionic fish.

[0018] A bionic fish motion control method based on a piezoelectric bimorph component disclosed by the present invention includes the following steps:

[0019] Step 1, input the target point coordinates (X, Y);

[0020] Step 2, collect the current position coordinates as (X0, Y0);

[0021] Step 3, calculate the target turning angle and the target forward distance:

[0022] Step 4, execute the conditional instruction of θ tra ∈(-0.1°, 0.1°)? The determination result is "no", that is Sequentially execute Step 5, otherwise jump to execute Step 14;

[0023] Step 5, execute the conditional instruction of θ tra <-35° or θ tra >35°? The determination result is "yes", that is θ tra >35°, sequentially execute Step 6, otherwise jump to execute Step 10;

[0024] Step 6, enter the high-maneuverability mode: turning angle control, allocate the swing angle θ i =k 2i θ tra and the phase lag angle w i ; turning speed control,

[0025] Step 7, apply a voltage excitation to the first upper piezoelectric wafer 4 on the first motion plate 5, the excitation voltage is the excitation time is 0.5T; apply a voltage excitation to the second upper piezoelectric wafer 8 on the second motion plate 9, the excitation voltage is the phase lag angle is w1, the excitation time is 0.5T; apply a voltage excitation to the third upper piezoelectric wafer 12 on the third motion plate 13, the excitation voltage is the phase lag angle is w2, the excitation time is 0.5T; apply a voltage excitation to the fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 on the bionic fish tail plate 17, the excitation voltage is U1, the excitation frequency is The excitation time is 0.5T;

[0026] Step 8, record the current position coordinates;

[0027] Step 9, jump to execute Step 3;

[0028] Step 10, enter the high-response mode: turning angle control, allocate the swing angle θ of each moving plate i =k 1i θ tra ; turning speed control,

[0029] Step 11, apply a voltage excitation to the first upper piezoelectric wafer 4 on the first moving plate 5, the excitation voltage is The excitation time is 0.5T; apply a voltage excitation to the second upper piezoelectric wafer 8 on the second moving plate 9, the excitation voltage is The excitation time is 0.5T; apply a voltage excitation to the third upper piezoelectric wafer 12 on the third moving plate 13, the excitation voltage is The excitation time is 0.5T; apply a voltage excitation to the fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 on the bionic fish tail plate 17, the excitation voltage is U1, and the excitation frequency is The excitation time is 0.5T;

[0030] Step 12, record the current position coordinates;

[0031] Step 13, jump to execute Step 3;

[0032] After repeatedly executing Step 3 to Step 13, at this time, the target turning angle θ of the bionic fish head 1 and the target point coordinates (X, Y) tra ∈(-0.1°, 0.1°). Next, it will enter the forward distance control stage;

[0033] Step 14, execute the S tra <3L? conditional instruction, the judgment result is "no", sequentially execute Step 15, otherwise jump to execute Step 17;

[0034] Step 15, calculate and control the swimming speed v of the bionic fish = v 1max ;

[0035] Step 16, apply a voltage excitation to the fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 on the bionic fish tail plate 17, the excitation voltage is U1, and the excitation frequency is f = f 1max , and the excitation time is T;

[0036] Step 17, calculate and control the swimming speed of the bionic fish

[0037] Step 18: Apply a voltage excitation to the fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 on the bionic fish tail plate 17. The excitation voltage is U1, and the excitation frequency is The excitation time is T;

[0038] Step 19: Execute S tra <0.1L? conditional instruction, the determination result is "no", jump to execute Step 14;

[0039] Repeatedly execute Step 14 to Step 15, finally realizing the position control of the bionic fish, and the high-response mode and high-maneuver mode are incorporated into the control method, thereby improving the speed and flexibility of the bionic fish simultaneously.

[0040] Step 20: End and exit the current control cycle.

