水下无人系统学报

Analysis of Damage Effectiveness for Underwater Vehicles Equipped with Terminal Guidance Mechanism

CAI Yi, MA Feng, ZHU Wei, JIA Xiyu, XUE Jianmin

, Available online , doi: 10.11993/j.issn.2096-3920.2026-0037

[Abstract](12) [FullText HTML] (3)

Abstract:
Under the background of the development of underwater precise and efficient damage technology, the damage effectiveness assessment for mobile targets needs to more comprehensively consider the integrated effects of multiple subsystem parameters such as guidance, fuze, and warhead. This paper proposes a damage effectiveness assessment method for underwater mobile weapons that introduces a terminal guidance mechanism. This method retrospectively analyzes the terminal guidance mechanism, introduces two types of error models for control and guidance, and performs Monte Carlo sampling on random trajectories to obtain the explosion point locations. The paper adopts three typical guidance laws, establishes a terminal trajectory model, and thereby achieves damage effectiveness analysis under mobile conditions. Case study analysis shows that compared to the direct aiming method, the sliding mode guidance law has a higher probability of severe damage when striking mobile targets. Taking the proportional navigation method striking a serpentine target as an example, the influence of multiple coupled parameters on the final damage effectiveness is analyzed. The results indicate that to achieve stable and efficient damage, the ammunition needs to reach 2 to 3 times the target speed, a guidance coefficient above 1.5, a relatively ideal fuze activation distance of 2.5m to 4m, and a relatively ideal delay time below 0.4s. This method can comprehensively consider the parameters of multiple subsystems such as guidance, fuze, and warhead, and can more accurately and comprehensively reflect the influence of parameters on damage results under mobile conditions, providing references for the optimal design and operational application of underwater weapons.

Effects of Front-Side Angles of Floating Boxes on the Navigation Performance of an Amphibious Vehicle in Calm Water

ZHANG Zhewei, XU Xiaojun, FENG Yikun, ZHANG Guoqing, JIN Haobin, GE Qiqian, WANG Jiancheng, ZHANG Xin

, Available online , doi: 10.11993/j.issn.2096-3920.2026-0092

[Abstract](17) [FullText HTML] (5) [PDF 5396KB](0)

Abstract:
To clarify the effects of the front-side angles of floating boxes on the resistance, attitude response, and local flow field of an amphibious vehicle in calm water, a specific amphibious vehicle was investigated based on the Reynolds-Averaged Navier–Stokes(RANS) equations. Within the framework of computational fluid dynamics(CFD), the shear stress transport(SST) k-ω turbulence model and the volume of fluid (VOF) free-surface model were employed to analyze the hydrodynamic effects of the front-side geometric angles of the floating boxes. By varying the front inclined angle α₁ and the outer guide-surface angle α₂, the resistance, pitch, heave, free-surface patterns, and pressure distributions were comparatively analyzed at a fixed displacement condition and a speed of 6m·s⁻¹. Towing-tank experiments were also conducted to validate the numerical method. The results show that, within the parameter ranges investigated, as α₁ increases from 15° to 35°, the normalized resistance R/∇ increases from 2.509 to 2.690, corresponding to an increase of approximately 7.2%. At larger α₁, the high-pressure region near the leading part of the floating box expands, accompanied by intensified free-surface disturbance and wave-making effects. The pitch angle first decreases slightly and then gradually increases, whereas the heave displacement first decreases and subsequently exhibits small fluctuations. Among the discrete cases investigated, the minimum heave displacement of 0.009 529 m occurs at α₁=25°, where R/∇ is 2.542, approximately 1.3% higher than that at α₁=15°, and the pitch angle is 4.255°. Therefore, the favorable values of α₁ differ among individual hydrodynamic performance indices, and an overall optimum cannot be identified without an explicitly defined multi-objective evaluation criterion. In comparison, variations in α₂ produce a smaller resistance response. At α₂=30°, R/∇ reaches the maximum value of 2.650 among the investigated cases, accompanied by relatively strong transverse-wave interference. The results indicate that the front-side angles of the floating boxes affect navigation resistance through changes in local pressure distribution, vehicle attitude response, and free-surface wave patterns, providing a reference for the selection and further optimization of the front-side geometric parameters of the floating boxes for the vehicle investigated in this study.

