水下无人系统学报

Application Analysis and Development Trend of Foreign Airborne Magnetic Anomaly Detection Equipment

TAO Rong-hua, WANG Dan, CHI Cheng

2021, 29(4): 369-373. doi: 10.11993/j.issn.2096-3920.2021.04.001

[Abstract](546) [PDF 514KB](246)

Abstract:
Currently, as the main non-acoustic submarine detection equipment, using an airborne magnetic anomaly detector (MAD) is one of the most reliable methods to detect, locate, identify, and track underwater submarines. The action distance of an airborne MAD has been greatly improved due to the rapid development of magnetic probe components, the magnetic compensation level, and magnetic target recognition technology; therefore, this equipment has been applied in local search and on-call anti-submarine operations. In this study, the technical performance and design characteristics of foreign advanced airborne magnetic anomaly detection equipment are analyzed regarding its application in supporting anti-submarine operations. Furthermore, the development trend of this technology is discussed, which indicates that the cooperation of the MAD performed by unmanned aerial vehicles (UAVs), manned aerial vehicles, and the MAD cluster will be the development focus.

Numerical Simulation Analysis of Flexible Hydrofoil Propulsion Performance for Wave Glider

LIU Fen, PENG Bin, SUN Xiu-jun, SANG Hong-qiang

2021, 29(4): 374-382. doi: 10.11993/j.issn.2096-3920.2021.04.002

[Abstract](266) [PDF 2253KB](105)

Abstract:
The hydrofoil is a key component that determines the capability of wave power conversions and the navigation performance of wave gliders. The propulsion performance of a flexible hydrofoil is investigated in this study. The passive deformation process of a flexible hydrofoil under active heave motion is simulated using the COMSOL Multiphysics software according to the motion characteristics of a hydrofoil when the wave glider is working. The effects of wave and pitching motion parameters and the Strouhal number on the propulsion performance of the hydrofoil are investigated. The simulation results show that the propulsion performance of the hydrofoil increases with wave height and Strouhal number and decreases with wave period within a certain range. When the wave period is high, the change in wave height and wave period has little effect on the propulsion performance of the hydrofoil. In contrast, when the pitch and wave periods are equal, the pitching motion has a positive effect on the performance.

Adaptive Predictive Control Based on Ship Magnetic Suspension Vibration Reduction Device

WANG Wei-ran, YAN Jing-hao, YANG Guan-jun, GE Hui-lin, ZHU Zhi-yu, ZHI Peng-fei

2021, 29(4): 383-390. doi: 10.11993/j.issn.2096-3920.2021.04.003

[Abstract](218) [PDF 1201KB](67)

Abstract:
Ship vibration generates different interference forces, resulting in the structural fatigue of important equipment and thereby affecting their service life. To reduce the impact of this interference on the devices, a magnetic suspension vibration reduction device is designed and applied to ships. A predictive control method based on an adaptive model to solve the problem of lift imbalance caused by different types of interference of water flow and hull steering is proposed in this paper. This control method is, therefore, adaptive and predictive. The model parameters in this predictive control can be updated in real time, greatly improving the accuracy of the predictive control. Finally, the results of relevant verifications show that this method has a faster response speed, stronger robustness, and strong anti-interference ability. Furthermore, it can be used to fulfill the vibration reduction requirements of important devices in special ships.

Mobile Underwater Acoustic Communication Method Based on VTR-PLFM Spread Spectrum Modulation

JI Zhao-sheng, WANG Hai-yan, SHEN Xiao-hong, LI Fu-long

2021, 29(4): 391-399. doi: 10.11993/j.issn.2096-3920.2021.04.004

[Abstract](196) [PDF 1495KB](207)

Abstract:
Aimed at solving the serious problems of multipath effects and Doppler effect in mobile underwater acoustic communication, this study presents a mobile underwater acoustic communication method based on virtual time reversal -piecewise linear frequency modulation(VTR-PLFM) spread spectrum modulation, to resist both Doppler and multipath interference. Using the piecewise linear frequency modulation(PLFM) signal to perform orthogonal spread spectrum modulation, the PLFM signal can resist broadband Doppler frequency shift, but the PLFM system cannot perform Doppler frequency shift compensation; the virtual time reversal(VTR) technology can be used to gather the energy of multipath signals, weaken the influence of multipath, and improve the performance of the system. In addition, due to the good correlation of PLFM signals, frequency division multiplexing(FDM) can be introduced to improve the utilization rate of the spectrum and the communication rate of the system. The simulation results show that the anti-Doppler frequency shift and VTR technology can effectively improve the performance of the PLFM system. The resulting PLFM system has a lower bit error rate at a lower signal-to-noise ratio and a higher data rate. A field test is conducted to verify the feasibility of the proposed method.

