A kind of cast-off type seabed sediment acoustic property in-situ measuring instrument

Abstract

The application provides a kind of cast-off seabed sediment acoustic property in-situ measuring instrument, belongs to geophysical prospecting equipment technical field, by cast-off part and floating part two parts composition.Casting-off part includes acoustic probe, counterweight and fuse separation mechanism, realize the sinking and contact seabed of instrument;Floating part includes battery cabin, fuse cabin, electronic cabin and buoyancy module, for control, data acquisition and floating.Acoustic probe is installed with receiving transducer, counterweight provides the gravity required for sinking, fuse separation mechanism realizes the separation of cast-off part and floating part.Battery cabin provides power, fuse cabin has fuse, electronic cabin includes electronic devices, underwater wet plug connector and the like.Buoyancy module controls the sinking posture and data transmission in the process of floating of instrument through tail wing and antenna.The measuring instrument solves the problems that existing cast-off measuring instrument cannot measure seabed sediment acoustic property, sinking process is unstable and floating separation is unreliable.

Description

Technical Field

[0001] This invention belongs to the technical field of geophysical exploration equipment, and specifically relates to an in-situ measuring instrument for the acoustic properties of seabed sediments that can be discarded. Background Technology

[0002] Seafloor sediments are an important subject of marine environmental research, and their acoustic properties are significant for seafloor mapping and oil exploration. Currently, the main methods for obtaining the acoustic properties of seafloor sediments are direct sampling analysis and inversion acoustic wave methods. The former requires seafloor sampling equipment and laboratory analysis, making it complex and time-consuming; the latter uses underwater acoustic detection to invert sound wave reflection and attenuation information, but requires a large number of known parameters and has relatively low accuracy. Therefore, developing a simple and effective in-situ measurement method for the acoustic properties of seafloor sediments is of significant research value.

[0003] With the development of technologies such as unmanned underwater vehicles (AUVs) and underwater acoustic detection, drop-based acoustic measurement methods have attracted widespread attention. This method involves deploying autonomously sinking measuring instruments, which then autonomously complete measurements on the seabed and surface to retrieve the data, avoiding complex seabed sampling and deployment operations and greatly improving work efficiency. However, existing drop-based measuring instruments have some problems: 1) They can only be used to measure the physical properties of seawater layers and cannot measure the acoustic properties of seabed sediments; 2) The sinking process is unstable and prone to deviating from the ideal trajectory; 3) The surfacing separation is unreliable, posing a risk of data loss. Therefore, it is necessary to propose new technical solutions to address these problems. Summary of the Invention

[0004] In view of this, the present invention provides a drop-type in-situ measuring instrument for acoustic properties of seabed sediments, which can solve the problems of existing drop-type measuring instruments that cannot measure the acoustic properties of seabed sediments, are unstable during the sinking process, and are unreliable during the surfacing separation.

[0005] This invention is implemented as follows:

[0006] The first aspect of the present invention provides a drop-out in-situ measuring instrument for the acoustic properties of seabed sediments, comprising: an acoustic probe, a counterweight, a fusible separation mechanism, a battery compartment, a fusible compartment, an electronic compartment, and a buoyancy module; the acoustic probe, counterweight, and fusible separation mechanism are the drop-out parts, and the battery compartment, fusible compartment, electronic compartment, and buoyancy module are the floating parts; the acoustic probe is installed at the lower end of the instrument and has two spaced-apart receiving transducers installed on it; the counterweight is a single piece of material used to provide the gravity required for the drop-out in-situ measuring instrument for the acoustic properties of seabed sediments to sink; the fusible separation mechanism is a spring-driven three-bar linkage consisting of a top rod, a connecting rod, and a latch, wherein the movement of the internal top rod driven by the spring drives the connecting rod and the latch to lock and unlock; the battery compartment, the counterweight, the fusible separation mechanism, the battery compartment ... The fuse compartment, electronics compartment, and buoyancy module are installed sequentially and fixedly connected to each other in the order described above. The battery compartment is located below and is connected to the fuse separation mechanism, but not fixedly connected to it. The battery compartment houses the batteries that provide power. The fuse compartment works in conjunction with the fuse separation mechanism to lock and unlock the latches in the mechanism, and it contains a fuse. The electronics compartment houses electronic devices, an underwater wet-plug connector, and an electric push rod. The two ports of the underwater wet-plug connector are respectively installed on the top rod of the fuse separation mechanism and the electric push rod. The connection and disconnection of the underwater wet-plug connector are achieved by the action of the electric push rod. The buoyancy module provides the buoyancy required for the battery compartment, fuse compartment, and electronics compartment to float. Its structure is designed with a tail fin for adjusting the descent attitude and an antenna for transmitting data.

[0007] The working principle of this invention is as follows: The measuring instrument is directly deployed from a mobile platform (such as a research vessel) into the seawater. Relying on its own weight, and with the help of its own shape, center of gravity, and tail fin control, the measuring instrument achieves rapid and stable vertical descent. After sinking to the seabed, the measuring instrument penetrates the sediment using its own kinetic energy and autonomously performs in-situ sediment measurements via the transmitting transducer on the tail fin and the receiving transducer on the acoustic probe, storing the results in the electronic compartment. After the measurement is completed, the fuse in the fuse compartment is melted, and the fuse separation mechanism releases the floating part. At the same time, the electric push rod in the electronic compartment disconnects the underwater wet-plug connector, and the floating part rises to the sea surface under its own buoyancy. The measurement data is then retrieved via the antenna on the buoyancy module.

[0008] Based on the above technical solution, the in-situ measurement instrument for the acoustic properties of discarded seabed sediments of the present invention can be further improved as follows:

[0009] The acoustic probe is a rod-shaped structure with a conical tip at one end. Two annular underwater acoustic receiver transducers are installed on the outer wall at a certain distance apart. The acoustic probe and the counterweight are fixedly connected to each other.

[0010] Furthermore, the counterweight is a frustum structure with a trapezoidal longitudinal section, including a short side and a long side. The short side corresponds to the section with a smaller diameter of the frustum structure, and the long side corresponds to the section with a larger diameter of the frustum structure. The acoustic probe is installed on the section with a smaller diameter, and the fusion separation mechanism is installed on the end with a larger diameter. The counterweight has through holes along the axis for routing the receiving transducer wiring.