A Review of Key Technologies for Underwater Resident AUV Docking

WANG Yun, WANG Meng, ZHANG Xilin, GUO Lei, SUN Zhilei

, Available online , doi: 10.11993/j.issn.2096-3920.2026-0051

[Abstract](16) [FullText HTML] (5) [PDF 19234KB](0)

Abstract:
Docking of autonomous underwater vehicles (AUVs) is a key link for underwater resident systems to achieve long-term continuous operation, energy replenishment, and data return, and its performance directly affects system operation efficiency and long-term reliability. In recent years, AUV docking technology for complex marine environments has evolved from early functional verification into a systematic technical framework covering docking station structures, positioning and navigation, planning and control, as well as energy and data management, exhibiting a development trend characterized by the deep coupling of structure, sensing, control, and energy. However, current studies still suffer from insufficient environmental adaptability, limited robustness under sensing degradation, inadequate evaluation of long-term operational reliability, and insufficient system-level collaborative design. This paper systematically reviews the recent progress in key technologies for AUV docking in underwater resident scenarios, including docking station structures, stage-based positioning and navigation, planning and control, and energy and data management, and analyzes their intrinsic relationships and the challenges they face. The results show that AUV docking technology is shifting from isolated performance improvement toward system-level fault tolerance and collaborative optimization under uncertainty.

Loss Evolution Characteristics of a Micro Axial-Flow Turbine Under Variable Operating Conditions

LI Xiangyu, YI Jinbao, MA Weifeng, WEN Menggang, HUANG qilong, YANG jun

, Available online , doi: 10.11993/j.issn.2096-3920.2026-0077

[Abstract](22) [FullText HTML] (11) [PDF 3076KB](2)

Abstract:
A study on the evolution mechanism of off-design losses is carried out to address the efficiency issues of micro axial-flow turbines in micro underwater vehicles operating over a wide speed range. A thermo-mechanical-fluid multi-physics coupling model is developed using the Modelica language, incorporating micro-scale nonlinear loss corrections such as disk friction loss, partial admission loss, tip clearance leakage loss, and exit velocity loss. Through transient simulations under a typical mission profile and full-speed-range parameter sweeps, the stage-wise evolution of the loss mechanism under variable operating conditions is revealed: during low-speed cruise, exit velocity loss, disk friction loss, and partial admission loss share comparable contributions, forming a co-dominant regime, while leakage loss remains relatively stable; during high-speed dash, partial admission loss and disk friction loss become the dominant loss sources. Further investigation shows that system performance is significantly influenced by both operating and geometric parameters. Increasing inlet pressure and temperature can reduce the loss proportion, but proper matching between inlet parameters and aerodynamic characteristics must be ensured. Controlling tip clearance, appropriately increasing the number of nozzles to raise the partial admission ratio, and adopting a small rotor exit angle can effectively suppress kinetic energy dissipation and micro-scale penalties, thereby improving the turbine efficiency over the whole operating range. The findings provide theoretical support and simulation-based guidance for energy management, definition of high-efficiency operating intervals, and structural optimization of micro power systems.

Research on path planning of underwater inspection robot based on improved ant colony algorithm

Shen Zhaowen, Pan Xinfeng, Huang Mengshi, Yang Tianci, Zhang Wenze, Yi Zhengyao

, Available online , doi: 10.11993/j.issn.2096-3920.2026-0066

[Abstract](49) [FullText HTML] (26)

Abstract:
Aiming at the problems of slow convergence speed, easy to fall into local optimum and poor environmental adaptability of traditional ant colony algorithm in path planning of underwater inspection robot, an improved ant colony algorithm suitable for path planning of underwater inspection robot is proposed. Firstly, the ant colony pheromone update strategy is optimized, and a comprehensive evaluation function including path length, safety, smoothness and water flow adaptability is constructed. The pheromone release coefficient is dynamically adjusted by the path fitness. Adjust the pheromone volatilization coefficient to adjust with the iterative process, and speed up the convergence speed in the later stage of the algorithm iteration; the water flow factor and obstacle distance factor are introduced into the heuristic function to guide the ants to choose a better path. Then the simulated annealing mechanism is integrated to avoid the algorithm falling into local optimum. Finally, the B-spline curve is used to smooth the path to reduce the energy consumption of the underwater vehicle. The simulation results show that the improved ant colony algorithm not only has faster convergence speed and fewer turning points, but also significantly shortens the optimal path length.

