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Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes/issues, but are citable by Digital Object Identifier (DOI).
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Cross-domain communication buoy system based on optimal communication link selection
XING Minghan, SHANG Zhigang, QIAO Gang, ZHOU Feng, NIE Donghu, ZHANG Tong, LI Tianshui, XIE Jiaxuan
, Available online  , doi: 10.11993/j.issn.2096-3920.2024-0113
The ocean buoy has the advantages of flexible use, convenient development and simple structure, and has been widely used in the marine field. However, the existing marine buoy communication mode is single, low reliability, high packet loss rate and poor real-time performance, which cannot meet the needs of large-scale marine data acquisition and cross-domain communication. In order to further strengthen the construction of marine global interconnection, this paper designs and manufactures a cross-domain communication buoy system with multi-source communication as the core. The system can complete the switching of multiple communication modes, multi-source information acquisition and multi-link real-time cross-domain communication. An optimal communication link selection algorithm is designed for the system. According to the real-time signal quality of each communication module, the optimal communication link is selected to improve the reliability of communication. At the same time, the communication module with poor signal quality is closed to reduce the problem of large redundancy and power consumption of system communication that may occur when multiple communication methods are used at the same time. The experimental results show that the system realizes the cross-domain transmission of water and underwater data, and the multi-source communication design is feasible. The communication links are stable and reliable, and the comprehensive communication success rate is more than 99%. It provides a reference scheme for the construction of marine global observation network and communication network.
A simplified modeling method of UVMS system dynamics based on quasi-Lagrange equation
YANG Qingyu, REN Ping, WANG Hao
, Available online  , doi: 10.11993/j.issn.2096-3920.2024-0002
As a kind of complex system with strong nonlinearity, strong coupling, time variance, redundancy and high dimension, the modeling, motion control and stability analysis of an underwater vehicle-manipulator system(UVMS) are very challenging. In the dynamic modeling, the traditional Lagrange equation is used to model the complex underwater vehicle-manipulator system with high degrees of freedom, which requires the operation of differentiation and partial differentiation of the generalized coordinates and their derivatives, respectively, and will face the problems of large amount of calculation and low modeling efficiency. Therefore, this paper aims to propose a simplified dynamic modeling method for 6 + n degree-of-freedom UVMS based on the quasi-Lagrange equation, which can reduce the computational complexity of the symbolic formula derivation, and improve the modeling efficiency and the accuracy of the results. Finally, the numerical simulation of a UVMS model is carried out with the physical parameters of BlueROV and Reach Alpha underwater manipulator, and the simulation results verify the complex coupling of the UVMS system. The dynamic model based on the proposed method has a clear symbolic form, which not only provides strong support for the study of control algorithms and the optimization of coupling forces, but also a basis for the design of dynamic parameters and the study of trajectory planning.
Analysis of Induced Current and Electromagnetic Safety of Hot-bridge Electric Explosive Device
ZHU Xiaonan, PAN Jin, YANG Jinhou, WANG Kaiguo, LIN Xiaochuan
, Available online  , doi: 10.11993/j.issn.2096-3920.2023-0134
Based on the basic theory of electromagnetic fields, the formation of the equivalent antenna of electric explosive device(EED) and its energy conversion process were theoretically analyzed, and CST software was used to simulate and model the formation of induced current in EED under the action of strong electromagnetic pulses. After validating the model, influence factors such as incident wave signal, lead wires layout, bridge wire resistance, etc. on the induced current were studied. According to simulation results, magnitude, frequency and the direction of incident wave, and the effective electromagnetic coupling area of the equivalent receiving antenna are major determining factors. Bridge wire resistance and induced current jointly determine the electromagnetic energy coupled to the EED. From the point of electromagnetic safety, the duration of continuous electromagnetic pulse action on EED shall not exceed 178 μs. The research content has certain reference significance for the safety protection of EED in weapon systems.
Review of Underwater Acoustic Communication based on Metamaterials
ZHOU Ping, JIA Han, YANG Jun
, Available online  , doi: 10.11993/j.issn.2096-3920.2024-0103
With the explosive growth in the data volume acquired from ocean explorations, achieving efficient underwater acoustic communication has become a critical issue. In recent years, acoustic metamaterials, as a sort of novel artificial composite materials, have demonstrated the ability to surpass the limitations of traditional materials through their exceptional acoustic parameter manipulation capabilities. Thus, acoustic metamaterials have shown promising applications in numerous areas such as underwater detection, underwater target identification, acoustic imaging, navigation, and underwater communication. This paper reviews the advancements on metamaterial-based underwater acoustic communication, focusing primarily on multiplex communication based on acoustic orbital angular momentum, underwater acoustic communication between specific transmitter and receiver based on beam steering of acoustic metasurface and trans-medium water-air acoustic communication, the key issues and technologies of which are summarized. Finally, we outline the current challenges and future prospects of metamaterial-based underwater acoustic communication.
