An underwater robot power folding passive sonar detection device and method

Abstract

The present application relates to underwater robot low resistance high performance passive sonar detection field, specifically relates to a kind of underwater robot power folding passive sonar detection device, comprising: be located on the folding and unfolding mechanism of AUV, hydrophone acoustic array, drive motor, controller, attitude sensor, acoustic array acquisition processing unit and communication module;The controller of the present device is communicated with AUV, controls motor action to realize and be connected with the acoustic array of folding and unfolding mechanism repeatedly folding and unfolding, and is unfolded to form hydrophone acoustic array, receives target radiated noise signal or echo signal, and signal is collected and stored, simultaneously, real-time processing and being connected with the correction target angle estimation result of attitude sensor communication, with AUV communication carries out further operation;The present application makes the influence of acoustic array folding state to platform motion performance as small as possible to maintain underwater robot as mobile platform motion advantage, and unfolded state can form large aperture high performance detection acoustic array to realize high performance detection.

Description

Technical Field

[0001] This invention relates to the field of low-drag, high-performance passive sonar detection for underwater robots, specifically to a powered folding passive sonar detection device and method for underwater robots, which is mounted on an underwater robot platform and mainly used for underwater target detection and acoustic intelligence gathering. Background Technology

[0002] Underwater robots possess mobile, controllable, and intelligent autonomous capabilities, enabling them to support rapid and maneuverable target detection needs and are a key element for future intelligent underwater network detection. However, due to limitations in the size, load, and motion performance of underwater robot platforms, the sonar detection devices currently carried by underwater robots are mainly miniaturized acoustic arrays designed for conventional ship towed / flank arrays or submarine / buoy arrays, or platform-adaptive miniaturized arrays. These are designed to meet the requirements within the platform's load range and with minimal impact on the platform's motion performance. However, these acoustic arrays suffer from small array apertures and weak detection performance, failing to meet the high-performance detection requirements such as high angular resolution and long distance.

[0003] To overcome the significant limitations imposed by the aperture of the acoustic arrays mounted on underwater robot platforms, there is an urgent need to develop new types of underwater robot sonar detection devices. Furthermore, considering the limited energy resources of current underwater robot platforms, priority should be given to developing new passive sonar detection devices for underwater robots. Summary of the Invention

[0004] The purpose of this invention is to provide a powered folding passive sonar detection device adapted to underwater robots, which has intelligent autonomous folding-unfolding and passive detection capabilities, in order to overcome the shortcomings of the sonar detection devices carried by underwater robots.

[0005] The technical solution adopted by the present invention to achieve the above objectives is: an underwater robot powered folding passive sonar detection device, comprising: a folding mechanism mounted on an AUV, a hydrophone acoustic array, a drive motor, a controller, an attitude sensor, an acoustic array acquisition and processing unit, and a communication module;

[0006] The drive motor is connected to the folding and unfolding mechanism and is used to drive the folding and unfolding mechanism to perform folding and unfolding actions;

[0007] The controller is connected to the drive motor and is used to receive the control commands of the AUV and the array status parameters of the drive motor, and then control the start and stop of the drive motor.

[0008] The folding and unfolding mechanism is used to repeatedly fold or unfold the hydrophone acoustic array connected to it, driven by the drive motor.

[0009] The hydrophone acoustic array is mounted on the folding mechanism and is used to collect acoustic data of the target in real time as the folding mechanism folds or unfolds.

[0010] The acoustic array acquisition and processing unit is used to acquire and store the electrical signals output by the hydrophone acoustic array, and process the electrical signals in combination with the AUV pose to obtain the target features and azimuth information, and then send them to the AUV through the communication module.

[0011] The attitude sensor is located in the control cabin of the AUV platform to acquire the attitude of the AUV. Another attitude sensor is deployed on the control board of the underwater robot's powered folding passive sonar detection device to sense the attitude of the sonar detection device itself. The data from both are sent to the acoustic array acquisition and processing unit.

[0012] The communication module is used to transmit commands and pose data between the acoustic array acquisition and processing unit and the AUV.

[0013] The connection method between the folding mechanism and the AUV includes any one of the following: rigid connection, flexible connection, or connection with the cable of the take-up and take-down winch installed on the AUV.

[0014] The folding mechanism is located at any position on the back, belly, bow, stern, or port and starboard sides of the AUV.

[0015] The hydrophone acoustic array is a single-element hydrophone acoustic array or a multi-element hydrophone acoustic array.

