水下无人系统学报

Research Advances of Biomimetic Artificial Lateral Line Detection Technology for Unmanned Underwater Swarm

HU Qiao, LIU Yu, ZHAO Zhen-yi, ZHU Zi-cai

2019, 27(2): 114-122. doi: 10.11993/j.issn.2096-3920.2019.02.001

[Abstract](1329) [PDF 1513KB](1064)

Abstract:
The existing acoustic and optical detection systems are susceptible to disturbance of underwater environment, so it is difficult for them to obtain accurate near-field sensing information for unmanned underwater swarm. This paper discusses the characteristics and difficulties of the detection technology for unmanned underwater swarm, and reviews the research advances both at home and abroad with respect to the artificial lateral line(ALL) array and the signal processing. The key problems existing in the current researches are pointed out, including perception principle, layout and micro-process of ALL, and application of artificial intelligence algorithm and the approaches for solving these problems are discussed.

Progress of Biomimetic Underwater Robot Based on Intelligent Actuating Materials: a Review

WANG Yan-jie, HAO Mu-yu, ZHANG Lin, LUO Min-zhou

2019, 27(2): 123-133. doi: 10.11993/j.issn.2096-3920.2019.02.002

[Abstract](960) [PDF 6203KB](837)

Abstract:
It is one of the current research hotspots of biomimetic underwater robot to study and imitate the motion modes of aquatic animals and apply the intelligent actuating materials to the structure and motion design of a biomimetic underwater robot. Combined with the advantages of aquatic animals and intelligent actuating materials, the biomimetic underwater robot designed with intelligent actuating materials is easier to be miniaturized and higher maneuverability, so it can carry out continuous and flex-ible movement, and realize complex underwater motion. Compared with the traditional actuating mode, the biomimetic actuating mode has significant advantages. In this paper, the motion mechanisms of several typical aquatic animals are introduced. Com-parison of performance specifications, advantages and disadvantages of four typical intelligent materials. The existing biomimetic underwater robots that imitate the propulsion modes of aquatic animals and design with intelligent materials, and their structural features are summarized. The motion efficiency of these robots are analyzed and compared. As a result, some key problems that need to be solved in future development of the biomimetic underwater robots are pointed out.

Underwater Electrocommunication Protocol Design for Underwater Robot

ZHANG Han, WANG Wei, XIE Guang-ming

2019, 27(2): 134-141. doi: 10.11993/j.issn.1673-1948.2019.02.003

[Abstract](876) [PDF 2076KB](590)

Abstract:
As a novel underwater communication method, electrocommunication has the following advantages: lower energy consumption, less susceptible to external interference, real-time, and high omnidirectional performance. It has become a potential method for underwater communication and networking among small underwater robots. In previous research activities, the electrocommunication system has been integrated into a boxfish-like robotic fish. However, when multiple robotic fishes(nodes) communicate, collision is unavoidable because they share same electrocommunication channel. In this paper, an electrocommunication protocol based on the carrier sense multiple access/collision avoidance (CSMA/CA) protocol of wireless communication networks is proposed to solve the collision problem. The operating mechanism of the protocol and the channel state detection method are introduced. In order to validate the effectiveness of the proposed protocol, MATLAB simulations and electrocommunication experiments using three robotic fishes were conducted. The results show that this protocol can effectively reduce the occurrence of communication collisions.

Flow Field Simulation of Synthetic Jet Actuator Based on Dielectric Elastomer

MA Wen-tao, TANG Chao, LI Bo, ZHU Zi-cai, CHEN Hua-ling

2019, 27(2): 142-148. doi: 10.11993/j.issn.2096-3920.2019.02.004

[Abstract](443) [PDF 2881KB](350)

Abstract:
Based on the biomimetic mechanism, a design method of synthetic jet actuator actuated by dielectric elastomer (DE) electro-deformation is proposed, and finite element simulation of the flow field in its working process is carried out. The results show that the fluid jet produced by the synthetic jet actuator has the characteristics of synthetic jet, which can form a series of vortex rings, and the jet maintains good directivity under the entrainment effect of the vortex ring. This design may have good application prospect to new generation of biomimetic synthetic jet actuating.