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0042] (1) Compared with the traditional fin-pushing bionic fish, the bionic fish proposed by the present invention adopts a multi-section structure. Benefiting from the high flexibility of the bionic fish structure, the proposed bionic fish can achieve two bionic motion modes, improving the propulsion efficiency of the bionic fish;

[0043] (2) The control method proposed by the present invention can autonomously switch the bionic motion mode according to the position of the input target point coordinates relative to itself. On the premise of ensuring the position control accuracy of the bionic fish, the efficiency of the bionic fish is further improved, greatly enhancing the adaptability and reliability of the bionic fish in the face of complex geographical environments and multi-task requirements;

[0044] (3) The structure of the embodiment provided by the present invention is more concise than that of the traditional multi-section bionic fish, the assembly process is simple, and the flexibility of the bionic fish can be further improved by reducing the axial dimension of the moving plate and increasing the number of moving plates, and the expandability is good; BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A two-dimensional cross-sectional view of a bionic fish based on the regulation of a piezoelectric bimorph component provided by an embodiment of the present invention;

[0046] Figure 2 An overall external view schematic diagram of the bionic fish skeleton provided by an embodiment of the present invention;

[0047] Figure 3 A three-dimensional external view schematic diagram of the bionic fish provided by an embodiment of the present invention;

[0048] Figure 4 An installation schematic diagram of the bionic fish head and the first moving plate provided by an embodiment of the present invention;

[0049] Figure 5 Schematic diagram of the installation of the first moving plate and the second moving plate provided by the embodiment of the present invention;

[0050] Figure 6 Assembly state diagram of the first moving plate and the second moving plate provided by the embodiment of the present invention;

[0051] Figure 7 Schematic diagram of the installation of the first moving plate and the first bionic fish housing provided by the embodiment of the present invention;

[0052] Figure 8 Flowchart of the bionic fish motion state control method based on piezoelectric bimorph provided by the embodiment of the present invention;

[0053] Figure 9 Working schematic diagram of each moving plate under the target horizontal offset x provided by the embodiment of the present invention.

[0054] Wherein: 1. Bionic fish head; 101. Trunnion; 2. Fish head cylindrical pin; 3. First lower piezoelectric wafer; 4. First upper piezoelectric wafer; 5. First moving plate; 501. Connecting hole; 502. Cylindrical sliding seat; 503. Rolling auxiliary surface; 504. Strip-shaped chuck; 6. First bionic fish housing; 601. Strip-shaped card slot; 7. Second lower piezoelectric wafer; 8. Second upper piezoelectric wafer; 9. Second moving plate; 901. Cylindrical ball head; 10. Second bionic fish housing; 11. Third lower piezoelectric wafer; 12. Third upper piezoelectric wafer; 13. Third moving plate; 14. Third bionic fish housing; 15. Fourth lower piezoelectric wafer; 16. Fourth upper piezoelectric wafer; 17. Bionic fish tail plate. Detailed implementation manners

[0055] The embodiments of the present invention will be described in detail below. The examples of the embodiments are all shown in the drawings. The same reference numerals in each drawing represent the same element, and the secondary reference numerals represent the important structures on the corresponding element. The drawings form a part of this application and are used together with the embodiments of the present invention to explain the principle of the present invention, rather than to limit the scope of the present invention.

[0056] First, a bionic fish regulated by a piezoelectric bimorph assembly according to an embodiment of the present invention will be specifically described below with reference to the drawings.

[0057] Please refer to Figures 1 to 6According to an embodiment of the present invention, a bionic fish based on the control of a piezoelectric dual-chip component mainly includes 1. a bionic fish head; 2. a fish head cylindrical pin; 3. a first lower piezoelectric chip; 4. a first upper piezoelectric chip; 5. a first moving plate; 6. a first bionic fish shell; 7. a second lower piezoelectric chip; 8. a second upper piezoelectric chip; 9. a second moving plate; 10. a second bionic fish shell; 11. a third lower piezoelectric chip; 12. a third upper piezoelectric chip; 13. a third moving plate; 14. a third bionic fish shell; 15. a fourth lower piezoelectric chip; 16. a fourth upper piezoelectric chip; 17. a bionic fish tail plate.

[0058] A bionic fish based on piezoelectric bimorph control, see Figure 1 、 2 As shown, the skeleton of the bionic fish provided by the embodiment of the present invention includes the first motion plate 5, the second motion plate 9, the third motion plate 13, the bionic fishtail plate 17 and piezoelectric chips symmetrically bonded thereon; the bionic fish head 1 is hinged to the first motion plate 5, the second motion plate 9, the third motion plate 13 and the bionic fishtail plate 17 in sequence through the structure above it, and the bionic fish head, each motion plate and the bionic fishtail plate can all rotate relative to each other.