[0016] The single-element hydrophone acoustic array includes: a single scalar or vector hydrophone; for non-self-contained hydrophones, power supply and signal transmission cables are also required.

[0017] The multi-element hydrophone acoustic array is composed of multiple hydrophones, which are arranged uniformly or non-uniformly on the folding mechanism.

[0018] The hydrophone is a transducer that converts sound signals into electrical signals. It is used to receive sound signals in water and can be piezoelectric, optical fiber, or other types of hydrophones.

[0019] The folding mechanism is either a rigid folding structure or a flexible folding structure;

[0020] The rigid retractable sonar detection device is either a sliding retractable sonar detection device or a linkage retractable sonar detection device.

[0021] The flexible folding sonar detection device is either a biomimetic squid tentacle-type folding sonar detection device or a wire spring-type folding sonar detection device.

[0022] The sliding retractable sonar detection device includes: a motor mounting base, a drive motor, a ball screw, a sonar mounting frame, and a sonar.

[0023] The motor mounting base is mounted on the AUV, and the drive motor is fixed on the motor mounting base and sealed. The drive motor is fixed to one end of the ball screw, and the motor output shaft of the drive motor is connected to the screw shaft of the ball screw through a coupling to provide a power source and transmit rotational motion. The ball screw converts the rotational motion into linear motion through a slider. A sonar mounting bracket is fixedly mounted on the slider, and the sonar is fixed on the sonar mounting bracket. As the slider moves, it drives the sonar mounting bracket to move back and forth in a straight line along the slide.

[0024] The linkage-type sonar detection device includes: a sonar arm, a sonar, a drive motor, a bevel gear output mechanism, a disc-type slide, a slider, a connecting rod, an upper connecting rod, and a lower connecting rod;

[0025] The disc slide is fixed to the AUV. The drive motor drives the bevel gear output mechanism for power transmission. The bevel gear output mechanism is fixed to the center of the disc slide and has a single-input, dual-output shaft design. The dual output shafts of the bevel gear are respectively hinged to the outermost sonar arms at both ends via connecting rods. The sonar arms are hinged at the root of the sonar arms via an upper connecting rod, thereby driving the movement of the driven sonar arms. The slider is hinged to the sonar arms and can slide in a circular motion within the disc slide. The sliders are hinged to each other via a lower connecting rod to control the opening angle of the sonar arms. The sonar arm located in the middle position is fixed. The sonar is fixed to the sonar arm and, with the circular motion of the sonar arm, drives the folding and unfolding motion of the sonar.

[0026] The biomimetic squid tentacle-type folding sonar detection device is a continuous underwater robotic arm, including: a hydraulic pump, a steel frame, a grid, internal pipes, a flexible skin, and a sonar.

[0027] The hydraulic pump is fixed inside the steel frame, and a mechanical arm composed of a grid extends hinged around the steel frame. The flexible skin is wrapped around the outside of the steel frame and the grid, and the sonar is fixed outside the flexible skin.

[0028] The fluid medium inside the hydraulic pump is a jet elastomer. One end of the internal pipe is fixedly connected to the grid, and the other end is fixedly connected to the output port of the hydraulic pump. The jet elastomer is driven by the hydraulic pump to flow between the hydraulic pump and the grid. The jet elastomer enters the grid wrapped with flexible material through the pipe. Under the pressure of the jet elastomer medium in the hydraulic pump, the grid expands in all directions, thereby generating a contraction tension similar to the muscles of a squid's tentacle, which in turn drives the movement of the robotic arm. The sonar follows the movement of the robotic arm.

[0029] The wire spring type folding sonar detection device includes: a tension spring, a rope, a drive motor, a rotating wheel, a base, a robotic arm, and a sonar.

[0030] The sonar is fixed on the robotic arm, and the end of the robotic arm is hinged to the base. One side of the tension spring is fixedly connected to the robotic arm, and the other side is fixedly connected to the base. One side of the rope is fixed to the robotic arm, and the other side is fixed to the wheel. The wheel is fixedly connected to the output shaft of the drive motor, and the drive motor is fixed to the base.

[0031] When the drive motor drives the wheel to tighten the rope, it overcomes the spring tension and the robotic arm opens. When the drive motor reverses, the rope is in a slack state. Under the action of the spring force, the robotic arm folds to a closed state, and the sonar follows the robotic arm in opening and closing movements.

