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EN
In this paper, we introduce a new risk evaluation model for evaluating the navigation safety zone for an entire ship route. This model considers a new algorithm to determine the navigational safety zone in real-time, and also takes the navigation officers’ perception while navigating a ship into consideration. The risk quantification has been developed using a questionnaire and incorporated into the new model. A simulation was carried out for the Osaka bay area in order to verify the usefulness of the proposed model. A new approach was employed to monitor the level of navigation safety along a ship route. The entire ship route is divided into small sections as a gridded matrix. The level of navigation safety can be quantified by means of a safety index on the basis of the ship’s navigation data within a specified distance range. The results show that the comparison between risks identified for different sections across the entire ship route is easy, which helps determine the navigational safety zone quickly. This model is expected to be able to serve as a new tool for managing safety throughout an entire ship route area in real-time in order to support the port safety authority or vessel traffic service center.
2
EN
This study deals with the development of ship watch keeping supporting aids that will be useful for ship deck officers in recognizing navigational harmful obstacles such as sea marks and small floating objects on the sea. The developed watch keeping supporting aids is made up of four components; a composite video sensor to produce video signal, a laser distance measuring part, a Pan/Tilt part and a central control part. The system was installed in a ship in order to verify its performance of the recognition ability on the sea. The comparison was made between the recognition ability of the system and that of watch keeping deck officers’. The image from the watch keeping supporting system was found to be more recognizable than that of a binocular telescope within a 5 km distance. The newly suggested system is expected to be used to recognize small dangerous floating objects more easily when navigation deck officers have a duty of watch keeping for navigation especially near harbor area.
3
Content available remote Ship Manoeuvring Performance Experiments Using a Free Running Model Ship
EN
In this paper, a 3m-class free running model ship will be introduced with its manoeuvring per-formance experiments. The results of turning circle test and zig-zag test will be explained. The developed system are equipped with GPS, main control computer, wireless LAN, IMU (Inertial Measurement Unit), self-propulsion propeller and driving rudder. Its motion can be controlled by RC (Radio Control) and wireless LAN from land based center. Automatic navigation is also available by pre-programmed algorithm. The trajectory of navigation can be stored by GPS and it provides us with important date for ship’s motion control experiments. The results of manoeuvring performance experiment have shown that the developed free run-ning model ship can be used to verify the test of turning circle and zig-zag. For next step, other experimental researches such as ship collision avoidance system and automatic berthing can be considered in the future.
4
Content available remote An Application of ANN to Automatic Ship Berthing Using Selective Controller
EN
This paper deals with ANN(Artificial Neural Networks) and its application to automatic ship berthing. As ship motions are expressed by a multi-term non-linear model, it is very difficult to find optimal methods for automatic ship berthing. When a ship makes its berthing operation, the ship’s inertia and slow motion make the ship approach to final berthing point with pre-determined navigation pattern. If the ship is out of the pre-determined navigation pattern, the berthing usually end in failure. It has been known that the automatic control for ship’s berthing cannot cope with various berthing situations such as various port shape and approaching directions. For these reasons, the study on automatic berthing using ANN usually have been carried out based on one port shape and predetermined approaching direction. In this paper, new algorithm with ANN controller was suggested to cope with these problems. Under newly suggested algorithm, the controller can select different weight on the link of neural networks according to various situations, so the ship can maintain stable berthing operation even in different situations. Numerical simulations are carried out with this control system to find its improvement.
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