[0059] Figure 4 This diagram illustrates the installation of the bionic fish head 1 and the first moving plate 5, provided in an embodiment of the present invention. The bionic fish head 1 has a trunnion 101 at its lower end, and a connecting hole 501 at its upper end. The bionic fish head 1 and the first moving plate 5 are connected via the trunnion 101, the connecting hole 501, and the pinhole of the fish head cylindrical pin 2. In the assembled state, the bionic fish head 1 and the fish head cylindrical pin 2 cannot rotate relative to each other, while the first moving plate 5 and the fish head cylindrical pin can rotate relative to each other.

[0060] Figure 5 The schematic diagram of the installation of the first moving plate 5 and the second moving plate provided in the embodiment of the present invention is that the lower end of the first moving plate 5 is provided with a cylindrical slide 502, and the upper end of the second moving plate 9 is provided with a cylindrical ball head 901. In the assembled state, the axis of the cylindrical slide 502 coincides with the axis of the cylindrical ball head 901, and the cylindrical slide 502 is closed along the rolling auxiliary surface 503 on the first moving plate 5 by utilizing the assembly process, thereby realizing the connection between the first moving plate 5 and the second moving plate 9 without affecting the relative rotation of the two moving plates. For the assembly state diagram of the two, please refer to Figure 6 The installation mode and matching relationship between the second motion plate 9 and the third motion plate 13 , and between the third motion plate 13 and the bionic fishtail plate are the same as those between the first motion plate 5 and the second motion plate 9 .

[0061] See Figure 2, the first lower piezoelectric wafer 3 and the first upper piezoelectric wafer 4 are respectively bonded to the upper and lower sides of the first moving plate 5 by epoxy resin glue. The second lower piezoelectric wafer 7 and the second upper piezoelectric wafer 8 are respectively bonded to the upper and lower sides of the second moving plate 9 by epoxy resin glue. The third lower piezoelectric wafer 11 and the third upper piezoelectric wafer 12 are respectively bonded to the upper and lower sides of the third moving plate 13 by epoxy resin glue. The fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 are respectively bonded to the upper and lower sides of the bionic fish tail plate 17 by epoxy resin glue.

[0062] The length of the piezoelectric bimorph accounts for 2 / 3 to 5 / 6 of the length of the moving plate to which it is bonded.

[0063] Figure 6 It is a schematic installation diagram of the first moving plate 5 and the first bionic fish shell 6 provided by the embodiment of the present invention. Bar-shaped chucks 504 are designed on both the upper and lower sides of the first moving plate 5, and bar-shaped slots 601 are correspondingly designed on both the upper and lower sides inside the first bionic fish shell 6. In the assembled state, the axes of the bar-shaped chucks 504 and the bar-shaped slots coincide, realizing the synchronous swing of the first moving plate 5 and the first bionic fish shell 6. The installation methods and cooperation relationships between the second moving plate and the second bionic fish shell, and between the third moving plate and the third bionic fish shell are the same as those between the first moving plate 5 and the first bionic fish shell 6.

[0064] In this embodiment, the bionic fish can have two motion modes, namely, a high-response mode and a high-maneuverability mode. In the high-response mode, the bionic fish can approach the target at a very fast speed; in the high-maneuverability mode, the bionic fish can swim stably in a complex environment. And by adding moving plates, more motion modes can be given to the bionic fish.

[0065] In this embodiment, by controlling the swing angles of the first moving plate 5, the second moving plate 9, and the third moving plate 13, the motion control of the bionic fish and the switching of the bionic motion modes in the embodiment of the present invention are realized. By controlling the swing frequency of the bionic fish tail plate 17, the swimming speed of the bionic fish is controlled.

[0066] In this embodiment, when the maximum driving voltage of each moving plate is U1, the swing angle is θ imax , when the swing angles of the first moving plate 5, the second moving plate 9, and the third moving plate 13 are independently driven to be θ i , the excitation voltage of each moving plate is

[0067] In this embodiment, let the maximum driving voltage of the bionic fish tail plate 17 be U1, and the maximum stable swimming speed in two bionic motion modes is v imax, the minimum speed for stable swimming is v imin , the corresponding maximum excitation frequency is f imax and the minimum excitation frequency is f imin , the body length of the bionic fish is L, and the distance between the starting point and the target point is S tra . According to Lighthill's slender body theory, when the swing amplitude of the bionic fish tail plate 17 is constant, the swimming speed of the bionic fish can be adjusted by adjusting the frequency of the excitation voltage of the bionic fish tail plate 17. When the swimming speed of the bionic fish is controlled to be v, the excitation voltage of the bionic fish tail plate 17 is U1, and the excitation frequency is

[0068] Furthermore, when the excitation voltage of the bionic fish tail plate 17 is U1 and the excitation frequency is f, it means that the excitation voltages on the fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 are both U1, and the excitation voltage frequencies are both f, but the phase difference of the excitation voltages on the fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 is 180°.

