水下无人系统学报

Ideas and Key Technologies of Collaborative Design for Underwater Weapon Power System

LIU Jing-yun, LIU Yi, SUN Tao, GAO Hui-zhong, LIU Yang

2022, 30(4): 413-421. doi: 10.11993/j.issn.2096-3920.202112020

[Abstract](203) [FullText HTML] (52) [PDF 1294KB](67)

Abstract:
After decades of development, China has gradually developed an independent design capability for underwater weapon power system technologies. However, there is a current need for a wide variety of products and a short research and development cycle; therefore, the original design and development model based on document-based system engineering cannot meet the demand for rapid design. Based on an analysis of the background requirements and current situation of the digital development of model-based system engineering, a three-step digital development scheme is proposed for the power system design of underwater weapons, including technological breakthroughs and solidification of key capabilities, model-driven collaborative design, and construction of digital twin prototypes. The architecture and key technologies of the digital collaborative design platform for the power system of underwater weapons are analyzed; the results can provide a reference for the digital development of power system design for underwater weapons.

Design of a Multi-target Interference Resistant Adaptive Detector under Homogeneous Reverberation Backgrounds

ZHU Dong-sheng, SU Xiao-jing, LIU Jin-wei, HAO Cheng-peng

2022, 30(4): 422-428. doi: 10.11993/j.issn.2096-3920.202106002

[Abstract](255) [FullText HTML] (45) [PDF 1283KB](42)

Abstract:
In this study, a new adaptive detector that can resist multi-target interference was proposed to improve the resistance to multi-target interference when using the constant false alarm rate(CFAR) method. This detector uses reference units as the feature value of the background environment and the TreeBagger algorithm for the construction of the estimator. In the training process, the reference units and TreeBagger algorithm were first used to construct the estimator, which was used to estimate the number of interference targets. In the detection process, the reference units were then used as the inputs of the estimator and the number of interference targets in the current background as the output of the estimator. Furthermore, the estimation results were used as the sequence threshold for the detector. Consequently, the detector was able to eliminate the interference targets and complete detection. The performance of the detector under homogeneous reverberation and multi-target interference backgrounds was then analyzed using the Monte Carlo simulation method, and a comparison of the results with those of existing methods was conducted, which showed that the proposed detector had a better performance at resisting multi-target interference.

Waypoint-tracking Control of a Benthic AUV Based on Model-free Adaptive Control Method

GAO Peng, WAN Lei, XU Yu-fei, CHEN Guo-fang, ZHANG Zi-yang

2022, 30(4): 429-440. doi: 10.11993/j.issn.2096-3920.202109021

[Abstract](2549) [FullText HTML] (109) [PDF 2852KB](74)

Abstract:
In this study, the model-free adaptive control(MFAC) method was applied to a waypoint-tracking control system to solve the problems of high uncertainty in the marine environment and difficulty in accurately determining the benthic autonomous undersea vehicle(AUV) model parameters. Moreover, an improved MFAC course controller was designed and the boundedness of the course control error was verified to solve the problems of a slow convergence rate and low tracking accuracy during course control due to the integral additive effect of the traditional MFAC method. Subsequently, a hyperbolic tangent speed adjustment strategy was proposed to solve the problem whereby the course control overshoot of the AUV is large at the waypoint switch when the closed line of sight(LOS) guidance algorithm is applied to waypoint-tracking control. And this strategy can significantly promote the smooth transition of the AUV at the waypoint switch and improve the convergence speed of the tracking error. Finally, an outfield test of the course control and waypoint-tracking control of the benthic AUV was conducted to verify the effectiveness and superiority of the proposed algorithm.

Optimization of Steering Control Parameters of Robot Fish in Variable Flow Field Based on PSO

WEN Jia-yan, WEN Lin-rong, XIE Guang-ming, LUO Wen-guang

2022, 30(4): 441-449. doi: 10.11993/j.issn.2096-3920.202109016

[Abstract](2105) [FullText HTML] (27) [PDF 1870KB](23)

Abstract:
Robotic fish are susceptible to interference from non-stationary flow fields and thus may deviate from the target course during navigation. In this study, course angle feedback is used to solve the problem of course deviation in a robotic fish without flow field sensors. First, a relationship between joint angular motion and joint torque is obtained by establishing the joint dynamics model of a robotic fish. In addition, a relationship between the propulsion and steering torque and swing posture is obtained. Subsequently, to maintain the stability of the robotic fish, a central pattern generator controller is used to adjust the closed-loop control system. Furthermore, this study takes the length of time during which the robot fish converges from a set course angle deviation to zero as an optimization index, and uses the particle swarm optimization algorithm to obtain the best controller parameters that can achieve rapid steering. The simulation analysis is performed based on the established dynamics model of a robotic fish, and the results verify the effectiveness and rationality of the proposed design method.

