| In recent years, China’s shipping industry is developing rapidly. Due to the adequacy of inland water resources, less pollution, low cost and large volume, the amount of inland waterway transport is increasing constantly. Inland river navigation is playing a more and more important role. Accompanied by a boom in inland river shipping industry, ship loading capacity increase, also increase the risk of the shipping transportation. Annual shipping accidents happen in the transport process, and it is on the rise, it largely affect shipping safety and navigation efficiency, this has a negative impact on economic development. Law enforcement at present, however, is the effective technical means for the navigation of vessels, even from the ship draft survey. Only line survey to test, to see the phenomenon of whether there is super to draft, whether there is violation.In order to improve the ship draft inspection status, improve draft detection precision, an automatic draft detection system is developed, the system is based on the working principle of ultrasonic ranging sensor. In the process of system operation, when there is a draft, to the administrative department of the warning. At present, the system has been put into operation in the three gorges ship lock, and running in good condition. System of the specific design method is:ultrasonic sensor is arranged on the inspection door bracket, placed in the appropriate depth in the underwater. System for ultrasonic sensors returned to real-time data,3d simulation shows on the computer, after calculation of maximum draught, the ship to see if more than maximum water depth of channel design, the data and results to wirelessly transmitted information management center.In order to further improve the measuring accuracy of draft system and improve the system reliability, this paper focuses on the structure due to the system or equipment introduced in all kinds of error in the operation process, in order to improve the accuracy.Mainly involves the ship draft precision calibration method of floating body of error compensation method, and the error compensation method based on the inspection door profile, reduce the error, and eliminate the unstable factors in the process of measurement. Draft detection system get data for the raw data, there might be defects of abnormal data and data, to construct3d model, not a bottom model of the complete and accurate. For the defects caused by damage of sensor data of the ship hull model matching used in data recovery. To eliminate the slipstream interference, by adopting the technology of curve matching to restore. And due to damage to sensor under water for a long time after the defect repair, data processing method based on curve matching and other technical data to the ship stern distortion reduction. Finally has carried on the comparison and actual measurement results and the simulation, determine the alignment precision.Finally has carried on the comparison and actual measurement results and the simulation, determine the alignment precision. Results show that the alignment precision of the system is0.40～+0.40m, meet the design requirement, the algorithm is practical and effective. |
PDF Full Text Request