[0069] Preferably, this embodiment discloses a bionic fish motion control method based on a piezoelectric bimorph component. The motion control method is used to achieve the position closed-loop control of the bionic fish, and on the basis of ensuring the position control accuracy requirements of the bionic fish, the autonomous switching of the bionic motion mode is realized simultaneously to improve the response speed and flexibility of the bionic fish.

[0070] In this embodiment, refer to Figure 9 , taking the midpoint of the bionic fish head 1 as the origin, a body coordinate system XOY is established, where the fish body coincides with the Y-axis. Assume that the angle between the connection line of the bionic fish head 1 and the target point and the positive direction of the X-axis is positive, and the angle with the negative direction of the X-axis is negative; when the excitation voltage of each motion plate is positive, it means exciting the upper piezoelectric wafer on the corresponding motion plate; when the excitation voltage of each motion plate is negative, it means exciting the lower piezoelectric wafer on the corresponding motion plate.

[0071] The control method of the present invention is as follows:

[0072] Step 1, input the target point coordinates (X, Y);

[0073] Step 2, collect the current position coordinates as (X0, Y0);

[0074] Step 3, calculate the target turning angle and the target forward distance:

[0075] Step 4, execute the θ tra ∈ (-0.1°, 0.1°)? Conditional instruction, the determination result is "no", that is Execute step 5 sequentially, otherwise jump to execute step 14;

[0076] Step 5, execute θ tra <-35° or θ tra >35°? Conditional instruction, the determination result is "yes", that is, θ tra >35°, execute step 6 sequentially, otherwise jump to execute step 10;

[0077] Step 6, enter the high-maneuver mode: turning angle control, allocate the swing angles θ of the respective moving plates i = k 2i θ tra and the phase lag angle w i ; turning speed control,

[0078] Step 7, apply a voltage excitation to the first upper piezoelectric wafer 4 on the first moving plate 5, and the excitation voltage is The excitation time is 0.5T; apply a voltage excitation to the second upper piezoelectric wafer 8 on the second moving plate 9, and the excitation voltage is The phase lag angle is w1, and the excitation time is 0.5T; apply a voltage excitation to the third upper piezoelectric wafer 12 on the third moving plate 13, and the excitation voltage is The phase lag angle is w2, and the excitation time is 0.5T; apply a voltage excitation to the fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 on the bionic fish tail plate 17, the excitation voltage is U1, and the excitation frequency is The excitation time is 0.5T;

[0079] Step 8, record the current position coordinates;

[0080] Step 9, jump to execute step 3;

[0081] Step 10, enter the high-response mode: turning angle control, allocate the swing angles θ of the respective moving plates i = k 1i θ tra ; turning speed control,

[0082] Step 11, apply a voltage excitation to the first upper piezoelectric wafer 4 on the first moving plate 5, and the excitation voltage is The excitation time is 0.5T; apply a voltage excitation to the second upper piezoelectric wafer 8 on the second moving plate 9, and the excitation voltage is The excitation time is 0.5T; apply a voltage excitation to the third upper piezoelectric wafer 12 on the third moving plate 13, and the excitation voltage is The excitation time is 0.5T; a voltage excitation is applied to the fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 on the bionic fish tail plate 17, the excitation voltage is U1, and the excitation frequency is The excitation time is 0.5T;

[0083] Step 12, record the current position coordinates;

[0084] Step 13, jump to and execute Step 3;

[0085] After repeatedly executing Step 3 to Step 13, at this time, the target turning angle θ of the bionic fish head 1 and the target point coordinates (X, Y) tra ∈(-0.1°, 0.1°). Next, it will enter the forward distance control stage;

[0086] Step 14, execute the S tra <3L? conditional instruction, the determination result is "no", sequentially execute Step 15, otherwise jump to and execute Step 17;

[0087] Step 15, calculate and control the swimming speed v of the bionic fish = v 1max ;