Research on Actuating Technology of IPMC-Based Biomimetic Robotic Fish

BIAN Chang-sheng, BAI Wan-fa, ZHU Zi-Cai, RU Jie, CHEN Hua-ling

2019, 27(2): 149-156. doi: 10.11993/j.issn.2096-3920.2019.02.005

[Abstract](625) [PDF 2784KB](441)

Abstract:
An ionic polymer-metal composite(IPMC) is suitable for the swing actuating structure of a biomimetic robotic fish because it is able to produce bending deformation under low voltage. In this paper, the research status of a biomimetic robotic fish based on soft smart materials is analyzed. It shows that actuating performance of the IPMC-based biomimetic robotic fish is unsatisfactory, such as slow speed and low load capacity, which are due to poor output force and low efficiency of the stacking structure. In order to improve the performance of the biomimetic robotic fish and widen its application, this paper matches overall performance of IPMC with the actuating demand of the biomimetic robotic fish. From the perspective of the materials, three actuating technologies for the biomimetic robotic fish are proposed as follows: the ultra-thick and large actuating force IPMC based on alcohol-assisted process; the fast response technology of IPMC based on impulsive voltage; and the spatial stacking structure actuating technology. Contrast experiments prove that these technologies can effectively improve the overall output force, the response speed, and the spatial stacking structure of stacking efficiency for IPMC actuating material. This study may provide a reference for the actuating structure design of the biomimetic robotic fish.

Speed Control System of Soft Robotic Fish Actuated by IPMC

CHANG Long-fei, LI Chao-qun, NIU Qing-zheng, YANG Qian, HU Xiao-pin, HE Qing-song, WU Yu-cheng

2019, 27(2): 157-165. doi: 10.11993/j.issn.2096-3920.2019.02.006

[Abstract](507) [PDF 1837KB](430)

Abstract:
Independent operation and closed-loop speed control are very important for practical application of ionic polymer-metal composite (IPMC)-actuated robotic fish. However, due to the low force output of IPMC, the load capacity of the robotic fish is limited, which poses demanding requirements for weight and volume of the sensors and control units. In addition, the speed signal acquisition and processing are relatively difficult, therefore the existing IPMC-actuated robotic fish usually adopts open-loop control, while the speed feedback control of the IPMC-based independent robotic fish has not yet been realized. This study fabricated an independent IPMC robotic fish without external power supply, and implemented its closed-loop speed control. An inertial measurement unit (IMU) device was used to measure the speed, and a proportional-integral-differential (PID) controller feedback speed control system was designed. The control system was simulated by MATLAB, and the printed circuit board (PCB) was fabricated by using such electronic devices as single-chip microcomputer and gyroscope. Some IPMC materials with good performance were used to make the prototype of the robotic fish with considerable load capacity. Experiment was carried out with preset speed of 3 mm/s and 6 mm/s, respectively, the results showed that the robotic fish could perform independently with precise speed control, and it reached the preset speed within 1.8 s. The steady-state error remained within mm/s, and the speed control error did not exceed 8%. This research may offer a reference for the study of closed-loop control of robotic fish swimming.

Modeling and Experimental Research of Integrating Propulsion Mechanism of Pectoral Fin’s Fluctuation and Swing for the Biomimetic Robotic Fish

FAN Zeng, WANG Yang-wei, LIU Kai, ZHAO Dong-biao

2019, 27(2): 166-173. doi: 10.11993/j.issn.2096-3920.2019.02.007

[Abstract](710) [PDF 1423KB](374)

Abstract:
For developing a high-performance biomimetic underwater thruster, this paper takes stingray as a biomimetic prototype and learns from the fish’s swing-mode propulsion mechanism to propose a new type of propulsion mode that integrates pectoral fin’s fluctuation and swing propulsion mechanisms. The mechanical structure and control system of the biomimetic robotic fish are designed, and a dynamic model integrating the pectoral fin’s fluctuation and swing propulsion mechanisms is built. Based on the theoretical analysis, the relations of the average propulsive force and swimming speed with the motion parameters such as area of swinging pectoral fin, the swing frequency, and amplitude are studied experimentally. The results show that the theoretical calculations and the experimental results have the same tendency; the average propulsive force and the average swimming speed of the robotic fish increase first and then decrease with the increase of the swing pectoral fin area, and they increase linearly with the swing frequency and amplitude increasing—the maximum average propulsive force reaches to 2.8 N, and the maximum swimming speed reaches to 121 mm/s. The research may provide a reference for improving swimming performance of the robotic fish.