[0032] A detection method for an underwater robot-powered foldable passive sonar detection device includes the following steps:

[0033] 1) The controller receives control commands sent by the AUV control system through the communication module, controls the drive motor to adjust the array state according to the type of control command, and at the same time, the drive motor feeds back the array state parameters to the controller.

[0034] 2) The controller continues to control the drive motor to adjust the folding mechanism in real time according to the array status parameters, so that the hydrophone acoustic array set on the folding mechanism reaches the set state;

[0035] 3) When the hydrophone acoustic array in the water detects the target radiated noise signal or echo signal, the acoustic array acquisition and processing unit acquires the electrical signal of the current hydrophone acoustic array. At the same time, it acquires the AUV platform pose sensed by the AUV control system's attitude sensor and the attitude of the underwater robot's powered folding passive sonar detection device itself through the communication module, so as to correct the processing results.

[0036] 4) The acoustic array acquisition and processing unit processes the electrical signals of the hydrophone acoustic array in real time to obtain the target azimuth information, stores the obtained target azimuth information, and sends it to the AUV control system through the communication module.

[0037] 5) After the AUV control system obtains new control commands based on the target orientation information, it repeats steps 1) to 4).

[0038] In step 1), the step of controlling the drive motor to adjust the array state according to the type of control command specifically involves:

[0039] 2-1) When the AUV sends a control command as an AUV static detection command, the controller controls the drive motor to keep the unfolding mechanism in the unfolded state according to the array status parameters, and the hydrophone acoustic array performs detection.

[0040] 2-2) When the AUV sends a control command for low-speed maneuverability detection and the folding mechanism is a rigid folding structure, the controller controls the drive motor to keep the folding mechanism in the unfolded state according to the array state parameters, and the hydrophone acoustic array performs detection.

[0041] 2-3) When the AUV sends a control command for low-speed maneuverability detection and the folding mechanism is a flexible folding structure, the controller controls the drive motor to keep the folding mechanism in a folded state according to the array state parameters, and the hydrophone acoustic array performs detection.

[0042] 2-4) When the AUV sends a control command for high-speed mobility detection, the controller controls the drive motor to keep the folding mechanism in a folded state according to the array status parameters, and the hydrophone acoustic array performs detection.

[0043] The acoustic array acquisition and processing unit processes the electrical signals of the hydrophone's acoustic array in real time to obtain target location information, specifically:

[0044] Step 1: The acoustic array acquisition unit transmits the acquired signal to the embedded CPU in frames. The dimension of the data matrix X of each frame is N×L, where N represents the number of acoustic array elements and L represents the number of snapshots required for processing.

[0045] Step 2: For each frame of data, calculate its received signal covariance matrix R. xx ,Right now:

[0046]

[0047] in,[·] H Indicates conjugate transpose;

[0048] Step 3: For R xx Perform eigenvalue decomposition, that is:

[0049] R xx =UΛU H =U S Λ S U S H +U N Λ N U N H

[0050] Among them, U S U is an N×K dimensional signal eigenvector matrix; N The noise eigenvector matrix is ​​N×(NK) dimensional; Λ S The K×K dimensional diagonal matrix corresponding to the signal eigenvalues; Λ N The noise eigenvalues ​​correspond to an (NK)×(NK) dimensional diagonal matrix.

[0051] Step 4: Construct the guide vector for the angle scan space, as follows:

[0052]

[0053] Where, θ k ∈[-π,π], k=1,2,…M represents the spatial spectrum scan azimuth angle, φ k ∈[0,π], k=1,2,…M represents the spatial spectrum scanning elevation angle, M represents the number of scanning angles, f0 is the signal center frequency, c is the speed of sound in water, (x i ,y i ,z i () represents the coordinates of the i-th element;

[0054] Step 5: Calculate the spatial spectrum, i.e.:

[0055]

[0056] Among them, the angles corresponding to the spectral peaks of the spatial spectrum are the azimuth and elevation angles of the target.

[0057] The present invention has the following beneficial effects and advantages:

[0058] 1. This invention proposes an innovative design concept for an underwater robot sonar detection device, which minimizes the impact of the folded state of the acoustic array on the platform's motion performance to maintain the underwater robot's motion advantage as a mobile platform, while the unfolded state can form a large-aperture, high-performance detection acoustic array to achieve high-performance detection.

[0059] 2. This invention proposes a design framework for a type of underwater robot powered folding passive sonar detection device, and provides a systematic description of the main components and possible design schemes of each mechanism of this type of sonar detection device, guiding the specific design of various subsequent models of this type of sonar detection device.