Simulation of Gap Flow of an Underwater Vehicle-Launch Tube

LIU Yuan-qing, ZHANG Chen-xing, CHEN Xiang-yan, WANG Fan-yu

2022, 30(4): 450-456. doi: 10.11993/j.issn.2096-3920.202109013

[Abstract](208) [FullText HTML] (42) [PDF 1930KB](36)

Abstract:
When the tail of an undersea vehicle passes through the seal ring, complex characteristics—such as high speed and separation flow—arise during the connection process of the bottom of the launch tube and the seal cavity. Considering these characteristics and using the dynamic boundary unsteady value simulation, the flow field evolution and pressure fluctuation characteristics in the vehicle-tube gap were studied under different initial pressure ratios and vehicle speeds. The results show that the instantaneous speed of the high-temperature and high-pressure gas at the bottom of the tube can exceed the speed of sound when entering the gap cavity in the initial stage of the tail connection. The airflow is reflected after hitting the seal ring away from the bottom of the tube and produces violent flow oscillations and pressure fluctuations. Owing to the movement of the vehicle, the connection area increases and the impact peak amplitude gradually decreases. The amplitude of pressure fluctuation increases linearly with the initial pressure ratio. When the initial pressure ratio is 3.0, the relative peak and valley values of the pressure fluctuation can reach 1.4 times and 0.5 times of the initial pressure, respectively. When the speed of the vehicle increases, the leakage rate and peak pressure increase and the time of occurrence is advanced; meanwhile, the pressure fluctuation period remains unchanged under the above parameters.

Control of the Consensus of Second-Order Multi-Agent Systems with Time Delay Based on Distributed PI

WANG Qi, GUO Fei, ZHANG An-tong, GUO Yu, QIANG Yi-ming

2022, 30(4): 457-464. doi: 10.11993/j.issn.2096-3920.202109002

[Abstract](281) [FullText HTML] (78) [PDF 877KB](26)

Abstract:
In recent years, multi-agent systems have developed rapidly owing to their wide application in many fields. The consensus problem is a popular research topic. However, the existence of communication delays and external disturbances can affect the consensus of multiagent systems. Therefore, this study focused on the problem of the consensus of second-order multi-agent systems with disturbances. The influences of constant and time-varying communication delays are also considered. A control protocol based on a distributed proportional integral(PI) is provided. The protocol assumes that the topology of the multiagent system is directed and contains a directed spanning tree. First, the consensus problem of the original system is transformed into a problem concerning the stability of the reduced-order system by state transformation. Then, the sufficient condition is derived using Lyapunov stability theory, graph theory, and matrix theory. Finally, a specific numerical simulation example is provided to verify that the proposed PI control protocol can effectively achieve the consensus of a second-order multiagent system with disturbance.

Method of Ship Wake Detection Based on Time-Frequency Analysis and Transfer Learning

LIU Gang, LI Yong-sheng, LIU Li-wen, WANG Chen-yu

2022, 30(4): 465-473. doi: 10.11993/j.issn.2096-3920.202108013

[Abstract](154) [FullText HTML] (129) [PDF 2853KB](39)

Abstract:
Ship wake detection is an effective method for undersea vehicles to detect and track surface ships. However, traditional wake detection methods based on time-domain features are limited by subjective experience and complex varying marine environments with certain limitations in the intelligent detection of ship wakes. Aiming at the problem of insufficient accuracy and efficiency of traditional wake detection methods in complex environments, this study introduces a deep learning theory to improve the independent learning and adaptive capabilities of the model. Subsequently, a novel ship wake detection method based on transfer learning and time-frequency analysis is proposed, considering the difficulty of obtaining ship wake samples. First, in this method, the time-frequency domain characteristics of the wake signal are extracted using short-time Fourier transform. Then, through the strategy of parameter freezing and fine-tuning, transfer learning based on a pre-trained convolutional neural network is completed. Finally, the effective detection of ship wakes using a small sample dataset is realized. Combining the wake detection experiment with actual measured data, the results show that, when compared with the traditional wake detection method, the correct rate of the wake detection method based on time-frequency analysis and transfer learning is increased by approximately 10%, with the highest reaching 97.49%. It combines the characteristics of a low time cost, low sample demand, and high recognition performance.

