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Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes/issues, but are citable by Digital Object Identifier (DOI).
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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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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:
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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