水下无人系统学报

Underwater Target Search and Tracking Based on Air-Sea Heterogeneous Unmanned Platform

DING Wenjun, CHAI Yajun, YANG Yuxian, LIU Jiamin, MAO Zhaoyong

, Available online , doi: 10.11993/j.issn.2096-3920.2024-0037

[Abstract](12) [FullText HTML] (6) [PDF 1658KB](2)

Abstract:
The marine heterogeneous unmanned systems can effectively enhance the implementation efficiency of complex missions. In this paper, autonomous undersea vehicles(AUVs) and unmanned aerial vehicles(UAVs) were used for searching and tracking unknown underwater targets in offshore waters. First, the underwater target search and tracking mission was described, and the mission was divided into two stages: target search and target tracking, with the objectives of maximizing the total search space of the AUV&UAV system and minimizing the end position error between the AUV and the underwater target, respectively. Then, a cross-domain collaborative search model of the AUV&UAV system was established, and constraints such as detection range and communication distance for AUVs and UAVs in the model were set. Finally, based on the traditional particle swarm optimization algorithm, an adaptive learning factor regulation strategy and an elite preservation strategy were employed for cross-domain collaborative search and tracking path planning, and search and tracking paths were generated. The simulation experiment demonstrates that the heterogeneous AUV&UAV system based on an improved particle swarm optimization algorithm can more efficiently search and track underwater targets.

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

[Abstract](9) [FullText HTML] (6) [PDF 2147KB](1)

Abstract:
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.

A Suicide Unmanned Vessel Defense Strategy Based on Sea and Air Unmanned Cluster

SUN Feng

, Available online , doi: 10.11993/j.issn.2096-3920.2024-0034

[Abstract](8) [FullText HTML] (5) [PDF 1430KB](2)

Abstract:
Recently, the use of unmanned surface vessel on the Russia-Ukraine conflict has received high attention, with consideration given to anti unmanned suicide vessel attacks, this paper introduces a new concept of countering unmanned suicide vessel harassment against surface targets, based on low-cost platforms such as unmanned surface vessel and unmanned aerial vehicle, employing the idea of "unmanned versus unmanned". It advocates for the coordinated use of multiple lightweight unmanned platforms with simple interaction and autonomous decision-making capabilities. By analyzing the typical capabilities of unmanned suicide vessels, it investigates key technologies such as sea-air coordinated task assignment and planning, cross-platform collaborative reconnaissance positioning, to construct a new type of reconnaissance and defense unmanned system. This system not only provides all-weather quasi-real-time coverage of key defense areas but also achieves agile confirmation and immediate response to invading suspicious targets. Furthermore, it expands the defense depth of high-value targets by establishing multiple layers of defense against clusters of unmanned suicide vessels in a "wolf pack" style attack.

Development and Future Trends of Autonomous Underwater Vehicle Swarming and Networking Technologies

YU Yang, SUN Siqing, ZHANG Lichuan, PAN Guang, WANG Peng

, Available online , doi: 10.11993/j.issn.2096-3920.2024-0055

[Abstract](26) [FullText HTML] (7) [PDF 2816KB](7)

Abstract:
Autonomous Underwater Vehicle (AUV) are employed across a wide range of applications, capable of undertaking various tasks in dangerous, harsh, and challenging underwater environments. These tasks include ocean resource exploration, water monitoring, and area denial, among others. However, the type and amount of sensors that a single AUV can carry are limited, unable to meet the diverse requirements for tasks in marine environments, including the need for extensive operational areas and prolonged operation periods. Thus, the development of swarming and networking technologies for AUV clusters is particularly significant. Utilizing key technologies such as underwater acoustic communication, cooperative detection, and control decision-making, AUVs can achieve networking and coordination among different types of vehicle platforms, forming either homogeneous or heterogeneous clusters for collaborative operations. Through such swarming and networking, the capabilities of underwater vehicle can be fully utilized, enabling information sharing, task cooperation, and resource integration among multiple platforms, thereby autonomously completing more complex maritime operations. This clustering approach not only improves the efficiency of task execution but also reduces operational costs and enhances detection, monitoring, and response capabilities in the marine domain. This paper introduces the research status of autonomous underwater vehicle swarm, summarizes the key technologies and challenges, and looks forward to future trends, providing a reference for foundational theoretical research and practical application studies in the field of autonomous underwater vehicle clusters.