Network Traffic Measurement Optimization for Cross-Domain Ad Hoc Networks: A Meta-Learning and Reinforcement Learning Approach
SONG Jian, NIE Laisen, TAO Zui, YUAN Qiendong
, Available online  , doi: 10.11993/j.issn.2096-3920.2024-0094
Cross-domain Ad Hoc network is a network that self-organizes nodes on different media and adapts to network topology. In cross-domain networks, direct measurement technology enables network managers to obtain accurate end-to-end network traffic information, to realize sampling and statistics of data packets, to obtain end-to-end network traffic information. However, considering the low computational power and low storage characteristics of some nodes in the cross-domain network, it is difficult for all nodes to run the network traffic measurement process. To run the measurement process on as few nodes as possible to obtain as much network traffic information as possible, this paper proposes a network traffic measurement optimization method based on meta-learning and Proximal Policy Optimization (PPO). This method determines the set of nodes that perform network traffic measurement in the next time slot according to the network operating environment of the previous time slot. Finally, this paper evaluates the performance of the proposed method using three real-world datasets. The experimental results show that the cross-domain Ad Hoc network traffic measurement optimization algorithm based on meta-learning and reinforcement learning can effectively select the nodes with large traffic flow, with faster convergence speed and measurement efficiency.
Effectiveness Evaluation of Underwater Heterogeneous Platforms Based on ADC Model
ZHANG Xin, PAN Jin, ZHANG Jing, CHEN Boheng
, Available online  , doi: 10.11993/j.issn.2096-3920.2023-0143
Equipment clusters are gradually emerging as a key way to improve the efficiency of underwater tasks. Traditional ADC models make it difficult to evaluate collaborative ability of an underwater heterogeneous platform composed of multi-type equipment. The reliability, endurance, and communication performance indicators with time variables are selected, and a comprehensive model of the tree structure is established, which can quantify the synergy factors numerically and objectively reflect the changes in synergistic ability during the platform task process. Based on this as the basis for constructing dynamic capacity matrix and using the individual as the sub-system, the environmental impact factor is introduced to reflect the impact of the surrounding environment on the equipment performance, and an improved ADC model is established for system effectiveness evaluation. Taking the underwater heterogeneous platform composed of AUVS and communication nodes as an example, the equipment capability and platform effectiveness in the mission cycle are evaluated. The research results indicated that this method can be well combined with multiple synergistic factors for effectiveness evaluation, which is feasible and effective. The improved ADC model can provide a reference for the efficiency evaluation of multi-type equipment collaborative operation tasks.
2FSK Communication System Demodulation Algorithm for Novel Acoustically Excited SLF Antennas
ZHANG Xiayu, ZHANG Jiahao, JIAO Jie, LIU Yi
, Available online  , doi: 10.11993/j.issn.2096-3920.2024-0106
There exist some problems for the acoustically excited super low frequency antennas, such as low transmission power and low received signal-to-noise ratio. And it is difficult to design narrow-band filter in traditional 2FSK non-coherent demodulation. Aiming at the above problems, a 2FSK weak signal demodulation method based on Duffing chaotic oscillator is proposed. Because the Duffing oscillator itself is sensitive to the phase, a phase synchronization method of “coarse synchronization + fine synchronization” is designed; The coarse synchronization is accomplished through the short-time Fourier transform, while the fine synchronization is achieved through the Duffing chaotic oscillator. Then, the chaotic oscillator is sensitive to the same-frequency periodic signal and immune to noise signals, and the signal passes through two Duffing oscillators in parallel, and the local signal frequency of the two is consistent with the two carrier frequencies. At a certain moment when one system must be in the large-scale periodic state and the other in the chaotic state, the two systems can be discriminated to realize signal demodulation. The simulation results show that the proposed Duffing oscillator demodulation algorithm outperforms the non-coherent and coherent demodulation algorithm by 5dB and 4dB in bit error rate, respectively.