[0060] 3. This invention proposes a novel detection operation mode for an integrated underwater robot sonar detection device, in which the underwater robot is equipped with the foldable passive sonar detection device for integrated operation. Throughout the detection mission, it remains a whole unit. The acoustic array adjusts its folding-unfolding state in real time according to the movement state of the underwater robot platform. Furthermore, the detection performance can be further improved by utilizing the platform's maneuverability during the detection process. Attached Figure Description

[0061] Figure 1 This is a schematic diagram of the overall structure and connection of the present invention.

[0062] Figure 2 This is a schematic diagram of the working mode of the detection device described in this invention.

[0063] Figure 3aThis is a schematic diagram of the rigid connection between the folding mechanism and the AUV of the present invention;

[0064] Figure 3b This is a schematic diagram of the flexible connection between the unfolding mechanism and the AUV of the present invention;

[0065] Figure 3c This is a schematic diagram showing the connection between the unfolding mechanism of the present invention and the retractable winch of the AUV;

[0066] Figure 4a This is a schematic diagram of the sliding folding sonar detection device of the present invention;

[0067] Figure 4b This is a schematic diagram of the structure of the linkage-type folding sonar detection device of the present invention;

[0068] Figure 4c This is a schematic diagram of the flexible folding sonar detection device of the present invention;

[0069] 1 is a sliding folding sonar detection device, 2 is a linkage folding sonar detection device, and 3 is a biomimetic squid tentacle folding sonar detection device.

[0070] Figure 5 This is a schematic diagram of the structure of the multi-element hydrophone acoustic array of the present invention;

[0071] Figure 6 This is a schematic diagram of the detection method of the detection device of the present invention. Detailed Implementation

[0072] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0073] like Figure 1 The diagram shown is a schematic of the overall structure of the present invention. The present invention provides a powered folding passive sonar detection device for underwater robots, comprising: a folding mechanism mounted on an AUV, a hydrophone acoustic array, a drive motor, a controller, an attitude sensor, an acoustic array acquisition and processing unit, and a communication module.

[0074] The drive motor is connected to the folding and unfolding mechanism and is used to drive the folding and unfolding mechanism to perform folding and unfolding actions;

[0075] The controller is connected to the drive motor and is used to receive the control commands of the AUV and the array status parameters of the drive motor, and then control the start and stop of the drive motor.

[0076] The folding and unfolding mechanism is used to repeatedly fold or unfold the hydrophone acoustic array connected to it, driven by the drive motor.

[0077] The hydrophone acoustic array is mounted on the folding mechanism and is used to collect acoustic data of the target in real time as the folding or unfolding mechanism is driven.

[0078] The acoustic array acquisition and processing unit is used to acquire and store the electrical signals output by the hydrophone acoustic array, and process the electrical signals in combination with the AUV pose to obtain the target orientation information, which is then sent to the AUV through the communication module.

[0079] An attitude sensor is installed in the control cabin of the AUV platform to acquire the attitude of the AUV. Another attitude sensor is installed on the control board of the underwater robot's powered folding passive sonar detection device to sense the attitude of the sonar detection device itself. The data from both are sent to the acoustic array acquisition and processing unit.

[0080] The communication module is used to transmit commands and pose data between the acoustic array acquisition and processing unit and the AUV.

[0081] In this invention, if the underwater robot powered folding passive sonar detection device is connected to the underwater robot platform in a rotatable manner, a controller, motor, and clamping device can be added to achieve rotation of the acoustic array at a given angle, thereby completing the target multi-angle tracking task.

[0082] In this invention, in order to improve the folding accuracy, the motor is preferably a brushed motor.

[0083] In this invention, in order to ensure compatibility with different underwater robot platforms, the communication module adopts a programmable design scheme that is compatible with multiple interface communication protocols.

[0084] In this invention, in order to improve the accuracy of the detection angle estimation, the attitude sensor is a high-precision (error less than 1°) attitude sensor;

[0085] The battery in this invention can be a self-contained battery or a battery connected to the underwater robot platform; the battery can be a primary battery, a secondary battery, or another type of battery.

[0086] like Figures 3a-3c The diagram shown illustrates the connection between the folding mechanism and the AUV according to the present invention. It shows that the connection between the folding mechanism and the AUV includes: a rigid connection, a flexible connection, or a connection with a cable connected to a take-up winch installed on the AUV. Any connection method can be applied in the present invention.