Cross-domain Collaborative Application and Technology Development of Maritime Unmanned Systems

QIU Zhiming, MENG Xiangyao, MA Yan, WANG Liang, XIAO Yujie

, Available online , doi: 10.11993/j.issn.2096-3920.2024-0053

[Abstract](33) [FullText HTML] (3) [PDF 1182KB](12)

Abstract:
Maritime Cross-domain unmanned systems collaboration is the future development trend and important way of application of maritime unmanned systems. With the rapid development of various maritime unmanned systems and their application in local wars and conflicts in the world, how to better use maritime unmanned systems has become the focus of research. Taking maritime unmanned systems in different spatial domains as the object, this paper summarizes the current maritime unmanned systems and the development status of foreign maritime cross-domain unmanned systems. The basic principles and methods of maritime cross-domain unmanned systems are analyzed, and the key issues of maritime cross-domain unmanned systems are put forward. On this basis, the key technologies that need to be paid attention to in the development of technology are sorted out. Finally, several enlightenments for future development are put forward, in order to provide reference for the application and technology development of maritime cross-domain unmanned systems.

Multi-UUV Collaborative Bearing-only Target Tracking Based on Boundary Constrained Particle Filter

HAN Bo, XU Hongli, QIU Shaoxiong, ZHANG Wenrui

, Available online , doi: 10.11993/j.issn.2096-3920.2024-0050

[Abstract](7) [FullText HTML] (3) [PDF 2400KB](1)

Abstract:
Aiming at the demand for multi unmanned undersea vehicles(UUV) collaborative detection of water surface targets in cross domain collaboration at sea, a multi UUV collaborative bearing only target tracking algorithm based on boundary constrained particle filtering is proposed to address the difficulties of filter initialization and packet loss in underwater acoustic data transmission faced by existing bearing only target tracking algorithms. Firstly, a master-slave collaborative detection model was proposed, which utilizes the follower to report the state estimation results to the navigator for data fusion. Secondly, based on the prior information of UUV sensors and targets, a reliable particle generation method for the initial stage and a particle weight optimization method for the indicator function in the update stage were designed. Finally, a distributed fusion algorithm based on gray prediction was proposed to obtain the target prediction results. The simulation experiment compared this algorithm with other common algorithms and verified the effectiveness and feasibility of the algorithm under communication packet loss and noise interference.

Key Technology and Verification of USV and UAV Cooperative Positioning Landing and Take-off

ZHENG Bing, Dong Chao, LIU Han, XIONG Junfeng, HUANG Chaoxiong

, Available online , doi: 10.11993/j.issn.2096-3920.2024-0026

[Abstract](15) [FullText HTML] (7) [PDF 2466KB](1)

Abstract:
Unmanned surface vessel(USV) single-platform execution mission is easily restricted by the platform, and the construction of USV and unmanned aerial vehicle(UAV) cross-platform system can realize the complementary advantages of the platform. In this paper, the USV and UAV take-off and landing and energy replenishment technologies are studied to realize the UAV and UAV enduring cooperative operation. Firstly, for the problem of UAV taking off and landing on dynamic UAV, we carry out the research on USV and UAV cooperative positioning take-off and landing technology, study the dynamic update model of USV’s and UAV’s speed and position information, and realize the high-precision take-off and landing of UAV at the USV end; Secondly, to address the problem of short endurance time of UAV, the research on UAV replenishment at the USV end is carried out, and the landing mechanism at the UAV end and the charging mechanism at the USV end are investigated to realize the rapid replenishment of UAV landing on the USV end; Finally, the performance of the USV and UAV cross-platform take-off and landing and replenishment system is verified on the sea, and the UAV is able to land and replenish at the USV end at the high-speed movement of 3.0 m/s, which meets the demand of the USV and UAV cross-platform execution mission on the sea.

Cross-Domain Unmanned Cluster Combat Supported by Satellite Internet

LI Mo, GUO Dong, ZHOU Donghong, DONG Guantao, LI Dongyu, CHU Hongbing, SHANG Zhigang

, Available online , doi: 10.11993/j.issn.2096-3920.2024-0043

[Abstract](10) [FullText HTML] (2) [PDF 1464KB](5)

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Cross-domain unmanned cluster is a disruptive new combat mode in the future, and its combat effectiveness is greatly affected by communication networking capabilities. In recent years, satellite Internet, with its technological advantages of wide coverage, low latency, high bandwidth, and low cost, has developed rapidly in the world, and it is the key to further developing the cross-domain unmanned cluster combat mode. In view of the development trend and practical needs of the future underwater unmanned system, the development and technical advantages of satellite Internet, as well as the concept of cross-domain unmanned cluster combat were introduced. The advantages of cross-domain unmanned cluster combat supported by satellite Internet were deeply analyzed. The air-sea cross-domain unmanned cluster combat network was proposed by combining satellite Internet technology and unmanned clusters in airspace, sea surface, and underwater combat domains. In addition, a comprehensive analysis of the technical architecture was given, providing a reference for future research on cross-domain unmanned cluster combat.