AUV Networking and Cooperative Navigation Based on Underwater Acoustic Communication

WANG Ting-ting, ZHANG Nan-nan, YUE Cai-qian, WANG Ao-bo, Lü Xue

2021, 29(4): 400-406. doi: 10.11993/j.issn.2096-3920.2021.04.005

[Abstract](576) [PDF 1458KB](244)

Abstract:
Constructing a robust underwater communication network to provide information related to formation support and navigation enhancement is the main objective of multi-autonomous undersea vehicle(AUV) formations. As a result, the allocation of limited resources to build a communication network that fulfills the requirements of multi-AUV formations in the actual environment, while considering limited underwater communication means and mature communication loads, is important for the research on multi-AUV cooperative operations. The application of networking and collaborative navigation engineering is insufficient in existing research on underwater mobile network formation, restricting the development in other layers. The multi-AUV network communication protocols, mechanisms, and enhanced implementation of cooperative navigation are therefore investigated in this study. A networking and coordination navigation scheme based on underwater acoustics communication is designed. This network is composed of three underwater acoustic communicators from Evologics, Germany. Experiments are thereafter conducted in an underwater formation composed of three AUVs. The results indicate that the communication network can provide effective communication and cooperation guarantee for the AUV formation.

Sliding Mode Controller Design Based on Quaternion Feedback for UVMS

DU Xiao-wei, HOU Dong-dong, WANG Hong-du, LI Ming

2021, 29(4): 407-414. doi: 10.11993/j.issn.2096-3920.2021.04.006

[Abstract](876) [PDF 1011KB](75)

Abstract:
With the development of lightweight and agile undersea vehicle manipulator systems(UVMSs), the demand for high-precision underwater attitude control is becoming increasingly prominent. Euler angle is traditionally used to represent the attitude; however, an inverse kinematic solution under a special attitude results in a singularity when this representation is employed. As a result, the requirements of special operations cannot be fulfilled through this representation. In this study, therefore, the quaternion is used to represent the posture of the rigid body of an undersea vehicle, and a quaternion-based kinematics model is established to avoid the gimbal lock. Furthermore, a dynamic model for the UVMS, sliding mode surface based on quaternion error, and position and attitude sliding mode controller are established. The stability of the system is analyzed by the generalized Lyapunov theory. In order to achieve a better control effect, this study uses the function of integrate time absolute error(ITAE) to design the fitness function and uses the genetic algorithm(GA) to optimize the controller parameters. The simulation results verify the effectiveness of the controller.

Analysis on Interference of Torpedo Navigation Attitude of Acoustic Fuze with Three Beams and Its Suppressing Method

TANG Bo, TAN Si-wei, ZHANG Jing-yuan, WU Di-xiao

2021, 29(4): 415-419. doi: 10.11993/j.issn.2096-3920.2021.04.007

[Abstract](185) [PDF 431KB](48)

Abstract:
In terms of ranging interference of an acoustic fuze due to torpedo navigation attitude changing, based on the basic principles of three-beam acoustic fuzes and interference generation, this paper applies Euler rotation theorem to spatial transformation of the beam vector and analyzes the ranging error of each beam with torpedo navigation attitude changing. Based on the acquisition of the navigation attitude data, a method is proposed to eliminate the ranging error of the acoustic fuze caused by the variation in the torpedo navigation attitude. These data are introduced into a fuze-ranging algorithm considering interference. A simulation test shows that the proposed method can effectively suppress the interference caused by the change in the torpedo navigation attitude.