Cloud-based Software-defined Acoustic for Cross-domain Communication System
YAO Kexing, GUAN Quansheng, XIE Jiaxuan, ZHAO Hao, WANG Yan
, Available online  , doi: 10.11993/j.issn.2096-3920.2024-0075
Typical marine monitoring applications need to transmit the data obtained from underwater to the monitoring center located on land. Due to the restriction of acoustic communication performance, the performance of data transmission across the water-air interface is difficult to further improve. In this paper, a cloud-based software-defined acoustic (C-SDA) architecture is proposed for the cross-interface system. C-SDA moves the underwater acoustic receiver from the surface relay to the cloud (i.e., the monitoring center), and uses the radio communication bandwidth to exchange the computing resources of cloud to demodulate and decode the acoustic signal. In this case, the dual-stack protocol of the surface gateway is simplified to a single-stack, which avoids packet capsulation and re-capsulation. The C-SDA not only enables advanced communication signal processing, but also promotes rapid technology update and iteration. The field-test experimental results show that, the proposed C-SDA can be applied to a higher performance equalizer and achieve a significant improvement in bit error rate, compared with the existing embedded underwater acoustic receiver.
Progress and Prospect of Underwater Information Acquisition Technique for Water Exit Trans-media Vehicle
ZHANG Xu, LI Wanpeng
, Available online  , doi: 10.11993/j.issn.2096-3920.2024-0044
The water exit process of trans-media vehicle involves multiphase flow, unsteady evolution of cavitation, strong transient effect and harsh load environment, which significantly affects the motion stability, water exit attitude and structural strength of vehicle. To fully understand and verify the vehicle water exit performance in the marine environment, the adapted underwater information acquisition technique is urgently required. In this paper, the research on underwater information acquisition technique for vehicle water exit test in the marine environment, such as target localization, phenomena observation, environmental measurement and information transmission, is summarized. Meanwhile, the new requirements of underwater information acquisition technique to adapt the modern trans-media vehicle with high-dynamic motion or deep water exit performance are analyzed, and the corresponding systematic, multimodal and digital technology trends are prospected, which may provide a sketchy reference for obtaining the high value underwater information in the sea test, managing the complex marine environment and interpreting underwater motion process.
Calculation of Torpedo Discovery Probability by Combining Analytical and Simulation Methods
DAI Zhen, YAN Yong, SHEN Xiangzhong
, Available online  , doi: 10.11993/j.issn.2096-3920.2023-0128
The analytical method and simulation method are commonly used to calculate the probability of torpedo discovery. The analytical method has a fast speed, but it is only applicable to some parameter error types. The simulation method is applicable to all parameter error types, but the computational efficiency is low. To address this issue, a discovery probability calculation method combining analytical and simulation methods is proposed. Firstly, the parameter masking interval is solved based on the idea of simulation methods. Then, the discovery probability is calculated using analytical methods, which significantly improves computational efficiency while ensuring accuracy. Finally, the effectiveness of the proposed algorithm is verified through simulation.
Research on algorithm of the acousto-optic communication from water to air
ZHOU Zhiquan, ZHAO XingKang, CHEN Yingnan, HUANG Jinxin, ZHAO Yang
, Available online  , doi: 10.11993/j.issn.2096-3920.2024-0098
To achieve underwater-to-air wireless communication across different media, this study utilizes laser interference for detecting underwater acoustic signals. Through simulation calculations, attenuation curves of acoustic signals at various water depths to the water surface, as well as micro-vibration curves on the water surface caused by different underwater acoustic power frequency signals, are obtained. A quantitative relationship between underwater sound source characteristics and disturbances on the water surface is established. Communication code elements for cross-media communication are designed, and various demodulation methods are compared. The analysis investigates the impact of parameter variations on the transmission error rate and accomplishes modulation and demodulation simulations of acoustic-laser communication. The findings guide parameter selection for practical cross-media communication experiments.
Experimental study of cross-medium communication of millimeter wave radar on a wave tank
ZENG Yuming, ZHANG Kun, LE Nanyan, SONG Chunyi, XU Zhi-wei
, Available online  , doi: 10.11993/j.issn.2096-3920.2024-0109
The wireless cross-domain communication technology for underwater equipment is an important challenge that urgently needs to be solved in marine technology. Millimeter wave radar could solve this problem by detecting the micro-wave vibration excited by sound waves on the water surface. Studying the impact of water surface waves is of great value for millimeter wave radar-based cross-medium communication. The recently introduced millimeter wave radar based cross-domain communication technology has not been extensively studied in terms of its impact on water surface waves. This article conducted cross-medium communication experiments on BPSK and BFSK modulation signals on a wave tank, tested and analyzed the impact of different amplitude water surface waves on cross-medium communication, and estimated the performance improvement of conventional spatial diversity technology. The experimental results show that moderate water surface waves have the least impact on the performance of millimeter wave radar-based cross-medium communication, and multi-channel data merging can improve cross-medium communication performance to a certain extent on wavy water surfaces. The research results of this article can provide a reference for practical applications of millimeter wave radar-based cross-medium communication on wavy water surfaces.