[0088] Step 16, apply a voltage excitation to the fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 on the bionic fish tail plate 17, the excitation voltage is U1, and the excitation frequency is f = f 1max , and the excitation time is T;

[0089] Step 17, calculate and control the swimming speed of the bionic fish

[0090] Step 18, apply a voltage excitation to the fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 on the bionic fish tail plate 17, the excitation voltage is U1, and the excitation frequency is The excitation time is T;

[0091] Step 19, execute the S tra <0.1L? conditional instruction, the determination result is "no", jump to and execute Step 14;

[0092] Repeatedly execute Step 14 to Step 15, finally realizing the position control of the bionic fish, and the high-response mode and high-maneuver mode are incorporated into the control method, thereby improving the speed and flexibility of the bionic fish at the same time.

[0093] Step 20, end and exit the current control cycle.

[0094] Next, according to the appendix Figure 9 Illustrate the movement process of the bionic fish under different target point coordinates (X, Y) by way of example:

[0095] Example 1: When the target point coordinates are (65, 65), the control steps are as follows:

[0096] Step 1, input the target point coordinates (65, 65);

[0097] Step 2, collect the current position coordinates as (0, 0);

[0098] Step 3, calculate the target turning angle and the target forward distance:

[0099] Step 4, execute the condition instruction of θ tra ∈(-0.1°, 0.1°)? The determination result is "no", that is Sequentially execute Step 5, otherwise jump to execute Step 14;

[0100] Step 5, execute the condition instruction of θ tra <-35° or θ tra >35°? The determination result is "yes", that is θ tra >35°, sequentially execute Step 6, otherwise jump to execute Step 10;

[0101] Step 6, enter the high-maneuverability mode: turning angle control, allocate the swing angles θ i =k 2i θ tra and the phase lag angle w i ; turning speed control,

[0102] Step 7, apply voltage excitation to the first upper piezoelectric wafer 4 on the first moving plate 5, the excitation voltage is The excitation time is 0.5T; apply voltage excitation to the second upper piezoelectric wafer 8 on the second moving plate 9, the excitation voltage is The phase lag angle is w1, the excitation time is 0.5T; apply voltage excitation to the third upper piezoelectric wafer 12 on the third moving plate 13, the excitation voltage is The phase lag angle is w2, the excitation time is 0.5T; apply voltage excitation to the fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 on the bionic fish tail plate 17, the excitation voltage is U1, the excitation frequency is The excitation time is 0.5T;

[0103] Step 8, record the current position coordinates;

[0104] Step 9, jump to execute Step 3;

[0105] Step 10, enter the high-response mode: control the turning angle, and allocate the swing angle θ of each moving plate i = k 1i θ tra ; Control the turning speed,

[0106] Step 11, apply a voltage excitation to the first upper piezoelectric wafer 4 on the first moving plate 5, and the excitation voltage is The excitation time is 0.5T; apply a voltage excitation to the second upper piezoelectric wafer 8 on the second moving plate 9, and the excitation voltage is The excitation time is 0.5T; apply a voltage excitation to the third upper piezoelectric wafer 12 on the third moving plate 13, and the excitation voltage is The excitation time is 0.5T; apply a voltage excitation to the fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 on the bionic fish tail plate 17, the excitation voltage is U1, and the excitation frequency is The excitation time is 0.5T;

[0107] Step 12, record the current position coordinates;

[0108] Step 13, jump to execute Step 3;

[0109] After repeatedly executing Step 3 to Step 13, at this time, the target turning angle θ between the bionic fish head 1 and the target point coordinates (65, 65) tra ∈ (-0.1°, 0.1°). Next, it will enter the forward distance control stage;

[0110] Step 14, execute the S tra <3L? conditional instruction. Assume that S tra is 20L at this time, and the determination result is "no", then sequentially execute Step 15, otherwise jump to execute Step 17;

[0111] Step 15, calculate and control the swimming speed v of the bionic fish = v 1max ;

[0112] Step 16, apply a voltage excitation to the fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 on the bionic fish tail plate 17, the excitation voltage is U1, and the excitation frequency is f = f 1max , and the excitation time is T;

[0113] Step 17, calculate and control the swimming speed of the bionic fish

[0114] Step 18, apply a voltage excitation to the fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 on the bionic fish tail plate 17, the excitation voltage is U1, and the excitation frequency is The excitation time is T;

[0115] Step 19, execute S tra <0.1L? Conditional instruction, assuming the target forward distance S at this time tra = 2L, the determination result is "no", jump to execute Step 14;

[0116] Repeatedly execute Step 14 to Step 15, finally realizing the position control of the bionic fish, and the high-response mode and high-maneuver mode are incorporated into the control method, thereby improving the speed and flexibility of the bionic fish at the same time.