Fault-tolerant Control of AUV Thruster Based on Adaptive Backstepping Sliding Mode

ZHANG Han-wen, WANG Jun-xiong

2021, 29(4): 420-427. doi: 10.11993/j.issn.2096-3920.2021.04.008

[Abstract](1695) [PDF 939KB](75)

Abstract:
To achieve the robustness requirements of an autonomous undersea vehicle(AUV) for motion control in the case of thruster failure, this study designs an adaptive backstepping sliding mode motion tracking controller for the six-degree-of-freedom nonlinear vector motion model of the AUV and uses it in the thrust allocation. In the thrust distribution, the fault characteristics of the thruster are considered, and a continuous time-varying fault model is established. The fault adjustment function is added by incorporating the fault information, through the pseudo-inverse technique, based on the configuration of the structure function of the adjustment controller. The control input can be changed to correct the fault, and the fault adjustment and control reconstruction are adopted for different types of faults. This method realizes a fault-tolerant control under the fault state of the thruster and effectively improves the application universality of the fault-tolerant control algorithm. A variety of failure modes are simulated to verify the effectiveness of the adaptive fault-tolerant controller for AUV motion control in the case of thruster failure.

Model and Algorithm Improvement for Unmanned Undersea Vehicle Navigation Based on Single Beacon

CHEN Xiang-guo, SHANG Fan, LAN Qiang

2021, 29(4): 428-434. doi: 10.11993/j.issn.2096-3920.2021.04.009

[Abstract](196) [PDF 477KB](81)

Abstract:
In the single beacon-based unmanned undersea vehicle(UUV) navigation algorithm, a small number of beacons, simple deployment and calibration at sea, and low maintenance costs are required. If combined with the inertial navigation system, this algorithm is expected to fulfill the needs for wide-area and low-cost underwater navigation. To solve the problems regarding its slow convergence speed and non-global observability, a single beacon underwater navigation algorithm, which increased target radial velocity observations, is proposed. The global observability of the system after the introduction of the target radial velocity observation is thereafter analyzed, and a new method to estimate the initial value and track the navigation is derived. Afterward, by combining this method with the extended Kalman filter algorithm, a 4-state 3-observation(4SV-3OB) single beacon navigation model is established. Finally, numerical simulations indicate that the convergence time of the 4SV-3OB is approximately 75% lower than that of the traditional single beacon navigation model. Simulation results show that adding the target radial velocity as a system observation can effectively simplify the process of initial value estimation and tracking in the single beacon navigation algorithm and can significantly reduce the convergence time of the navigation algorithm.

Monocular Vision Guided Lamp Array Tracking Method for the UUV Recovery Process

ZHANG Wei, PAN Jun, GONG Peng, LI Zi-xuan, GUO Shuai-ke, GAO Sai-bo

2021, 29(4): 435-441. doi: 10.11993/j.issn.2096-3920.2021.04.010

[Abstract](788) [PDF 2776KB](81)

Abstract:
An unmanned undersea vehicle(UUV) is restricted by its carrying load and environment during underwater operation, reducing the maximum operation time and distance. As a result, periodical UUV recovery is necessary to supply it with energy, obtain data, and arrange new tasks. Further study on UUV vision tracking is important to realize a rapid, accurate, and safe UUV recovery. In this study, problems caused by the monocular visual multi-target tracking for UUV recovery are investigated. A recovery tracking method of UUVs based on the nonlinear Kalman filter and asymmetric light array is proposed. First, underwater images collected by the monocular camera are preprocessed to extract characteristic information of the light source array. Afterward, the target trajectory is determined through a method based on the asymmetric L-shaped light source array. The optimal cost matrix is thereafter established by weighing the observer and the filter, and the detection is matched to the target trajectory using the improved Hungarian algorithm. Prior results of the Kalman filter are modified according to these results. Finally, the engineering effectiveness of the proposed method is verified through underwater target tracking experiments.

Sensorless Control of Underwater Propulsion PMSM Based on Parameter Identification

CHEN Yao-wei, ZENG Qing-jun, DAI Xiao-qiang, WU Wei, LI Hong-yu, YAO Zhen-qiu

2021, 29(4): 442-450. doi: 10.11993/j.issn.2096-3920.2021.04.011

[Abstract](193) [PDF 804KB](59)

Abstract:
In the operation of an underwater propeller, parameters of the permanent magnet synchronous motor(PMSM), such as stator resistance and inductance, are changed based on the temperature and current, resulting in a large error of the rotor position and speed, which are estimated by a sensorless control algorithm. In this paper, a sensorless control method is proposed to control an underwater propeller based on the Luenberger observer combined with parameter identification. In this method, based on a double closed-loop vector control strategy, recurrence least square(RLS) combined with a forgetting factor is adopted as an online parameter identification algorithm to evaluate the stator resistance and motor inductance. The initial resistance and inductance parameters in the Luenberger observer model are thereafter replaced using the same algorithm. The back electromotive force estimated through the Luenberger observer is used as the input of the phase-locked loop. Finally, the position and speed of the rotor are obtained from the output of the phase-locked loop. The simulation results show that the rotor position and speed can be rapidly and accurately identified by Luenberger observer when this parameter identification technique, which reduces the sensitivity of motor parameters on sensorless control system, is used.