Research on communication technology of far-sea cross-domain buoys based on HF sky-wave propagation
XIAO Longzhong, ZHANG Song, LIU Zhenji, ZHAO Yi
, Available online  , doi: 10.11993/j.issn.2096-3920.2024-0033
With the continuous development of long-distance sea scientific exploration technology, the demand for cross-domain reliable transmission is becoming more and more serious, HF sky-wave propagation communication is limited by the working frequency,and the use scenarios are seriously limited.For the cross-domain long-distance transmission requirements of far-reaching Marin science exploration short message transmission,this paper presents a relay communication technology for cross-domain short message transmission that can be used in far-reaching sea research scenarios.Based on this technology,the communication scheme,working principle,working flow and working method are designed,by designing variable length flexible short wave antenna and water cooling integrated power amplifier assembly,it ensures the advantages of high antenna gain,strong sea condition adaptation,and cross water medium transmission.Through simulation analysis,it shows that the proposed communication method can effectively guarantee the communication effect,solve the problem of cross-domain long-distance reliable communication of short messages in the high sea conditions and complex interference environment,to make up for the information of the other side under the harsh environment such as the deactivation of satellite communication means,for the distance at sea the development of cross-domain communication provides certain technical support.
A Study on Laser-Induced Acoustic Water-to-Air Cross-Medium Communication Method Based on PWM Modulation
CHEN Yingnan, ZHAO Yang, ZHOU Zhiquan, CAO Yifei, ZHANG Faxiang
, Available online  , doi: 10.11993/j.issn.2096-3920.2024-0019
In light of the demand for integrated communication networks spanning sea, air, and space, laser-induced acoustic communication has emerged as a critical technology for facilitating nodeless communication between airborne platforms and underwater targets, garnering increasing attention in research and application. Traditional modulation and demodulation techniques based on single-pulse recognition have achieved satisfactory communication outcomes at low repetition frequencies. However, at higher repetition rates, these techniques face challenges due to exacerbated interference among pulses, significantly disrupting bit determination and leading to high error rates that impede effective communication. Addressing this issue, this study introduces a novel laser-induced acoustic communication method employing Pulse Width Modulation (PWM). Experiments utilized an Nd:YAG pulsed laser with a maximum repetition rate of 500 Hz, adjusting the number of laser pulses to generate PWM signals of varying widths, with bit recognition at the receiving end based on pulse width. The PWM-based communication method effectively minimizes decoding errors due to inter-pulse interference, achieving commendable performance at the highest repetition rate of 400 Hz with an error rate of just 8%. This improvement significantly enhances the reliability and effectiveness of laser-induced acoustic communication at high repetition frequencies.
Design of Low-Power Cross-Domain Communication Buoy System
, Available online  , doi: 10.11993/j.issn.2096-3920.2024-0035
Aiming at cross-domain interaction of information above and below the water surface in cross-domain cooperative operations, a low-power cross-domain communication buoy system was designed, taking advantage of the buoy's flexible deployment, long-term concealment, and flexible payload characteristics. This system mainly supports deep-sea deployment at great depths, long-term silent watch, and coverts cross-domain communication upon activation. Additionally, it can self-destruct critical components according to preset instructions, thus avoiding the exposure risk of surfaced communication on platforms such as submarines, and is relatively easy to deploy and sustain. Test results indicate that the designed system features high pressure resistance, low-power consumption, and certain scalability, offering good prospects for application.
