Editorial

10 pages, 224 KiB

Open AccessEditorial

Frontiers in Deep-Sea Equipment and Technology

by Weicheng Cui, Lian Lian and Guang Pan

J. Mar. Sci. Eng. 2023, 11(4), 715; https://doi.org/10.3390/jmse11040715 - 26 Mar 2023

Cited by 2 | Viewed by 2043

The conflict between population, resources, and environment in the twenty-first century made the ocean the strategic space and resource treasure of human society to realize sustainable development [...] Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

Research

Jump to: Editorial, Review

18 pages, 31301 KiB

Open AccessArticle

A Manta Ray Robot with Soft Material Based Flapping Wing

by Qimeng Liu, Hao Chen, Zhenhua Wang, Qu He, Linke Chen, Weikun Li, Ruipeng Li and Weicheng Cui

J. Mar. Sci. Eng. 2022, 10(7), 962; https://doi.org/10.3390/jmse10070962 - 14 Jul 2022

Cited by 23 | Viewed by 3699

Abstract

Recent research on robotic fish mainly focused on the bionic structure design and realizing the movement with smart materials. Although many robotic fish have been proposed, most of these works were oriented toward shallow water environments and are mostly built with purely rigid [...] Read more.

Recent research on robotic fish mainly focused on the bionic structure design and realizing the movement with smart materials. Although many robotic fish have been proposed, most of these works were oriented toward shallow water environments and are mostly built with purely rigid structures, limiting the mobility and practical usability of robotic fish. Inspired by the stability of the real manta ray, a manta ray robot design is proposed with soft material made flapping wing based on an open-source ROV (Remotely Operated Vehicle). The flapping wing structure with three different materials mimics the wide pectoral fins of real manta rays, which have bones, muscles, and skin. Furthermore, its modular design makes it easy to install and disassemble. The kinematic and hydrodynamic analysis of the manta ray robot are simulated in this paper. The actual manta ray robot is fabricated and several sets of test are performed in the pool. The robot can swim forward continually and stably with a simple rolling and pitching pattern. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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21 pages, 6439 KiB

Open AccessArticle

Multi-AUV Cooperative Navigation Algorithm Based on Temporal Difference Method

by Ranzhen Ren, Lichuan Zhang, Lu Liu, Dongwei Wu, Guang Pan, Qiaogao Huang, Yuchen Zhu, Yazhe Liu and Zixiao Zhu

J. Mar. Sci. Eng. 2022, 10(7), 955; https://doi.org/10.3390/jmse10070955 - 12 Jul 2022

Cited by 8 | Viewed by 1810

Abstract

To reduce the cooperative positioning error and improve the navigation accuracy, a single master–slave AUV cooperative navigation method is proposed in this paper, which mainly focuses on planning the optimal path of the master AUV by the time difference (TD) method, under the [...] Read more.

To reduce the cooperative positioning error and improve the navigation accuracy, a single master–slave AUV cooperative navigation method is proposed in this paper, which mainly focuses on planning the optimal path of the master AUV by the time difference (TD) method, under the premise that the path of the slave AUV has been planned. First, the model of multi-AUV cooperative navigation is established, and the observable problem of the system is analyzed. Second, for the single master–slave AUV cooperative navigation system, a Markov decision process (MDP)-based multi-AUV cooperative navigation model is established, and the master AUV path planning method is designed based on the TD method. Finally, the extended Kalman filter (EKF) and unscented Kalman filter (UKF) nonlinear filtering algorithms are applied to simulate and verify the algorithm that is proposed in this paper. The results show that the theoretical positioning error of the slave AUV can be controlled to about 3.2m by planning the path of the master AUV using the TD method. This method can not only reduce the observation error and positioning error of the slave AUV during the whole cooperative navigation process, but also keep the relative measurement distance between the master AUV and the slave AUV within an appropriate range. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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14 pages, 4775 KiB

Open AccessArticle

A Novel Integrated Gliding and Flapping Propulsion Biomimetic Manta-Ray Robot

by Daili Zhang, Guang Pan, Yonghui Cao, Qiaogao Huang and Yong Cao

J. Mar. Sci. Eng. 2022, 10(7), 924; https://doi.org/10.3390/jmse10070924 - 04 Jul 2022

Cited by 15 | Viewed by 2827

Abstract

Bionic underwater robots are the intersection of biology and robotics; they have the advantages of propulsion efficiency and maneuverability. A novel vehicle that combines a gliding and flapping propulsion inspired by a manta ray is presented in this article. The outstanding character of [...] Read more.

Bionic underwater robots are the intersection of biology and robotics; they have the advantages of propulsion efficiency and maneuverability. A novel vehicle that combines a gliding and flapping propulsion inspired by a manta ray is presented in this article. The outstanding character of the robot is that its integrated maneuverable flapping propulsion relies on two bionic flexible pectoral fins and long-range efficient gliding propulsion, which is based on a buoyancy-adjustment system and a mass-adjustment system. We designed the biomimetic manta ray robot and analyzed the principle of the gliding and flapping system in this paper. The gliding propulsion capability and the flapping propulsion performance are verified through gliding and swimming experiments. In conclusion, the designed bionic manta robot provides a platform with practical application capabilities in marine environment detection, concealed reconnaissance, and aquaculture. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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26 pages, 20995 KiB

Open AccessArticle

Prediction of Cavitation Performance over the Pump-Jet Propulsor Using Computational Fluid Dynamics and Hybrid Deep Learning Method

by Chengcheng Qiu, Qiaogao Huang and Guang Pan

J. Mar. Sci. Eng. 2022, 10(7), 918; https://doi.org/10.3390/jmse10070918 - 02 Jul 2022

Cited by 5 | Viewed by 1571

Abstract

The cavitation performance of an oblique flow field is different from that under a pure axial flow field. This study analyzed the hydrodynamic performance, bearing force, and tip clearance flow field under different rotating speeds and different cavitation numbers in an oblique flow [...] Read more.

