Design method of miniaturized multi-profile underwater acoustic buoy

Abstract

The application discloses a design method of a miniaturized multi-profile underwater acoustic buoy, and belongs to the technical field of underwater acoustic buoys, and comprises the following steps: S1, performing platform main body structure unit design; S2, performing buoy platform buoyancy driving unit design; S3, performing buoy energy unit design; S4, performing water motion analysis on the buoy platform designed in the above steps; and S5, designing an acoustic detection system suitable for the miniaturized multi-profile underwater acoustic buoy. The buoy designed in the application can autonomously complete water target detection and information feedback, and has multi-platform deployment functions such as ship-borne deployment, underwater carrying and unmanned aerial vehicle air drop, and can realize efficient and rapid delivery and deployment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of underwater acoustic buoys, and particularly relates to a design method of a miniaturized multi-profile underwater acoustic buoy. BACKGROUND

[0002] At present, the underwater target detection mode of the deep sea ocean area in China mainly relies on the traditional water surface warships and aviation sonar, and the efficiency-cost ratio is extremely low and is seriously affected by the severe sea conditions, and the underwater monitoring and early warning capability seriously lags behind the demand of marine safety. As one of the important means of unmanned detection of underwater targets, the underwater acoustic buoy is an important part of the construction of the underwater detection system capability, and has great significance for improving the underwater target detection capability. However, the existing underwater acoustic buoys are mostly large in size, single in function and not flexible in launching mode, so it is necessary to study the design method of the underwater acoustic buoy to design the underwater acoustic buoy meeting the actual needs. SUMMARY

[0003] In order to overcome the shortcomings of the prior art, the application discloses a design method of a miniaturized multi-profile underwater acoustic buoy, which can improve the profile buoy miniaturization, multi-platform deployment and target detection, and can independently complete the underwater target detection and information transmission, and has the functions of ship-borne deployment, underwater carrying and unmanned aerial vehicle air drop, and can realize efficient and rapid delivery and deployment.

[0004] In order to achieve the above purpose, the technical scheme of the application is:

[0005] A design method of a miniaturized multi-profile underwater acoustic buoy, wherein the underwater acoustic buoy comprises a platform main body structure unit, a platform buoyancy driving unit, an energy unit, a buoy platform main control unit and an acoustic detection system, and the design method comprises the following steps:

[0006] S1: According to the acoustic detection application requirements of the buoy, the platform main body structure unit is designed, a buoy basic platform with small size, light weight, strong impact resistance and multi-platform deployment function is developed, and the acoustic system integration application requirements are met;

[0007] S2: The buoy platform buoyancy driving unit is designed, which is used for adjusting the buoyancy of the buoy, and the buoy is floated and submerged by changing the volume of the buoy;

[0008] S3: The buoy energy unit is designed to provide energy for the platform movement and the acoustic system work;

[0009] S4: The buoy platform designed in the above steps is analyzed in water movement;

[0010] S5: design the acoustic detection system suitable for the miniaturized multi-profile underwater acoustic buoy, the hardware of the acoustic detection system includes one vector hydrophone and four-channel underwater acoustic signal processor; the software of the acoustic detection system is used to control the completion of underwater acoustic signal receiving, target direction measurement and autonomous detection, and send target information and floating instruction to the buoy platform main control unit.

[0011] Preferably, in the step S1, the buoy base platform includes a buoy main cabin body and a buoy acoustic cabin section, and the step S1 specifically comprises:

[0012] (1) buoy main cabin body strength and stability calculation: including pressure-resistant shell thickness calculation, rib size calculation, rib spacing calculation and cabin body strength and stability checking;

[0013] The shell calculation thickness t is:

[0014] (1);

[0015] Wherein, The pressure is Mpa; The radius of the cylindrical shell is mm; The material yield strength is N / mm 2 ;

[0016] The rib spacing Satisfies:

[0017] (2);

[0018] Wherein, The elastic modulus is N / mm 2 ; The shell thickness is mm;

[0019] The selection of the rib section should make its moment of inertia satisfy:

[0020] (3);

[0021] The local buckling theory critical pressure of the shell plate is:

[0022] (4);

[0023] In formula (4), The circumferential instability wave number is;

[0024] ​In the design of the cabin structure size, the general method of optimization design is adopted to adjust the design variables: the numerical values of the shell thickness, the rib spacing and the rib size, while meeting the constraint conditions of the design variables and the state variables, i.e. the maximum stress and the critical stress, i.e. the maximum stress and the critical stress meet the material strength and the stability requirements of the structure, so that the objective function is optimal, and then the weights of the cabin structures of various schemes are compared to obtain the optimal cabin structure design scheme meeting the conditions;

[0025] (2) Buoy acoustic cabin section design:

[0026] The buoy acoustic cabin section is located at the head of the platform main structure unit, including an antenna cabin, a vector hydrophone, a fairing and a through-cabin piece. The acoustic cabin section is installed with an integrated antenna, which communicates and supplies power through a watertight cable. The upper end cover of the platform main structure unit is designed as a flat cover to install the vector hydrophone, and an antenna, debugging, hydrophone and tension hole are designed. The overall low-drag streamline shape of the buoy antenna cabin is adopted to reduce the water impact, and double radial sealing is adopted to ensure the reliability of the sealing;