Broadband Cognitive Stacked Networks for the Cross Domain Decentralized Networking Communications at Sea

LI Zhongxiao, LUO Rong, WANG Gang, ZHANG Weiqiang

, Available online , doi: 10.11993/j.issn.2096-3920.2024-0036

[Abstract](11) [FullText HTML] (5) [PDF 2410KB](2)

Abstract:
With the increasingly severe situation of enemy confrontation at sea, multi-platform deployment in deep ocean is needed. Maritime Wireless Communication relying on single band including HF、V/UHF and Microwave frequency can no longer meet the communication support needs of multiple datalink networking, flexible resource allocation, and systematic anti-interference for distributed maritime operations. This paper proposes a new network communication architecture based on broadband cognitive layered network to meet the requirements of multiple datalink networking communication technology in distributed maritime operations. The integrated RF front-end is used for broadband RF resource management, and the data link fusion meta model is formed by unifying bandwidth, time slot, and time and space. On this basis, a software communication system backend is adopted for multi chain fusion and layered networking. Through technologies such as broadband spectrum sensing, cognitive spectrum access, and task driven adaptive networking, dynamic adaptation to multi domain communication environments such as air, sea, and submarine is achieved, as well as cognitive decision-making in strong enemy adversarial environments. This can enhance the expansion, cross domain transmission, and anti-interference communication capabilities of maritime communication networks. This paper conducts in-depth research on the key technologies of broadband cognitive stacked networks, which can provide reference for the architecture design and technical research in the maritime communication field.

Development Overview and Inspiration of Collaborative Application of Heterogeneous Unmanned Clusters at Sea

SUN Haiwen, WANG Xiye, WANG Zhaochen, MENG Xangyao, CHEN Ting, JIN Zirong

, Available online , doi: 10.11993/j.issn.2096-3920.2024-0032

[Abstract](14) [FullText HTML] (4) [PDF 1566KB](4)

Abstract:
Unmanned system clusters, with their significant characteristics such as high coordination, complete autonomy, and collective intelligence, can directly affect and change the style of maritime operations. Various maritime powers around the world are competing to conduct research on the collaborative application of heterogeneous unmanned equipment. This article focuses on analyzing the current development status and typical combat application cases of the collaborative application of heterogeneous unmanned clusters in the world's oceans. Based on this, Analyze and summarize the operational styles and characteristics of collaborative use of heterogeneous unmanned clusters at sea, and finally propose inspiration and suggestions for the future development of collaborative use of heterogeneous unmanned clusters at sea.

Research on numerical calculation of vehicle water exit under different sailing conditions

LIU Pingan, CHU Yue, HUANG Xi, GAO Song, JI Zhentao, ZHOU Xiaohu

, Available online , doi: 10.11993/j.issn.2096-3920.2024-0017

[Abstract](15) [FullText HTML] (6) [PDF 2473KB](2)

Abstract:
Vehicle exiting-water process is very complicated, accompanied by multiphase flow, cavitation, phase transition and turbulence instability, and the applied force is highly unsteady and nonlinear. Mostly, studies of vehicle exiting-water with cavitation focus on the vertical or oblique exiting-water internationally, and is focus on the trajectory and attitude of the vehicle.There are few studies on the exiting-water process of the supercavitation vehicle. In this paper, based on STAR-CCM+ software, overlapping grid technology is used to for meshing, VOF model is used to capture the gas-liquid interface, Schnerr-Sauer model describes the cavitation process around the vehicle, and a numerical calculation model of the exiting-water process is established. The flow field and cavitation evolution laws under different conditions that includes initial velocity, initial water depth and ventilate mass flow are obtained, and the hydrodynamic and kinematic characteristics of the supercavitating vehicle are analyzed. The simulation results show that the underwater motion of the vehicle with different initial motion velocity presents two different modes. Under different water depths, the initial cavitation number is different. Cavitation around the vehicle is more likely to rupture in deeper waters. The cavitation morphology can be improved effectively by increasing the ventilation flow rate.

Analysis of Effects of Speed on Oblique Water Entry Process of a Cylinder Under Ice-Hole Constraint

LU Lin, YANG Zhe, CHEN Kaimin, CHENG Yongdong, YANG Shuai

, Available online , doi: 10.11993/j.issn.2096-3920.2024-0027

[Abstract](17) [FullText HTML] (5) [PDF 2737KB](2)