[0117] Step 20, end, exit the current control cycle.

[0118] Example 2: When the target point coordinates are (-32, 20), the control steps are as follows:

[0119] Step 1, input the target point coordinates (-32, 20);

[0120] Step 2, collect the current position coordinates as (0, 0);

[0121] Step 3, calculate the target turning angle and the target forward distance:

[0122] Step 4, execute θ tra ∈ (-0.1°, 0.1°)? Conditional instruction, the determination result is "no", that is Sequentially execute Step 5, otherwise jump to execute Step 14;

[0123] Step 5, execute θ tra <-35° or θ tra > 35°? Conditional instruction, the determination result is "no", that is θ tra > -35°, jump to execute Step 10;

[0124] Step 6, enter the high-maneuver mode: turning angle control, allocate the swing angle θ of each motion plate i = k 2i θ tra and the phase lag angle w i ; turning speed control,

[0125] Step 7, apply a voltage excitation to the first upper piezoelectric wafer 4 on the first motion plate 5, the excitation voltage is The excitation time is 0.5T; apply a voltage excitation to the second upper piezoelectric wafer 8 on the second motion plate 9, the excitation voltage is The phase lag angle is w1 and the excitation time is 0.5T; a voltage excitation is applied to the third upper piezoelectric wafer 12 on the third moving plate 13, and the excitation voltage is The phase lag angle is w2 and the excitation time is 0.5T; a voltage excitation is applied to the fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 on the bionic fish tail plate 17, the excitation voltage is U1, and the excitation frequency is The excitation time is 0.5T;

[0126] Step 8, record the current position coordinates;

[0127] Step 9, jump to execute Step 3;

[0128] Step 10, enter the high-response mode: turning angle control, allocate the swing angle θ of each moving plate i = k 1i θ tra ; turning speed control,

[0129] Step 11, apply a voltage excitation to the first upper piezoelectric wafer 4 on the first moving plate 5, and the excitation voltage is The excitation time is 0.5T; apply a voltage excitation to the second upper piezoelectric wafer 8 on the second moving plate 9, and the excitation voltage is The excitation time is 0.5T; apply a voltage excitation to the third upper piezoelectric wafer 12 on the third moving plate 13, and the excitation voltage is The excitation time is 0.5T; apply a voltage excitation to the fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 on the bionic fish tail plate 17, the excitation voltage is U1, and the excitation frequency is The excitation time is 0.5T;

[0130] Step 12, record the current position coordinates;

[0131] Step 13, jump to execute Step 3;

[0132] After repeatedly executing Step 3 to Step 13, at this time, the target turning angle θ of the bionic fish head 1 and the target point coordinates (-32, 20) tra ∈ (-0.1°, 0.1°). Next, it will enter the forward distance control stage;

[0133] Step 14, execute S tra < 3L? conditional instruction. Assume that S tra is 6L at this time, and the judgment result is "no", then sequentially execute Step 15, otherwise jump to execute Step 17;

[0134] Step 15, calculate and control the swimming speed v of the bionic fish = v 1max ;

[0135] Step 16: Apply a voltage excitation to the fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 on the bionic fish tail plate 17. The excitation voltage is U1, the excitation frequency is f = f 1max , and the excitation time is T;

[0136] Step 17: Calculate and control the swimming speed of the bionic fish

[0137] Step 18: Apply a voltage excitation to the fourth lower piezoelectric wafer 15 and the fourth upper piezoelectric wafer 16 on the bionic fish tail plate 17. The excitation voltage is U1, and the excitation frequency is The excitation time is T;

[0138] Step 19: Execute S tra <0.1L? conditional instruction. Assume that the target forward distance S tra = 2L, and the determination result is "no". Then jump to execute Step 14; otherwise, sequentially execute Step 20;

[0139] Step 20: End and exit the current control cycle;