[0087] The folding mechanism can be located anywhere on the AUV's back, belly, bow, stern, or port and starboard sides. For example... Figure 2 and Figure 3a As shown, in this embodiment, the folding mechanism is located on the back of the AUV;

[0088] like Figures 4a-4b As shown, the folding mechanism can be a rigid folding structure or a flexible folding structure;

[0089] The rigid folding sonar detection device is either a sliding folding sonar detection device or a linkage folding sonar detection device.

[0090] The flexible folding sonar detection device can be either a biomimetic squid tentacle-type folding sonar detection device or a wire spring-type folding sonar detection device.

[0091] Among them, such as Figure 4a The diagram shown is a structural schematic of the sliding folding sonar detection device of the present invention. The sliding folding sonar detection device includes: a motor mounting base, a drive motor, a ball screw, a sonar mounting frame, and a sonar.

[0092] The motor mounting base is mounted on the AUV, and the drive motor is fixed on the motor mounting base and sealed. The drive motor is fixed to one end of the ball screw, and the motor output shaft of the drive motor is connected to the screw shaft of the ball screw through a coupling to provide a power source and transmit rotational motion. The ball screw converts the rotational motion into linear motion through a slider. A sonar mounting bracket is fixedly mounted on the slider, and the sonar is fixed on the sonar mounting bracket. As the slider moves, it drives the sonar mounting bracket to move back and forth in a straight line along the slide.

[0093] like Figure 4b The diagram shown is a schematic of the linkage-type folding sonar detection device of the present invention. The linkage-type folding sonar detection device includes: a sonar arm, a sonar, a drive motor, a bevel gear output mechanism, a disc-type slide, a slider, a connecting rod, an upper connecting rod, and a lower connecting rod.

[0094] The disc slide is fixed on the AUV. The drive motor drives the bevel gear output mechanism for power transmission. The bevel gear output mechanism is fixed at the center of the disc slide and has a single-input, dual-output shaft design. The dual output shafts of the bevel gear are respectively hinged to the outermost sonar arms at both ends via connecting rods. The sonar arms are hinged at the root of the sonar arms via an upper connecting rod, thereby driving the movement of the driven sonar arms. The slider is hinged to the sonar arms and can slide in a circular motion within the disc slide. The sliders are hinged to each other via a lower connecting rod to control the opening angle of the sonar arms. The sonar arm located in the middle position is fixed, and the sonar is fixed to the sonar arm. With the circular motion of the sonar arm, the sonar's folding and unfolding motion is driven.

[0095] like Figure 4c The diagram shown is a schematic of the flexible folding mechanism of the present invention, wherein the flexible folding mechanism includes: a biomimetic squid tentacle-type folding mechanism and a wire spring-type folding structure;

[0096] Among them, the biomimetic squid tentacle-type folding sonar detection device belongs to the continuous underwater robotic arm, including a hydraulic pump, steel frame, grid, jet elastomer, pipe, flexible skin, and sonar.

[0097] The hydraulic pump is fixed inside the steel frame, and a robotic arm composed of a grid extends out from the steel frame. A flexible skin is wrapped around the outside of the steel frame and the grid. The sonar is fixed outside the flexible skin. The fluid medium inside the hydraulic pump is a jet elastomer. One end of the internal pipe is fixed to the grid, and the other end is fixed to the output port of the hydraulic pump. The hydraulic pump drives the jet elastomer to flow between the hydraulic pump and the grid. The jet elastomer enters the grid wrapped by the flexible material through the pipe. The grid expands in all directions under the pressure of the jet elastomer medium, thereby generating a contraction tension similar to the muscles of a squid's tentacle, which in turn drives the movement of the robotic arm. The sonar follows the movement of the robotic arm.

[0098] A wire-spring type folding sonar detection device includes a tension spring, a rope, a drive motor, a rotating wheel, a base, a robotic arm, and a sonar. The sonar is fixed to the robotic arm, and the end of the robotic arm is hinged to the base. One side of the tension spring is fixedly connected to the robotic arm, and the other side is fixedly connected to the base. One side of the rope is fixed to the robotic arm, and the other side is fixed to the rotating wheel. The rotating wheel is fixedly connected to the output shaft of the drive motor, and the drive motor is fixed to the base. When the drive motor drives the rotating wheel to tighten the rope, it overcomes the spring tension, and the robotic arm opens. When the drive motor reverses, the rope is in a slack state, and under the action of the spring force, the robotic arm folds to a closed state. The sonar follows the robotic arm in its unfolding and closing movements.