The cavitation performance of an oblique flow field is different from that under a pure axial flow field. This study analyzed the hydrodynamic performance, bearing force, and tip clearance flow field under different rotating speeds and different cavitation numbers in an oblique flow field. Furthermore, this study proposed a hybrid deep learning model CNN-Bi-LSTM to quickly and accurately predict the bearing force of a pump-jet propulsor (PJP), which will solve the problem of time-consuming calculation and consumption of considerable computing resources in traditional computational fluid dynamics. The Shear–Stress–Transport model and Reynolds-averaged Navier–Stokes equations were utilized to procure the training and testing datasets. The training and testing datasets were reasonably divided in the ratio of 7:3. The results show that the propulsion efficiency decreased more obviously under higher rotating speed conditions, with a maximum decrease of up to 13.59%. The small cavitation numbers 1.4721 and high oblique angle significantly impacted the efficiency reduction; the maximum efficiency loss exceeded 20%. Thus, a small cavitation number 1.4721 is extremely detrimental to the propulsion efficiency of the PJP due to the large cavitation area. Moreover, the intensity of the tip clearance vortex continuously increased with the rotating speed. The CNN-Bi-LSTM deep model successfully predicted the phase difference and trend change of the propulsor bearing force under different conditions. The prediction difference was large at the crest and trough of the bearing force, but it is within the acceptable error range. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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22 pages, 9032 KiB

Open AccessArticle

Deep-Sea Underwater Cooperative Operation of Manned/Unmanned Submersible and Surface Vehicles for Different Application Scenarios

by Lei Yang, Shengya Zhao, Xiangxin Wang, Peng Shen and Tongwei Zhang

J. Mar. Sci. Eng. 2022, 10(7), 909; https://doi.org/10.3390/jmse10070909 - 01 Jul 2022

Cited by 13 | Viewed by 3733

Abstract

In this paper, we propose three cooperative operational modes of manned and unmanned submersibles for a range of different deep-sea application scenarios. For large-scale exploration, a lander or an unmanned surface vehicle (USV) is paired with one or more autonomous underwater vehicles (AUVs), [...] Read more.

In this paper, we propose three cooperative operational modes of manned and unmanned submersibles for a range of different deep-sea application scenarios. For large-scale exploration, a lander or an unmanned surface vehicle (USV) is paired with one or more autonomous underwater vehicles (AUVs), while the liberated research vessel R/V can transport the manned submersible to another area for diving operations. When manned submersibles and AUVs perform small-scale accurate measurements, the research vessel R/V supports both submersible types for diving operations and has a positioning and communication time allocation mechanism for cooperative operations. Through the analysis of the operating efficiency of different modes, we found that the cooperative operational mode based on the pure research vessel R/V is suitable for local small-scale accurate detection, and the cooperative operational mode based on the USV/lander system is suitable for large-scale and long-distance underwater operations. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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17 pages, 5486 KiB

Open AccessArticle

Similarity Evaluation Rule and Motion Posture Optimization for a Manta Ray Robot

by Yonghui Cao, Shumin Ma, Yingzhuo Cao, Guang Pan, Qiaogao Huang and Yong Cao

J. Mar. Sci. Eng. 2022, 10(7), 908; https://doi.org/10.3390/jmse10070908 - 30 Jun 2022

Cited by 11 | Viewed by 2325

Abstract

The current development of manta ray robots is usually based on functional bionics, and there is a lack of bionic research to enhance the similarity of motion posture. To better exploit the characteristics of bionic, a similarity evaluation rule is constructed herein by [...] Read more.

The current development of manta ray robots is usually based on functional bionics, and there is a lack of bionic research to enhance the similarity of motion posture. To better exploit the characteristics of bionic, a similarity evaluation rule is constructed herein by a Dynamic Time Warping (DTW) algorithm to guide the optimization of the control parameters of a manta ray robot. The Central Pattern Generator (CPG) network with time and space asymmetry oscillation characteristics is improved to generate coordinated motion control signals for the robot. To optimize similarity, the CPG network is optimized with the genetic algorithm and particle swarm optimization (GAPSO) to solve the problems of multiple parameters, high non-linearity, and uncertain parameter coupling in the CPG network. The experimental results indicate that the similarity between the forward motion pose of the optimized manta ray robot and the manta ray is improved to 88.53%. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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13 pages, 2727 KiB

Open AccessArticle

Effect of Cross-Joints Fin on the Thrust Performance of Bionic Pectoral Fins

by Yang Lu, Yonghui Cao, Guang Pan, Qiaogao Huang, Xin Dong and Yong Cao

J. Mar. Sci. Eng. 2022, 10(7), 869; https://doi.org/10.3390/jmse10070869 - 24 Jun 2022

Cited by 4 | Viewed by 1741

Abstract

Cownose rays have a high forward propulsive performance due to their unique oscillating fin structure (named the cross-bracing structure), which differs from undulatory fish. The cross-bracing structure obtained through anatomy, on the other hand, is extremely complex. Hence, researchers used simple structures to [...] Read more.

Cownose rays have a high forward propulsive performance due to their unique oscillating fin structure (named the cross-bracing structure), which differs from undulatory fish. The cross-bracing structure obtained through anatomy, on the other hand, is extremely complex. Hence, researchers used simple structures to model the biological structure to target the individual factors that affect cownose ray cruising performance. This paper simplified the cross-bracing fin structure to a cross-joints fin (CJF) structure with 18 designs. CJFs had five different joint widths (2 mm, 3 mm, 4 mm, 5 mm, and 6 mm) in both spanwise and chordwise directions, and these had two fin thicknesses (1.5 mm, 2.5 mm). The joint widths of CJF are related to the stiffness of the spanwise and chordwise fins (Fin stiffness increases with joint width). The experiments were conducted in a still water tank (1.5 m × 0.8 m × 0.8 m) with three stroke amplitudes (30°, 50°, 70°) and three flapping frequencies (0.4 Hz, 0.6 Hz, 0.8 Hz) for each fin, making up 162 distinct sets of data. The experimental results showed the following: (1) at low wingtip Reynolds numbers, the high stiffness of the CJF causes a significant reduction in thrust. In particular, high stiffness results in a low thrust averaged from all motion parameters; (2) at high wing tip Reynolds numbers, the effect of changing spanwise stiffness on thrust is more significant than the effect of changing chordwise stiffness. This paper compares the effects of spanwise and chordwise stiffness on thrust performance, indicating that the magnitude of spanwise stiffness should be considered when designing the bionic oscillating pectoral fin structure. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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25 pages, 11679 KiB

Open AccessArticle

A Prototype Design and Sea Trials of an 11,000 m Autonomous and Remotely-Operated Vehicle Dream Chaser

by Zhe Jiang, Bin Lu, Biao Wang, Weicheng Cui, Jinfei Zhang, Ruilong Luo, Gaosheng Luo, Shun Zhang and Zhongjun Mao

J. Mar. Sci. Eng. 2022, 10(6), 812; https://doi.org/10.3390/jmse10060812 - 14 Jun 2022

Cited by 6 | Viewed by 2518

Abstract

To better study the biology and ecology of hadal trenches for marine scientists, the Hadal Science and Technology Research Center (HAST) of Shanghai Ocean University proposed to construct a movable laboratory that includes a mothership, several full-ocean-depth (FOD) submersibles, and FOD landers to [...] Read more.