Motion Simulation of Spatial Sampling of Mesoscale Processes for Underwater Gliders

QIN Yue, WANG Guan-lin, GUAN Sheng, WANG Yan-feng, DING Jun-hang

2022, 30(4): 474-484. doi: 10.11993/j.issn.2096-3920.202112003

[Abstract](239) [FullText HTML] (80) [PDF 2890KB](30)

Abstract:
Marine mesoscale processes, including vortices, fronts, and internal waves, are a class of important dynamic processes in the ocean that have a significant influence on global climate change and the transport of marine energy, heat, and materials. The observation and investigation of such processes also have important practical significance in the field of marine resources, organism exploration, and military domains. Underwater gliders have recently become important devices for observing mesoscale processes. “Petrel-Ⅱ,” a type of autonomous underwater glider, is considered the main focus of this study. First, a dynamics model is established based on the momentum and angular momentum theorems. Simulink is then used to confirm the feasibility of the proposed model. According to the simulation results, the proposed dynamic model can realize motion simulation well. Finally, based on the different requirements for the detection of several mesoscale processes, different sampling motion schemes are presented, and a motion simulation of spatial sampling is provided. This study could provide a reference and optimization parameters for future practical observations and applications.

Numerical Simulation on Flow Field Characteristics of Vehicle Planing

LIU Fu-qiang, SUN Yuan, WANG Guang-ping, WANG Xue-feng

2022, 30(4): 485-493. doi: 10.11993/j.issn.2096-3920.202107003

[Abstract](243) [FullText HTML] (73) [PDF 3581KB](27)

Abstract:
This study employed the shear stress transport(SST) k-ω turbulence model and used the volume of fluid(VOF) wave and the multiple reference frame(MRF) model motion reference system to construct a numerical simulation model of vehicle planing implemented in STAR-CCM+ numerical simulation software, whereby its feasibility was verified. This model was then used to numerically simulate the planing conditions of a vehicle at different speeds and to study its flow field and hydrodynamic characteristics. The simulation results show that when the planing speed of the vehicle was higher than 30 m/s, cavitation occurs at the tail end of the vehicle. This results in the pressure inside the cavity being lower than the pressure on the wetted surface of the tail, causing the cavity to deform and the liquid level to curl up towards the tail, resulting in splashes. Subsequently, a closed cavity is formed at the tail, and there is an inner flow around the cavity, within which there is a low-pressure area. At this time, the lift on the vehicle is negative. When the speed increases, the cavity collapses and joins the atmosphere, and the lift is significantly increased. When the vehicle planes at different speeds, the flow field is obviously different, so are the lift coefficient and the drag coefficient; the lift even turns negative. This is mainly due to the difference in the wetting distribution and surface pressure distribution of the vehicle, caused by different cavitation effects at the tail of the vehicle at different speeds. The results can provide a theoretical reference for engineering applications of vehicle planing.

DR/USBL Integrated Navigation Algorithm for HOV

LIU Xian-jun, YE Peng, ZHANG Tong-wei, LIU Xi-xiang, SHENG Guang-run

2022, 30(4): 494-499. doi: 10.11993/j.issn.2096-3920.202105003

[Abstract](221) [FullText HTML] (133) [PDF 1547KB](30)

Abstract:
An economically feasible integrated navigation algorithm is designed for deep-sea human-occupied vehicles(HOV) operating near the seafloor. The algorithm utilizes the Doppler velocity log and a strapped-down compass carried by the HOV to form a dead reckoning(DR) system. A four-dimensional Kalman filter is designed to integrate DR with the position information provided by an ultra-short baseline(USBL) acoustic positioning system to constitute a DR/USBL integrated navigation system. Considering that the actual measurements of the USBL usually contain a large number of outliers with few missing values, an online data-cleaning scheme using DR is designed. This design is robust and can provide continuous and consistent measurements for DR/USBL. Finally, semi-physical simulation results based on sea trial data show that the DR/USBL integrated navigation system can effectively integrate the advantages of the two systems to provide smoother and more accurate positioning information; the positioning error is within 25 m.

