References
1) “A Report on Working Group for Examination of Ultra-small Reactor Utilization to Oceanographic Research,” Marine Reactor Research Committee of JAERI, 1999.
2) Materials provided by Dr. Izuo Aya (SRI).
3) S. Tamura et al., Proceedings of Multiphase Flow Symposium of Japan, vol. 17, 1998.
4) T. Goto et al., preprint of MESJ, vol. 62, 1999.
[Tomoji TAKAMASA]
11. Automatic Control
11.1 Intelligent Drag Suction Dredger by Fuzzy Control
The Machine Engineering Department of the Port and Harbour Research Institute of the Ministry of Transport developed the automation by the fuzzy control as one of “Development of Working Boat and Working Machines of Excellent Performance” which is one of the major researches, and ensured the dredging efficiency as high as that by veteran crews on board tests, and realized its automation and labor saving.
The conventional automation of the drag suction dredger has been the ON-OFF control with the set value as the boundary, or the sequence control to realize the control in accordance with the preset procedure, and can not be fully compatible with the working conditions compared with the operation of veteran crews, and the quantity of the dredged earth has been often small. In order to solve the problem, the development of an automation device by the fuzzy control was started, and the on-board tests have been carried out on 1] control of the ship speed, 2] control of the number of revolution of the dredging pump, and 3] control of the water jet.
As a result, the quantity of the dredged earth was improved by approximately 10% compared with the conventional automatic operation. Concerning the ship speed, a smooth control close to the manual operation was realized. Concerning the water jet, the dredging pump can be started/stopped at appropriate frequency, and can be prevented from being blocked. The intelligent dredging system capable of automatically optimizing the dredging control parameters according to the sea bottom condition is now under development.
11.2 4000m3 Type Relay Pump Barge “KIRYU”
“KIRYU” is equipped with the sophisticated control system and monitoring system, and capable of achieving the operation, the monitoring and the recording on the comprehensive control panel in the operation room. Focusing on the smooth operation of the discharge and feed works, the start/stop of the generator engines, the discharge and feed pump engines, the auxiliary engines, etc., the control of the number of revolution of the discharge and feed pump, and the opening/closing of the discharge and feed line are remotely controllable, and in addition, the following control functions are provided.
(1) Automatic control of discharge and feed
The discharge and feed pump clutch, the discharge and feed line valve, the jet pump and valves, and the rotation of the discharge and feed pump are automatically controlled based on the data from the water level gauge for the mud hold, the flow meter, the mud content meter, etc.
(2) Control of ship position
The windlass is equipped with the speed control function and the automatic tension function by the inverter control, and the position of the ship is monitored by the GPS, and the control function to wind/unwind the windlass to return the ship to the original position when the positional deviation of the ship is generated by the external forces such as the ship-contact force, the current and the wind, is also equipped.
11.3 1000 m3/h Tremie Process Type Sand Spray Ship “WTS-1000”
(1) Ship position control system
RTK-GPS and the gyro-compass are jointly used to calculate the ship position and the proceeding direction, and the deviation from the set course, the deviation in the azimuth angle, and the proceeding speed are displayed on the monitor on the real time basis. The track of the ship during the sand spraying work is recorded in the hard disk, and the already-executed range and the non-executed range can be easily and clearly displayed by arbitrarily setting the working days or the working period, and achieving the monitor display and the printer output.
(2) Ship operating winch control system
The angle of every ship operation wire, the total operation quantity, and the tension are detected, each ship operating winch is controlled to achieve the automatic operation so that the ship may proceed on the course set based on the data from the RTK-GPS ship position control system at the specified speed and in the specified direction. The operation in the forward/astern direction and in the right-to-left direction can be controlled by the joystick through the one-lever operation.