[0099] like Figure 5 The diagram shown is a structural schematic of the multi-element hydrophone acoustic array of the present invention. The hydrophone acoustic array is connected to the folding mechanism, which is a sound-transparent mechanism composed of one or more sound-transparent materials such as fiberglass, rubber, carbon fiber, and titanium alloy. It can be placed inside a low-resistance streamlined sound-transparent protective cylinder.

[0100] The hydrophone acoustic array can be a single-element hydrophone acoustic array or a multi-element hydrophone acoustic array.

[0101] A single-element hydrophone acoustic array includes: a single scalar or vector hydrophone; for non-self-contained hydrophones, power supply and signal transmission cables are also required.

[0102] The multi-element hydrophone acoustic array consists of multiple hydrophones arranged uniformly or non-uniformly on the folding mechanism.

[0103] A hydrophone is a transducer that converts sound signals into electrical signals. It is used to receive sound signals in water and can be piezoelectric, fiber optic, or other types of hydrophones.

[0104] like Figure 6The diagram shows the principle of the detection method of the detection device of the present invention. The detection method of the underwater robot powered folding passive sonar detection device of the present invention includes the following steps:

[0105] 1) The controller receives control commands sent by the AUV control system through the communication module, controls the drive motor to adjust the array state according to the type of control command, and at the same time, the drive motor feeds back the array state parameters to the controller.

[0106] 2) The controller continues to control the drive motor to adjust the folding mechanism in real time according to the array status parameters, so that the hydrophone acoustic array set on the folding mechanism reaches the set state;

[0107] 3) When the hydrophone acoustic array in the water detects the target radiated noise signal or echo signal, the acoustic array acquisition and processing unit acquires the electrical signal of the current hydrophone acoustic array. At the same time, it acquires the AUV platform pose sensed by the AUV control system's attitude sensor and the attitude of the underwater robot's powered folding passive sonar detection device itself through the communication module, so as to correct the processing results.

[0108] 4) The acoustic array acquisition and processing unit processes the electrical signals of the hydrophone acoustic array in real time to obtain the target azimuth information, stores the obtained target azimuth information, and sends it to the AUV control system through the communication module.

[0109] 5) After the AUV control system obtains new control commands based on the target orientation information, it repeats steps 1) to 4).

[0110] like Figure 2 The diagram shown illustrates the working mode of the detection device of the present invention. Specifically, in step 2), the drive motor is controlled to adjust the array state according to the type of control command.

[0111] 2-1) When the AUV sends a control command as an AUV static detection command, the controller controls the drive motor to keep the unfolding mechanism in the unfolded state according to the array status parameters, and the hydrophone acoustic array performs detection.

[0112] 2-2) When the AUV sends a control command for low-speed maneuverability detection and the folding mechanism is a rigid folding structure, the controller controls the drive motor to keep the folding mechanism in the unfolded state according to the array state parameters, and the hydrophone acoustic array performs detection.

[0113] 2-3) When the AUV sends a control command for low-speed maneuverability detection and the folding mechanism is a flexible folding structure, the controller controls the drive motor to keep the folding mechanism in a folded state according to the array state parameters, and the hydrophone acoustic array performs detection.

[0114] 2-4) When the AUV sends a control command for high-speed mobility detection, the controller controls the drive motor to keep the folding mechanism in a folded state according to the array status parameters, and the hydrophone acoustic array performs detection.

[0115] like Figure 6 As shown, in the detection method of the present invention, the acoustic array acquisition and processing unit processes the electrical signals of the hydrophone acoustic array in real time to obtain the target azimuth information, specifically:

[0116] Step 1: The acoustic array acquisition unit transmits the acquired signal to the embedded CPU in frames. The dimension of the data matrix X of each frame is N×L, where N represents the number of acoustic array elements and L represents the number of snapshots required for processing.

[0117] Step 2: For each frame of data, calculate its received signal covariance matrix R. xx ,Right now:

[0118]

[0119] in,[·] H Indicates conjugate transpose;

[0120] Step 3: For R xx Perform eigenvalue decomposition, that is:

[0121] R xx =UΛU H =U S Λ S U S H +U N Λ N U N H

[0122] Among them, U S U is an N×K dimensional signal eigenvector matrix; N The noise eigenvector matrix is ​​N×(NK) dimensional; Λ S The K×K dimensional diagonal matrix corresponding to the signal eigenvalues; Λ N The noise eigenvalues ​​correspond to an (NK)×(NK) dimensional diagonal matrix.