[0027] (3) Buoy force-bearing assembly design:

[0028] In order to avoid the impact damage to the buoy at the moment of the buoy being placed into water, a pull rod and a tension beam are designed inside the buoy shell. The pull rod and the tension beam tension the both ends of the shell, thereby providing a prestress to the shell, so as to improve the strength of the buoy shell and avoid the direct stress on the internal platform buoyancy driving unit;

[0029] (4) Underwater carrying scheme design:

[0030] In order to realize the underwater carrying and placing function of the buoy, the buoy is designed with a front guide and a rear guide. The front guide and the rear guide are both made of 6061 aluminum alloy. The outer surfaces of the front and rear sides of the buoy shell are respectively fixed with a front fixed ring and a rear fixed ring. The outer surfaces of the front fixed ring and the rear fixed ring are respectively and uniformly provided with a plurality of sliding grooves. A front guide is installed in one sliding groove of the front fixed ring, and front fixed blocks are installed in the remaining sliding grooves. A rear guide is installed in one sliding groove of the rear fixed ring, and rear fixed blocks are installed in the remaining sliding grooves. The front fixed blocks are used to install the head protection cover of the buoy shell, and together with the rear fixed blocks, are used to install the middle section protection cover of the buoy shell. The front guide and the rear guide are used to connect with the underwater launching platform.

[0031] (5) Air drop scheme design:

[0032] The float air-drop component is a float parachute, which adopts a circular parachute design; since the parachute is an important tool for completing the air-drop task, the float needs to consider the parachute performance of weight, volume, parachute opening force, landing speed, drag coefficient, meet the parachute shape and stability design requirements, and pass the safety calculation of pressure strength checking and fatigue strength checking to ensure that the parachute can meet the needs of the air-drop task;

[0033] To ensure the normal work of the float after entering the water, the float is additionally provided with a parachute body separation mechanism; the float shell is connected with the float parachute through the parachute body separation mechanism, the parachute body separation mechanism comprises: an inertia sleeve with a stepped cross section, a separation sleeve is penetrated in the inertia sleeve, a first end of the separation sleeve is located outside the end of the small-diameter section of the inertia sleeve, a tail end penetrates through the inner hole of the inertia sleeve and is screwed with a limiting nut, the first end of the separation sleeve is outwardly folded to form an annular end cover, an inertia spring is arranged outside the small-diameter section, one end of the inertia spring is abutted with the inner surface of the annular end cover, and the other end is abutted with the outer surface of the side of the large-diameter section of the inertia sleeve towards the annular end cover, the first end of the separation sleeve is used to connect a float joint, the float joint is arranged on the outer surface of the float shell, the float joint comprises a connecting rod, a limiting block fixedly arranged on the outer surface of the connecting rod, one end of the connecting rod is inserted into the first end of the separation sleeve, the limiting block is abutted with the outer surface of the first end of the separation sleeve, an annular groove is arranged on the outer surface of the rod body of the connecting rod located in the first end of the separation sleeve, a plurality of through holes are uniformly distributed on the outer wall of the separation sleeve opposite to the annular groove, a stop steel column is arranged in the through hole, the first end of the inertia sleeve is inwardly folded to form a limiting ring, in the initial state, the inner surface of the limiting ring is abutted with the outer end of the through hole, and the stop steel column is restricted from being clamped with the annular groove to limit the float joint from being separated from the separation sleeve, a stop nut is fixedly connected to the end of the separation sleeve away from the float joint, and a separation spring is arranged between the opposite ends of the connecting rod and the stop nut;

[0034] At the moment when the float shell enters the water, the inertia sleeve moves towards the first end and approaches the annular end cover under the action of inertia and overcomes the elastic force of the inertia spring, the stop steel column moves towards the tail end of the inertia sleeve and is separated from the limiting ring under the driving of the connecting rod, the stop steel column moves out of the separation sleeve through the through hole due to the extrusion of the rod body outside the annular groove, the separation spring is compressed and deformed, and then the float joint is ejected from the parachute body separation mechanism through the reset of the separation spring; to avoid misoperation, a positioning hole penetrating the inner surface of the separation sleeve is further arranged on the outer surface of the inertia sleeve, an insurance pin is arranged in the positioning hole, and the insurance pin is used to limit the relative movement of the inertia sleeve and the separation sleeve; in order to facilitate the connection with the float parachute, an umbrella connecting threaded hole is arranged on the outer surface of the inertia sleeve.