To better study the biology and ecology of hadal trenches for marine scientists, the Hadal Science and Technology Research Center (HAST) of Shanghai Ocean University proposed to construct a movable laboratory that includes a mothership, several full-ocean-depth (FOD) submersibles, and FOD landers to obtain samples in the hadal trenches. Among these vehicles, the project of an FOD autonomous and remotely-operated vehicle (ARV) named “Dream Chaser” was started in July 2018. The ARV could work in both remotely-operated and autonomous-operated modes, and serves large-range underwater observation, on-site sampling, surveying, mapping, etc. This paper proposed a novel three-body design of the FOD ARV. A detailed illustration of the whole system design method is provided. Numerical simulations and experimental tests for various sub-systems and disciplines have been conducted, such as resistance analysis using the computational fluid mechanics method and structural strength analysis for FOD hydrostatic pressure using the finite element method and pressure chamber tests. In addition, components tests and the entire system tests have been performed on land, underwater, and in the pressure chamber in the laboratory of HAST, and the results are discussed. Extensive experiments of two critical components, i.e., the thrusters and ballast-abandoning system, have been conducted and further analyzed in this paper. Finally, the procedures and results of lake trials, South China Sea trials and the first phase of Mariana Trench sea trials of the ARV in 2020 are also introduced. This paper provides a design method for the novel three-body FOD ARV. More importantly, the lessons learned from the FOD pressure test, lake tests, and sea trials, no matter the success or failure, will guide future endeavors and the application of ARV Dream Chaser and underwater vehicles of this kind. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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17 pages, 7688 KiB

Open AccessArticle

Effects of Bionic Pectoral Fin Rays’ Spanwise Flexibility on Forwarding Propulsion Performance

by Junjie He, Yonghui Cao, Qiaogao Huang, Guang Pan, Xin Dong and Yong Cao

J. Mar. Sci. Eng. 2022, 10(6), 783; https://doi.org/10.3390/jmse10060783 - 06 Jun 2022

Cited by 10 | Viewed by 2131

Abstract

Oscillating pectoral fins’ spanwise flexibility is a key factor influencing the forwarding propulsion performance of bionic cownose rays, including thrust and heave-pitch stability. This study explores the effects of the bionic pectoral fin ray’s spanwise flexibility on its propulsion performance via experiments. Inspired [...] Read more.

Oscillating pectoral fins’ spanwise flexibility is a key factor influencing the forwarding propulsion performance of bionic cownose rays, including thrust and heave-pitch stability. This study explores the effects of the bionic pectoral fin ray’s spanwise flexibility on its propulsion performance via experiments. Inspired by the cownose ray, a pair of bionic pectoral fins with fin rays and fabric skin was designed, and two motors drive the controllable flapping motion. The bionic pectoral fins’ flexibility can be quantified by using fin rays’ bending stiffness. The experiments were carried out in a water tank to measure the thrust, the lift force, and the pitch moment of the bionic cownose ray. The fin rays are divided into plastic sheets of five thicknesses and three fin rays with more obvious stiffness variations. The movement parameters included the following: the flapping frequency of 0.3–0.7 Hz, the flapping amplitude of 20–40°, and the phase difference of 20–40°. The experimental results show that the stiffness of the bionic pectoral fin rays plays an important role in the thrust, lift force, and pitch moment. The fin rays with high stiffness root segment and low stiffness tip segment have lower lift and pitch moment while maintaining a high thrust. This shows that the pectoral fins’ flexible characteristics of the cownose ray are of great significance to the design of the bionic prototype. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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17 pages, 5121 KiB

Open AccessArticle

Bioinspired Central Pattern Generator and T-S Fuzzy Neural Network-Based Control of a Robotic Manta for Depth and Heading Tracking

by Yonghui Cao, Yu Xie, Yue He, Guang Pan, Qiaogao Huang and Yong Cao

J. Mar. Sci. Eng. 2022, 10(6), 758; https://doi.org/10.3390/jmse10060758 - 30 May 2022

Cited by 9 | Viewed by 1674

Abstract

Aiming at the difficult problem of motion control of robotic manta with pectoral fin flexible deformation, this paper proposes a control scheme that combines the bioinspired Central Pattern Generator (CPG) and T-S Fuzzy neural network (NN)-based control. An improved CPG drive network is [...] Read more.

Aiming at the difficult problem of motion control of robotic manta with pectoral fin flexible deformation, this paper proposes a control scheme that combines the bioinspired Central Pattern Generator (CPG) and T-S Fuzzy neural network (NN)-based control. An improved CPG drive network is presented for the multi-stage fin structure of the robotic manta. Considering the unknown dynamics and the external environmental disturbances, a sensor-based classic T-S Fuzzy NN controller is designed for heading and depth control. Finally, a pool test demonstrates the effectiveness and robustness of the proposed controller: the robotic manta can track the depth and heading with an error of ±6 cm and ±6°, satisfying accuracy requirements. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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17 pages, 5981 KiB

Open AccessArticle

An Arm-Claw-Type Manipulator for Rapid Deep Water Salvage with a General Support Vessel, Part A: Prototype and Test

by Yibo Nan, Feng Long, Feihong Yun, Shaoming Yao, Liquan Wang, Chao Li, Pengpeng Wang, Ming Liu and Zhibo Li

J. Mar. Sci. Eng. 2022, 10(6), 715; https://doi.org/10.3390/jmse10060715 - 24 May 2022

Cited by 2 | Viewed by 1817

Abstract

This paper proposed a concept prototype of the arm-claw-type manipulator with a general purpose support vessel for the rapid salvage of deep submergence vehicles, aircraft, satellites, etc. The key functions were realized, including object clamping, claw butting and locking, position and posture adjustment, [...] Read more.

This paper proposed a concept prototype of the arm-claw-type manipulator with a general purpose support vessel for the rapid salvage of deep submergence vehicles, aircraft, satellites, etc. The key functions were realized, including object clamping, claw butting and locking, position and posture adjustment, awareness, positioning, and navigation. The prototype was successfully tested in a lake environment on a hollow and cylindrical object. The arm-claw-type manipulator is suitable for the rapid salvage of cylindrical objects in an underwater environment to minimize the clamping force and possible clamping damage on the object being salvaged. Four propeller thrusters with a symmetrical arrangement can be used for the adjustment of position and posture in underwater environments, to match the orientation of the object. Cameras capture the profile images of the underwater salvage object and can be used for posture adjustment, but in dark, deep-water environments, sonar can be used in the place of underwater cameras. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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17 pages, 6616 KiB

Open AccessArticle

Experimental and Numerical Study on the Hydraulic Characteristics of an S-Type Bidirectional Shaft Tubular Pump

by Jiaqi Chen, Jieyun Mao, Hongbo Shi and Xikun Wang

J. Mar. Sci. Eng. 2022, 10(5), 671; https://doi.org/10.3390/jmse10050671 - 14 May 2022

Cited by 5 | Viewed by 1572

Abstract

In order to study the characteristics of a bidirectional shaft tubular pump with S-type symmetric airfoil blades, a prototype model was designed, manufactured, and tested. The energy characteristics, cavitation characteristics, and runaway characteristics of the pump were obtained under forward and reverse operating [...] Read more.