[0011] Furthermore, the fuse separation mechanism includes a top rod, a latch, a connecting rod, a spring, and a fuse separation base. The top rod, latch, and connecting rod are all hinged by pins and fixed to the fuse separation base. A through hole is opened at the top of the top rod for the fuse wire to pass through. The mechanism controls the locking and unlocking of the latch by the up and down movement of the top rod and the drive of the connecting rod. A spring is installed at the bottom of the top rod in the center of the fuse separation base. When locked, the top rod drives the latch to swing inward into the instrument and lock onto the latch on the wall of the fuse compartment, locking the counterweight to the battery compartment and the electronic compartment, while compressing the bottom spring.

[0012] Furthermore, the battery compartment is a cylindrical sealed pressure-resistant structure with an axial through hole at the center. It is installed at the upper end of the fuse separation mechanism but is not fixed to the fuse separation mechanism. It is used to separate from the fuse separation mechanism under the action of external force. The purpose of the through hole in the center of the battery compartment is to leave space for the top rod and wires in the fuse separation mechanism. The battery compartment is sealed with a battery, which is responsible for providing power to the entire instrument.

[0013] Furthermore, the fuse compartment is an open structure for free seawater inflow. The fuse compartment is fixedly connected to the battery compartment. The bottom center of the fuse compartment has an opening with the same diameter as the battery compartment for the wires and the push rod of the fuse separation mechanism to pass through. There are four axially evenly distributed latches on the wall of the fuse compartment. When the latches of the fuse separation mechanism are locked, they can be locked onto their respective latches. The fuse compartment is fixedly connected to the battery compartment and the electronics compartment. Two symmetrically distributed fuses are installed inside the fuse compartment. The fuse wires are installed on the fuses and can pass through the hole at the upper end of the push rod when the push rod in the fuse separation mechanism compresses the spring, thus counteracting the spring force and preventing the push rod from moving upward.

[0014] Furthermore, the electronic compartment is a cylindrical pressure-resistant sealed structure, housing a control module and a data communication module, which are fixedly connected to the fuse compartment. Additionally, an electric push rod is installed inside the electronic compartment. The telescopic rod of the electric push rod, after being sealed, extends from below the electronic compartment and into the fuse compartment. Underwater wet-plug connectors are installed on the telescopic rod of the electric push rod and the top rod of the fuse separation mechanism, respectively. Initially, the electric push rod is in the extended state. After the in-situ measurement of the acoustic characteristics of the ejected seabed sediment is completed, the telescopic rod of the electric push rod is retracted, driving the underwater wet-plug connector, thereby achieving the separation of the wiring between the surfacing and ejected sections.

[0015] Furthermore, in addition to providing the buoyancy required for the ascending part, the buoyancy module also has four tail fins evenly distributed around its circumference, which are responsible for controlling the attitude of the in-situ measurement instrument for the acoustic properties of the seabed sediment during its descent. Transmitting transducers are installed below two of the fins, and an antenna for communication is installed at the top of the buoyancy module. The buoyancy module is fixed to the electronic cabin.

[0016] Furthermore, the installation sequence of the acoustic probe, counterweight, fuse separation mechanism, battery compartment, and fuse compartment is as follows: First, complete the mutual assembly of the acoustic probe, counterweight, and fuse separation mechanism, and assemble the internal linkage mechanism of the fuse separation mechanism. Then, fix the battery compartment and fuse compartment together. Next, pass the top rod of the fuse separation mechanism and related wiring through the central through hole of the battery compartment and fuse compartment. The battery compartment fits onto the fuse separation base through the stepped structure at the bottom, making it less prone to shaking, but still able to move upward along the axial direction. At the same time, the spring is compressed, so that the buckle is tightly fastened to the latch on the wall of the fuse compartment, realizing the locking of the counterweight with the battery compartment and fuse compartment. Meanwhile, the through hole at the top of the top rod can be aligned with the wire hole of the fuse. At this time, the fuse wire is inserted so that it can counteract the force of the spring. In this way, the locking and unlocking of the fuse separation mechanism can be achieved by controlling the melting of the fuse wire.

[0017] Furthermore, the structural parameters of the measuring instrument satisfy the following multi-objective optimization model: with the objectives of maximizing measurement accuracy, optimizing sinking stability, maximizing buoyancy reliability, and minimizing system weight; by solving the multi-objective optimization model, the optimized structural parameters of the measuring instrument can be obtained.

[0018] Compared with existing technologies, the advantages of the in-situ measurement instrument for the acoustic properties of discarded seabed sediments provided by this invention are:

[0019] 1. The sinking process is more stable. The invention employs an optimized counterweight structure and buoyancy module design, enabling precise control of the sinking attitude and speed. The counterweight has a trapezoidal frustum structure, taking into account factors such as center of gravity position, hydrodynamic performance, and structural strength; the four tail fins on the buoyancy module can actively adjust the attitude to ensure that the instrument penetrates the seabed vertically.

[0020] 2. More reliable separation upon buoyancy. The invention employs a fuse-based separation mechanism to reliably separate the buoyancy section from the ejection section. This mechanism, through a spring-driven three-bar linkage, securely locks the counterweight and releases it quickly upon fuse activation, ensuring stability during the buoyancy process.

[0021] 3. Drop-off Seabed Sediment Measurement. The invention employs a design concept combining a drop-off section and a floating section, enabling unmanned, autonomous, in-situ drop-off measurement of seabed sediments. The drop-off section has an overall conical structure, allowing it to effectively penetrate the sediment; the floating section is locked and separated from the drop-off section via a fusion separation mechanism, enabling the upward transmission of measurement data.

[0022] This solves the problems of existing drop-and-release measuring instruments, such as inability to measure the acoustic properties of seabed sediments, instability during the sinking process, and unreliable separation upon surfacing. Attached Figure Description

[0023] Figure 1 A schematic diagram of the overall structure of an in-situ instrument for measuring the acoustic properties of discarded seabed sediments;

[0024] Figure 2 A schematic diagram of the cross-sectional structure of an in-situ instrument for measuring the acoustic properties of discarded seabed sediments;

[0025] Figure 3a A schematic diagram of the locking state of the fuse separation mechanism of the in-situ measuring instrument for the acoustic properties of discarded seabed sediments.

[0026] Figure 3b A schematic diagram of the detachment mechanism of a discard-type in-situ acoustic property measuring instrument for seabed sediments in the released state.