[0123] Step 4: Construct the guide vector for the angle scan space, as follows:

[0124]

[0125] Where, θ k ∈[-π,π], k=1,2,…M represents the spatial spectrum scan azimuth angle, φ k∈[0,π], k=1,2,…M represents the spatial spectrum scanning elevation angle, M represents the number of scanning angles, f0 is the signal center frequency, c is the speed of sound in water, (x i ,y i ,z i () represents the coordinates of the i-th element;

[0126] Step 5: Calculate the spatial spectrum, i.e.:

[0127]

[0128] Among them, the angles corresponding to the spectral peaks of the spatial spectrum are the azimuth and elevation angles of the target.

[0129] Example:

[0130] like Figure 6 As shown, this embodiment only illustrates one circuit diagram under the implementation of a detection device using a rigid connection and an attitude sensor configured on the connected AUV platform. The controller of the detection device receives instructions from the AUV platform and controls the motor to adjust the array state. Combined with the collected or feedback array state parameters, the controller further controls the motor action to bring the acoustic array to the set state. The hydrophone acoustic array receives the target radiated noise signal or echo signal. The acquisition module collects the signal, the processing module processes the collected signal in real time, and the communication module obtains the AUV platform attitude sensed by the attitude sensor for correcting the processing results. The storage module can store the collected signal, the extracted target features, and the processed results such as the target orientation according to the set requirements. The communication module transmits the target features extracted by the processing module and the processed results to the AUV to support the subsequent work of the robotic detection device.

[0131] This invention proposes an innovative design concept for an underwater robot sonar detection device, which minimizes the impact of the folded acoustic array on the platform's motion performance to maintain the underwater robot's motion advantage as a mobile platform, while the unfolded state can form a large-aperture, high-performance detection acoustic array to achieve high-performance detection.

[0132] In summary, the wet end of the underwater robot powered folding passive sonar detection device of the present invention has multiple possible forms. The embodiments described above only illustrate several implementation methods of the present invention and should not be construed as limiting the scope of the present invention. The detection device can be connected in various ways, such as rigid connection, flexible connection, and retractable winch connection.

[0133] There are several options for the connection location of the detection device, such as connection to the back, belly, bow, stern, or side.

[0134] The folding and unfolding mechanism of the detection device 1 can be configured in various ways, such as a sliding folding and unfolding mechanism, a linkage folding and unfolding mechanism, and a flexible folding and unfolding mechanism. Among these, the folding and unfolding forms of the detection device can take many forms, such as a linear folded state, a cylindrical folded state, an umbrella-shaped folded state, a linear unfolded state, a circular unfolded state, a planar unfolded state, and a volumetric unfolded state.

[0135] The acoustic array of the detection device can be configured in different ways, such as single-element arrays or multi-element arrays (including ring-shaped multi-element arrays and circumferential multi-element arrays extending in a symmetrical direction).

[0136] The above description is merely an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, extensions, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A powered folding passive sonar detection device for underwater robots, characterized in that, include: The components mounted on the AUV include a folding mechanism, a hydrophone acoustic array, a drive motor, a controller, an attitude sensor, an acoustic array acquisition and processing unit, and a communication module. The drive motor is connected to the folding and unfolding mechanism and is used to drive the folding and unfolding mechanism to perform folding and unfolding actions; The controller is connected to the drive motor and is used to receive the control commands of the AUV and the array status parameters of the drive motor, and then control the start and stop of the drive motor. The folding and unfolding mechanism is used to repeatedly fold or unfold the hydrophone acoustic array connected to it, driven by the drive motor. The folding mechanism is a flexible folding structure; the flexible folding sonar detection device is a biomimetic squid tentacle-type folding sonar detection device. The biomimetic squid tentacle-shaped folding sonar detection device is a continuous underwater robotic arm, including: a hydraulic pump, steel frame, grid, internal pipes, flexible skin, and sonar; The hydraulic pump is fixed inside the steel frame, and a mechanical arm composed of a grid extends hinged around the steel frame. The flexible skin is wrapped around the outside of the steel frame and the grid, and the sonar is fixed outside the flexible skin. The fluid medium inside the hydraulic pump is a jet elastomer. One end of the internal pipe is fixedly connected to the grid, and the other end is fixedly connected to the output port of the hydraulic pump. The jet elastomer is driven by the hydraulic pump to flow between the hydraulic pump and the grid. The jet elastomer enters the grid wrapped with flexible material through the pipe. Under the pressure of the jet elastomer medium in the hydraulic pump, the grid expands in all directions, thereby generating a contraction tension similar to the muscles of a squid's tentacle, which in turn drives the movement of the robotic arm. The sonar follows the movement of the robotic arm. The hydrophone acoustic array is mounted on the folding mechanism and is used to collect acoustic data of the target in real time as the folding mechanism folds or unfolds. The acoustic array acquisition and processing unit is used to acquire and store the electrical signals output by the hydrophone acoustic array, and process the electrical signals in combination with the AUV pose to obtain the target features and azimuth information, and then send them to the AUV through the communication module. The attitude sensor is located in the control cabin of the AUV platform to acquire the attitude of the AUV. Another attitude sensor is deployed on the control board of the underwater robot's powered folding passive sonar detection device to sense the attitude of the sonar detection device itself. The data from both are sent to the acoustic array acquisition and processing unit. The communication module is used to transmit commands and pose data between the acoustic array acquisition and processing unit and the AUV.