In order to study the characteristics of a bidirectional shaft tubular pump with S-type symmetric airfoil blades, a prototype model was designed, manufactured, and tested. The energy characteristics, cavitation characteristics, and runaway characteristics of the pump were obtained under forward and reverse operating conditions for five different blade angles. Based on the basic equations of the pump and the inlet and outlet velocity triangles, combined with model tests and numerical simulations, the hydraulic performance of the pump was extensively analyzed and evaluated. In addition, semi-empirical equations for reverse efficiency and runaway characteristics were proposed. The dynamic pressure-drop coefficients were introduced to compare the cavitation performance under different flow rates in forward and reverse operations. The results reveal that the efficiency of the pump in reverse operation is greater than that of forward operation only under a very small flow rate. While the cavitation performance of the bidirectional pump in the two operating modes is almost the same, the runaway speed and backflow rate in forward operation are considerably greater than those of reverse operation. The results provide an important reference for the safe and stable operation of bidirectional shaft tubular pumps. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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14 pages, 3805 KiB

Open AccessArticle

Sparse Polynomial Chaos Expansion for Uncertainty Quantification of Composite Cylindrical Shell with Geometrical and Material Uncertainty

by Ming Chen, Xinhu Zhang, Kechun Shen and Guang Pan

J. Mar. Sci. Eng. 2022, 10(5), 670; https://doi.org/10.3390/jmse10050670 - 14 May 2022

Cited by 3 | Viewed by 1728

Abstract

The geometrical dimensions and mechanical properties of composite materials exhibit inherent variation and uncertainty in practical engineering. Uncertainties in geometrical dimensions and mechanical properties propagate to the structural performance of composite cylindrical shells under hydrostatic pressure. However, traditional methods for quantification of uncertainty, [...] Read more.

The geometrical dimensions and mechanical properties of composite materials exhibit inherent variation and uncertainty in practical engineering. Uncertainties in geometrical dimensions and mechanical properties propagate to the structural performance of composite cylindrical shells under hydrostatic pressure. However, traditional methods for quantification of uncertainty, such as Monte Carlo simulation and the response surface method, are either time consuming with low convergence rates or unable to deal with high-dimensional problems. In this study, the quantification of the high-dimensional uncertainty of the critical buckling pressure of a composite cylindrical shell with geometrical and material uncertainties was investigated by means of sparse polynomial chaos expansion (PCE). With limited design samples, sparse PCE was built and validated for predictive accuracy. Statistical moments (mean and standard deviation) and global sensitivity analysis results were obtained based on the sparse PCE. The mean and standard deviation of critical buckling pressure were 3.5777 MPa and 0.3149 MPa, with a coefficient of variation of 8.801%. Global sensitivity analysis results from Sobol’ indices and the Morris method showed that the uncertainty of longitudinal modulus has a massive influence on the critical buckling pressure of composite cylindrical shell, whereas the uncertainties of transverse modulus, shear modulus, and Poisson’s ratio have a weak influence. When the coefficient of variation of ply thickness and orientation angle does not surpass 2%, the uncertainties of ply thickness and orientation angle have a weak influence on the critical buckling pressure. The study shows that the sparse PCE is effective at resolving the problem of high-dimensional uncertainty quantification of composite cylindrical shell with geometrical and material uncertainty. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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16 pages, 3588 KiB

Open AccessArticle

Research on the Depth Control Strategy of an Underwater Profiler Driven by a Mixture of Ocean Thermal Energy and Electric Energy

by Qingchao Xia, Bingzhe Chen, Xiaotong Sun, Canjun Yang, Sheng Zhang and Yanhu Chen

J. Mar. Sci. Eng. 2022, 10(5), 640; https://doi.org/10.3390/jmse10050640 - 08 May 2022

Cited by 2 | Viewed by 1518

Abstract

Marine resources are rich and contain an enormous amount of energy. The exploration of marine resources and the effective use of ocean energy have gradually become the research focus of scholars all over the world. A profiler driven by ocean thermal energy can [...] Read more.

Marine resources are rich and contain an enormous amount of energy. The exploration of marine resources and the effective use of ocean energy have gradually become the research focus of scholars all over the world. A profiler driven by ocean thermal energy can monitor the vertical profile of the surrounding sea area for a long time. To realize the levitation at a fixed water depth on the premise of saving energy, in this paper, a new buoyancy regulation system driven by the mixture of ocean thermal energy and electric energy is designed, and a new depth control strategy for the hybrid drive is proposed. Compared with the traditional profiler, the new profiler, in which the main energy required for buoyancy regulation is provided by ocean thermal energy, can reduce electrical energy consumption. Simulations of SMC (sliding mode control) and conventional PID control were conducted, and the results showed that the SMC method has advantages in terms of response speed, overshoot, and energy saving. A lake test was conducted and the results showed that the new control method can make the equipment reach the fixed water depth position; however, due to the complex water flow environment, the precision and stability of the controller need to be improved in the future. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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19 pages, 8938 KiB

Open AccessArticle

Black-Box Modelling and Prediction of Deep-Sea Landing Vehicles Based on Optimised Support Vector Regression

by Hongming Sun, Wei Guo, Yanjun Lan, Zhenzhuo Wei, Sen Gao, Yu Sun and Yifan Fu

J. Mar. Sci. Eng. 2022, 10(5), 575; https://doi.org/10.3390/jmse10050575 - 24 Apr 2022

Cited by 4 | Viewed by 1554

Abstract

Due to the nonlinearity of the deep-seafloor and complexity of the hydrodynamic force of novel structure platforms, realising an accurate motion mechanism modelling of a deep-sea landing vehicle (DSLV) is difficult. The support vector regression (SVR) model optimised through particle swarm optimisation (PSO) [...] Read more.