[0027] Figure 4a A schematic diagram of the detachment mechanism for an in-situ measuring instrument for the acoustic properties of discarded seabed sediments;

[0028] Figure 4b A schematic diagram of the detachment principle of the detachment mechanism of the in-situ measurement instrument for the acoustic properties of discarded seabed sediments;

[0029] Figure 5 A schematic diagram illustrating the signal propagation principle of an in-situ measuring instrument for the acoustic properties of discarded seabed sediments.

[0030] Figure 6 A schematic diagram illustrating the structural separation principle of an in-situ acoustic property measurement instrument for discarded seabed sediments.

[0031] In the diagram: 1. Acoustic probe, 11. Receiving transducer, 2. Counterweight, 3. Fuse separation mechanism, 31. Top rod, 32. Buckle, 33. Connecting rod, 34. Spring, 35. Fuse separation base, 4. Battery compartment, 41. Battery, 5. Fuse compartment, 51. Fuse, 52. Fuse wire, 6. Electronic compartment, 61. Electric push rod, 62. Underwater wet-plug connector, 7. Buoyancy module, 71. Transmitting transducer, 72. Antenna. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0033] like Figures 1 to 6As shown, the in-situ measurement instrument for the acoustic properties of seabed sediments, which can be discarded, includes: an acoustic probe 1, a counterweight 2, a fusible separation mechanism 3, a battery compartment 4, a fusible compartment 5, an electronics compartment 6, and a buoyancy module 7. The acoustic probe 1, counterweight 2, and fusible separation mechanism 3 are the discarded parts and will not be retrieved after measurement; the battery compartment, fusible compartment, electronics compartment, and buoyancy module are the floating parts. The acoustic probe 1 is a rod-shaped structure with a conical tip at one end. Two annular underwater acoustic receiving transducers 11, spaced a certain distance apart, are installed on its outer wall. The acoustic probe 1 and the counterweight 2 are fixedly connected to each other. The counterweight 2 is a frustum structure. The acoustic probe 1 is installed on the section with the smaller diameter, and the fusible separation mechanism 3 is installed on the section with the larger diameter. Its function is only to provide necessary buoyancy and adjust the center of gravity. The counterweight 2 has through holes along its axis for routing cables to the receiving transducers 11. The fuse separation mechanism 3 is a three-bar linkage consisting of a top rod 31, a latch 32, a connecting rod 33, a spring 34, and a fuse separation base 35. The top rod 31, latch 32, and connecting rod 33 are all hinged by pins and fixed to the fuse separation base 35. The top rod 31 has a through hole at its top for the fuse wire 52 to pass through. The mechanism controls the locking and unlocking of the latch 32 by the up and down movement of the top rod 31, driven by the connecting rod 33. At the bottom of the top rod 31, there is a spring 34 installed at the center of the fuse separation base 35. When the installation is locked, that is, when the top rod 31 moves down, the top rod 31 drives the latch 32 to swing inward into the instrument and lock onto the latch on the wall of the fuse compartment 5, locking the counterweight 2 to the battery compartment 4 and the electronic compartment 6. At the same time, the bottom spring 34 is in a compressed state. When the fuse wire 52 has not yet melted, the force of the spring 34 is offset, so that the top rod cannot move upward. After the measurement is completed, the control system energizes the fuse 51, melting the fuse wire 52. The push rod 31 moves upward under the action of the spring 34, releasing the latch 32 and causing the floating part to detach from the bottom acoustic probe 1 and counterweight 2 under the action of the spring force. The battery compartment 4 is a cylindrical sealed pressure-resistant structure with an axial through hole in the center. It is installed at the upper end of the fuse separation mechanism 3, but is not fixed to the fuse separation mechanism 3. It can be separated from the fuse separation mechanism 3 under the action of external force. The purpose of the through hole in the center of the battery compartment 4 is to leave space for the push rod 31 and wires in the fuse separation mechanism 3. The battery compartment 4 is sealed with a battery 41, which is responsible for providing power to the entire instrument.The fuse compartment 5 is an open structure that allows seawater to flow in freely. The fuse compartment 5 is fixedly connected to the battery compartment 4. The bottom center of the fuse compartment 5 has an opening with the same diameter as the battery compartment 4, for the wires and the push rod 31 of the fuse separation mechanism 3 to pass through. There are four axially evenly distributed latches on the wall of the fuse compartment 5. When the latches 32 of the fuse separation mechanism 3 are locked, they can be locked onto their respective latches. The fuse compartment 5 is fixedly connected to the battery compartment 4 and the electronics compartment 6. Two symmetrically distributed fuses 51 are installed inside the fuse compartment 5. The fuse wire 52 is installed in the fuse 51 and can pass through the hole at the upper end of the push rod 31 when the push rod 31 in the fuse separation mechanism 3 compresses the spring 34, thus counteracting the force of the spring 34 and preventing the push rod 31 from moving upward. The electronic compartment 6 is a cylindrical pressure-resistant sealed structure, which houses the necessary control modules and data communication modules and is fixedly connected to the fuse compartment 5. In addition, the electronic compartment 6 is also equipped with an electric push rod 61. The telescopic rod of the electric push rod 61 is sealed and extends from the bottom of the electronic compartment into the fuse compartment 5. The telescopic rod of the electric push rod 61 and the top rod 31 of the fuse separation mechanism 3 are respectively equipped with underwater wet-plug connectors 62. The electric push rod 61 is initially in the extended state. After the in-situ measurement of the acoustic characteristics of the ejected seabed sediment is completed, the telescopic rod of the electric push rod 61 is retracted to drive the underwater wet-plug connectors 62, thereby realizing the separation of the wiring between the floating part and the ejected part. The buoyancy module 7 is responsible for providing the buoyancy required for the floating part of the structure. At the same time, the buoyancy module 7 also has four wing-shaped structures evenly distributed around the circumference, which are responsible for controlling the attitude of the in-situ measurement instrument of acoustic characteristics of the seabed sediment during sinking. Transmitting transducers 71 are installed below the two wings, and an antenna 72 for communication is installed on the upper end of the buoyancy module 7. The buoyancy module 7 also needs to be fixed to the electronic compartment 6.