Numerical Simulation of Underwater Gas Jet Fields with the Continuous Change of Ambient Pressure

WANG Jia-wen, QI Xiao-bin, WANG Rui, LI Rui-jie, LIANG Jing-qi

2022, 30(4): 500-506. doi: 10.11993/j.issn.2096-3920.202108017

[Abstract](156) [FullText HTML] (75) [PDF 2360KB](24)

Abstract:
Deep-sea antisubmarine missiles undergo significant changes in water depth during underwater navigation. It is of great importance to study the structure of the gas jet and working characteristics of the underwater solid propellant rocket engine of antisubmarine missiles during continuous changes in environmental depth pressure. Utilizing the volume of fluid (VOF) multiphase model, this study combines the user-defined function (UDF) with the dynamic mesh technique to establish an axisymmetric dynamic model of an underwater solid propellant rocket engine, as well as simulates the process of vertical motion of the underwater engine to a depth of 250 m. The results show that the gas jet no longer breaks and strikes back at the end of the nozzle during underwater motion. During the formation of the supersonic jet, the shock wave is gradually pushed out of the nozzle outlet, and finally, a conical shock wave with a fixed position is formed. Below a depth of 100 m, the flow field characteristics of the gas jet are significantly affected by the ambient pressure, and the flow field structure shows apparent compressibility. At a speed of 200 m/s, the gas jet obstruction effect is weakened, which reduces the effect of the ambient pressure on the working characteristics of the underwater engine. The study of the flow field characteristics of underwater gas jets subjected to continuous changes in ambient pressure can provide a reference for exploring the working performance of underwater engines in deep-water vertical motion.

Operational Simulation and Efficiency Analysis of Torpedo Electromagnetic Fuse Jammer

LIU Wen-yu, GAO Yong-qi, ZHANG Hong-gang

2022, 30(4): 507-513. doi: 10.11993/j.issn.2096-3920.202109017

[Abstract](409) [FullText HTML] (46) [PDF 2163KB](67)

Abstract:
Torpedo electromagnetic fuse jammers are a type of weapon equipment used against wake-homing torpedoes in the wake area of surface ships. The operational parameters of the jammer determine its countering effectiveness. Therefore, to ensure that the torpedo electromagnetic fuse jammer can produce sufficient counter-effectiveness, a operational model for the jammer is built, and simulation research is conducted on the relationship between deployment interval, deployment quantity, operating radius, and success probability of using a torpedo electromagnetic fuse jammer against wake-homing torpedoes. The simulation results show that the use of such jammers can effectively protect surface ships and their operational capabilities, and the three parameters have a significant influence on the success probability of using electromagnetic fuse jammers against wake-homing torpedoes. By analyzing the simulation results, it can be concluded that the best combination of the jammer deployment interval and quantity which satisfying the requirements of the jamming effect can be obtained for a certain operating radius. This research provides a valuable reference for the determination of torpedo electromagnetic fuse jammer performance indexes.

Research on the Establishment Time of Underwater Inflatable Positive Buoyancy for Vehicle

SUN Yuan, WANG Guang-ping, LI Chun-yu, WANG Xue-feng

2022, 30(4): 514-518. doi: 10.11993/j.issn.2096-3920.202106010

[Abstract](250) [FullText HTML] (64) [PDF 1335KB](29)

Abstract:
To improve the safety of the vehicle underwater recovery, the designed shutdown depth of the vehicle shall match the inflation time of the floating device. At present, the research results on underwater inflation time of vehicle floating device are not universal, and they are not suitable for different structural forms of floatation collar and different structural forms of inflation pipelines. Because the composition of the inflation pipeline of the floating device is not suitable for using the traditional method to test the pipeline flow coefficient, the pipeline flow coefficient test method is redesigned to measure the flow coefficient of the inflation pipeline, and then the inflation time of the floating device is calculated by using the inflation time calculation model under the condition of fixed product adiabatic deflation. The calculation results are in good agreement with the test data, It can provide reference for navigation depth design and shutdown process.

Analysis of Impact of the Former Running Noise on Active Acoustic Homing Detection of the Latter during Two Torpedoes Salvo and Countermeasures

DENG Xin-wen, XIE Yong

2022, 30(4): 519-522. doi: 10.11993/j.issn.2096-3920.202202001

[Abstract](293) [FullText HTML] (124) [PDF 1022KB](27)

Abstract:
In anti-submarine warfare, the salvo of two active acoustic homing torpedoes is the main torpedo attack method for submarines, which can expand the search area of the torpedoes and cover a larger target scattering zone. Based on analyzing the methods of salvo of two active acoustic homing torpedoes, the organization and implementation of parallel salvo, and the impact mechanism of the former torpedo’s running noise on active acoustic homing detection of the latter, a model to describe the impact of the former torpedo’s running noise on the latter’s active acoustic homing acquisition range is developed. According to the results of a numerical example, the former torpedo’s running noise has a significant impact on the active acoustic homing acquisition range of the latter torpedo; the impact differs from the interval between the salvo of the torpedoes. Finally, suggestions are provided on how to reduce the impact of the former torpedo’s running noise in actual operation.