Due to the nonlinearity of the deep-seafloor and complexity of the hydrodynamic force of novel structure platforms, realising an accurate motion mechanism modelling of a deep-sea landing vehicle (DSLV) is difficult. The support vector regression (SVR) model optimised through particle swarm optimisation (PSO) was used to complete the black-box motion modelling and vehicle prediction. In this study, first, the prototype and system composition of the DSLV were proposed, and subsequently, the high-dimensional nonlinear mapping relationship between the motion state and the driving forces was constructed using the SVR of radial basis function. The high-precision model parameter combination was obtained using PSO, and, subsequently, the black-box modelling and prediction of the vehicle were realised. Finally, the effectiveness of the method was verified through multi-body dynamics simulation and scaled test prototype data. The experimental results confirmed that the proposed PSO–SVR model could establish an accurate motion model of the vehicle, and provided a high-precision motion state prediction. Furthermore, with less calculation, the proposed method can reliably apply the model prediction results to the intelligent behaviour control and planning of the vehicle, accelerate the development progress of the prototype, and minimise the economic cost of the research and development process. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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15 pages, 5602 KiB

Open AccessArticle

Design and Experimental Research on a Bionic Robot Fish with Tri-Dimensional Soft Pectoral Fins Inspired by Cownose Ray

by Lingkun Chen, Shusheng Bi, Yueri Cai, Yong Cao and Guang Pan

J. Mar. Sci. Eng. 2022, 10(4), 537; https://doi.org/10.3390/jmse10040537 - 14 Apr 2022

Cited by 13 | Viewed by 2959

Abstract

Bionic propulsion has advantages over traditional blade propellers, such as efficiency and noise control. Existing research on ray-inspired robot fish has mainly focused on a single type of pectoral fin as bionic propeller, which only performed well in terms of pure speed or [...] Read more.

Bionic propulsion has advantages over traditional blade propellers, such as efficiency and noise control. Existing research on ray-inspired robot fish has mainly focused on a single type of pectoral fin as bionic propeller, which only performed well in terms of pure speed or maneuverability. Rarely has the performance of different fin types been compared on the same platform to find an optimal solution. In this paper, a modularized robot fish with high-fidelity biomimetic pectoral fins and novel multi-DOF propelling mechanism is presented. A kinematic model of the pectoral fin based on motion analysis of a cownose ray is introduced as guidance for the propelling mechanism design. A high-fidelity parametric geo-model is established and evaluated based on statistical data. The design and fabrication process of the 3D soft bionic fins, as well as the robot platform, is also elaborated. Through experiments comparing the performance of different fin types constructed with different materials and approaches, it was found that the new soft fins made of silicon rubber have better performance than traditional fins constructed with a flexible inner skeleton and a permeable outer skin as a result of better 3D profile preservation and hydrodynamic force interaction. The robot ray prototype also acquires a better combination of high speed and maneuverability compared to results of previous research. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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24 pages, 1647 KiB

Open AccessArticle

Vertical Motion Control of an Underwater Glider with a Command Filtered Adaptive Algorithm

by Mingjie Li, Baoheng Yao, Caoyang Yu and Lian Lian

J. Mar. Sci. Eng. 2022, 10(4), 531; https://doi.org/10.3390/jmse10040531 - 12 Apr 2022

Cited by 2 | Viewed by 1554

Abstract

Underwater gliders are widely used in oceanic observation, which are driven by a hydraulic buoyancy regulating system and a movable mass. Better motion performance can help us to accomplish observation tasks better. Therefore, a command filtered adaptive algorithm with a detailed system dynamic [...] Read more.

Underwater gliders are widely used in oceanic observation, which are driven by a hydraulic buoyancy regulating system and a movable mass. Better motion performance can help us to accomplish observation tasks better. Therefore, a command filtered adaptive algorithm with a detailed system dynamic model is proposed for underwater gliders in this paper. The dynamic model considers seawater density variation, temperature variation and hull deformation according to dive depth. The hydraulic pump model and the movable mass dynamic are also taken into account. An adaptive nonlinear control strategy based on backstepping technique is developed to compensate the uncertainties and disturbances in the control system. To deal with the command saturation and calculation of derivatives in the backstepping process, command filtered method is employed. The stability of the whole system is proved through the Lyapunov theory. Comparative simulations are conducted to verify the effectiveness of the proposed controller. The results demonstrate that the proposed algorithm can improve the motion control performance for underwater gliders under uncertainties and disturbances. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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17 pages, 5336 KiB

Open AccessArticle

Analysis, Simulation and Experimental Study of the Tensile Stress Calibration of Ceramic Cylindrical Pressure Housings

by Peng Wang, Yanhui Wang, Shaoqiong Yang, Wendong Niu, Xuehao Wang and Penghao Li

J. Mar. Sci. Eng. 2022, 10(4), 499; https://doi.org/10.3390/jmse10040499 - 04 Apr 2022

Cited by 5 | Viewed by 1674

Abstract

Engineering ceramics have extremely high values for both specific modulus and specific compressive strength, making them one of the most promising materials for enhancing the carrying capability of full ocean depth (FOD) submersibles. However, due to the low tensile strength of most ceramic [...] Read more.

Engineering ceramics have extremely high values for both specific modulus and specific compressive strength, making them one of the most promising materials for enhancing the carrying capability of full ocean depth (FOD) submersibles. However, due to the low tensile strength of most ceramic materials, the tensile stress generated at the contact surface of ceramic pressure housings under hydrostatic pressure may exceed the material’s limits and thus lead to cracking failure. Currently, there are no valid calibration methods for the tensile stress caused by material discontinuities at the contact surface. In this paper, an approximate model is established based on contact mechanics. The absolute error of the approximate model, as verified by the simulation results for nine groups of ceramic pressure housings, does not exceed 14.2%. It is also concluded that the smaller the difference in Young’s modulus between the ceramics and metals, the higher the tensile strength safety factor. In addition, two hydrostatic pressure experiments were carried out to further verify the results of the approximate model and the numerical solutions. The approximate model is oriented to the reliable design of ceramic pressure housings. It will play an important role in improving the carrying capacity and observation capability of FOD submersibles. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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23 pages, 10740 KiB

Open AccessArticle

Structural Analysis and Experimental Study on the Spherical Seal of a Subsea Connector Based on a Non-Standard O-Ring Seal

by Dong Liu, Feihong Yun, Kefeng Jiao, Liquan Wang, Zheping Yan, Peng Jia, Xiangyu Wang, Weifeng Liu, Xiaoquan Hao and Xiujun Xu

J. Mar. Sci. Eng. 2022, 10(3), 404; https://doi.org/10.3390/jmse10030404 - 10 Mar 2022

Cited by 11 | Viewed by 3606

Abstract

Underwater oil and gas pipelines are prone to alignment differences and angle offsets during docking, and the spherical flange connector can address this problem. Its main function is to enable compensation of the different angles of the pipeline during docking and to apply [...] Read more.