[0034] Because the fuse separation mechanism 3 of the present invention requires sufficient space during installation, the acoustic probe 1, counterweight 2, fuse separation mechanism 3, battery compartment 4 and fuse compartment 5 must be installed first, and sufficient wire length must be reserved. Only after these five parts are fully installed can the electronic compartment 6 and buoyancy module 7 be loaded onto the fuse compartment 5. Specifically, after assembling the acoustic probe 1, counterweight 2, and fuse separation mechanism 3, and completing the assembly of the linkage mechanism inside the fuse separation mechanism, first fix the battery compartment 4 and the fuse compartment 5 together. Then, pass the top rod 31 of the fuse separation mechanism 3 and related wiring through the central through hole of the battery compartment 4 and the fuse compartment 5. The battery compartment 4 fits onto the fuse separation base 35 through the stepped structure at the bottom, making it less prone to shaking, but still allowing it to move upward axially. At the same time, the spring 34 is compressed, causing the buckle 32 to lock tightly onto the latch on the wall of the fuse compartment 5, thus locking the counterweight 2 to the battery compartment 4 and the fuse compartment 5. Meanwhile, the through hole at the top of the top rod 31 can be aligned (or close to) with the wire hole of the fuse 51. At this time, the fuse wire 52 is inserted, which can counteract the force of the spring 34. In this way, the locking and unlocking of the fuse separation mechanism 3 can be achieved by controlling the melting of the fuse wire 52. After that, normal assembly is sufficient.

[0035] The structural parameters of the measuring instrument satisfy the following multi-objective optimization model: maximizing measurement accuracy, optimizing sinking stability, maximizing buoyancy reliability, and minimizing system weight; solving the multi-objective optimization model yields the optimized structural parameters of the measuring instrument; specifically, the structural parameters include the distance L between the transmitting and receiving transducers, and the counterweight mass. Buoyancy of the rising part , Counterweight frustum structure taper angle wing-shaped structure spanwise length Total system length Battery compartment volume System power consumption Measurement time Spring preload Locking force Acoustic probe cone tip angle Center of gravity position The wall thickness of each sealed compartment Contact area between buckle and bayonet .

[0036] The multi-objective optimization model is specifically represented as follows:

[0037] Objective function 1 - Maximize measurement accuracy:

[0038] ;

[0039] In the formula, For the first Theoretical values ​​for each measuring point; These are measured values; The tilt angle of the acoustic probe; To reduce interference with the received transducer signal; The weighting coefficient has a range of values. ; The number of measurement points;

[0040] Objective function 2 - optimal sinking stability:

[0041] ;

[0042] In the formula, The angular velocities are the horizontal and vertical angular velocities; Vertical velocity; The attitude angle; The weighting coefficient has a range of values. ; The sinking time;

[0043] Objective function 3 - Maximizes the reliability of upward movement:

[0044] ;

[0045] In the formula, The probability of successful separation; Failure rate; For runtime;

[0046] Objective function 4 - Minimize system weight:

[0047] ;

[0048] In the formula, For the first The density of each component; For the corresponding volume; Total number of components;

[0049] The constraints must include at least:

[0050] 1. The distance L between the transmitting transducer and the receiving transducer is greater than 3 to 4 acoustic wavelengths;

[0051] 2. Buoyancy ratio constraint: ;

[0052] 3. Dynamic stability constraints: ;

[0053] In the formula, The damping coefficient; Allowable error;

[0054] 4. Structural strength constraints: In the formula, The maximum stress; Allowable stress;

[0055] The solution method for the multi-objective optimization model adopts the improved NSGA-III algorithm, and the specific solution steps are as follows:

[0056] Step 1: Initial population generation:

[0057] ;

[0058] In the formula, For the first Each individual represents a set of structural parameters; Population size;

[0059] Step 2: Fitness Calculation

[0060] ;

[0061] In the formula, For the first The weights of each objective; The objective function value;

[0062] Step 3: Non-dominated sorting:

[0063] ;

[0064] In the formula, For indicator functions; express Dominate ;

[0065] Step 4: Crowding Calculation:

[0066] ;

[0067] Step 5: Select Operation:

[0068] ;

[0069] In the formula, For offspring population; For selection operators based on non-dominated sorting;

[0070] Step 6: Cross operation:

[0071] ;

[0072] In the formula, The cross coefficient follows the rules. Uniform distribution;

[0073] Step 7: Mutation operation:

[0074] ;

[0075] In the formula, These are normally distributed random numbers.

[0076] Step 8: Termination Judgment:

[0077] The computation stops when the number of iterations reaches its maximum value or the population converges, and the Pareto optimal solution set is output.

[0078] Parameter acquisition method:

[0079] 1. Obtained through finite element simulation:

[0080] ;

[0081] In the formula, For acoustic field potential; Wave number;

[0082] 2. The results were obtained through water tank testing.

[0083] Experimental steps: (1) Deploy a photoelectric tracking system in the water tank; (2) Install reflective markers on the measuring instrument; (3) Deploy the measuring instrument and record the motion trajectory; (4) Obtain the angular velocity time history through data processing;

[0084] 3. Obtained through reliability testing:

[0085] Experimental steps: (1) Conduct (2) Record the number of successful separation tests; (3) Calculation ;

[0086] 4. The results were obtained through stress analysis:

[0087] ;

[0088] In the formula, Radial stress; For circumferential stress; This refers to shear stress.

[0089] Optional optimization models may also include the following constraints:

[0090] (1) The distance L between the transmitting transducer and the receiving transducer is greater than 3 to 4 acoustic wavelengths;

[0091] (2) The ratio of the mass M of the counterweight to the buoyancy F of the floating part should satisfy: 1.2≤M / F≤1.5. This constraint ensures the rationality of the sinking speed.

[0092] (3) The taper angle θ of the counterweight frustum structure should satisfy: 10°≤θ≤25°. This constraint is used to optimize the hydrodynamic performance.

[0093] (4) The ratio of the spanwise length S of the four wing-shaped structures of the buoyancy module to the total length H of the instrument should satisfy: 0.15≤S / H≤0.25. This constraint is used to ensure attitude stability.

[0094] (5) The relationship between the battery compartment volume V and the total system power consumption P and measurement time T should satisfy: V≥αPT, where α is the safety factor and 1.2≤α≤1.5;

[0095] (6) The ratio of the spring preload F1 to the locking force F2 of the fusible separation mechanism should satisfy: 2≤F1 / F2≤3. This constraint ensures the reliability of separation.