Research on Abnormal Ultra-shallow Shutdown of Undersea Vehicles

LI Hou-quan, FENG Xiao-tao, ZHANG Xiao-fang, ZHAO Zhi-bo

2022, 30(4): 523-527. doi: 10.11993/j.issn.2096-3920.202112019

[Abstract](132) [FullText HTML] (39) [PDF 990KB](23)

Abstract:
Concerning the problem of abnormal ultra-shallow shutdown protection, undersea vehicles navigate at a set depth even if they are not navigating at ultra-shallow protection depths. Various factors that may lead to the abnormal shutdown of undersea vehicles are analyzed. The numerical simulation method is used to analyze the effect of fluid pressure on different positions of the underwater vehicle at different speeds. The distribution law of hydrodynamic errors, which are observed when an abnormal shutdown of undersea vehicles occurs, is obtained based on sea trial data. The numerical simulation and the trials indicate that, when the vehicle navigates near the minimum depth, there will be a fluid pressure difference between the front and back depth transducers on the vehicle, which varies with the speed of the vehicle. When the speed of the vehicle exceeds a certain value, the fluid pressure error will be so large that the back depth transducer will indicate a normal depth while the front transducer will indicate an ultra-shallow state, thus resulting in an abnormal shutdown.

Data-driven Autonomous Decision-making Method for the Effective Position of AUV Torpedo Attacks

GUO Li-qiang, MA Liang, ZHANG Hui, YANG Jing

2022, 30(4): 528-534. doi: 10.11993/j.issn.2096-3920.202108009

[Abstract](3230) [FullText HTML] (44) [PDF 1210KB](636)

Abstract:
Autonomous decision-making capability is a distinctive feature that distinguishes unmanned undersea vehicles from manned platforms. This capability is characterized by a short autonomous decision-making time, high decision-making accuracy, and executable decision-making solutions. In this study, an autonomous decision-making method that combines operational simulation with ensemble learning was proposed to overcome the shortcomings of traditional effective position decision-making methods with regard to the attack effect and decision speed when an autonomous undersea vehicle(AUV) launches an attack against a surface ship using an acoustic homing torpedo. First, many basic experimental data sets were obtained by optimizing the probability of acoustic homing torpedo detection targets. Subsequently, a detection probability attack judgment threshold was designed to convert the AUV’s effective position decision-making into a binary classification problem and form the classification experimental data. Finally, the classification performance of the support vector machine, random forest, and XGBoost were analyzed and it was concluded that ensemble learning is more suitable for this unbalanced sample classification problem. Furthermore, the adaptability of this model under multiple task thresholds and its generalization ability in complex marine environments were tested. The test results showed that this method can meet the AUV’s autonomous attack decision-making requirements and significantly accelerate the decision-making speed while ensuring the effectiveness of the torpedo attack. Therefore, this study provides a reference for research on the attack planning module of equipment.

Method of Adaptability Assessment of an Intercept Missile in Challenging Marine Conditions

SHAO Zong-zhan, XIONG Yong, DAI Wen-liu

2022, 30(4): 535-542. doi: 10.11993/j.issn.2096-3920.202202008

[Abstract](136) [FullText HTML] (32) [PDF 2488KB](26)

Abstract:
The main mission of an intercept missile equipped on surface warships is to intercept incoming anti-ship torpedoes as a hard-kill countermeasure. After the intercept missile receives the ignition signal from the system, the engine ignites and the body of the intercept missile flies out of the launching tube. When the missile enters water, the acoustic fuse completes separation process by igniting the suspension device to separate the missile body, and the air collar inflates and floats. Finally, the missile body starts to operate normally when it is stably suspended. Therefore, whether the launch, flight, and water-entering separation processes of the intercept missile are normal significantly affects its operational effectiveness. However, there are a series of practical problems concerning the intercept missile test in challenging marine conditions, such as difficulties in organizing and implementing testing, product recovery, and obtaining test data measurement. According to the technical characteristics and operating environment of the equipment, this paper proposes the performance requirements that should be satisfied when using the intercept missile. A comprehensive assessment method combining experimental verification and simulation calculations is proposed for the assessment. Studies regarding whether the attack angle, water-entering overload, and connector stress performance of the intercept missile can satisfy the requirements of challenging marine conditions are described. The results show that the intercept missile can meet the performance requirements of challenging marine conditions in the aforementioned three aspects. The findings can provide technical support for making evaluation conclusions on the adaptability of intercept missiles in challenging marine conditions.

2022 Vol. 30, No. 4

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