[0035] Preferably, the step S2 is specifically:

[0036] The buoyancy driving unit is used for adjusting the buoyancy of the buoy, and the buoyancy driving unit realizes the floating and diving of the buoy by changing the volume of the buoy, and mainly comprises a hydraulic pump, a speed reduction motor, an oil tank, an electromagnetic reversing valve, an oil bag, a valve body, a pipeline, a pressure sensor, a liquid level sensor and various connecting pieces; the oil tank is connected with the buoy shell, the oil tank is connected with the buoy shell, the oil tank is provided with a liquid level sensor, the hydraulic pump is a bidirectional pump, the hydraulic pump is connected with the speed reduction motor, the oil tank is connected with the oil bag through the hydraulic pump, and a pressure sensor is also installed on the pipeline between the bidirectional hydraulic pump and the oil bag;

[0037] When the buoy is powered on, under the driving of the control unit, the hydraulic pump fills the oil tank with hydraulic oil through the hydraulic valve into the oil bag, and the oil tank stops when the oil drops to a specified height, and the buoy is in a maximum positive buoyancy state; when the buoy needs to dive, the motor drives the hydraulic pump to reverse to pump the oil back to the oil tank, thereby reducing the volume of the buoy and making the buoy dive. By controlling the amount of oil pumped, the sinking speed and the final suspension depth of the buoy are changed; when the buoy needs to float up, the hydraulic pump fills the oil into the oil bag, increases the volume of the buoy, and the buoy floats up and communicates out of the water.

[0038] Preferably, the step S3 is specifically:

[0039] ① Power-off control is performed on the circuit which is not used temporarily;

[0040] ② The control strategy is optimized to reduce the total power consumption of the motor, that is, the pressure data sampling frequency is reasonably selected, the number of motor adjustments and the time of each adjustment are reasonably configured, and the power consumption is reduced;

[0041] ③ Reasonable power management is performed, the battery is divided into several groups according to the battery characteristics, and the batteries are reasonably used, so as to ensure the power supply capacity and prolong the service life of the battery.

[0042] Preferably, the step S4 is specifically:

[0043] The buoyancy adjustment amount of the buoy is used to calculate whether the buoy can dive to a set water depth and float up in a specific sea area, and the factors affecting the buoyancy of the buoy include seawater density, shell compression, external structure compression, hydraulic oil compression and buoy movement speed;

[0044] The force calculation formula of the buoy in water is:

[0045] (5);

[0046] In formula (5), is the resultant force of the buoy, is the total mass of the buoy, is the seawater density, is the fixed displacement volume of the buoy, Vd is the displacement of the buoy, Cd is the viscous drag coefficient, Cd is the viscous drag coefficient;

[0047] The adjustment of the oil tank is divided into two parts, one part is zero buoyancy adjustment, the volume change is , the other part is non-zero buoyancy adjustment, the volume change is , then formula (5) becomes:

[0048] (6);

[0049] In formula (6), , we can get:

[0050] (7);

[0051] The range of seawater density is 1.022-1.032 g / cm 3 , the total displacement of the buoy is 30 L, and the volume change of the oil tank that needs to be adjusted is 350 mL; non-zero buoyancy adjustment is to adjust the motion of the buoy, according to formula (6), formula (5), we get:

[0052] (8);

[0053] The buoy automatically controls the depth, and the underwater motion equation of the buoy is:

[0054] (9);

[0055] The underwater motion of the buoy is a combination of countless variable acceleration motions. The depth of the buoy is calculated by iterating the underwater motion of the buoy, and the speed of the buoy when it finally moves at a constant speed in a certain density layer is calculated. The displacement of each variable acceleration combination is added up to get the depth value of the buoy. The solution of the underwater motion speed of the buoy is:

[0056] (10);

[0057] The acceleration solution is:

[0058] (11);

[0059] The displacement solution is:

[0060] (12);

[0061] In formula (12),

[0062] (13);

[0063] , is the deep sea water density at time t, is the buoy volume at time t.

[0064] Preferably, the step S5 is specifically as follows:

[0065] The vector hydrophone of the acoustic detection system of the buoy has a sound pressure channel and three vector channels, the sound pressure channel adopts a radial polarization piezoelectric ceramic pipe, the vector channels adopt three-axis piezoelectric acceleration sensors, and the sound pressure channel and the vector channels adopt a sub-module shielding and packaging technology to realize low-noise design.

[0066] The design method of the miniaturized multi-profile underwater acoustic buoy has the following beneficial effects:

[0067] The design method is aimed at key technologies such as miniaturization of profile buoys, multi-platform deployment, and target detection, and can develop a miniaturized multi-profile underwater acoustic buoy with target detection function. The buoy designed by the method can autonomously complete underwater target detection and information transmission, and has multi-platform deployment functions such as ship-borne deployment, underwater transportation, and unmanned aerial vehicle air drop, and can realize efficient and rapid deployment. BRIEF DESCRIPTION OF DRAWINGS

[0068] Figure 1 Overall scheme of the miniaturized multi-profile underwater acoustic buoy;

[0069] Figure 2 Schematic diagram of the front or rear guide structure (both structures are the same);

[0070] Figure 3 Schematic diagram of the umbrella body separation mechanism (left) and the separation process (right);

[0071] Figure 4 Schematic diagram of the buoyancy driving unit;

[0072] Figure 5 , Four Hardware component structure block diagram of the channel underwater acoustic signal processor;

[0073] Figure 6 Design drawing of the buoy force-bearing assembly;