2. The underwater robot powered folding passive sonar detection device according to claim 1, characterized in that, The folding mechanism is located at any position on the back, belly, bow, stern, or port and starboard sides of the AUV.

3. The underwater robot powered folding passive sonar detection device according to claim 1, characterized in that, The hydrophone acoustic array is a single-element hydrophone acoustic array or a multi-element hydrophone acoustic array. The single-element hydrophone acoustic array includes: a single scalar or vector hydrophone; for non-self-contained hydrophones, power supply and signal transmission cables are also required. The multi-element hydrophone acoustic array is composed of multiple hydrophones, which are arranged uniformly or non-uniformly on the folding mechanism. The hydrophone is a transducer that converts sound signals into electrical signals. It is used to receive sound signals in water and can be piezoelectric, optical fiber, or other types of hydrophones.

4. The detection method of the underwater robot powered folding passive sonar detection device according to claim 1, characterized in that, Includes the following steps: 1) The controller receives control commands sent by the AUV control system through the communication module, controls the drive motor to adjust the array state according to the type of control command, and at the same time, the drive motor feeds back the array state parameters to the controller. 2) The controller continues to control the drive motor to adjust the folding mechanism in real time according to the array status parameters, so that the hydrophone acoustic array set on the folding mechanism reaches the set state; 3) When the hydrophone acoustic array in the water detects the target radiated noise signal or echo signal, the acoustic array acquisition and processing unit acquires the electrical signal of the current hydrophone acoustic array. At the same time, it acquires the AUV platform pose sensed by the AUV control system's attitude sensor and the underwater robot's powered folding passive sonar detection device's own attitude through the communication module, so as to correct the processing results. 4) The acoustic array acquisition and processing unit processes the electrical signals of the hydrophone acoustic array in real time to obtain the target azimuth information, stores the obtained target azimuth information, and sends it to the AUV control system through the communication module. 5) After the AUV control system obtains new control commands based on the target orientation information, it repeats steps 1) to 4).

5. The detection method of the underwater robot powered folding passive sonar detection device according to claim 4, characterized in that, The acoustic array acquisition and processing unit processes the electrical signals of the hydrophone's acoustic array in real time to obtain target location information, specifically: Step 1: The acoustic array acquisition unit transmits the acquired signal to the embedded CPU in frames, with each frame containing a data matrix. The dimension is ,in Indicates the number of elements in the acoustic array. Indicates the number of snapshots required for processing; Step 2: For each frame of data, calculate its received signal covariance matrix. ,Right now: ； in, Indicates conjugate transpose; Step 3: [Regarding...] Perform eigenvalue decomposition, that is: ； in, for 3D signal eigenvector matrix; for 3D noise eigenvector matrix; For signal feature values 3D diagonal matrix; For noise feature values 3D diagonal matrix; Step 4: Construct the guide vector for the angle scan space, as follows: ； in, Indicates the azimuth angle of the spatial spectrum scan. Indicates the pitch angle of the spatial spectrum scan. Indicates the number of scanning angles. The center frequency of the signal. The speed of sound in water, Indicates the first The coordinates of each array element; Step 5: Calculate the spatial spectrum, i.e.: ； Among them, the angles corresponding to the spectral peaks of the spatial spectrum are the azimuth and elevation angles of the target.

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