[0096] (7) The cone tip angle β of the acoustic probe should satisfy: 30°≤β≤45°. This constraint is used to optimize the soil penetration resistance.

[0097] (8) The center of gravity of the whole machine should be located at a distance d below the upper surface of the counterweight, which should satisfy: 0.2H≤d≤0.3H, where H is the total length of the instrument. This constraint ensures the stability of the sinking.

[0098] (9) The wall thickness t of each sealed compartment should satisfy: t≥kP0h / σs, where k is the safety factor and is taken as 1.5-2.0, P0 is the design water depth pressure, h is the compartment diameter, and σs is the allowable stress of the material;

[0099] (10) The contact area A between the buckle of the fuse separation mechanism and the fuse compartment buckle should satisfy: A≥βF2, where β is the surface pressure coefficient and is taken as 0.8-1.2, and F2 is the locking force.

[0100] Step S1: Initial population generation.

[0101] First, an initial population needs to be generated. This population consists of individual Composition, each individual This represents a set of structural parameters. Specifically, these parameters can be randomly generated within the feasible region using a uniform distribution method. One feasible solution is used as the initial population. .

[0102] Step S2: Fitness calculation.

[0103] For each individual Its fitness needs to be calculated. The fitness function is a weighted sum of four objective functions, namely:

[0104] ;

[0105] in, For the first The weight coefficients of each objective function. For the first The objective function in an individual The value at that location.

[0106] Step S3: Non-dominated sorting.

[0107] The population was analyzed using a non-dominated sorting method. Perform layering. Specifically, define indicator functions. ,like Dominate Its value is 1 if it is 1, otherwise it is 0. Then calculate the value for each individual. Non-dominant hierarchy .

[0108] Step S4: Crowding Calculation.

[0109] For each individual Calculate its congestion level , representing the sparseness of the individual in the target space. The formula for calculating crowding is:

[0110] ;

[0111] in, and The first The maximum and minimum values ​​of each objective function.

[0112] Step S5: Select operation.

[0113] Based on the aforementioned non-dominated ordering and crowding information, the NSGA-III algorithm's selection strategy can be used to select the current population. and offspring population Selection is made to obtain the next generation of the population. .

[0114] Step S6: Cross operation.

[0115] For the selected individual pairs New individuals can be obtained by using convex combination to perform cross operations. :

[0116] ;

[0117] in, The cross coefficient follows the rules. The uniform distribution.

[0118] Step S7: Mutation operation.

[0119] For newly generated individuals The mutation operation can be performed using Gaussian mutation to obtain the mutated individuals:

[0120] ;

[0121] in, This indicates that the expression follows a pattern with a mean of 0 and a variance of . Random numbers that follow a normal distribution.

[0122] Step S8: Terminate the judgment.

[0123] Repeat steps S2 to S7 until the number of iterations reaches the maximum value or the population converges, then output the current Pareto optimal solution set.

[0124] Parameter acquisition method:

[0125] 1. Measurement point values Acquisition:

[0126] Solving the acoustic field equations using finite element simulation Obtain, among which For acoustic field potential For wave number.

[0127] 2. Angular velocity and Acquisition:

[0128] The measurements were obtained through a water tank test. The specific steps were as follows: (1) a photoelectric tracking system was set up in the water tank; (2) reflective markers were installed on the measuring instrument; (3) the measuring instrument was deployed and the motion trajectory was recorded; (4) the angular velocity time history was obtained through data processing.

[0129] 3. Probability of successful separation Acquisition:

[0130] Obtained through reliability testing. The specific steps are: (1) Conduct (2) Record the number of successful separation tests; (3) Calculation .

[0131] 4. Maximum stress Acquisition:

[0132] Obtained through stress analysis. The calculation formula is:

[0133] ;

[0134] in, Radial stress, For circumferential stress, This is shear stress.

[0135] In addition, the following constraints may also be considered:

[0136] (1) The distance L between the transmitting transducer and the receiving transducer is greater than 3-4 acoustic wavelengths. (2) Counterweight mass With buoyancy The ratio should satisfy: .

[0137] (3) Taper angle of the counterweight frustum structure Should meet: .

[0138] (4) Span length of the buoyancy module airfoil structure Total length of the instrument The ratio should satisfy: .

[0139] (5) Battery compartment volume Should meet: ,in For safety factor and , For system power consumption, For measuring time.

[0140] (6) Spring preload of the fuse separation mechanism With locking force The ratio should satisfy: .

[0141] (7) Acoustic probe cone tip angle Should meet: .

[0142] (8) Overall center of gravity position Should meet: ,in This refers to the total length of the instrument.

[0143] (9) Wall thickness of each sealed compartment Should meet: ,in For safety factor and , To design water depth pressure, The diameter of the compartment, This represents the allowable stress of the material.

[0144] (10) The contact area between the latch of the fuse separation mechanism and the latch of the fuse compartment Should meet: ,in The surface pressure coefficient and , This refers to the locking force.

[0145] By solving this multi-objective optimization problem, the optimal size ratio of each component can be obtained, thereby achieving comprehensive optimization of measurement accuracy, sinking stability, buoyancy reliability, and system weight.

[0146] In use, after assembling the structure and ensuring the proper locking of the fusion separation mechanism 3, this invention can be directly deployed into seawater. Due to its structure and mass distribution—heavy and small at the bottom and light and large at the top—it can gradually adjust its attitude like a "roly-poly toy" during descent, stabilizing the angle between the instrument's axis and the vertical direction within a very small range. Simultaneously, the tail fin structure helps the instrument's overall attitude return to a vertical state. Therefore, after rapid descent to the seabed, it can essentially guarantee the instrument's vertical penetration. After penetration, the control system can detect instrument stability (e.g., via an accelerometer) and begin measuring sediment. After the measurement is completed, the control system supplies power to the fuse wire 52 through the fuse 51. After the fuse wire 52 melts, it can no longer resist the force of the spring 34 in the fuse separation mechanism 3. As a result, the push rod 31 moves upward under the action of the spring 34, the buckle 32 is released, and the battery compartment 4 and the module above it are separated from the fuse separation mechanism 3 and the counterweight 2 below under the action of the spring 34 and its own buoyancy. This allows the measured data to float to the sea surface and be transmitted back through the antenna 72.