[0074] 1, pull rod; 2, tension beam; 3, sliding groove; 4, buoy joint; 5, annular end cover; 6, inertial spring; 7, umbrella threaded hole; 8, inertia sleeve; 9, stop steel column; 10, positioning hole; 11, separation spring; 12, stop nut; 13, limit nut; 14, guide; 15, fixed block. DETAILED DESCRIPTION

[0075] The following description is only for the preferred embodiments of the present application, and is not intended to limit the protection scope of the present application, and any modification, equivalent replacement and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0076] In the most basic embodiment, a design method of a miniaturized multi-profile underwater acoustic buoy, as shown in the accompanying drawings, the underwater acoustic buoy comprises a platform main body structure unit, a platform buoyancy driving unit, an energy unit, a buoy platform main control unit and an acoustic detection system, and the design method comprises the following steps: Figures 1-6

[0077] S1: for the acoustic detection application requirement of the buoy, the platform main body structure unit is designed, a buoy basic platform with small volume, light weight, strong impact resistance and multi-platform laying function is developed, and the acoustic system integration application requirement is met;

[0078] S2: the buoy platform buoyancy driving unit is designed, the unit is used for adjusting the buoyancy of the buoy, and the buoy is floated and submerged by changing the volume of the buoy;

[0079] S3: the buoy energy unit is designed, and energy is provided for the platform movement and the acoustic system work;

[0080] S4: the buoy platform designed in the above steps is analyzed in water movement;

[0081] S5: an acoustic detection system suitable for the miniaturized multi-profile underwater acoustic buoy is designed, the acoustic detection system hardware comprises one vector hydrophone and a four-channel underwater acoustic signal processor; the acoustic detection system software is used to control the completion of underwater acoustic signal receiving, target direction measurement and autonomous detection, and sends target information and floating instructions to the buoy platform main control unit.

[0082] The shape of the buoy involved in the present application can be the conventional shape disclosed in the prior art, and the shape and structure of the buoy are not discussed in detail here, and the contents not mentioned are solved by the prior art.

[0083] In a further embodiment, as shown in the accompanying drawings, in the step S1, the buoy basic platform comprises a buoy main cabin body and a buoy acoustic cabin section, and the step S1 specifically comprises: Figures 1-6

[0084] (1) buoy main cabin body strength and stability calculation:

[0085] The cabin body strength and stability calculation process comprises the thickness of the pressure-resistant shell, the size and spacing of the ribs and the like, and the checking of the cabin body strength and stability. The shell calculation thickness t is:

[0086] (1); ​​

[0087] Rib spacing Satisfy:

[0088] (2);

[0089] The selection of the rib section should make its moment of inertia satisfy:

[0090] (3);

[0091] The critical pressure of the local instability theory of the shell plate is:

[0092] (4);

[0093] In the design of the cabin body structure size, the general method of optimization design is adopted, the values of the design variables (shell thickness, rib spacing and rib size) are adjusted, and the constraint conditions of the design variables and state variables (maximum stress, critical stress) are satisfied, that is, the maximum stress and the critical stress satisfy the material strength and the stability requirement of the structure, so that the optimization scheme of the target function (that is, the minimum weight of the cabin body structure) is optimal. Then compare the weight of the cabin body structure of each scheme, and get the optimal design scheme of the cabin body structure that meets the conditions.

[0094] (2) Buoy acoustic cabin section design:

[0095] The buoy acoustic cabin section is located at the head of the platform, which includes an antenna cabin, a vector hydrophone, a fairing and a through-cabin piece. The acoustic cabin section is installed with an integrated antenna, which communicates and powers through a watertight cable. The upper end cover of the buoy is designed with a flat cover to install the vector hydrophone, and the antenna, debugging, hydrophone and tensioning (vacuum) holes are designed. The overall low-drag streamline shape of the buoy antenna cabin is adopted to reduce the water impact, and double radial sealing is adopted to ensure the reliability of the sealing.

[0096] (3) Buoy force-bearing assembly design:

[0097] As shown in Figure 6 , in order to avoid the impact damage of the buoy when it is placed into water, a pull rod 1 and a tension beam 2 are designed inside the shell. This design can improve the strength of the buoy shell and avoid the direct stress of the internal platform buoyancy driving unit. As shown in Figure 6 , the pull rod and the tension beam tighten the two ends of the shell, providing pre-stress to the shell, thereby effectively improving the strength of the shell and avoiding the direct stress of the internal platform buoyancy driving unit.

[0098] (4) Underwater carrying scheme design:

[0099] ​In order to realize the underwater carrying and deploying function of the buoy, the buoy is designed with a front guide and a rear guide; the front guide and the rear guide are both made of 6061 aluminum alloy; the front and rear sides of the outer surface of the buoy shell are respectively fixed with a front fixed ring and a rear fixed ring; the outer surfaces of the front fixed ring and the rear fixed ring are respectively and uniformly provided with a plurality of sliding grooves 3; a front guide is installed in one of the sliding grooves 3 of the front fixed ring, and front fixed blocks are installed in the remaining sliding grooves; a rear guide is installed in one of the sliding grooves 3 of the rear fixed ring, and rear fixed blocks are installed in the remaining sliding grooves; the front fixed blocks are used to install the head protection cover of the buoy shell, and together with the rear fixed blocks, are used to install the middle section protection cover of the buoy shell; the front guide and the rear guide are used to be connected with the underwater launching platform.