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Supercavity technology has received extensive attention from scholars at home and abroad in recent years. The polar ice region is bound to have a significant effect on the cavity evolution and motion characteristics of supercavitating projectiles. For the water entry problem of supercavitating weapons in an ice environment, a numerical method for the oblique water entry cylinder under ice-hole constraint is established based on the N-S equations by introducing the VOF model and combined with the overlapping mesh technique. On this basis, the numerical simulation of the water entry process of the cylinder through the ice hole under different velocities is carried out, and the cavity evolution and impact characteristics of the cylinder in the water entry process are analyzed. The results show that ice-hole constraint restricts the flow of water in the ice hole such that direct contact between the cavity wall and the ice-hole wall results in a curved cavity wall on the water-away side. At the same time, the ice hole constraints increase the cylinder impact load, which accelerates the underwater velocity decay of the cylinder and contributes to a larger deflection angle of the cylinder than in the ice-free environment. However, as the velocity of the cylinder into the water increases, the water-away side wall bends to an essentially similar extent due to the near-wall effect. Moreover, the impact load of the cylinder into the water increases, resulting in a faster decay of the underwater velocity of the cylinder, as well as a gradual increase in the deflection angle. The influence law of water entry velocity on the cavity evolution and motion characteristics under the ice-hole constraint can provide a certain reference basis for the stability of water entry of polar supercavitating weapons.

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

[Abstract](7) [FullText HTML] (4) [PDF 1358KB](1)

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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.

Simulation of jet development and cavitation characteristics of a hollow projectile entering water

XIANG Junbang, WANG Xiaoguang, KANG Huifeng, XUAN Jialin, YANG Liu

, Available online , doi: 10.11993/j.issn.2096-3920.2023-0163

[Abstract](23) [FullText HTML] (7) [PDF 1689KB](5)

Abstract:
The hollow projectile, characterized by its hollow interior and intricate flow dynamics, has garnered significant attention due to its lightweight, stability, and potent destructive capabilities. In its water entry process, the formation of high-speed water jets is a crucial factor influencing the water entry of hollow projectiles. Consequently, studying the impact of the through-hole aperture of hollow projectiles on jet and water entry characteristics holds considerable importance. This paper establishes a vertical water entry simulation model for hollow projectiles with different aperture diameters. It compares the pressure characteristics within the hole and the variations in vacuole development among projectiles with different aperture diameters. A correlation is identified between the aperture ratio and the intensity of intra-hole pressure at the moment of initial collision. Observations reveal that the projectile's height and velocity decrease with an increase in the aperture ratio, correlating with the pressure gradient phenomenon within the hollow hole. Additionally, the intensity of the pressure gradient diminishes as the aperture ratio increases. The study briefly describes the development of the cavitation phenomenon in hollow projectiles and provides a comparative elaboration on the effect of the aperture ratio on cavitation. Results indicate a gradual decrease in the amount of vapor produced by the projectile with an increase in the aperture ratio, leading to an earlier closing time of the vacuole. This research contributes valuable insights into the complex dynamics of hollow projectile water entry.

Finding Probability of Submarine-Launched Acoustic Homing Torpedo Based on Gaussian Process Regression

REN Bin, XIE Chao

, Available online , doi: 10.11993/j.issn.2096-3920.2023-0113

[Abstract](16) [FullText HTML] (6) [PDF 1401KB](0)

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The determination of the probability associated with submarine-launched acoustic homing torpedoes significantly influences tactical formulation. Conventional analytical and statistical algorithms encounter challenges in balancing the trade-off between the speed and precision of probability assessment. In response to this issue, this paper introduces a novel estimation model for assessing the probability of detection based on Gaussian process regression. Additionally, a methodology is proposed for generating training data using an analytical model. Subsequently, numerical simulations were conducted within a specific battlefield scenario. The outcomes illustrate the superior performance of the proposed method, offering valuable theoretical insights for informed decision-making in relevant battlefield contexts.

Cooperative Countermeasure Strategy of Sea-Air Cross-Domain Unmanned Platforms For Saturation Attack of Suicide UAVs

LIANG Xiao, CHEN Cong, LIU Dianyong, YU Changdong, LI Wei

, Available online , doi: 10.11993/j.issn.2096-3920.2024-0007

[Abstract](11) [FullText HTML] (6) [PDF 1667KB](4)

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Aiming at the problem of anti-suicide unmanned aerial vehicle saturation attacks in the marine environment, this paper studies the cooperative countermeasure strategy of sea and air cross-domain unmanned platforms under the condition that the number of targets far exceeds ours, and proposes a cooperative algorithm combining improved genetic algorithm and coalition formation game. Firstly, according to the sea-air cross-domain unmanned platform's attack characteristics and motion characteristics, the cost function is designed by combining the maximum and minimum strategies. Then, the genetic algorithm is improved according to the task requirements, the crossover and mutation processes are guided and restricted, and a feasible countermeasure scheme is generated based on improving the efficiency of the genetic algorithm. Finally, the coalition formation rules are designed, and the coalitions reach Nash stability through changing members between the coalitions. The countermeasure scheme can still be continuously and stably optimized for many operators. Simulation comparison experiments show that the proposed strategy is feasible and superior and can provide a reasonable and efficient countermeasure scheme when the target is subjected to a saturation attack. This can provide a reference for large-scale cross-domain unmanned swarm combat research.