[0147] Specifically, the principle of this invention is:

[0148] 1. The acoustic probe is the core component of the instrument, equipped with two spaced underwater acoustic receiving transducers. During descent, the acoustic probe is perpendicularly incident on the seabed to measure the time difference and amplitude attenuation of sound waves, thereby obtaining parameters such as sound velocity and attenuation coefficient. To optimize its penetration performance, the acoustic probe employs a special conical tip design, which minimizes penetration resistance and improves measurement accuracy.

[0149] 2. The counterweight is a key component required for the instrument's descent. To balance descent stability and structural strength, the counterweight employs a trapezoidal frustum structure, with the shorter side corresponding to the smaller diameter segment and the longer side corresponding to the larger diameter segment. This structure not only keeps the center of gravity within a reasonable range, but the tilt angle of the frustum also optimizes hydrodynamic characteristics, ensuring stability during the descent process.

[0150] 3. The fuse-operated separation mechanism is crucial for separating the buoyant and ejected sections. This mechanism consists of components such as a push rod, connecting rod, and latch, which are locked and released via springs. After measurement, the fuse activates, causing the push rod to move upwards, separating the connecting rod and latch, thus enabling the autonomous release of the buoyant section. To ensure reliable separation, the fuse-operated separation mechanism is designed with preload, locking force, and contact area in mind, guaranteeing a separation success rate of up to 98%.

[0151] 4. The battery compartment, fuse compartment, and electronics compartment constitute the core structure of the surfacing section. The battery compartment contains sealed batteries that provide power to the entire instrument; the fuse compartment contains fuses that work in conjunction with the fuse separation mechanism; and the electronics compartment houses electronic equipment such as control modules, data communication modules, and electric actuators, enabling the separation of circuits between the surfacing and ejection sections.

[0152] 5. The buoyancy module is crucial for achieving stable descent and reliable ascent. This module has four circumferentially distributed wing-like structures that actively adjust the attitude during descent, ensuring a vertical entry into the sea. A communication antenna is also installed at the top of the module for data transmission. By rationally designing the buoyancy, smooth ascent is achieved without excessive buoyancy that could affect measurement stability.

[0153] 6. The working principle of this invention is as follows: The measuring instrument of this invention is directly deployed from a mobile platform (such as a research vessel) into the seawater. Relying on its own gravity, and with the help of its own shape, center of gravity position, and tail fin control, the measuring instrument achieves rapid and stable vertical sinking. After sinking to the seabed, the measuring instrument penetrates the sediment using its own kinetic energy and autonomously performs in-situ sediment measurements through the transmitting transducer on the tail fin and the receiving transducer on the acoustic probe, storing the results in the electronic compartment. After the measurement is completed, the fuse wire is melted by the fuse in the fuse compartment, and the fuse separation mechanism releases the floating part. At the same time, the electric push rod in the electronic compartment disconnects the underwater wet plug-in connector, and the floating part rises to the sea surface under its own buoyancy. The measurement data is then recovered through the antenna on the buoyancy module.

[0154] In summary, this invention enables in-situ, drop-type measurement of the acoustic properties of seabed sediments. Through optimized design of components such as the acoustic probe, counterweight, fusion separation mechanism, and electronic chamber, it achieves improved measurement accuracy, stability during the sinking process, reliability of the surfacing separation, and reduction of the overall weight. It is a high-performance drop-type in-situ measuring instrument for the acoustic properties of seabed sediments.

[0155] The following is an example of a specific application scenario of the present invention:

[0156] The in-situ measurement instrument for the acoustic properties of seabed sediments, which can be discarded, mainly consists of an acoustic probe, a counterweight, a fusible separation mechanism, a battery compartment, a fusible compartment, an electronics compartment, and a buoyancy module. The working principle and structural design are illustrated below with a specific embodiment.

[0157] The main parameters of the measuring instrument are shown in Table 1. The diameter D of the acoustic probe is 60mm, and the distance L between the transmitting and receiving transducers is 700mm. The counterweight mass M is 6kg, and the buoyancy F of the upper part is 45N. The taper angle of the counterweight's frustum structure is... The angle is 12°. The spanwise length S of the four wing-shaped structures of the buoyancy module is 220 mm, and the total system length H is 1 m. The battery compartment volume V is 800 cm³. The system power consumption P is 100W, and the measurement time T is 5 minutes. The spring preload of the fuse separation mechanism... The locking force is 200N. The value is 500N. The angle of the conical tip of the acoustic probe is... The angle is 40°, and the center of gravity d is 0.3m. The wall thickness t of each sealed compartment is 5mm, and the contact area A between the buckle and the latch is 160mm². .

[0158] Table 1 Main parameters of the measuring instrument

[0159]

[0160] The working process of this measuring instrument is as follows:

[0161] 1. The acoustic probe is installed at the lower end of the instrument and is equipped with two underwater acoustic receiving transducers spaced 100mm apart. When penetrating the seabed sediment and starting the measurement, the acoustic signal will reach the two transducers sequentially. By measuring the propagation time difference and amplitude attenuation of the sound waves, parameters such as sound velocity and attenuation coefficient can be obtained, thereby realizing in-situ measurement of the acoustic properties of the seabed sediment.

[0162] 2. The counterweight adopts a trapezoidal frustum structure with a short side diameter of 60mm, a long side diameter of 120mm, and a height of approximately 310mm. This structure can control the center of gravity at 0.3m, which is beneficial to the stability during the sinking process. At the same time, the 12° inclination angle of the frustum surface can also optimize the hydrodynamic performance and reduce the resistance to soil penetration.

[0163] 3. The fuse separation mechanism consists of a push rod, connecting rod, and latch, and is locked to the battery compartment and fuse compartment by a 200N spring preload. After measurement, the action of two symmetrically arranged fuses causes the push rod to move upward, driving the connecting rod and latch to separate, thereby achieving the autonomous release of the buoyancy section. The locking force F of this mechanism is... With a strength of 500N, it can reliably keep the counterweight fixed.

[0164] 4. The battery compartment is sealed and has a volume of 800 cm³. The battery pack. The fuse compartment contains two fuses that work in conjunction with the fuse release mechanism. The electronics compartment houses control modules, data communication modules, and electric push rods, enabling the separation of wiring between the buoyancy and jettison sections.

[0165] 5. The buoyancy module has four 220mm long wing-shaped structures evenly distributed around its circumference, allowing for attitude adjustment during descent to ensure vertical entry into the sea. The buoyancy of the surfacing portion is 45N, forming a buoyancy ratio of 1.2-1.5 with the 6kg counterweight, achieving smooth surfacing without excessive buoyancy that could affect measurement stability. A communication antenna is installed at the top of the module for real-time transmission of measurement data.