[0100] (5) Air drop scheme design:

[0101] The buoy air drop component is a buoy parachute; the buoy parachute adopts a circular parachute design; since the parachute is an important tool for completing the air drop task, the buoy needs to consider the weight, volume, parachute performance of opening force, landing speed and drag coefficient, and meet the design requirements of parachute shape and stability, and the safety calculation of pressure strength checking and fatigue strength checking, to ensure that the parachute can meet the needs of the air drop task;

[0102] In order to ensure the normal work of the buoy after entering the water, the buoy is additionally provided with a parachute body separation mechanism; the buoy shell is connected with the buoy parachute through the parachute body separation mechanism; the parachute body separation mechanism comprises: an inertia sleeve 8 with a stepped cross section; a separation sleeve is penetrated in the inertia sleeve; the front end of the separation sleeve is located outside the small diameter section end of the inertia sleeve 8, the tail end penetrates through the inner hole of the inertia sleeve 8 and is screwed with a limiting nut 13; the front end of the separation sleeve is outwardly folded to form an annular end cover 5; an inertia spring 6 is provided outside the small diameter section; one end of the inertia spring 6 abuts against the inner surface of the annular end cover 5, and the other end abuts against the outer surface of the large diameter section of the inertia sleeve 8 on the side facing the annular end cover 5; the front end of the separation sleeve is used to connect a buoy joint 4; the buoy joint 4 is provided on the outer surface of the buoy shell; the buoy joint 4 comprises a connecting rod (not marked in the figure) and a limiting block (not marked in the figure) fixedly provided on the outer surface of the connecting rod; one end of the connecting rod is inserted into the front end of the separation sleeve; the limiting block abuts against the outer surface of the front end of the separation sleeve; the outer surface of the rod body of the connecting rod inside the front end of the separation sleeve is provided with an annular groove (not marked in the figure); a plurality of through holes (not marked in the figure) are uniformly distributed on the outer wall of the separation sleeve opposite to the annular groove; a stop steel column 9 is arranged in the through hole; the front end of the inertia sleeve 8 is inwardly folded to form a limiting ring (not marked in the figure); in the initial state, the inner surface of the limiting ring abuts against the outer end of the through hole, and restricts the stop steel column 9 from being clamped with the annular groove to limit the buoy joint 4 from being separated from the separation sleeve.

[0103] A stop nut 12 is fixedly connected to the end of the separation sleeve away from the buoy connector, and a separation spring 11 is provided between the opposite ends of the connecting rod and the stop nut;

[0104] At the moment the buoy shell enters the water, the inertia sleeve, under the action of inertia, overcomes the elastic force of the inertia spring 6 and moves towards the head end, approaching the annular end cap 5. The stop steel column 9, driven by the connecting rod, moves towards the tail end of the inertia sleeve 8 and breaks free from the constraint of the limiting ring. Due to the compression of the rod body outside the annular groove of the connecting rod, the stop steel column 9 moves outward through the through hole to the separation sleeve. The separation spring is compressed and deformed. Then, the buoy connector is ejected from the parachute separation mechanism by the reset of the separation spring. To avoid malfunction, a positioning hole 10 penetrating the inner surface of the separation sleeve is provided on the outer surface of the inertia sleeve. A safety pin is provided in the positioning hole 10 to limit the relative movement of the inertia sleeve and the separation sleeve. To facilitate connection with the buoy parachute, a parachute threaded hole 7 is provided on the outer surface of the inertia sleeve.

[0105] In a further embodiment, such as Figures 1-6 As shown, step S2 specifically involves:

[0106] The buoyancy drive unit is used to adjust the buoyancy of the buoy. It achieves the buoy's ascent and descent by changing its volume. It mainly includes a hydraulic pump, a geared motor, an oil tank, a solenoid directional valve, an oil bladder, a valve body, pipelines, a pressure sensor, a level sensor, and various connecting components. The buoyancy drive unit is composed as follows: Figure 4 As shown. The buoy shell is connected to an oil bladder, the oil tank is connected to the buoy shell, and a liquid level sensor is installed in the oil tank. The hydraulic pump is a bidirectional pump and is connected to a geared motor. The oil tank is connected to the oil bladder through the hydraulic pump. A pressure sensor is also installed on the pipeline between the bidirectional hydraulic pump and the oil bladder.

[0107] When the buoy is powered on, the hydraulic pump, driven by the control unit, fills the oil bladder with hydraulic oil from the tank through the hydraulic valve. The oil level in the tank drops to a specified height and then stops, at which point the buoy is in its maximum positive buoyancy state. When the buoy needs to submerge, the motor drives the hydraulic pump to reverse and pump oil back from the oil bladder to the tank, reducing the buoy's volume and allowing it to submerge. By controlling the amount of oil pumped, the buoy's sinking speed and final suspension depth can be changed. When the buoy needs to rise, the hydraulic pump fills the oil bladder with oil, increasing the buoy's volume, causing it to rise and surface for communication.