AUV Path Planning Method Based on RRT* and Improved Artificial Potential Field

LIU Yuqing, CHEN Mojiang, HAO Chengpeng

, Available online , doi: 10.11993/j.issn.2096-3920.2026-0025

[Abstract](65) [FullText HTML] (29) [PDF 6989KB](7)

Abstract:
Aiming at the problem that the complex ocean current environment significantly affects the navigation efficiency of autonomous underwater vehicles (AUVs), this paper proposes an energy consumption-optimized path planning algorithm (FAPF-Bi-RRT*) that integrates bidirectional rapidly-exploring random tree with flow field-guided sampling and improved artificial potential field method. Firstly, a multi-strategy sampling probability correction method based on flow field information is designed. By calculating the consistency measure between the flow field and the target direction, the sampling weight is dynamically adjusted to guide the random tree to expand toward downstream and low-energy-consumption areas, thus solving the blind search problem of the traditional RRT*. Secondly, an adaptive flow field potential field model is established, which converts the pushing and resistance effects of ocean currents into potential field gradients. An adaptive adjustment mechanism of flow field gain is introduced into the artificial potential field to assist node expansion and reconnection in real time, thereby avoiding countercurrent traps. Finally, a composite cost function including path length and energy consumption is constructed for progressive optimization. Simulation results under real terrain and flow field data show that while ensuring probabilistic completeness and obstacle avoidance capability, the proposed algorithm reduces the path length by approximately 14% and the path energy consumption by approximately 10% compared with the traditional Bi-RRT* algorithm in strong flow field environments. This realizes efficient and energy-saving path planning in complex marine environments.

Hydrodynamic Characteristics of Underwater Vehicles Under the Flow Disturbance Condition of Submarine

HUANG Chuang, HAO Sihan, ZHANG Chenchen, QIN Kan, XU Haiyu

, Available online , doi: 10.11993/j.issn.2096-3920.2025-0165

[Abstract](304) [FullText HTML] (109) [PDF 4530KB](5)

Abstract:
A numerical model of an underwater vehicle in the flow field of the submarine is established by combining the overset grid technology and the moving reference frame. The rationality of the numerical method is verified by comparing the simulation results with the standard model test data reported in the literature. The effects of the flow around the submarine on the external flow field and hydrodynamic characteristics of the vehicle are investigated. The results show that the underwater vehicle is most significantly affected by the flow around the submarine when it is located at the front side of the submarine, and the drag coefficient, lateral force coefficient, and yaw moment coefficient of the vehicle exhibit nonlinear characteristics. As the distance between the vehicle and the submarine increases, the influence of the flow around the submarine on the hydrodynamic characteristics of the underwater vehicle gradually weakens, and the influence can be neglected when the distance is greater than 1.75 times the diameter of the submarine. With the increase in the speed of the submarine, the hydrodynamic parameters of the vehicle are more strongly affected by the flow around the submarine. The research results can provide a reference can provide a reference for the prediction of launching initial trajectory of underwater vehicles.

Entry-Exit Water Perception and Damage Monitoring of Rotors for Cross-Media Vehicle

Bo Fusen, Pan Deng, Fang Ziyi, Fu Bowei, Li Hanyang, Liu Zhihai

, Available online , doi: 10.11993/j.issn.2096-3920.2026-0045

[Abstract](96) [FullText HTML] (44)

Abstract:
In the process of medium conversion, the rotor of cross-medium vehicle faces complex instantaneous strain problems due to the sudden change of medium physical parameters. Long-term alternating load can easily lead to the initiation, propagation and even fracture of blade microcracks, which seriously threatens the operational reliability and task continuity of the vehicle. In order to solve the core problems of rotor inlet and outlet water state perception and damage monitoring, this paper constructs a complete technical system of ' signal acquisition-processing-feature extraction-model training-state perception ': The experimental device controls the inlet and outlet water of the rotor drive structure through the guide rail, and uses the fiber grating demodulator to collect the whole process signal of the rotor inlet and outlet water in real time. The singular point elimination method is selected to identify and eliminate the abnormal data points, and the characteristics of the signal entering water, water and outlet water are completely retained. The timestamp and amplitude information of the time series are retained by image conversion, and the time correlation characteristics are enhanced and the redundancy is eliminated. Then the feature signal and the converted image are used for model training. The results show that the training model realizes the accurate identification and real-time damage warning of the rotor inlet and outlet water state of the cross-media vehicle, provides decision support for the route adjustment of the vehicle, effectively improves its intelligent perception and penetration ability, and promotes the in-depth application of optical monitoring technology in the field of new weapon equipment and national defense.