[0140] Combined with the control steps in Examples 1-2, the control method proposed by the present invention can, according to the input target point coordinates, through the closed-loop control of the position of the bionic fish, not only ensure the high-precision control of the position of the bionic fish regulated by the piezoelectric bimorph component, but also take into account the requirements of the rapidity and flexibility of the bionic fish. Compared with the traditional multi-segment fin-driven bionic fish, the present invention benefits from the bionic fish skeleton structure with a higher degree of freedom, and at the same time supplemented by the control method proposed by the present invention, can enable the bionic fish to autonomously switch the bionic motion mode according to the position of the target point relative to its own position, greatly improving the adaptability and reliability of the bionic fish in the face of complex geographical environments and multi-task requirements.

[0141] Those skilled in the art can understand that all or part of the processes of implementing the methods in the above embodiments can be completed by writing computer programs into relevant hardware. The programs can be stored in a readable storage medium on the hardware. Among them, the readable storage medium includes, but is not limited to, memories with storage and memory functions such as single-chip microcomputers.

Claims

1. A bionic fish based on piezoelectric bimorph regulation, characterized in that, include: A moving plate group, the moving plate group includes three moving plates, the upper end of the first moving plate is designed with a connecting hole, and the lower end is designed with a cylindrical slide seat, the upper ends of the second and third moving plates are designed with cylindrical ball heads, and the lower ends are designed with cylindrical slide seats, in the assembled state, the axis of the cylindrical slide seat and the cylindrical ball head coincide, and the assembly process is used to close the cylindrical slide seat along the auxiliary surface of the moving plate, thereby realizing the connection of each of the moving plates without affecting the relative rotation of the two moving plates; A bionic fish head, connected to the first motion plate via a trunnion, a connecting hole, and the pinhole of the fish head cylindrical pin. In the assembled state, the bionic fish head and the fish head cylindrical pin cannot rotate relative to each other, while the first motion plate and the fish head cylindrical pin can rotate relative to each other; A bionic fishtail plate, wherein the upper end of the bionic fishtail plate is designed with a cylindrical ball head, which is connected to the cylindrical slide seat at the lower end of the third motion plate. In the assembled state, the bionic fishtail plate can rotate left and right relative to the third motion plate; Piezoelectric dual chips are bonded to the upper and lower sides of each corresponding moving plate by epoxy resin glue. The piezoelectric dual chips are connected to wires. Applying a DC voltage to the piezoelectric dual chips can make the moving plate and bionic fishtail plate connected to the piezoelectric dual chips swing.

2. The biomimetic fish based on piezoelectric bimorph regulation according to claim 1, characterized in that, The length of the piezoelectric bimorph is 5 / 6 to 2 / 3 of the length of the moving plate connected thereto.

3. The biomimetic fish based on piezoelectric bimorph regulation according to claim 2, characterized in that, Each of the moving boards is designed with a strip-shaped clamping head on the upper and lower sides, and each of the bionic fish shells is correspondingly designed with a strip-shaped clamping groove on the upper and lower sides. In the assembled state, the axes of the strip-shaped clamping head and the strip-shaped clamping groove coincide, thereby realizing the synchronous swing of each of the moving boards and the bionic fish shells.