[0108] In a further embodiment, such as Figures 1-6 As shown, step S3 specifically involves:

[0109] Currently, the commonly used power source for underwater unmanned mobile platforms is typically primary or secondary lithium batteries. To reduce power consumption and extend the buoy's lifespan, this invention adopts the following technical aspects:

[0110] ①Power-off control for the circuit which is not used temporarily, such as power-off of the acoustic system and the corresponding data acquisition circuit during the sinking or floating process, power-off of all sensors and the corresponding circuit when transmitting data to the satellite on the sea surface, and power-off of the pressure sensor and the corresponding circuit during the pressure data acquisition gap in the floating process;

[0111] ②Optimization of the control strategy to reduce the total power consumption of the motor, i.e. reasonable selection of the pressure data sampling frequency, reasonable configuration of the number of motor adjustments and the running time of each adjustment to reduce power consumption;

[0112] ③Reasonable power management, according to the battery characteristics, the battery is divided into several groups, and reasonable inter-battery matching is carried out to ensure the power supply capacity and prolong the service life of the battery.

[0113] The buoy development scheme selects soft-packaged lithium manganese dioxide batteries, the battery pack includes four groups of 24V battery packs, each group of batteries is composed of 8 lithium manganese battery cells of CP8543115 type connected in series, and the battery pack is wrapped with PVC material. The battery pack output voltage range is 24.5VDC~25.8VDC under no load, and the capacity of each single battery is 12Ah. Four groups of parallel battery packs are installed in the buoy, and the total capacity is 48Ah, 1100Wh.

[0114] In further embodiments, as shown in Figures 1-6 , the step S4 is specifically:

[0115] The buoy buoyancy adjustment amount is used to calculate whether the buoy can achieve the requirement of diving to the set water depth and floating up in a specific sea, and the factors affecting the buoyancy of the buoy are: seawater density, shell compression, external structure compression, hydraulic oil compression and buoy movement speed;

[0116] The force calculation formula of the buoy in water is:

[0117] (5);

[0118] In formula (5), is the resultant force of the buoy, is the total mass of the buoy, is the seawater density, is the fixed displacement volume of the buoy, is the displacement volume changed by the oil bladder, is the viscous drag coefficient, is the differential pressure drag coefficient;

[0119] The adjustment of the oil bladder is divided into two parts, one part is zero buoyancy adjustment, and the volume change amount is , and the other part is non-zero buoyancy adjustment, and the volume change amount is , then formula (5) becomes:

[0120] (6);

[0121] In formula (6), , we have:

[0122] (7);

[0123] The sea water density varies from 1.022 to 1.032 g / cm3, the total displacement volume of the buoy is 30 L, and the volume variation of the oil bag to be adjusted is 350 mL; the non-zero buoyancy adjustment is to adjust the movement of the buoy, according to formula (6) and formula (5), we have:

[0124] (8);

[0125] The buoy automatically controls the depth, and the underwater movement equation of the buoy is:

[0126] (9);

[0127] The underwater movement of the buoy is a combination of infinite variable acceleration movements, the depth of the buoy is iterated, the speed of the buoy when doing uniform motion in a certain density layer is calculated, the displacement of each variable acceleration movement combination is accumulated, and the depth value of the buoy is obtained, and the solution of the underwater movement speed of the buoy is:

[0128] (10);

[0129] The acceleration solution is:

[0130] (11);

[0131] The displacement solution is:

[0132] (12);

[0133] In formula (12),

[0134] (13);

[0135] , is the sea water density at the depth of t, is the volume of the buoy at t.

[0136] In further embodiments, as shown in Figures 1-6 , step S5 is specifically:

[0137] The vector hydrophone of the acoustic detection system of the buoy has a sound pressure channel and three vector channels. The sound pressure channel adopts a radial polarization piezoelectric ceramic pipe, the vector channels adopt three axial piezoelectric acceleration sensors, and the sound pressure channel and the vector channels adopt a shielding and packaging technology in a modular manner to realize low-noise design.