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

[Abstract](17) [FullText HTML] (4) [PDF 7339KB](1)

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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

[Abstract](16) [FullText HTML] (8) [PDF 2309KB](4)

Abstract:
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

[Abstract](10) [FullText HTML] (3) [PDF 3657KB](0)

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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.

Nonlinear Programming Based Fault-tolerant Control for X-rudder Underwater Vehicles with Rudder Failures

CHEN Ying

, Available online , doi: 10.11993/j.issn.2096-3920.2023-0133

[Abstract](25) [FullText HTML] (5) [PDF 2576KB](6)

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X rudder has been increasingly applied to autonomous underwater vehicles in recent years due to its better maneuverability and safety. To fully utilize the fault-tolerant capability of the X rudder, this paper proposes a fault-tolerant motion control algorithm for underwater vehicles oriented towards rudder failures and deploys it on a prototype of an X rudder underwater vehicle. The fault-tolerant motion control algorithm consists of two parts: dynamics control and control allocation. In the dynamics control, the introduction of a multi-loop incremental feedback control algorithm in the output virtual rudder instruction can make it smooth and gentle. The control allocation algorithm converts the virtual rudder command to the control input of the X rudder actuator by solving a nonlinear programming problem with the optimization goal of minimizing the allocation error and control output, and considering the constraints of rudder failure, rudder angle saturation, and other physical limitations. This also enables the X rudder underwater vehicle to have fault-tolerant motion capabilities. Field trial results show that the rudder instructions generated by the fault-tolerant motion control algorithm proposed in this paper are smooth, and the X rudder underwater vehicle still maintains a certain control capability after the rudder failure. This has certain guiding significance for the design of a fault-tolerant steering system applied to X rudder underwater vehicles.

Hydropower plant underwater inspection robot path planning based on improved hybrid motion sparrow search algorithm

ZENG Xuewen, HUANG Xiuhua, CHEN Min, ZHOU Da, ZHANG Fulin

, Available online , doi: 10.11993/j.issn.2096-3920.2023-0162

[Abstract](16) [FullText HTML] (5) [PDF 1372KB](3)

Abstract:
Path planning for underwater remotely operated vehicle(ROV) is a prerequisite for underwater inspection operation of hydropower station. Aiming at the complex environment under the reservoir of power station and the existing path planning algorithms that have the problems of long planning time, poor stability of algorithms, easy to fall into the local optimum, and the generation of paths that are not smooth, this paper puts forward a path planning method for hydropower station ROV based on the improved hybrid motion sparrow search algorithm. Firstly, the good point set is introduced to improve the sparrow population initialization method, which improves the population diversity; secondly, the hybrid motion strategy is proposed to optimize the sparrow population position updating method, which improves the algorithm's convergence accuracy and stability; then, the multivariate objective function, which contains time cost, path threat, current disturbance and penalty function, is established by combining with the actual engineering problems and considering the factors of large underwater flow velocity of reservoirs, strong magnetic field, obstacles, and the cost of input; finally, the triple B-spline interpolation is used to obtain the optimal smooth path. Finally, the optimal smooth path is obtained by three times B-spline interpolation. The simulation results show that compared with other path planning algorithms, the proposed method performs better in terms of computational accuracy, convergence speed and stability, and is suitable for underwater inspection tasks of hydropower stations.

Research on Temperature Adaptability of Special Hydraulic Buffer Cylinders

DAI Shaoyuan, LI Ka-fu, CHENG Junfeng, DUAN Hao

, Available online , doi: 10.11993/j.issn.2096-3920.2023-0105

[Abstract](11) [FullText HTML] (2) [PDF 3047KB](2)

Abstract:
During the research on vibration reduction and noise reduction of underwater weapons, it was found that the special buffer hydraulic cylinders, as an important transmission component, is one of the main sources of noise. Therefore, the design of the buffer device for the special oil cylinder is particularly important, and the prediction of the buffer effect is the core issue of buffer design. Due to the special working conditions of the special buffer hydraulic cylinders, it is mostly in standby mode. When a startup is started after a long interval, the hydraulic oil temperature in the buffer chamber is equal to the installation environment temperature. There will be a large temperature difference in the hydraulic oil in the buffer chamber between the first startup and subsequent startups. In order to ensure that the working requirements can be met even under extreme temperature conditions, temperature adaptability research needs to be conducted on the special buffer hydraulic cylinders. Firstly, a mathematical model of the motion process of a special oil cylinder was established. Under extreme oil temperature conditions of 10 ± 2 ℃, 40 ± 2 ℃, and fuel supply pressure of 7.5 ± 0.2, the flow field was numerically simulated using Fluent. Then, temperature adaptability tests were conducted in a large temperature box, and the full stroke motion time and vibration acceleration level parameters of the special buffer hydraulic cylinders were tested under two extreme temperature conditions. Finally, it was found through comparison that the experimental results were similar to the theoretical analysis and met the corresponding indicator requirements, which can provide reference for the design and vibration reduction and noise reduction work of special buffer cylinders in the future.