Study on Submarine Magnetic Field Simulation with Energized Coil
GUAN Feng, SHENG Zhaohua
, Available online  , doi: 10.11993/j.issn.2096-3920.2024-0040
Due to the advantages of high fidelity, adjustable magnetic field distribution and intensity, good maneuverability, low environmental dependence and high safety of submarine magnetic field, the method of concentric magnetic field with current coil has attracted more and more attention. It is necessary to conduct in-depth research on the distribution characteristics of the electric coil submarine magnetic field simulator in order to better guide its design. In this paper, the calculation method of the space magnetic field of submarine and the space magnetic field of any current wire is given, and the submarine magnetic field simulation factory scheme of split-type three axis orthogonal coil is proposed, and the space magnetic field distribution characteristics of this scheme and the submarine are compared and studied. The results show that the three axis orthogonal coil method can simulate the distribution characteristics of submarine space magnetic field well, but cannot fully reflect the distribution scale. This article provides technical reference for submarine magnetic field simulation.
Analysis of the Development Status and Trend of U.S. for Underwater Special Operations Equipment
ZHANG Zhiwei, FANG Zejiang, HE Runmin, ZHAO Qi, ZHU Zhaotong
, Available online  , doi: 10.11993/j.issn.2096-3920.2023-0166
In recent years, as the western countries led by the United States have shifted their strategic focus from ocean to offshore, the shallow waters in the offshore have become the focus of attack and defense for all countries. With the distributed combat background of manned and unmanned cooperation, underwater special operations platforms have begun to play an increasingly important role. This article is based on the latest defense research and procurement budget for the US fiscal year 2024, and focuses on the development status and research trends of underwater special operations equipment such as Swimmer Delivery Vehicle (SDV), Dry Combat Submersible (DCS), Dry Deck Shelter (DDS), Combat Diving (CBDIV), Undersea Craft Mission Equipment (UCME), and Small Underwater Unmanned Vehicle (SUUV) in underwater system projects, intended to provide useful references for future research on underwater special equipment.
A Task-Oriented Routing Protocol for Sea-Air Cross-Domain Networks
ZHANG Haobo, WANG Biao, HAN Zhaoyue
, Available online  , doi: 10.11993/j.issn.2096-3920.2024-0015
With the increasing frequency of maritime and aerial operations, sea-air cross-domain networks have become a pivotal technology for achieving effective communication. Comprising underwater and surface subnets, these networks aim to fully utilize resources, enabling multiple diverse applications to share the same physical infrastructure. In this scenario, different data packets coexist within the same network, requiring differentiated transmission strategies to meet application demands. However, existing routing protocols often fail to provide personalized services based on application requirements. To address this issue, this paper proposes a task-oriented routing protocol for sea-air cross-domain networks. The protocol adjusts the calculation method of forwarding factors based on the types of tasks, thereby selecting the most suitable next-hop node for specific task types. Furthermore, this paper introduces a preprocessing layer into the protocol stack to facilitate communication between heterogeneous networks. Simulation experiments conducted using NS3 demonstrate that, compared to other typical protocols, the proposed protocol consistently achieves optimal transmission strategies based on specific task requirements.
Study on field Data Fusion and calibration techniques of MEMS Array
Ruan Wei, Huang Hai, Hong Jianying, Qin Bin
, Available online  , doi: 10.11993/j.issn.2096-3920.2023-0140
Aiming at the poor repeatability and large random noise of micro electro mechanical system. Using Allan method to analyze the random walk of MEMS. The information fusion algorithm of array gyro is designed by using Allan variance identification value and weighted least square method, which can effectively reduce the angle random walk and respond to the true angular rate in real time under both static and dynamic conditions. For MEMS gyro constant zero bias, Combined with the observability of the error of the inertial navigation system, Design two-position calibration scheme to complete system-level calibration of constant drift. Simulation results show that The method proposed in this paper is effectively reduce the angle random walk and the constant drift of MEMS gyro, Significantly improve the inertial measurement accuracy of MEMS.
Research on the method of torpedo powerhouse segment vibration damping based on acoustic metamaterials
SUN Xu-yang, ZHOU Jing-jun, WANG Qian, ZHANG Zhi-min
, Available online  , doi: 10.11993/j.issn.2096-3920.2024-0063
The acoustic stealth performance of torpedoes directly affects the safety of the launching platform, the concealment of the torpedo attack, and the effectiveness of wire-guided guidance. However, the current widely adopted vibration and noise reduction means are ineffective in controlling the low and medium frequency vibration of torpedoes. In order to solve this problem, the present study is carried out to investigate the vibration damping method of acoustic metamaterials for the torpedo powerhouse section. Firstly, the vibration response characteristics of the power module under axial excitation are analysed, and a cantilever beam local resonance unit structure is designed, and the bandgap characteristics and vibration damping effect of the structure are systematically and deeply analysed. Then, for the supporting structure of the power section, a vibration reduction scheme based on acoustic metamaterials is proposed, and it is found that acoustic metamaterials have a significant attenuation effect on vibration within the corresponding bandgap, and the attenuation of some measurement points can be as high as 11.95 dB. Finally, the validity of the acoustic metamaterials damping scheme is verified through tests, which provides a idea for solving the low-frequency vibration problem in the power section of the torpedo.