Claims

1. A design method for a miniaturized multi-profile underwater acoustic buoy, characterized by: The underwater acoustic buoy includes a platform main structure unit, a platform buoyancy drive unit, an energy unit, a buoy platform main control unit, and an acoustic detection system. The design method includes the following steps: S1: To meet the application requirements of acoustic detection of buoys, the main structural unit of the platform is designed, and a buoy base platform with small size, light weight, strong impact resistance and multi-platform deployment function is developed, which also meets the requirements of acoustic system integration application. S2: Design of the buoyancy drive unit for the buoy platform. This unit is used to adjust the buoyancy, which achieves the buoy's ascent and descent by changing the buoy's volume. S3: Design the buoy power unit to provide power for platform movement and acoustic system operation; S4: Perform water motion analysis on the buoy platform designed in the above steps; S5: Design an acoustic detection system suitable for miniaturized multi-profile underwater acoustic buoys. The hardware of the acoustic detection system includes a vector hydrophone and a four-channel underwater acoustic signal processor. The software of the acoustic detection system is used to control the underwater acoustic signal reception, target orientation measurement and autonomous detection, and to send target information and buoy command to the main control unit of the buoy platform. In step S1, the buoy base platform includes the buoy main hull and the buoy acoustic section. Specifically, step S1 is as follows: (1) Calculation of the strength and stability of the main hull of the buoy: including the calculation of the thickness of the pressure hull, the calculation of the rib size, the calculation of the rib spacing, and the verification of the strength and stability of the hull; The calculated thickness t of the shell is: （1）； in, Pressure, unit MPa; The radius of the cylindrical shell is in mm. Yield strength of the material, in N / mm² 2 ; Intercostal space satisfy: （2）； in, This is the elastic modulus, in N / mm. 2 ; The thickness of the shell is in mm; The selection of rib cross-sections should ensure that their moments of inertia satisfy the following: （3）； Theoretical critical pressure for local instability of shell plates for: （4）； In formula (4), The circumferential instability wavenumber; When designing the dimensions of the cabin structure, the general method of optimization design is adopted to adjust the values ​​of design variables: shell thickness, rib spacing and rib size. At the same time, the constraints of design variables and state variables, namely maximum stress and critical stress, are satisfied. That is, the maximum stress and critical stress meet the requirements of material strength and structural stability, so that the objective function is optimal. Then, the weight of the cabin structure of each scheme is compared to obtain the optimal cabin structure design scheme that meets the conditions. (2) Design of the buoy acoustic section: The buoy acoustic section is located at the head of the main structural unit of the platform and includes an antenna compartment, a vector hydrophone, a fairing, and a through-compartment. The acoustic section is equipped with an integrated antenna, which communicates and is powered via a watertight cable. The upper cover of the main structural unit of the platform adopts a flat cover design to install the vector hydrophone and is designed with antenna, tuning, hydrophone, and tensioning holes. The buoy antenna compartment adopts a low-resistance streamlined shape to reduce water entry impact and adopts a double radial seal to ensure the reliability of the seal. (3) Design of buoy load-bearing components: To prevent the buoy from being damaged by the impact of the buoy cloth when it is put into the water, tie rods and tension beams are designed inside the buoy shell. The tie rods and tension beams tighten the two ends of the shell, providing prestress to the shell, thereby improving the strength of the buoy shell and preventing the buoyancy drive unit of the platform inside the shell from being directly stressed. (4) Underwater transport scheme design: To enable underwater deployment and transport of the buoy, the buoy is designed with a front guide and a rear guide. Both the front and rear guides are made of 6061 aluminum alloy. A front fixing ring and a rear fixing ring are fixedly fitted on the front and rear sides of the outer surface of the buoy shell, respectively. The outer surfaces of the front and rear fixing rings are evenly provided with several grooves. The front guide is installed in one groove of the front fixing ring, and the front fixing block is installed in the remaining grooves. The rear guide is installed in one groove of the rear fixing ring, and the rear fixing block is installed in the remaining grooves. The front fixing block is used to install the head protective cover of the buoy shell, and together with the rear fixing block, it is used to install the middle section protective cover of the buoy shell. The front and rear guides are used to connect to the underwater launch platform. (5) Airdrop plan design: The buoy airdrop component is a buoy parachute, which adopts a circular parachute design. Since the parachute is an important tool for completing the airdrop mission, the buoy needs to take into account the parachute performance in terms of weight, volume, opening force, landing speed, and drag coefficient, and meet the design requirements of parachute shape and stability. Safety calculations, including pressure resistance and fatigue strength checks, are used to ensure that the parachute can meet the needs of the airdrop mission. To ensure the buoy functions properly after entering the water, it is equipped with a parachute separation mechanism. The buoy shell is connected to the buoy parachute via this mechanism. The parachute separation mechanism includes: an inertial sleeve with a stepped cross-section, through which a separation sleeve passes. The first end of the separation sleeve is located outside the small-diameter section of the inertial sleeve, and the second end passes through the inner hole of the inertial sleeve and is screwed with a limit nut. The first end of the separation sleeve is folded outward to form an annular end cap. An inertial spring is fitted over the small-diameter section, with one end abutting against the inner surface of the annular end cap and the other end abutting against the outer surface of the large-diameter section of the inertial sleeve facing the annular end cap. The first end of the separation sleeve is used to connect to the buoy connector, which is located on the outer surface of the buoy shell. The buoy connector includes a connecting rod and a limiting block fixedly disposed on the outer surface of the connecting rod. One end of the connecting rod is inserted into the first end of the separating sleeve. The limiting block abuts against the outer surface of the first end of the separating sleeve. The outer surface of the connecting rod located inside the first end of the separating sleeve has an annular groove. Multiple through holes are evenly distributed on the outer wall of the separating sleeve opposite to the annular groove. A stop steel column is disposed in the through hole. The first end of the inertia sleeve is folded inward to form a limiting ring. In the initial state, the inner surface of the limiting ring abuts against the outer port of the through hole and constrains the stop steel column to engage with the annular groove to prevent the buoy connector from disengaging from the separating sleeve. A stop nut is fixedly connected to the end of the separating sleeve away from the buoy connector. A separation spring is disposed between the opposite ends of the connecting rod and the stop nut. At the moment the buoy shell enters the water, the inertia sleeve, under the action of inertia, overcomes the elastic force of the inertia spring and moves towards the front end, approaching the annular end cap. The stop steel column, driven by the connecting rod, moves towards the rear end of the inertia sleeve and breaks free from the constraint of the limiting ring. Due to the compression of the rod body outside the annular groove of the connecting rod, the stop steel column moves outward through the through hole to the separation sleeve, the separation spring is compressed and deformed, and then the buoy connector is ejected from the parachute separation mechanism by the reset of the separation spring. To avoid malfunction, a positioning hole penetrating the inner surface of the separation sleeve is provided on the outer surface of the inertia sleeve. A safety pin is provided in the positioning hole to limit the relative movement of the inertia sleeve and the separation sleeve. To facilitate connection with the buoy parachute, a parachute threaded hole is provided on the outer surface of the inertia sleeve.