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

[Abstract](24) [FullText HTML] (11) [PDF 1637KB](11)

Abstract:
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

[Abstract](18) [FullText HTML] (4) [PDF 1953KB](0)

Abstract:
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

[Abstract](21) [FullText HTML] (3) [PDF 3645KB](6)

Abstract:
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

[Abstract](19) [FullText HTML] (7) [PDF 4727KB](1)

Abstract:
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

[Abstract](29) [FullText HTML] (5) [PDF 4337KB](6)

Abstract:
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.

Energy-optimal Path Planning for AUV under Ocean Current Environment Based on Improved PSO-Lévy algorithm

YANG Huizhen, WANG Zijiang, ZHOU Zhuoyu, YANG Jun, LI Jianguo

, Available online , doi: 10.11993/j.issn.2096-3920.2023-0062

[Abstract](40) [FullText HTML] (6) [PDF 2276KB](5)

Abstract:
To obtain energy-efficient obstacle avoidance paths of autonomous underwater vehicle (autonomous underwater vehicle, AUV) in dynamic current environment. A three-dimensional dynamic ocean current environment model based on dynamic current velocity field and underwater topographic obstacles was established. The objective function for optimal energy consumption based on kinematic constraint and the obstacle constraint is established. An improved particle-swarm-optimization-Lévy (PSO-Lévy) algorithm based on weight adjustment mechanism and random wandering mechanism is proposed. By executing long-step random walk operation and regulating the velocity of particles with certain probability, the improved algorithm can get longer step and jump out of local optimum. Simulation results show that the proposed method can plan the optimal path with low energy consumption and short distance, and can effectively ensure path safety and displaying higher efficiency.

Development characteristics of underwater detonation gas jets in confined spaces

XU Zhiqian, KANG Yang, LI Ning, HUANG Xiaolong, LI Can, WENG Chunsheng

, Available online , doi: 10.11993/j.issn.2096-3920.2023-0104

[Abstract](28) [FullText HTML] (5) [PDF 2794KB](2)

Abstract:
To explore the development characteristics of gas jets generated by pulsed detonation hydroramjet working underwater in open-ended water guides, numerical simulations and experimental validations were conducted on underwater detonation gas jets within a cylindrical confined space by utilizing the detonation of combustible gases to generate pulsating bubbles. A flow model of a single gas jet in a confined space was established based on the Reynolds-averaged Navier-Stokes equations, the K-epsilon two-equation model, and the Volume of Fluid (VOF) interface tracking method coupled with the advection equation. The CompressibleInterFoam solver in OpenFOAM was employed for numerical simulations of pulsed detonation gas jets in confined spaces. The results showed that the amplitude of the leading shock wave in the confined space changed insignificantly compared to free underwater space. However, the pressure disturbance caused by the gas jet significantly increased, and its duration prolonged. Additionally, it led to a noticeable increase in pressure within the confined space compared to outside the confined space. The pulsation period of gas bubbles in the confined space extended to approximately 60 ms, and the radial dimension of the confined space had little effect on the fluctuation period of the gas bubbles. It can be seen that confined space can increase the near field pressure at the outlet of the underwater detonation tube and extend the action time of the gas jet. The research results have important guiding significance for the study of thrust performance improvement methods for pulse detonation hydroramjet.

Model free adaptive path following control based on active disturbance rejection theory for AUV

FU Shaobo, GUAN Xiawei, ZHANG Hao

, Available online , doi: 10.11993/j.issn.2096-3920.2023-0120

[Abstract](43) [FullText HTML] (5) [PDF 3356KB](7)

Abstract:
Aiming at the task requirements of accurate recovery of autonomous underwater vehicles (AUVs), a model-free adaptive path tracking control based on active disturbance rejection theory (ADRC-MFAC) is proposed from the perspective of modelless control in view of the insufficient path tracking accuracy caused by model uncertainty and vulnerability to environmental interference in AUV motion. According to the characteristics of second-order model system and line-of-sight guidance, the algorithm redesigned the control input criterion function to improve model free adaptive control(IMFAC),solved the problem that MFAC is applicable to self-balancing system. Introduced tracking dif-ferentiator to smooth the desired signal and designed linear extended state observer considering the influence of unknown compound interference, compensated the estimated disturbance in the controller, improved the stability of the control system and improved robustness. With the same of disturbance, the proposed control scheme can improve 42.37% of robustness and 45% of accuracy with PID. The result shows that ADRC-MFAC can significantly improve the anti-interference performance of AUV, and improve the path tracking accuracy.