Intelligent Detection of Artificial Lateral Line for Biomimetic Robotic Fish Based on EMD and SVM

LIU Yu, HU Qiao, ZHAO Zhen-yi, WEI Chang

2019, 27(2): 174-180. doi: 10.11993/j.issn.1673-1948.2019.02.008

[Abstract](577) [PDF 1415KB](339)

Abstract:
In view of the problems that underwater acoustic perception and information interaction system are often disturbed by reverberation or multipath effects, and the optical sensing is easily affected by water turbidity, a novel intelligent detection method of underwater moving target based on artificial lateral line(ALL) is proposed to accurately detect target in complicated underwater interferences for a biomimetic robotic fish. Firstly, the original signals received by the ALL system are decomposed into different intrinsic mode functions(IMFs) via empirical mode decomposition(EMD) to separate target signal from interferences. Secondly, the characteristic frequency of the vibrating target representing different fish is obtained from the IMFs to detect the underwater moving target. Finally, the power spectrums of the IMFs are input into the support vector machines(SVMs) to recognize the azimuth of underwater moving target intelligently. Water tank tests with combination of the proposed method with ALL detection are conducted, and the results show that the proposed method has better detection performance than the traditional methods, such as fast Fourier transform(FFT) and neural network.

Analysis of Single Beacon Navigation Accuracy and Path Planning

LIANG Guo-long, ZHANG Xin-yu, SUN Si-bo, FU Jin

2019, 27(2): 181-188. doi: 10.11993/j.issn.2096-3920.2019.02.009

[Abstract](718) [PDF 1285KB](473)

Abstract:
Compared with traditional navigation, single beacon navigation has the advantages of simple distribution and low cost, however, its accuracy of navigation needs to be further improved. This paper deduces the single beacon navigation accuracy theoretically by means of partial differential matrix, and analyzes the robustness of single beacon navigation to several kinds of errors. Then, based on analysis of single beacon navigation accuracy, a path planning scheme, as well as optimum selection of positioning points and path optimization, is presented. Simulation experiment validates the correctness of the partial differential matrix method and the effectiveness of the path planning scheme. This research may provide a reference for autonomous undersea vehicle(AUV) precise guidance.

Bionic Imaging of Underwater Multiple Targets with High Resolution Based on SCAT Model

SU Meng-na, LIANG Hong, YANG Chang-sheng

2019, 27(2): 189-193. doi: 10.11993/j.issn.2096-1509.2019.02.010

[Abstract](421) [PDF 511KB](298)

Abstract:
The spectrogram correlation and transformation(SCAT) model, as the classic model in bat echo processing, has high range resolution. It is used to replace the artificial sonar for better underwater target location, which has become the developing trend of underwater acoustic detection. In this study, based on simple and reasonable assumptions, the range resolution of the SCAT model is strictly deduced, which is a reciprocal of 2 times the maximum center frequency of the filterbank. Then, a bionic imaging method of multiple targets with high resolution is proposed, which can be applied to a variety of imaging cases such as aeroacoustics, radar, and underwater as long as the model parameters are modified adaptively. Simulation results in underwater environment show that the bionic imaging method of multiple targets with high resolution can achieve underwater two-dimensional acoustic imaging with a higher range resolution than traditional correlator.

Deployment Planning Algorithm of Unmanned Underwater Swarm Based on Probability Model of Single-platform Detection

SHENG Xue-li, LI Peng-fei, GUO Long-xiang, LU Dian, HAN Xiao

2019, 27(2): 194-199. doi: 10.11993/j.issn.2096-3920.2019.02.011

[Abstract](695) [PDF 790KB](364)

Abstract:
In marine environment monitoring, offshore exploration, military tactical reconnaissance and other missions, the detection performance of unmanned underwater swarm depends on the deployment planning of swarm and the detection performance model of single platform. In this paper, a probability model of single platform for area detection is proposed based on the active sonar process and the navy interim surface ship model(NISSM) sonar model. An unmanned platform deployment planning algorithm in a specified area using a Gaussian mutation operator and a tournament selection mechanism is proposed based on cuckoo search algorithm. Simulation result indicates that the probability model of single-platform detection can give detection probability of each point in a region quantitatively, and can effectively reflect the uncertainty of detection information, which is induced by the restriction of platform’s parameter and marine environment. And the attenuation of the platform detection capability relates to the false alarm probability. The proposed algorithm performs better than the cuckoo search algorithm in terms of higher slope of the evolution curve, and faster convergence speed. For different number of platforms, the effective detection coverage rate of the unmanned platform deployment planning algorithm is more than 0.8, 0.2 higher than that of the random deployment.