Research on Screw Propulsion Performance of Amphibious Robot
XU Pengfei, WANG Zipeng, LIN Hailong, KAI Yan
, Available online  , doi: 10.11993/j.issn.2096-3920.2023-0167
The traditional amphibious locomotion mode is the dual system of wheel or track and propeller. In contrast, single-system amphibious locomotion has become a research hotspot in recent years because of its low complexity and high efficiency. As a single-system amphibious motion mode, screw propulsion has a good adaptability in semi-fluid environment such as swamp and beach. Over the years, there have been many research designs on its driving on land, but few studies on its driving in water. In this paper, the underwater performance of the screw propulsion device is studied, and the design method of the screw cylinder is proposed according to the principle of screw propulsion. The hydrodynamic simulation method is used to calculate the thrust of the screw cylinder at different submerged depths, and it is found that the thrust generated by the screw cylinder is the largest at 0.9 times the submerged depth. Based on the self-designed and developed amphibious robot prototype, the underwater propulsion test was carried out, and the results showed that the underwater screw cylinder propulsion state was stable. Further, the response surface method is used to optimize the design of the screw cylinder from the two aspects of screw blade height and pitch, and the optimization results can increase the propulsion efficiency by 18.2% compared with the original design scheme.
Robust beamforming technology for small platform conformal array based on covariance matrix fitting
GONG Shiyu, FANG Erzheng, ZHANG Jianing
, Available online  , doi: 10.11993/j.issn.2096-3920.2024-0001
To address the challenges of detection on small-scale platforms like unmanned undersea vehicles(UUV), which are characterized by their maneuverability and the constraints of limited array apertures, we design various beamforming algorithms leverage U-shaped conformal planar arrays specifically tailored for compact platforms. This study evaluates the impact of factors such as snapshot rate, input signal-to-noise ratio(SNR), and inaccuracies in the steering vector on the robustness of these beamforming techniques. While the Minimum Variance Distortionless Response(MVDR) method is noted for its superior array gain, its performance significantly deteriorates in the presence of steering vector errors and inaccuracies in the covariance matrix estimation. To mitigate these issues, this paper introduces the covariance matrix fitting and the dual-constraint covariance matrix fitting beamforming approaches, enhancing the original method's robustness. The efficacy of the algorithm of this paper is validated through numerical simulations by comparing it with various beamforming techniques, thereby assessing their robustness in conformal arrays used on underwater small-scale platforms. Additionally, the reliability of these methods is further corroborated through experimental in an anechoic pool, taking into account the positional inaccuracies of the array elements.
Study on Light Scattering Characteristics of Dirty Bubbles
DONG Min, ZHANG Jiansheng, YAN Linbo, JIAO Guijin, YAO Yuan
, Available online  , doi: 10.11993/j.issn.2096-3920.2023-0116
In order to provide a more thorough explanation of the light scattering properties of wake in real marine environments, this study examines the variations in light scattering properties of wake bubbles induced by organic matter films in actual marine settings. Drawing on scattering theory, the study simulates the scattering intensity distribution, scattering coefficient, scattering phase function, and polarization degree of clean bubbles, as well as organic bubbles enveloped in protein and lipid films, under varying wavelengths of incident light. The simulation findings reveal that the scattering coefficients of clean bubbles and the two types of organic bubbles with membranes fluctuate around 2.025, with the organic bubbles exhibiting significantly larger oscillation amplitudes than the clean bubbles. Notably, at a scattering angle of 180°, the scattering intensity and scattering phase function of organic bubbles enveloped in oil and protein experience a notable increase. These organic bubbles have the potential to amplify the amplitude of scattering coefficient oscillations and the intensity of backscattering. The simulation results offer theoretical and empirical support for wake detection in real marine environments, and also provide a practical foundation for research on marine pollution and water quality assessment.