Digital Development Method of Torpedo Weapon Equipment Based on MBSE

WEN Zhiwen, WANG Zhong, XIE Bin, CAI Weijun, ZHANG Meiru

, Available online , doi: 10.11993/j.issn.2096-3920.2023-0031

[Abstract](21) [FullText HTML] (12) [PDF 3852KB](4)

Abstract:
With the development and application of torpedo weapons and equipment in future wars, new requirements for digitization, intelligence, and agility have been put forward. In order to solve the practical problems faced by torpedoes in the traditional text based on the development mode, such as the separation of the overall and subsystems, the separation of the design process and the production process, leading to untimely detected errors, insufficient early verification, incomplete information transmission, inconsistent model data, incomplete verification scope and unclear process traceability, the torpedo development cycle should be shortened and the development efficiency and quality should be improved. On the basis of the practical application research of MBSE at home and abroad, combining advanced system engineering methods and integrating new technologies, this paper proposes digital research and development method for torpedo weapon equipment based on MBSE, which integrates MBSE thinking methods with torpedo technology characteristics and research and development processes, constructs MBSE technology system of cross-stage, cross-discipline and cross-level for the entire lifecycle of torpedoes, proposes a digital application framework and technical roadmap for MBSE torpedo, and refines the main key technologies that need to be addressed in the digital development process of MBSE torpedo. The method proposed in this paper provides reference for the digital development practice of torpedo weapon equipment, and lays the foundation for the comprehensive digital transformation of torpedo weapon equipment.

Study on kinetic parameters and phenomena of Li/SF₆ reaction

WU Haoqi, LUO Zhengyuan, BAI Bofeng

, Available online , doi: 10.11993/j.issn.2096-3920.2023-0108

[Abstract](20) [FullText HTML] (5) [PDF 2697KB](6)

Abstract:
In order to investigate the phenomenon and kinetic parameters of Li/SF₆ combustion under different temperature and pressure conditions, the ignition delay period of Li/SF₆ combustion test platform was measured by using the shock wave induced high pressure thermal load excitation when the temperature range was 830 K~1 400 K and the pressure range was 0.8 atm~11 atm. The law of Li/SF₆ combustion process and basic luminescence phenomena were investigated by visualization experiment section. Based on the typical Arrhenius dependence between ignition delay period and temperature and pressure, the reaction kinetic parameters were obtained by multiple linear regression method. The results show that the ignition delay period of Li/SF₆ combustion decreases with the increase of temperature and pressure, and the luminescence phenomenon gradually changes from red isolated fire nucleus to white bright flame with the increase of pressure. The pre-index factor A, exponential factor n and activation energy Ea are obtained based on the experimental ignition delay period, which provides an important basis for the identification of combustion characteristics and the construction of numerical simulation.

Dynamic Path Generation Method for UUV Terrain Tracking Using Forward-Looking and Altimetry Sonar

CHEN Tao, WAN Shou

, Available online , doi: 10.11993/j.issn.2096-3920.2023-0047

[Abstract](21) [FullText HTML] (3) [PDF 1242KB](0)

Abstract:
Maintaining fixed altitude tracking navigation of seafloor terrain is a common form of motion, which is used by unmanned undersea vehicle(UUV) on marine survey and underwater target search missions, the core of this motion is how UUV can detect unknown undulating seafloor terrain in real time, and generate tracking paths online and dynamically based on detection information, so as to achieve fixed altitude tracking navigation on the terrain while avoiding collision with the terrain. In this paper, to solve the above problems, a method is proposed, which is of detecting terrain information based on forward looking sonar, and dynamically generating tracking path based on polynomial fitting. First, UUV uses forward looking sonar to conduct real-time detection of seafloor terrain. After affine processing of the obtained terrain detection data, fixed-height affine data with discrete characteristics can be obtained. Then, the cubic polynomial method based on least squares criterion is used to fit the affine data, and the navigation path of UUV terrain tracking based on polynomial function description is generated. Finally, a dynamic execution framework including sonar detection, data affine, path generation and tracking control is designed, in order to realize the real-time terrain tracking navigation mission of UUV. In this paper, through simulation of tracking on typical seafloor 'uphill' and 'mountainous' terrain, effectiveness and feasibility of the proposed tracking path generation and dynamic execution framework were demonstrated.