4. A control method for a bionic fish regulated by a piezoelectric bimorph as described in any one of claims 1 - 3, characterized in that, The control method includes a motion control preparation stage, a motion posture control stage and a forward speed control stage. The motion control preparation stage includes the following steps: Step 1: Input the target point coordinates (X, Y); Step 2: Collect the current position coordinates as (X0, Y0); Step 3: Calculate the target turning angle and target forward distance: Step 4, execute θ tra ∈ (-0.1 o , 0.1 o )? Conditional instruction, the determination result is "No", that is Sequentially execute Step 5, otherwise jump to execute Step 14; Step 5, execute θ tra <-35 o or θ tra >35 o ? Conditional instruction, the judgment result is "yes", that is, θ tra >35 o , sequentially execute Step 6, otherwise jump to execute Step 10. The motion posture control stage comprises the following steps: Step 6, enter the high-maneuverability mode: control the turning angle, and allocate the swing angle θ of each motion plate i = k 2i θ tra and the phase lag angle w i ; control the turning speed, Step 7, apply a voltage excitation to the first upper piezoelectric wafer on the first moving plate, and the excitation voltage is The excitation time is 0.5T; apply a voltage excitation to the second upper piezoelectric wafer on the second moving plate, and the excitation voltage is The phase lag angle is w1, and the excitation time is 0.5T; apply a voltage excitation to the third upper piezoelectric wafer on the third moving plate, and the excitation voltage is The phase lag angle is w2, and the excitation time is 0.5T; apply a voltage excitation to the fourth lower piezoelectric wafer and the fourth upper piezoelectric wafer on the bionic fish tail plate, the excitation voltage is U1, and the excitation frequency is f = The excitation time is 0.5T; Step 8, record the current location coordinates; Step 9, jump to step 3; Step 10, enter the high-response mode: turning angle control, allocate the swing angle θ of each motion plate i = k 1i θ tra ; turning speed control, Step 11: applying voltage excitation to the first upper piezoelectric chip on the first moving plate, the excitation voltage is The excitation time is 0.5T; a voltage excitation is applied to the second upper piezoelectric chip 8 on the second moving plate, and the excitation voltage is The excitation time is 0.5T; a voltage excitation is applied to the third upper piezoelectric chip on the third moving plate, and the excitation voltage is The excitation time is 0.5T; voltage excitation is applied to the fourth lower piezoelectric chip and the fourth upper piezoelectric chip on the bionic fishtail plate, the excitation voltage is U1, and the excitation frequency is The excitation time is 0.5T; Step 12, record the current location coordinates; Step 13, jump to step 3; After repeatedly executing steps 3 to 13, the target turning angle θ of the bionic fish head and the target point coordinates (X, Y) at this time tra ∈ (-0.1 o , 0.1 o ); The forward speed control stage includes the following steps: Step 14, execute S tra <3L? conditional instruction, the determination result is "no", sequentially execute Step 15, otherwise jump to execute Step 17; Step 15, calculate and control the swimming speed of the bionic fish v = v 1max ; Step 16: Apply voltage excitation to the fourth lower piezoelectric chip and the fourth upper piezoelectric chip on the bionic fishtail plate, the excitation voltage is U1, and the excitation frequency is f=f 1max , the excitation time is T; Step 17: Calculate and control the swimming speed of the bionic fish Step 18, apply a voltage excitation to the fourth lower piezoelectric wafer and the fourth upper piezoelectric wafer on the bionic fish tail plate, the excitation voltage is U1, and the excitation frequency is The excitation time is T; Step 19, execute S tra <0.1L? Conditional instruction, the determination result is "No", jump to execute Step 14; Steps 14 and 15 are repeatedly performed to finally realize the position control of the bionic fish. In addition, a high response mode and a high maneuverability mode are embedded in the control method, thereby simultaneously improving the speed and flexibility of the bionic fish. Step 20: End and exit the current control cycle.

5. The control method of the bionic fish regulated by the piezoelectric bimorph according to claim 4, characterized in that, The motion control method achieves precise control of the position of the bionic fish through closed-loop control of the bionic fish's posture and swimming speed. The control principles of the bionic fish's posture and swimming speed are as follows: Bionic fish attitude control: When the maximum driving voltage of each motion plate is U1, the swing angle is θ imax , when the first motion plate, the second motion plate, and the third motion plate are independently driven to swing at an angle of θ i , the excitation voltage of each motion plate is Bionic fish swimming speed control: Assume that the maximum driving voltage of the bionic fish tail fin plate is U1, and the maximum speed of stable swimming in two bionic motion modes is v imax , and the minimum speed of stable swimming is v imin , the corresponding maximum excitation frequency is f imax and the minimum excitation frequency is f imin , the body length of the bionic fish is L, and the distance between the starting point and the target point is S tra . According to Lighthill's slender body theory, when the swing amplitude of the bionic fish tail fin plate is constant, the swimming speed of the bionic fish can be adjusted by adjusting the frequency of the excitation voltage of the bionic fish tail fin plate. When controlling the swimming speed of the bionic fish to be v, the excitation voltage of the bionic fish tail fin plate is U1, and the excitation frequency is Further, when the excitation voltage of the bionic fish tail plate is U1 and the excitation frequency is f, it means that the excitation voltages on the fourth lower piezoelectric wafer and the fourth upper piezoelectric wafer are both U1, and the excitation voltage frequencies are both f, but the phase difference of the excitation voltages on the fourth lower piezoelectric wafer and the fourth upper piezoelectric wafer is 180 o .

Images