Unsupervised Controllable Enhancement of Underwater Images Based on Multi-Attribute Representation Disentanglement
ZHOU Shijian, ZHU Pengli, CHEN Han, LIU Siyuan
, Available online  , doi: 10.11993/j.issn.2096-3920.2023-0165
The unsupervised enhancement technique for underwater images exhibits a limited adaptability towards various distortions inherent in multi-class distortion underwater images. The structural content of the images tends to change alongside the style attributes during the enhancement process, resulting in uncontrolled enhancement effects that impede the stability and accuracy of subsequent environmental perception and processing. To address this issue, a method based on multi-domain representation disentanglement for controllable unsupervised enhancement of underwater images is proposed in the paper. Initially, a framework of multi-domain unified representation disentanglement cycle-consistent adversarial translations is devised, thereby enhancing the algorithm's adaptability to multiple distortion factors. Subsequently, a dual-encoding conditional decoding network structure is constructed. Finally, a series of losses for multi-domain attribute representation disentanglement is designed to enhance the independence and controllability of quality, content, style, and other attribute representations. Experimental results demonstrate that the proposed algorithm not only eliminates various distortions such as color aberration, blur, noise, and low illumination in underwater images but also enables controllable enhancement through linear interpolation of image style codes for underwater images.
Cooperative Hunting Method for Multiple-Agents Using Differential Games Based on Escape Angle
YANG Huizhen, LI Jianguo, WU Tianyu, YANG Jun, WANG Zijiang
, Available online  , doi: 10.11993/j.issn.2096-3920.2023-0142
Aiming at the problem that the adversarial single-target actively escapes, a game model of multi-agent cooperative encirclement problem is established using differential game (DG) theory. Introducing The escape angle correlation term is introduced into the traditional payment function which includes the distance cost such that the escape probability of the target is reduced; At the same time, the encirclement problem is converted into multiple groups of pursuit and escape countermeasures, and Particle Swarm Optimization (PSO) algorithm is used to solve the optimal strategy that satisfies the Nash equilibrium. The simulation results show the effectiveness of the algorithm based on DG-PSO fusion. Then experiments based on multiple autonomous surface vehicles shows that the designed hunting algorithm is effective.
The control method of deep-sea vector propulsion motor based on position-sensorless and variable carrier frequency
Huang Xiaoyan, Liu Yabing, Gu Yujie, Zhang Qiang, Wang Yuankui
, Available online  , doi: 10.11993/j.issn.2096-3920.2023-0129
In order to improve the performance of vector propulsion motors in deep-sea exploration, this paper proposes a control method for deep-sea vector propulsion motors based on the surface-mounted permanent magnet synchronous motors , combined with Periodic Carrier Frequency Modulation (PCFM) technology and improved Sliding Mode Observer (SMO) position-sensorless control technology.Through simulations of motor carrier frequency variation, motor start-up speed variation, and load disturbance, this paper analyses the simulation results of the proposed control method. The results show that the speed estimation of the studied control method is accurate and has good dynamic tracking performance. The error rate at the rated rotation speed is only 0.32%, and the error rate at 0.5 times the rated rotation speed is only 0.09%.Besides, the proposed control method has obvious high frequency harmonic expansion frequency suppression effect and good dynamic anti-interference performance.Combined with the simplification effect of reducing the motor structure brought by the position sensor, the control method proposed in this paper can effectively reduce the failure rate of the deep-sea vector propulsion motor operation, reduce the high-order fixed frequency harmonics that are easy to be detected,improve the reliability of the deep sea vector propulsion motor and stealth, provide efficient and reliable guarantee for deep sea UUV.
Study on Laser Transmission Characteristics of Wake Bubble Curtain
JIAO Guijin, ZHANG Jiansheng, YAN Linbo, DONG Ming, YAO Yuan
, Available online  , doi: 10.11993/j.issn.2096-3920.2023-0093
In the wake region generated in the course of navigation, the scattering phenomenon occurs when the laser passes through the wake region of the bubble. Through the detection and analysis of the scattered light, the purpose of detecting and identifying the ship can be achieved. In this paper, the influence of wake bubble curtain on laser transmission characteristics is investigated, and the light intensity change of wake bubble curtain is detected based on fiber optic spectrometer. The laboratory simulated the change of light intensity of wake bubble curtain under different pressures when the thickness of wake bubble curtain 5 cm away from the water surface and 15 cm and 20 cm away from the water surface were 10 cm and 15 cm respectively, and also explored the change of light intensity of forward scattering and backward dispersion with the change of pressure. The experimental results show that the variation of light intensity decreases with the increases of pressure. When the pressure increases, the concentration of the bubble also increases, and the radius of the bubble will also increases with the increases. The higher the bubble concentration, the smaller the change of light intensity. With the increase of forward scattered light gradually decreases and linearly changes, while the intensity of backward scattered light increases with the increase of air pressure.
