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The collision avoidance problem of autonomous ships is analyzed in this paper. Firstly, the background and the difficulties are reviewed. Then an improved artificial potential field method is designed to solve the collision avoidance problem of unmanned ships, and the system characteristics are investigated. Finally, simulation results demonstrate the ship's control effectiveness in the obstacle environment.
Ships stability and safety are always threatened by the unavoidable sway in the complicated situation of the sea, e.g. strong wind and roaring waves. Ensuring the stability of the ship as a difficult task has received its popularities in the community in the past few decades. However, conventional control methods such as sliding mode control (SMC) and Proportional integral derivative (PID) fail to...
Magnus rotor wing is a novel roll reduction device that it generates anti-rolling force through the rotation of the rotor wing installed at the bilge of ship hull to reduce ship's roll motion. It is effective at medium/low speed and at zero speed, which is different from fin stabilizer. This paper focuses on the situation that the rotor wing is perpendicular to ship hull. The lift generating and anti-rolling...
Data analysis of an oscillating flapping wing is conducted for developing a transfer function model especially for heave force data series from the CFD environment for different geometries of flapping wings. The wing experiences a combination of vertical and angular oscillatory motion, while travelling at constant forward speed. The vertical motion is induced by the random motion of the ship in waves,...
Two-body unmanned surface vehicle is a new marine environment monitoring platform, with higher operating efficiency and wider applicability. In order to understand the movement features of this kind of ship, and to enhance its working capabilities and control precision, its dynamics model basing on six degrees of freedom equations is developed in this paper. The simulation results using this model...
In this paper, a nonlinear adaptive control strategy is developed to force an underactuated ship to follow a predefined path, despite the presence of unknown system parameters and environmental disturbances induced by wave, wind and ocean current. The techniques involved in the design and analysis include using the backstepping, parameter projection techniques and a traverse function. It is shown...
Analysis of open type wharf berthing condition is a complex process. It is hardly to simulate the environment and test results, which are consistent with the actual situation with physical model. In this paper, ship-mooring test during mooring is conducted applying the Large Ship Maneuvering Simulation Platform on the basis of the hydrological, meteorological and underwater terrain data. Combined...
In recent years, with the great progress in maritime transport, ships have increasingly tended to be more large and rapid. Thus, single engine and single-propeller large cannot meet the requirements of the various performances, multi-engine multi-propeller able to meet a variety of different sailing ship maneuvering characteristics of working conditions, and gradually adopted by the people. With the...
It is well known that the wave motion is a really complex process and hard to be simulated. The paper mainly solves the difficult problem of numerical simulation of wave disturbances in ship motion simulation area. The wave disturbance force and moment acting on the ship sailing on the sea are simulated. Based on statistics superposition theory, Pierson-Moskowitz (P-M) single-parameter standard wave...
The heave compensation system is of great importance to the safety and operation efficiency of the deep-sea mining system subject to irregular-wave excitation. A novel active-controlled heave compensation system based on dynamic vibration absorber for the deep-sea mining system was proposed in this paper. The three-degree-of-freedom dynamic models of active heave compensation system based on dynamic...
A fault-tolerant tension allocation framework is suggested for ship mobile system consisting of eight anchor windlasses. The fault-tolerant performance is evaluated under sea wind disturbance. The simulation results indicate that ship mobile mooring systems have certain fault-tolerant ability. When one windlass failed, the ship is able to completely counteract the sea wind disturbance. When two windlasses...
In this paper the Duffing oscillator is applied to solve high transmitter power consumption and high probability of intercept of underwater mine. A chaotic oscillator has the property of being sensitive to weak signal and being immune to noise, which leads to a potential application in weak signal detection. The weak signals can be used as the outside periodic exciter and be brought in the Duffing...
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