[0166] Based on the above design, this in-situ instrument for measuring the acoustic properties of discarded seabed sediments can achieve the following performance:

[0167] 1. Measurement accuracy improved by over 20%. The acoustic probe adopts a special conical tip design, which can minimize the resistance to soil penetration. At the same time, the interval measurement method of two underwater acoustic receiving transducers greatly improves the measurement accuracy of sound velocity and attenuation coefficient.

[0168] 2. Excellent stability during descent. The trapezoidal frustum structure of the counterweight and the four tail fins of the buoyancy module can precisely control the instrument's descent attitude and speed. Pool tests show that the trajectory deviation is only 3%.

[0169] 3. High reliability of buoyancy separation. The fuse separation mechanism securely fixes the counterweight with a locking force of 500N, and can quickly release when the fuse is activated. Reliability tests show that the separation success rate reaches 98%.

[0170] 4. Significantly reduced overall weight. Through optimized design, the total weight of this measuring instrument is only about 15kg, greatly improving the ease of deployment and retrieval.

[0171] In summary, this in-situ measurement instrument for the acoustic properties of seabed sediments, through the systematic optimization design of components such as the acoustic probe, counterweight, and fusion separation mechanism, comprehensively outperforms existing technologies in key indicators such as measurement accuracy, sinking stability, surfacing reliability, and overall weight, providing a high-performance new solution for the in-situ measurement of the acoustic properties of seabed sediments.

[0172] Example 2: Optimization of Measuring Instrument Structural Parameters Based on Multi-Objective Optimization

[0173] The in-situ measurement instrument for the acoustic properties of seabed sediments, which can be discarded, involves several key structural parameters, such as the distance L between the transmitting and receiving transducers, the mass M of the counterweight, the magnitude of the buoyancy F, and the taper angle of the counterweight frustum structure. The buoyancy module wing length S, etc., are important parameters. The appropriate values ​​of these parameters significantly impact the instrument's measurement accuracy, sinking stability, surfacing reliability, and overall weight. To comprehensively optimize these performance indicators, a multi-objective optimization model was established and solved using an improved NSGA-III algorithm.

[0174] The specific expression of the multi-objective optimization model is as follows:

[0175] Objective function 1 - Maximize measurement accuracy:

[0176] ;

[0177] Objective function 2 - optimal sinking stability:

[0178] ;

[0179] Objective function 3 - Maximizes the reliability of upward movement:

[0180] ;

[0181] Objective function 4 - Minimize system weight:

[0182] ;

[0183] in, For the first The theoretical value of each measuring point These are measured values. The tilt angle of the acoustic probe. To receive transducer signal interference, and These are the weighting coefficients. The number of measurement points; and They are the horizontal and vertical angular velocities, respectively. Vertical velocity, For attitude angle, and These are the weighting coefficients. The sinking time; For the probability of successful separation, For failure rate, For runtime; For the first Density of individual components For the corresponding volume, This represents the total number of components.

[0184] The optimization solution process is as follows:

[0185] Step 1. Initial population generation. Populations are randomly generated within the feasible region of each parameter. Individuals, as the initial population .

[0186] Step 2. Fitness Calculation. Based on the aforementioned objective function formula, calculate the fitness for each individual. fitness .

[0187] Step 3. Non-dominated sorting. The non-dominated sorting strategy of the NSGA-III algorithm is used to calculate the non-dominated level of each individual. .

[0188] Step 4. Crowding Calculation. Calculate the crowding degree for each individual based on the sparsity of the target space. .

[0189] Step 5. Selection Operation. Based on non-dominated sorting and crowding information, the NSGA-III algorithm's selection strategy is adopted to select from... and Selecting to generate the next generation population .

[0190] Step 6. Cross-operation. For the selected individuals... New individuals are obtained by using convex combination to perform crossover. .

[0191] Step 7. Mutation operation. For the newly generated individuals... Gaussian mutation is used to obtain new individuals after mutation. .

[0192] Step 8. Termination judgment. Repeat steps 2-7 until the number of iterations reaches the maximum value or the population converges, then output the Pareto optimal solution set.

[0193] By solving the multi-objective optimization model, the optimal values ​​of each structural parameter of the measuring instrument were obtained, as shown in Table 2. Among them, the distance L between the transmitting and receiving transducers is 700 mm, and the counterweight mass... It weighs 6 kg and has a buoyancy of 6 kg. The counterweight is 45N, with a cone angle of truncated cone. The angle is 12°, and the buoyancy module wingspan is [missing information]. The total length of the system is 220mm. The battery compartment volume is 1m. 800cm System power consumption 100W, measurement time For 5 minutes, spring preload The locking force is 200N. 500N, probe tip angle The angle is 40°, and the center of gravity is located at... The thickness is 0.36m, and the cabin wall thickness is... The contact area of ​​the buckle is 5mm. 160mm .

[0194] Table 2 Optimized Measuring Instrument Structure Parameters

[0195]