Underwater oil and gas pipelines are prone to alignment differences and angle offsets during docking, and the spherical flange connector can address this problem. Its main function is to enable compensation of the different angles of the pipeline during docking and to apply a non-standard spherical sealing structure using O-rings to the connection. In this paper, the study of a spherical sealing structure using O-rings was based on a spherical structural model of the connector. The Mooney–Rivlin constitutive equation and material parameters of the O-ring were determined according to nonlinear theory. The structure of the non-standard spherical sealing groove was designed and analysed with reference to the standard sealing groove, the calculation expression of the spherical groove specific size was deduced, and the width and depth of the groove were determined. A finite element analysis of the non-standard O-ring sealing structure was carried out using ANSYS Workbench software; the effects of different pressures and compression ratios on the O-ring sealing performance were analysed and studied in terms of von Mises stress, contact pressure and contact width of different contact surfaces so as to determine a more reasonable compression ratio in the sealing structure. Finally, the theoretical analysis of the non-standard spherical sealing structure using O-rings was validated by testing, and it was proven that it could maintain a good seal under high pressure. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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19 pages, 7055 KiB

Open AccessArticle

Asymmetrical Oscillating Morphology Hydrodynamic Performance of a Novel Bionic Pectoral Fin

by Cheng Xing, Yong Cao, Yonghui Cao, Guang Pan and Qiaogao Huang

J. Mar. Sci. Eng. 2022, 10(2), 289; https://doi.org/10.3390/jmse10020289 - 19 Feb 2022

Cited by 20 | Viewed by 2347

Abstract

This research proposes a novel bionic pectoral fin and experimentally studied the effects of the oscillation parameters on the hydrodynamic performance of a bionic experimental prototype. Inspired by manta rays, the bionic pectoral fin was simplified and modeled based on the natural pectoral [...] Read more.

This research proposes a novel bionic pectoral fin and experimentally studied the effects of the oscillation parameters on the hydrodynamic performance of a bionic experimental prototype. Inspired by manta rays, the bionic pectoral fin was simplified and modeled based on the natural pectoral fin skeleton structure and oscillation morphology of this underwater creature. A dual-degree-of-freedom bionic pectoral fin was designed. The active spatial motion was realized by the space six-link mechanism driven by two motors, and the passive deformation was achieved by carbon fiber. The motion analysis of the bionic pectoral fin proves that the pectoral fin can realize an “8”-shaped spatial trajectory. An experimental prototype was developed accordingly. The experimental prototype could flap between 0.1 Hz and 0.6 Hz and produce a maximum thrust of 20 N. The hydrodynamic performance under different oscillation parameters was studied experimentally in a water pool. The experimental results indicate that the hydrodynamic performance of the pectoral fin oscillation is closely related to the motion equation parameters including the amplitude, frequency, phase difference, and initial bias. In addition to considering the impact of parameters on thrust and lift, the influences of asymmetrical oscillation on the position of the equivalent point were also studied. The results show that the pectoral fin proposed in this research exhibited the expected spatial deformation and outstanding hydrodynamic performance. The obtained results shed light on the updated design and control of a bionic robot fish. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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14 pages, 4772 KiB

Open AccessArticle

Buckling and Post-Buckling Behavior of Perfect/Perforated Composite Cylindrical Shells under Hydrostatic Pressure

by Ke-Chun Shen, Zhao-Qi Yang, Lei-Lei Jiang and Guang Pan

J. Mar. Sci. Eng. 2022, 10(2), 278; https://doi.org/10.3390/jmse10020278 - 17 Feb 2022

Cited by 6 | Viewed by 2183

Abstract

In this paper, the buckling and post-buckling behavior of perfect and perforated composite cylindrical shells subjected to external hydrostatic pressure was experimentally investigated. Three filament wound composite cylindrical shells were fabricated from T700-12K Carbon fiber/Epoxy, two of which were perforated and reinforced. A [...] Read more.

In this paper, the buckling and post-buckling behavior of perfect and perforated composite cylindrical shells subjected to external hydrostatic pressure was experimentally investigated. Three filament wound composite cylindrical shells were fabricated from T700-12K Carbon fiber/Epoxy, two of which were perforated and reinforced. A test platform was established that allows researchers to observe the deformation of composite cylindrical shells under hydrostatic pressure in real-time during test. According to experimental observation, strain response and buckling deformation wave were discussed. Comparative analysis was carried out based on the experimental observation and finite element prediction. Results show that the deformation of composite cylindrical shell under hydrostatic pressure included linear compression, buckling and post-buckling processes. The buckling behavior was a progressive evolution process which accounted for 20% of the load history, and strain reversal phenomenon generally occurred at the trough of the buckling wave. As for the postbuckling deformation, the load carrying capacity of the shell gradually decreased while the magnitude of strain continued increasing. Both the perfect and perforated composite cylindrical shells collapsed at the trough of the buckling wave. Comparing with the perfect shell, it was validated the reinforcement design could effectively ensure the load carrying capacity of the perforated composite cylindrical shell. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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18 pages, 4053 KiB

Open AccessArticle

Trans-Media Kinematic Stability Analysis for Hybrid Unmanned Aerial Underwater Vehicle

by Tongjin Wei, Di Lu, Zheng Zeng and Lian Lian

J. Mar. Sci. Eng. 2022, 10(2), 275; https://doi.org/10.3390/jmse10020275 - 16 Feb 2022

Cited by 12 | Viewed by 2312

Abstract

In recent years, hybrid unmanned aerial underwater vehicles (HAUVs), which are capable of air–water trans-media motion, have been increasingly developed. For most HAUVs, air–water trans–media motion is a relatively dangerous and difficult process. Therefore, it is of great significance to study the particular [...] Read more.

In recent years, hybrid unmanned aerial underwater vehicles (HAUVs), which are capable of air–water trans-media motion, have been increasingly developed. For most HAUVs, air–water trans–media motion is a relatively dangerous and difficult process. Therefore, it is of great significance to study the particular process. This paper presents the first study on the kinematic stability of the air–water trans–media motion of HAUVs. First, a simplified dynamic model of HAUVs is proposed, including the hydrodynamic forces and the time–varying buoyancy. Then, based on the proposed model and the Hurwitz method, this paper derives the air–water trans–media kinematic stability criterion for HAUVs. This criterion can be applied to most air–water trans–media motions that satisfy the assumptions in this paper. Finally, this paper takes “Nezha”, a novel HAUV, as an example to analyze its air–water trans–media kinematic stability. The results show that the proposed criterion is effective in judging the vehicle’s design, including the geometry and thruster power, which are important factors in the performance of the trans–media process. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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19 pages, 8084 KiB

Open AccessArticle

Neural Network Non-Singular Terminal Sliding Mode Control for Target Tracking of Underactuated Underwater Robots with Prescribed Performance

by Liwei Guo, Weidong Liu, Le Li, Yichao Lou, Xinliang Wang and Zhi Liu

J. Mar. Sci. Eng. 2022, 10(2), 252; https://doi.org/10.3390/jmse10020252 - 12 Feb 2022

Cited by 14 | Viewed by 1812

Abstract

This paper proposes a neural network-based nonsingular terminal sliding mode controller with prescribed performances for the target tracking problem of underactuated underwater robots. Firstly, the mathematical formulation of the target tracking problem is presented with an underactuated underwater robot model and the corresponding [...] Read more.