2. The design method for a miniaturized multi-profile underwater acoustic buoy as described in claim 1, characterized in that: The specific steps of step S2 are as follows: The buoyancy drive unit is used to adjust the buoyancy of the buoy. It achieves the buoy's ascent and descent by changing the buoy's volume. It mainly includes a hydraulic pump, a geared motor, an oil tank, an electromagnetic reversing valve, an oil bladder, a valve body, pipelines, a pressure sensor, a level sensor, and various connecting parts. The oil bladder is connected to the outside of the buoy shell, and the oil tank is connected to the buoy shell. A level sensor is installed inside the oil tank. The hydraulic pump is a bidirectional pump and is connected to the geared motor. The oil tank is connected to the oil bladder through the hydraulic pump. A pressure sensor is also installed on the pipeline between the bidirectional hydraulic pump and the oil bladder. When the buoy is powered on, the hydraulic pump, driven by the control unit, fills the oil bladder with hydraulic oil from the tank through the hydraulic valve. The oil level in the tank drops to a specified height and then stops, at which point the buoy is in its maximum positive buoyancy state. When the buoy needs to submerge, the motor drives the hydraulic pump to reverse and pump oil back from the oil bladder to the tank, reducing the buoy's volume and causing it to submerge. By controlling the amount of oil pumped, the buoy's sinking speed and final buoyancy depth can be changed. When the buoy needs to rise, the hydraulic pump fills the oil bladder with oil, increasing the buoy's volume, causing it to rise and surface for communication.

3. The design method for a miniaturized multi-profile underwater acoustic buoy as described in claim 2, characterized in that: The specific steps of step S3 are as follows: ① Power off circuits that are not in use temporarily; ② Optimize the control strategy to reduce the total power consumption of the motor, that is, to reasonably select the pressure data sampling frequency, so as to achieve a reasonable configuration of the number of motor adjustments and the time of each adjustment operation, thereby reducing power consumption; ③ Implement reasonable power management. Based on the characteristics of the batteries, divide them into several groups and use them in a reasonable combination to ensure power supply capacity and extend battery life.

4. The design method for a miniaturized multi-profile underwater acoustic buoy as described in claim 3, characterized in that: The specific steps of S4 are as follows: The buoyancy adjustment is used to calculate whether the buoy can dive to a set depth and rise in a specific sea area. Factors affecting the buoyancy include: seawater density, hull compression, external structure compression, hydraulic oil compression, and buoy speed. The formula for calculating the forces acting on a buoy in water is: （5）； In formula (5), The net force acting on the buoy, For the total mass of the buoy, The density of seawater, To fix the drainage volume of the buoy, The volume of water drained due to the change in the volume of the oil bladder. The coefficient of viscous drag. This is the pressure drag coefficient; The adjustment of the oil bladder is divided into two parts: one part is zero buoyancy adjustment, and the volume change is... The other part is non-zero buoyancy adjustment, with a volume change of... Then formula (5) becomes: （6）； In formula (6), We can obtain: （7）； The density of seawater varies from 1.022 to 1.032 g / cm³. 3 The total displacement volume of the buoy is 30L, so the required change in oil bladder volume is 350mL. Non-zero buoyancy adjustment is to adjust the movement of the buoy, and according to formulas (6) and (5), we get: （8）； The buoy automatically controls its depth; its underwater motion equation is as follows: （9）； The underwater motion of a buoy is a combination of countless variable acceleration motions. By iterating through the depth of the buoy's underwater motion, the velocity of the buoy when it finally moves at a constant speed in a certain density layer is calculated. The displacement of each variable acceleration motion combination is accumulated to obtain the buoy's depth value. The solution for the buoy's underwater motion velocity is: （10）； The acceleration solution is: （11）； The displacement solution is: （12）； Formula (12): (13); , Let be the density of seawater at depth t. Let t be the volume of the buoy at time t.

5. The design method for a miniaturized multi-profile underwater acoustic buoy as described in claim 4, characterized in that: Step S5 is as follows: The buoy acoustic detection system's vector hydrophone has both a sound pressure channel and three vector channels. The sound pressure channel uses a radially polarized piezoelectric ceramic tube, while the vector channels use a triaxial piezoelectric accelerometer. Both the sound pressure channel and the vector channels employ modular shielding and encapsulation technology to achieve a low-noise design.

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