Study on the Favorable Advance Angle Based on Maximum Entropy Distribution under the Uncertainty of Self guided Action Distance

DAI Zhen, HAN Qingwei, LI Yang, WU Jiwei, SHEN Xiangzhong

, Available online , doi: 10.11993/j.issn.2096-3920.2023-0102

[Abstract](9) [FullText HTML] (9) [PDF 1079KB](0)

Abstract:
In response to the problem of solving the favorable lead angle in the case of uncertain homing range of torpedoes, the influence of homing range on torpedo firing is first analyzed. It is pointed out that when the actual homing range of torpedoes is less than its binding value, the favorable lead angle obtained from the calculation will be smaller, and the probability of torpedo discovery will be significantly reduced. Secondly, the weighted average discovery probability of torpedoes was defined, and based on this, a favorable lead angle calculation method was proposed to maximize the weighted average discovery probability. Then, based on the principle of maximum entropy, two maximum entropy distribution models for the actual homing range of torpedoes were given, and the formula for solving the favorable lead angle under this distribution model was obtained. Finally, the favorable advance angle of torpedo homing was obtained through simulation under the condition of uncertain operating distance.

Research on ROV Motion Control Algorithm Based on RBF Neural Network Compensation

ZHANG Shuaijun, LIU Weidong, LI Le, LIU Jingbin, GUO Liwei, XU Jingming

, Available online , doi: 10.11993/j.issn.2096-3920.2023-0033

[Abstract](73) [FullText HTML] (26) [PDF 5907KB](9)

Abstract:
Aiming at the problem of motion control of work-class ROV under the uncertainty of model parameters and the disturbance of external environment, an adaptive double-loop sliding mode control strategy based on radial basis function neural network is proposed. Firstly, the integral sliding mode control method with improved reaching rate is adopted for the position control of the ROV outer loop, and the integral sliding mode control method with exponential reaching rate is adopted for the speed control of the ROV inner loop. Secondly, in order to further improve the chattering problem of Sliding mode control, the hyperbolic tangent function is introduced as the sliding mode switching term. Subsequently, the RBF neural network control technology is used to estimate and compensate the uncertain parameters and external disturbances of the ROV model. Finally, the stability of the whole closed-loop system is proved by using Lyapunov stability theory, and the motion control of the work-class ROV is simulated numerically. The simulation results verified that the controller designed in this paper can achieve precise control of ROV navigation and effectively suppress the influence of model uncertainty parameters and external disturbances on ROV motion.

Review of Visual Control Technologies for Underwater Vehicles

GAO Jian, HE Yaozhen, CHEN Yimin, ZHANG Yuanxu, YANG Xubo, LI Yufeng, ZHANG Zhenchi

, Available online , doi: 10.11993/j.issn.2096-3920.2023-0061

[Abstract](102) [FullText HTML] (6) [PDF 3013KB](32)

Abstract:
Visual control is a method of control that utilizes visual information for environmental and self-awareness. In this paper, this technology was applied to the control of underwater vehicles, and an analysis of relevant research progress, challenges, and trends in different application scenarios was presented. The current development and task scenarios of visual control for underwater vehicles were first introduced. The focus was on the introduction of underwater image enhancement, target recognition, and pose estimation technologies. A summary and analysis of the current development of visual control technology for underwater vehicles were then provided based on three task scenarios: underwater visual odometry and target tracking, underwater vehicle docking, and underwater operational tasks such as target grasping. Finally, the challenges and development trends of visual control for underwater vehicles were outlined.

Adaptive Neural Network-Based Prescribed Performance Control of AUVs with Input Saturation

XU Wenfeng, LIU Jiapeng, YU Jinpeng, HAN Yaning

, Available online , doi: 10.11993/j.issn.2096-3920.2023-0041

[Abstract](49) [FullText HTML] (16) [PDF 2777KB](3)

Abstract:
Aiming at the problems of system uncertainty and input saturation of autonomous underwater vehicle(AUV), an improved adaptive neural network-based prescribed performance control strategy is proposed to track the desired trajectory. Firstly, nonlinear transformation is introduced to ensure that the position error remains within the preset time-varying range, improving control accuracy. Based on backstepping and Lyapunov functions, a virtual control law for the system is designed. Then, the neural network technology is used to process the unknown parameters of the system model, and the real control law of the system is reconstructed, which simplifies the traditional backstepping control strategy and effectively reduces the computational complexity. Then, based on the Lyapunov stability theory, the error signals of AUV system are all bounded. Finally, compared with traditional dynamic surface control methods, simulation results show that the proposed control strategy has better control performance and can effectively overcome the impact of uncertainty on system performance when considering input saturation, achieving effective tracking of target trajectories.

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