This paper proposes a neural network-based nonsingular terminal sliding mode controller with prescribed performances for the target tracking problem of underactuated underwater robots. Firstly, the mathematical formulation of the target tracking problem is presented with an underactuated underwater robot model and the corresponding control objectives. Then, the target tracking errors from the line-of-sight guidance law are transformed using the prescribed performance technique to achieve good dynamic performance and steady-state performance that meet the pre-set conditions. Meanwhile, considering the model’s uncertainties and the external disturbances to the underwater robots, a target tracking controller is proposed based on the radial basis function (RBF) neural network and the non-singular terminal sliding mode control. Lyapunov stability analysis and homogeneity theory prove the tracking errors can converge on a small region that contains the origin with prescribed performance in finite time. In the simulation comparison, the controller proposed in this paper had better dynamic performance, steady-state performance and chattering supression. In particular, the steady-state error of the tracking error was lower, and the convergence time of the tracking error in the vertical distance was reduced by 19.1%. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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20 pages, 6859 KiB

Open AccessArticle

A Compact Design of Underwater Mining Vehicle for the Cobalt-Rich Crust with General Support Vessel Part A: Prototype and Tests

by Chao Xie, Lan Wang, Ning Yang, Casey Agee, Ming Chen, Jinrong Zheng, Jun Liu, Yuxiang Chen, Lixin Xu, Zhiguo Qu, Shaoming Yao, Liquan Wang and Zongheng Chen

J. Mar. Sci. Eng. 2022, 10(2), 135; https://doi.org/10.3390/jmse10020135 - 20 Jan 2022

Cited by 8 | Viewed by 3632

Abstract

This paper proposed a compact design of the subsea cobalt-rich crust mining vehicle with a general purpose support vessel for subsea resource exploration, sample collection, and research. The necessary functions were considered in the concept design, including walk, crushing/mining, sample collection, cutter head [...] Read more.

This paper proposed a compact design of the subsea cobalt-rich crust mining vehicle with a general purpose support vessel for subsea resource exploration, sample collection, and research. The necessary functions were considered in the concept design, including walk, crushing/mining, sample collection, cutter head adaptation, vehicle orientation, crust texture measurement, awareness, positioning, and navigation. The prototype was tested in both tank and subsea environment. The sea trials were carried out with the support of a general purpose support vessel. The track design worked well in both the tank and subsea environment and the mining vehicle walked smoothly in the sea trial. The crust was crushed to the size of 2 mm and 10 mm with different cutting parameters and successfully collected by the jet pump, 6 kg in total. The crust texture was measured by the onboard sonar successfully and can be used for cutting parameter selection. The cameras captured the images of the subsea environment, but the actions of crushing and sample collection produced plumes, which blocked the camera vision. In the situation, the front image sonar can be used to keep the vehicle away from big rocks. The mining vehicle is not limited to the mining and sampling of subsea cobalt-rich crust. Most of the subsea solid resources on the seabed can be considered to use the compact mining vehicle for sampling and related research. The only issues to be considered are the crushing ability and sample size required. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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11 pages, 4039 KiB

Open AccessArticle

Buckling of a Composite Cylindrical Shell with Cantilever-like Boundary Conditions under Hydrostatic Pressure

by Ke-Chun Shen, Lei-Lei Jiang, Zhao-Qi Yang and Guang Pan

J. Mar. Sci. Eng. 2022, 10(2), 126; https://doi.org/10.3390/jmse10020126 - 19 Jan 2022

Cited by 7 | Viewed by 2158

Abstract

In this study, an analytical solution for the buckling of a composite cylindrical shell subjected to hydrostatic pressure is proposed. The boundary conditions of the composite cylindrical shell are cantilever-like, with one end fixed and the other end connected to a rigid disk. [...] Read more.

In this study, an analytical solution for the buckling of a composite cylindrical shell subjected to hydrostatic pressure is proposed. The boundary conditions of the composite cylindrical shell are cantilever-like, with one end fixed and the other end connected to a rigid disk. The differential equations are solved using the Galerkin method. The axial displacement of the shell is approximated by the first mode shape of the transverse vibration of the clamped sliding beam. The circumferential displacement and deflection are approximated by the first derivation of the beam function. Based on this solution, an analytical formula enabling prediction of the critical buckling pressure and buckling mode of composite orthotropic cylindrical shells is derived. A finite element analysis and external hydrostatic pressure test are conducted to verify the proposed approach. The efficiency and accuracy of the analytical solution in predicting the critical buckling pressure and buckling mode are demonstrated. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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21 pages, 8162 KiB

Open AccessArticle

Alignment Error Modelling, Analysis and Experiment of the Deep-Water Bolt Flange Automatic Connection Tool

by Pengpeng Wang, Haixia Gong, Liquan Wang, Feihong Yun, Yibo Nan, Ming Ju, Chao Li, Honghai Wang and Kai Xu

J. Mar. Sci. Eng. 2022, 10(1), 64; https://doi.org/10.3390/jmse10010064 - 05 Jan 2022

Cited by 1 | Viewed by 1398

Abstract

A deep-water bolt flange automatic connection tool plays a very important role in the process of offshore oil exploitation and transportation. In the connection process, the alignment error of bolts and nuts is the key factor to ensure the connection process is successful. [...] Read more.

A deep-water bolt flange automatic connection tool plays a very important role in the process of offshore oil exploitation and transportation. In the connection process, the alignment error of bolts and nuts is the key factor to ensure the connection process is successful. Using the kinematics modeling method, this paper created the alignment error model of the deep-water bolt flange automatic connection tool and analyzed the influence of manufacturing accuracy on the alignment error of bolts and nuts through computer simulation software. Based on the error matching design method, the manufacturing accuracy of parts were optimized with a part-size-based priority sequence to ensure the bolt–nut alignment error was within the allowable limits. The land tests, the pool tests and the sea test were carried out. The test results showed that the bolt and nut can be connected in the subsea environment reliably. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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16 pages, 2518 KiB

Open AccessArticle

Research on Sailing Efficiency of Hybrid-Driven Underwater Glider at Zero Angle of Attack

by Xin Tian, Lianhong Zhang and Hongwei Zhang

J. Mar. Sci. Eng. 2022, 10(1), 21; https://doi.org/10.3390/jmse10010021 - 26 Dec 2021

Cited by 6 | Viewed by 2504

Abstract

The sailing efficiency of an underwater glider, an important type of marine environment detection and data collection equipment, directly affects its range and duration. The zero-angle-of-attack gliding can be achieved by adjusting the wing installation angle to minimize the drag and improve the [...] Read more.