A UAV-USV Collaborative Water Depth Inversion Model Based on Multi-Modal Heterogeneous Sensors

Lin Zibo, Lai Yunshan, Zhang Runda

, Available online , doi: 10.11993/j.issn.2096-3920.2026-0006

[Abstract](116) [FullText HTML] (52)

Abstract:
In response to the low accuracy of water depth inversion in complex water environments using a single remote sensing platform or homogeneous data, this paper proposes a collaborative water depth inversion model between unmanned aerial vehicles and unmanned ships based on multimodal heterogeneous sensors. The model first extracts the target water body through multi spectral index joint extraction, and then integrates dual platform multimodal sensor data. It uses gradient boosting decision tree (GBDT) to mine nonlinear mapping relationships and invert water depth. The experiment shows that the model has a coefficient of determination of 0.971, a root mean square error of 0.31 m, and the water depth fluctuation is controlled within ± 0.2 m. The accuracy is significantly better than traditional comparison methods.

Design and Application of Vehicle Mounted Industrial CT Nondestructive Testing System and Underwater Unmanned Equipment Defect Recognition Software

MA Junli, WANG Shuai, LIU Wenbin, GAO Haoyang, LI Chenhui, ZHANG Xitong, SU Chenghai

, Available online , doi: 10.11993/j.issn.2096-3920.2025-0171

[Abstract](493) [FullText HTML] (297) [PDF 4796KB](39)

Abstract:
To satisfy the inspection demands of unmanned undersea equipment that are stored in remote areas, unsuitable for frequent transportation and difficult to conduct centralized testing, this paper builds a vehicle-mounted industrial computed tomography(CT) nondestructive defect detection and identification system with hardware subsystems including power supply, X-ray source, detection, acquisition and transmission. Combined with deep neural networks, an image recognition software for defects in industrial CT inspection products is developed to process inspection images and realize the identification and marking of internal product defects. Practical test results demonstrate that the proposed system can effectively detect and identify pores, cracks, debonding and other internal defects in high-energy fillers of unmanned undersea equipment. The imaging accuracy exceeds 98%, and both the missed detection rate and false alarm rate of defect identification are no more than 5%. This system can adapt to different materials and shapes of the products, and can operate in various environments. It has a promising application prospect.

A TCN-Attention-Based Pseudo-Velocity Measurement Generation Method for Loosely Coupled SINS/DVL Integrated Navigation

WANG Guoxiang, HAN Xingcheng, GAO Shengwen, WANG Ling

, Available online , doi: 10.11993/j.issn.2096-3920.2026-0047

[Abstract](529) [FullText HTML] (300) [PDF 3674KB](57)

Abstract:
DVL unavailability degrades the accuracy of loosely coupled SINS/DVL integrated navigation for autonomous underwater vehicles. To address this problem, a pseudo-DVL velocity measurement generation method based on a temporal convolutional network with an attention mechanism (TCN-Attention) is proposed. The method uses the angular velocity and specific force measured by the inertial measurement unit (IMU), together with the attitude, position, and velocity obtained from inertial navigation computation, as sequential inputs. During the DVL-available stage, supervised samples are constructed using DVL velocity for offline network training. During the DVL-unavailable stage, the trained model outputs pseudo-velocity measurements, which are incorporated into the extended Kalman filter (EKF) update to suppress inertial error accumulation. Causal dilated convolutions are adopted to extract temporal features, and an attention mechanism is introduced to enhance the representation of key dynamic segments such as turning, acceleration, and deceleration. Simulation results based on 16 trajectory datasets show that, compared with the temporal convolutional network (TCN) and the gated recurrent unit with attention model (GRU-Attention), the proposed method achieves better performance in east- and north-velocity errors as well as absolute trajectory error, and reconstructs trajectories closer to the ground truth, demonstrating its effectiveness and robustness under continuous DVL-outage conditions.

Research on Factors Affecting Leakage Current of Lithium Reserve Battery Packs

GAO Xinlong, JIA Bin, LIN Pei, CHENG Haichao, LI Xuehai

, Available online , doi: 10.11993/j.issn.2096-3920.2026-0083

[Abstract](486) [FullText HTML] (262) [PDF 995KB](74)

Abstract:
The distribution of leakage current of lithium reserve battery packs where the battery cells are in a common electrolyte state was studied, using the equivalent circuit simulation calculation method. The effects of the series cells quantity, electrolyte conductivity, and the structural characteristics of the injection tube on the leakage current were analyzed. A leakage current experimental device for battery modules was established. By comparing the measured results with the simulation results, the validity of the simulation calculation method was confirmed.

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