Modeling and Efficiency Analysis of the Hydro-electric Conversion Process of Underwater Glider Powered by Ocean Thermal Energy

WANG Guo-hui, YANG Ya-nan, WANG Yan-hui, WANG Shu-xin

2021, 29(4): 451-458. doi: 10.11993/j.issn.2096-3920.2021.04.012

[Abstract](224) [PDF 3104KB](84)

Abstract:
Ocean thermal energy power supply is an effective technique to increase the duration and range of underwater gliders. The optimization of the energy transfer path and improvement of the energy conversion efficiency are crucial for improving the operation of underwater gliders. Based on the energy conversion mechanism and loss mechanism of the mechanical energy-electric energy conversion process in the ocean thermal energy power supply system of underwater gliders, this study establishes the parametric energy balance equation, mechanical energy-electric energy conversion model, and conversion efficiency calculation equation of the hydraulic motor and generator and other key devices as well as performs an efficiency analysis of the energy conversion process. The relative error in the conversion efficiency of pressure-kinetic energy and kinetic-electric energy conversions, when comparing the results of the platform test and the model simulation, are 6.37% and 5.12%, respectively. The accuracy of the model is therefore verified, as these relative errors are small. As a result, the optimal design and prototyping of the ocean thermal energy power supply are performed. In the sea trial, the test prototype can harvest 6 701 J of electrical energy, and the energy conversion efficiency of the pressure-electric energy conversion process can reach 38.86%, validating the accuracy and effectiveness of the proposed model.

Design and Simulation of Second-order Elliptic Gear in Proportional Controller

LI Yong-dong, BAI Kun-xue, MA Xiao-lu, YI Yin, NIU Hong-lei

2021, 29(4): 459-463. doi: 10.11993/j.issn.2096-3920.2021.04.013

[Abstract](145) [PDF 748KB](49)

Abstract:
The tri-proportion controller is the key component of underwater thermal energy supply systems. Ensuring the accurate proportional ratio of the propellant components is the main problem to be solved in the development of the proportional controller. In this study, a proportional controller with a second-order elliptic gear structure is proposed, which compensates for some shortcomings of the blade scale proportional controller. The distribution characteristics of the gear on the joint curve are obtained according to the gear meshing and convert tooth principle of second-order elliptic gears. The tooth shape of this gear is designed using the CAXA/UG computer-aided design technology. Modeling and motion simulation of this elliptic gear, which is used in the proportional controller, are thereafter performed. The simulation results can be used as a theoretical reference for the design and processing of the tri-proportion controller of this second-order elliptic gear structure.

Study on the Initiation Regularity of Warhead under Fragment Impact

HA Hai-rong, WANG Tuan-meng, LU Zhong-bao, LI Qin

2021, 29(4): 464-470. doi: 10.11993/j.issn.2096-3920.2021.04.014

[Abstract](165) [PDF 1640KB](62)

Abstract:
For the fragment impact safety of a full-scale warhead with RS211 charge, in this paper, the full-scale simulation model of a fragment impact warhead with RS211 charge is established by using the non-linear finite element software LS-DYNA. Experimental tests are then conducted to verify the simulation results. The average error of the final velocity of the shell expansion is 3.7%, indicating that the accuracy of the simulation is reasonable; therefore, the model can be used in simulation research. Finally, the initiation regularity of the fragment impact warhead, considering different values of velocity, mass, and shape, is studied, resulting in the initiation threshold. The velocity threshold of a cylindrical fragment with a cone top impacting and initiating warhead is 1 360 m/s. When the velocity is 1 830 m/s, the mass threshold of this cylindrical fragment is 11 g. Four types of fragments, which can be detonated when the warhead is charged, formed by different shapes impact the warhead at 1 830 m/s. However, the peak pressure of spherical fragments impacting the warhead is smaller than those of the others, probably due to their smooth shape, in which sharp angles are absent. This paper can be used as a reference to research the safety of a full-scale warhead fragment impact.