The sailing efficiency of an underwater glider, an important type of marine environment detection and data collection equipment, directly affects its range and duration. The zero-angle-of-attack gliding can be achieved by adjusting the wing installation angle to minimize the drag and improve the sailing efficiency, and thus further improving performance of the glider. This paper first presents the dynamic characteristics of a hybrid-driven underwater glider with a certain wing installation angle when it is sailing at zero angle of attack in buoyancy-driven mode and hybrid-driven mode. In buoyancy-driven mode, with a given wing installation angle, the glider can achieve zero-angle-of-attack gliding only at a specific glide angle. In hybrid-driven mode, due to the use of a propulsion system, the specific glide angle that allows the zero-angle-of-attack gliding in buoyancy-driven mode is expanded to a glide angle range bounded by zero degrees. Then, the energy consumption per meter is introduced as an indicator of sailing efficiency, and the effects of glide angle and wing installation angle on sailing efficiency of the zero-angle-of-attack glider in two driving modes are studied under the conditions of given net buoyancy and given speed, respectively. Accordingly, the optimal wing installation angle for maximizing the sailing efficiency is proposed. Theoretical analysis shows that the sailing efficiency of a zero-angle-of-attack glider can be higher than that of a traditional glider. Considering the requirements of different measurement tasks, a higher sailing efficiency can be achieved by setting reasonable parameters and selecting the appropriate driving mode. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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21 pages, 36351 KiB

Open AccessArticle

Optimization and Experimental Study of the Subsea Retractable Connector Rubber Packer Based on Mooney-Rivlin Constitutive Model

by Kefeng Jiao, Feihong Yun, Zheping Yan, Gang Wang, Peng Jia, Liquan Wang, Dong Liu and Xiaoquan Hao

J. Mar. Sci. Eng. 2021, 9(12), 1391; https://doi.org/10.3390/jmse9121391 - 06 Dec 2021

Cited by 11 | Viewed by 2263

Abstract

The sealing performance of the rubber packer is of vital importance for the subsea retractable connector, and the cross-sectional shape of the rubber packer is one of the most important factors affecting it. The compression distance of the rubber packer is increased by [...] Read more.

The sealing performance of the rubber packer is of vital importance for the subsea retractable connector, and the cross-sectional shape of the rubber packer is one of the most important factors affecting it. The compression distance of the rubber packer is increased by 19.54% utilizing the established two-dimensional numerical model. In addition, a new parameter called the anti-shoulder extrusion variable was defined in this paper. Shoulder extrusion will not occur when using this variable as a constraint during simulation. In general, the upper end and the lower end of a rubber packer are subject to different constraints, and the structural parameters of the rubber packer affect each other in terms of sealing performance. Therefore, the importance and originality of this study are exploring the optimization of the thickness and chamfer angles of the upper and lower ends of the rubber packer by use of a combination of the response surface optimization method and the multi-objective genetic algorithm, taking the thickness and chamfer angles of the upper and lower ends as design variables, and the stress on the inner side of the casing wall and the axial force of the compressed rubber packer as optimization objectives. Besides that, the anti-shoulder extrusion variables are also introduced as constraints to prevent shoulder extrusion. Ultimately, the cross-sectional shape of the rubber packer with a smaller-thickness and larger-angle upper end, and a larger-thickness and smaller-angle lower end can be obtained. The result to emerge from the test in this paper is that the pipe pressure that can be sealed by the optimized rubber packer structure is 25.61% higher than that before optimization. The anti-shoulder extrusion variable and the asymmetric cross-sectional shape of the rubber packer proposed in this paper shed new light on the finite element simulation of rubber and the research on similar seals. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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Review

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31 pages, 9781 KiB

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Recent Progress in Modeling and Control of Bio-Inspired Fish Robots

by Boai Sun, Weikun Li, Zhangyuan Wang, Yunpeng Zhu, Qu He, Xinyan Guan, Guangmin Dai, Dehan Yuan, Ang Li, Weicheng Cui and Dixia Fan

J. Mar. Sci. Eng. 2022, 10(6), 773; https://doi.org/10.3390/jmse10060773 - 02 Jun 2022

Cited by 25 | Viewed by 6003

Abstract

Compared with traditional underwater vehicles, bio-inspired fish robots have the advantages of high efficiency, high maneuverability, low noise, and minor fluid disturbance. Therefore, they have gained an increasing research interest, which has led to a great deal of remarkable progress theoretically and practically [...] Read more.

Compared with traditional underwater vehicles, bio-inspired fish robots have the advantages of high efficiency, high maneuverability, low noise, and minor fluid disturbance. Therefore, they have gained an increasing research interest, which has led to a great deal of remarkable progress theoretically and practically in recent years. In this review, we first highlight our enhanced scientific understanding of bio-inspired propulsion and sensing underwater and then present the research progress and performance characteristics of different bio-inspired robot fish, classified by the propulsion method. Like the natural fish species they imitate, different types of bionic fish have different morphological structures and distinctive hydrodynamic properties. In addition, we select two pioneering directions about soft robotic control and multi-phase robotics. The hybrid dynamic control of soft robotic systems combines the accuracy of model-based control and the efficiency of model-free control, and is considered the proper way to optimize the classical control model with the intersection of multiple machine learning algorithms. Multi-phase robots provide a broader scope of application compared to ordinary bionic robot fish, with the ability of operating in air or on land outside the fluid. By introducing recent progress in related fields, we summarize the advantages and challenges of soft robotic control and multi-phase robotics, guiding the further development of bionic aquatic robots. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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18 pages, 2261 KiB

Open AccessReview

Biomimetic Aquatic Robots Based on Fluid-Driven Actuators: A Review

by Kunlang Bu, Xiaobo Gong, Changli Yu and Fang Xie

J. Mar. Sci. Eng. 2022, 10(6), 735; https://doi.org/10.3390/jmse10060735 - 27 May 2022

Cited by 13 | Viewed by 3607

Abstract

Biomimetic aquatic robots are a promising solution for marine applications such as internal pipe inspection, beach safety, and animal observation because of their strong manoeuvrability and low environmental damage. As the application field of robots has changed from a structured known environment to [...] Read more.

Biomimetic aquatic robots are a promising solution for marine applications such as internal pipe inspection, beach safety, and animal observation because of their strong manoeuvrability and low environmental damage. As the application field of robots has changed from a structured known environment to an unstructured and unknown territory, the disadvantage of the low efficiency of the propeller propulsion has become more crucial. Among the various actuation methods of biomimetic robots, many researchers have utilised fluid actuation as fluid is clean, environmentally friendly, and easy to obtain. This paper presents a literature review of the locomotion mode, actuation method, and typical works on fluid-driven bionic aquatic robots. The actuator and structural material selection is then discussed, followed by research direction and application prospects of fluid-driven bionic aquatic robots. Full article

(This article belongs to the Special Issue Frontiers in Deep-Sea Equipment and Technology)

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