Influence of Cavitator Cone Angle on Supercavitation Flow of Projectile in Initial Stage of Transonic Water-Entry

WANG Rui, DANG Jian-Jun, YAO Zhong, QI Xiao-Bin

2019, 27(2): 200-205. doi: 10.11993/j.issn.2096-3920.2019.02.012

[Abstract](427) [PDF 4095KB](396)

Abstract:
To further understand the influence of cavitator on projectile’s navigation state, taking cavity formation and development of a projectile as the object during transonic water-entry process, the cavitation flows during transonic water-entry process by projectiles with different cavitator cone angles of 90°, 120°, 150° and 180° are simulated by using the commercial software Fluent combining with the user-defined function(UDF), the multiphase flow model (VOF implicit) and dynamic mesh, in which the compressibility of liquid is taken into account. And then the influences of the cone angle on the impact load and flow field characteristics during the projectile’s transonic water-entry process are discussed. The results show that the cone angle has significant influences on the distribution of flow field parameters and drag characteristics of projectiles: with the increase in the cone angle, the distance from the shock surface to the hysteresis point of cavitator and the angle of the shock wave decrease accordingly; in the initial stage of transonic water-entry, the impact load coefficient increases with the increase of the cone angle, and the impact peak arrives earlier with narrower peak pulse width. This study may provide a reference for the design of head shape of the supercavity projectile.

Thermal-Flow Coupling Simulation Analysis of Small and Special Underwater Gas Turbine Disk

XIAO Yan-bin, SHI Xiao-feng, YI Yin, FENG Qi-xi, YI Jin-bao, ZHAO Hai-tao

2019, 27(2): 206-211. doi: 10.11993/j.issn.2096-3920.2019.02.013

[Abstract](361) [PDF 4492KB](443)

Abstract:
For the high temperature and high-speed incoming flow of small and special underwater gas turbines and the high rotary speed of the turbine disk, the temperature field of the disk and its channel are simulated by using the shear stress transport(SST) turbulence model for the fluid domain and the conjugate heat transfer method for the solid domain. Then, the temperature field is loaded into the strength analysis to simulate the thermal stress and deformation of the disk under the worst conditions. Calculation results show that the turbine disk temperature reaches the extreme value when the number of nozzles is 3; and the reverse exhaust can effectively reduce the surface temperature of the turbine disk, but its function will be limited. Without any cooling measures, the maximum temperature of the disk exceeds the maximum temperature tolerance of the material, and there is a large disk elongation in its extreme temperature range, moreover, the maximum stress value of the disk at high temperature and high rotary speed exceeds the allowable stress of the material. Therefore, certain cooling measures should be taken for the disk areas where the temperature is higher. This research may provide a reference for safety design of gas turbines.

Thermodynamic Performance Analysis of a New Type of UUV Power System Based on Li/SF₆ Energy

BAI Jie, DANG Jian-jun, CAO Lei-lei

2019, 27(2): 212-216. doi: 10.11993/j.issn.2096-3920.2019.02.014

[Abstract](647) [PDF 428KB](473)

Abstract:
To develop an unmanned undersea vehicle(UUV) with the performances of long endurance, long range and deep depth, a new thermoelectric power system using Li/SF₆ as energy is proposed. The system adopts Rankine cycle, and its fuel’s energy density can reach 600 Wh/kg, which is three times higher than that of the current battery. The solution algorithm for the working medium parameters’ effects on the system performance is established, and then the influences of evaporator outlet temperature, pressure, and condenser pressure on the system performance are analyzed. The results show that, within the scope of certain parameters, 0.8% increase in the system efficiency is gained for every 100 K increase in the evaporator outlet temperature; the system efficiency rises by 0.5% for every 1 MPa increase in the evaporator pressure; and the system efficiency rises by 0.2% for every 0.01 MPa decrease in the condenser pressure. This system gives a new solution to enhancing UUV energy supply, and the obtained conclusions may provide a reference for the power system design of an UUV.

Simplified Modeling and Vibration Analysis of Power and Propulsion System for Torpedo

ZHANG Kai, YIN Shao-ping, CAO Xiao-juan, GUO Jun, YANG Yang

2019, 27(2): 217-224. doi: 10.11993/j.issn.2096-3920.2019.02.015

[Abstract](532) [PDF 4505KB](397)

Abstract:
To reduce the noise of a thermal power torpedo, a method for simplified finite element modeling and vibration response analysis of its power and propulsion system excited by multiple excitation sources is proposed. The finite element model including each vibration isolating link is established. Simplified modeling of the front and rear vibration isolating rings of shafting, the vibration isolating rings of whole power plant and the coupler is carried out, and the static stiffness in each direction is determined by finite element static simulation. Then, the exciting forces of engine, propulsion shafting system and propeller on the model are extracted and applied to the finite element model. The structural vibration response of the shell surface is obtained based on the modal superposition method. This study may provide a reference for design of torpedo vibration isolation and further optimization of vibration isolation parameters.

2019 Vol. 27, No. 2

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