[0196] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. An in-situ measurement instrument for the acoustic properties of discarded seabed sediments, comprising: The instrument comprises an acoustic probe, a counterweight, a fuse separation mechanism, a battery compartment, a fuse compartment, an electronics compartment, and a buoyancy module. The acoustic probe, counterweight, and fuse separation mechanism are the ejection components, while the battery compartment, fuse compartment, electronics compartment, and buoyancy module are the buoyancy components. The acoustic probe is mounted at the lower end of the instrument and has two spaced-apart receiving transducers. The counterweight is a single piece of material used to provide the gravity required for the ejection-type in-situ acoustic characteristic measurement instrument of seabed sediments to sink. The fuse separation mechanism is a spring-driven three-bar linkage consisting of a push rod, a connecting rod, and a latch. The spring drives the movement of the internal push rod. The movement drives the connecting rod and latch to lock and release; the battery compartment, fuse compartment, electronic compartment, and buoyancy module are installed sequentially and fixedly connected to each other, with the battery compartment located below and connected to the fuse separation mechanism, but not fixedly connected to it; the battery compartment houses the battery that provides power; the fuse compartment works in conjunction with the fuse separation mechanism to lock and release the latches in the fuse separation mechanism, and a fuse is installed inside; the electronic compartment houses electronic devices, an underwater wet-plug connector, and an electric push rod, with the two ports of the underwater wet-plug connector respectively installed on the top rod and the electric push rod of the fuse separation mechanism. The underwater wet-plug connector is disconnected via the movement of an electric push rod. The buoyancy module provides the buoyancy required for the battery compartment, fuse compartment, and electronics compartment to rise to the surface. Its structure includes a tail fin for adjusting descent attitude and an antenna for transmitting data. The fuse separation mechanism includes a push rod, a latch, a connecting rod, a spring, and a fuse separation base. The push rod, latch, and connecting rod are all hinged by pins and fixed to the fuse separation base. A through hole is opened at the top of the push rod for the fuse wire to pass through. This mechanism controls the locking and unlocking of the latch by the up-and-down movement of the push rod, driven by the connecting rod. A [missing information - likely a design element] is located at the bottom of the push rod. The spring installed at the center of the fuse separation base, when locked in place, causes the top rod to swing the latch inwards and lock it onto the latch on the fuse compartment wall, thus locking the counterweight to the battery compartment and electronics compartment, while simultaneously compressing the bottom spring. The structural parameters of the measuring instrument satisfy the following multi-objective optimization model: maximizing measurement accuracy, optimizing sinking stability, maximizing buoyancy reliability, and minimizing system weight. Solving the multi-objective optimization model yields the optimized structural parameters of the measuring instrument. Specifically, the structural parameters include the distance L between the transmitting and receiving transducers, the counterweight mass, and the... Buoyancy of the rising part , Counterweight frustum structure taper angle wing-shaped structure spanwise length Total system length Battery compartment volume System power consumption Measurement time Spring preload Locking force Acoustic probe cone tip angle Center of gravity position The wall thickness of each sealed compartment Contact area between buckle and bayonet ; The multi-objective optimization model is specifically represented as follows: Objective function 1 - Maximize measurement accuracy: ; In the formula, For the first Theoretical values ​​for each measuring point; These are measured values; The tilt angle of the acoustic probe; To reduce interference with the received transducer signal; The weighting coefficient has a range of values. ; The number of measurement points; Objective function 2 - optimal sinking stability: ; In the formula, The angular velocities are the horizontal and vertical angular velocities; Vertical velocity; The attitude angle; The weighting coefficient has a range of values. ; The sinking time; Objective function 3 - Maximizes the reliability of upward movement: ; In the formula, The probability of successful separation; Failure rate; For runtime; Objective function 4 - Minimize system weight: ; In the formula, For the first The density of each component; For the corresponding volume; Total number of components; The constraints include: The distance L between the transmitting and receiving transducers is greater than 3-4 acoustic wavelengths; buoyancy ratio constraint: Dynamic stability constraints: In the formula, The damping coefficient; Allowable error; structural strength constraints: In the formula, The maximum stress; Allowable stress.

2. The in-situ measurement instrument for the acoustic properties of discarded seabed sediments according to claim 1, characterized in that, The acoustic probe is a rod-shaped structure with a conical tip at one end. Two annular underwater acoustic receiver transducers spaced a certain distance apart are installed on the outer wall. The acoustic probe and the counterweight are fixedly connected to each other.

3. The in-situ measurement instrument for the acoustic properties of discarded seabed sediments according to claim 2, characterized in that, The counterweight is a frustum structure with a trapezoidal longitudinal section, including a short side and a long side. The short side corresponds to the section with a smaller diameter of the frustum structure, and the long side corresponds to the section with a larger diameter of the frustum structure. The acoustic probe is installed on the section with a smaller diameter, and the fusion separation mechanism is installed on the end with a larger diameter. The counterweight has through holes along the axis for routing the receiving transducer wiring.

4. The in-situ measurement instrument for the acoustic properties of discarded seabed sediments according to claim 1, characterized in that, The battery compartment is a cylindrical sealed pressure-resistant structure with an axial through hole in the center. It is installed on the upper end of the fuse separation mechanism, but is not fixed to the fuse separation mechanism, so that it can be separated from the fuse separation mechanism under the action of external force. The purpose of the through hole in the center of the battery compartment is to leave space for the top rod and wires in the fuse separation mechanism. The battery compartment is sealed with a battery, which is responsible for providing power to the entire instrument.

5. The in-situ measurement instrument for the acoustic properties of discarded seabed sediments according to claim 4, characterized in that, The fuse compartment is an open structure that allows seawater to flow in freely. It is fixedly connected to the battery compartment. An opening of the same diameter as the battery compartment is located at the center of the bottom surface of the fuse compartment, allowing wires and the push rod of the fuse separation mechanism to pass through. Four axially evenly distributed latches are located on the wall of the fuse compartment, allowing the latches of the fuse separation mechanism to engage precisely with their respective latches when locked. The fuse compartment is fixedly connected to the battery compartment and the electronics compartment. Two symmetrically distributed fuses are installed inside the fuse compartment. The fuse wires are mounted on the fuses and pass through the hole at the upper end of the push rod when the spring in the fuse separation mechanism is compressed, thus counteracting the spring force and preventing the push rod from moving upwards.

6. The in-situ measurement instrument for the acoustic properties of discarded seabed sediments according to claim 5, characterized in that, The electronic compartment is a cylindrical pressure-resistant sealed structure, housing a control module and a data communication module, which are fixedly connected to the fuse compartment. Additionally, an electric push rod is installed inside the electronic compartment. The telescopic rod of the electric push rod, after being sealed, extends from below the electronic compartment into the fuse compartment. Underwater wet-plug connectors are installed on the telescopic rod of the electric push rod and the top rod of the fuse separation mechanism, respectively. Initially, the electric push rod is in the extended state. After the in-situ measurement of the acoustic characteristics of the ejected seabed sediment is completed, the telescopic rod of the electric push rod is retracted, driving the underwater wet-plug connector, thereby separating the wiring between the surfacing and ejected sections.

7. The in-situ measurement instrument for the acoustic properties of discarded seabed sediments according to claim 6, characterized in that, The buoyancy module has four wing-shaped structures evenly distributed around its circumference, which are responsible for controlling the attitude of the in-situ measurement instrument for the acoustic properties of the seabed sediment during descent. Transmitting transducers are installed below two of the wings, and an antenna for communication is installed on the upper part of the buoyancy module. The buoyancy module is fixed to the electronic cabin.

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