System Capability Assessment Modeling Based on Characteristic Parameters
LIANG Xiaoling, DENG Jianhui, CHEN Sijun
, Available online  , doi: 10.11993/j.issn.2096-3920.2023-0126
This paper proposes a neuro-fuzzy system to establish a vulnerability model of the aviation insurance system, introduces fuzzy rules into the framework of the neural network, and establishes an evaluation model for the system's task capabilities. This method combines the reasoning ability of fuzzy logic and the infinite approximation function ability of neural networks to establish an alternative model of the real system, which is more universal. Secondly, an intelligent optimization algorithm is used to make the alternative model as close as possible to the real model, getting rid of the influence of the unknown weight coefficient in the system that relies on experts or experience, and endows the neural fuzzy network with learning capabilities. The experimental results and analysis show that the assessment model is comprehensive and reasonable and can be applied to aviation insurance system capability assessment research.
Research on Liquid metal-based Triboelectric Whisker Sensor
LI Yuanzheng, WANG Tianrun, GUAN Tangzhen, XU Peng, WANG Hao, XU Minyi
, Available online  , doi: 10.11993/j.issn.2096-3920.2023-0125
To enhance the maneuverability and adaptability of underwater robots, it is essential to improve their perception of the surrounding environment. Inspired by the hair follicle structure of animal whiskers, this paper proposes a liquid metal-based triboelectric whisker sensor (LTWS) combined with liquid metal-based triboelectric nanogenerators. This sensor serves as a supplement to optical and acoustic perception technologies for underwater robots in turbid water with low visibility, enhancing the robots' information perception capabilities. The LTWS mainly consists of carbon fiber whiskers, silicone sheaths, triggers, shape memory alloy springs, sensing units, and a base. The subtle deflection of the carbon fiber whiskers drives the trigger to approach and squeeze the corresponding direction of the sensing unit, thereby generating an electric signal. The sensing signal of LTWS has a linear relationship with the lateral displacement of the tentacles, and the sensitivity can reach 7.9 mV/mm. It is worth mentioning that the touch frequency has a small impact on the output signal. LTWS enriches the perception methods of underwater robots, providing a new approach for marine information perception.
Scattered Light Compensation Combined with Color Preservation and Contrast Balance for Underwater Image Enhancement
NING Zemeng, LIN Sen, LI Xingran
, Available online  , doi: 10.11993/j.issn.2096-3920.2023-0131
Aiming at the problems of color deviation, low contrast and blurring in underwater images, an underwater image enhancement method based on scattering light compensation combined with color preservation and contrast balance is proposed. Firstly, the relative total variational model is used to separate the structure and texture layer. Among them, the color deviation of the structural layer is corrected by defining a compensation coefficient error matrix based on the RGB spatial mapping relationship, and the texture layer is enhanced by filtering separation and fusion to prevent the initial feature loss of the image. Besides, color preservation-contrast limiting adaptive histogram equalization based on the spatial transformation is performed to further improve the contrast and brightness. Finally, the double-stream enhanced results are fused to obtain the output. It is verified by various evaluations on different datasets that the proposed method has better performance in balancing color deviation, enhancing details, and dehazing, which has practical application value in underwater computer vision tasks.
GPA based domain adaptive feature refinement method for underwater target detection
LIU Qidong, SHEN Xin, LIU Hailu, CONG Lu, FU Xianping
, Available online  , doi: 10.11993/j.issn.2096-3920.2023-0149
Underwater environments are often more susceptible to domain shift and reduced detection accuracy during underwater object detection due to the influence of lighting, sediment, and other factors. In response to this phenomenon, this article proposes a domain adaptive underwater target detection method based on graph induced alignment. Graph induced prototype alignment (GPA) obtains instance level features in the image through graph based information propagation between region proposals, and then derives prototype representations for each category for category level domain alignment. The above operations can effectively aggregate different modal information of underwater targets, thereby achieving alignment between the source and target domains and reducing the impact of domain offset. In addition, in order to focus the neural network on instance level features under different water distribution, a Convolutional Block Attention module (CBAM) was also added to it. The experimental results have shown that GPA can effectively align instance features in the source and target domains in underwater environments, while CBAM can make the network pay more attention to instance features in images and improve detection accuracy.