Near Field Shock Wave Numerical Simulation of Cylindrical Charge Underwater Explosion

HUANG Hong, LU Xi, WANG Jian

2021, 29(4): 471-476. doi: 10.11993/j.issn.2096-3920.2021.04.015

[Abstract](204) [PDF 580KB](63)

Abstract:
Cylindrical charge, which is a common charge structure for an underwater explosion, is mainly used in far-field underwater explosions. However, there is little research on the near-field shock wave. In order to obtain the parameters related to the forward near-field shock wave power of conventional cylindrical charge underwater explosion, the near-field shock wave power field with the vertical distance of the front-end cylindrical charge x and horizontal distance y is established. In this paper, the underwater explosion process of TNT spherical charge based on equal charge and cylindrical charge, whose ratio of length to diameter ranges from 1.1~2, is simulated using the AUTODYN simulation software. The near-field shock wave attenuation law of cylindrical charge underwater explosion is analyzed. By combining the Cole empirical formula, the simulation value of the cylindrical charge is optimized, and an empirical formula for the forward near-field shock wave pressure peak of cylindrical charge is obtained through logistic regression. The average error of pressure peak is approximately 5%, validating the accuracy of this formula. The research results can be used for the calculation of the near field power assuming a cylindrical charge underwater explosion.

Undersea Vehicle Separation Characteristics

XIAO Qian-jin, XIA Xing-long, QIAN Jia-chang, LIU Hua-ping, ZHOU Qi

2021, 29(4): 477-482. doi: 10.11993/j.issn.2096-3920.2021.04.016

[Abstract](136) [PDF 3028KB](62)

Abstract:
The characteristics of underwater separation are crucial to the success of the launch of an undersea vehicle. In this study, the underwater separation of the vehicle and barrel platform in suspend-state is investigated. The influence of ejection gas pressure and temperature on the hydrodynamic and motion characteristics of the vehicle and barrel platform during the launch is numerically simulated using a fluid volume function(VOF) multiphase flow model and dynamic mesh. The results show that the ejection gas pressure has little effect on the relative displacement between the vehicle and the barrel platform when the tail exits the barrel. Furthermore, the displacement ratio is the same as the inverse ratio of its mass. The hydrodynamic fluctuation and impact peak increase with the ejection gas pressure after the tail exits the barrel. Moreover, the temperature of ejection gas has no significant influence on the motion characteristics during the ejection. The hydrodynamic fluctuation increases with gas temperature after ejection.

Method of Power Generation Based on Tethered Underwater Kite System

CHENG Wen-xin, WEN Zhi-wen, YANG Zhi-dong, CAI Wei-jun

2021, 29(4): 483-487. doi: 10.11993/j.issn.2096-3920.2021.04.017

[Abstract](182) [PDF 1712KB](74)

Abstract:
With the continuous development of marine technology, underwater energy demand, especially in the deep sea, has become increasingly prominent. However, the existing underwater power generation methods generate insufficient output power and offer low work efficiency. To solve these problems, this paper proposes a power generation method based on a tethered underwater kite system that is suitable for low-velocity sea areas. This method significantly increases the power generation output by increasing the relative speed of the tethered underwater kite and water flow. The system has a simple and novel structure, long working hours, and high energy transformation efficiency. In this paper, the Euler-Lagrangian method is used for mathematical modeling and simulation. The simulation results show that this method can effectively solve the problem caused by the low output power of the traditional stationary water turbine power generation method in the deep sea.

General Cross-platform Software Framework Design and Application for Vessel Weapon Launch System

AN Na, JIANG Yang

2021, 29(4): 488-495. doi: 10.11993/j.issn.2096-3920.2021.04.018

[Abstract](149) [PDF 417KB](68)

Abstract:
Almost all of the master control software of a vessel weapon launch system is currently based on a specific software and hardware platform as the operating environment. Furthermore, this platform has poor portability, which is not conducive to secondary developments, maintenance, and upgrade of the system. In this paper, natural cross-platform features of C++, such as Qt, POSIX, and middleware, are used to create a cross-platform software framework that is suitable for the development of the master control software for the weapon launch system of a vessel. The framework eliminates product interface differences through middleware technology and uses virtualization technology to realize the digital simulation of master control software peripherals. The application of this framework in practical situations has proved that it can significantly improve the platform portability of the master control software, reducing the cost of this task and shortening the time required to complete the development of the launch system.

2021 Vol. 29, No. 4

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