| Scince the first bridge collision accident was reported, it is easy for the people to get the news involved with losses and disasters from the ship-bridge collision affairs either in china or in the world wide. Altough many experts around the world have made extremely great efforts to study on the ship-birdge collision avoidance and have acquired many achievements, they do not work out an effective pattern for the ship-bridge collision avoidance.By analysis, we find that there is no pattern in which the ship-bridge collision avoidance theory is studied comprehensively.The current patterns focus on either strengthening the bridge piers or the risk probability research.One of the common features of those patterns is that the factor of the ship’s operators have been neglected totally.In other words, the early-warning and pre-control way for guiding and reminding the operators to handle the ship is neglected.In this dissertation,the ship-bridge collision avoidance technology based on the ship maneuvering equations and the video information detection includes two parts,i.e.,the situation prediction technology and the ship’s maneuvering and track pre-controlling&collision avoidance technology.The former is focused on predicting the ship’s track in the water area near the bridge and judging the collision situation, the latter is an intelligent controlling technology which combines the ship’s maneuvering knowledge and the imitation knowledge.The author tries to solve this problem more effectively by using the multidisciplinary way. Thus, a comprehensive active ship-bridge collision avoidance system is established, which intergrates the video information detection system and the ship maneuvering&controlling system in the water areas near the bridge. Based on the factors above, the main achievements of the dissertation are as follows:(1) Through reviewing the ship-bridge collision cases in the literature around the world, the dissertation illustrates the reasons cause the accident elaborates the current study patterns in collision avoidance describes the application of the two main centered goals,i.e.,computer video detection and maneuvering imitation in the ship-bridge collision avoidance aspect, and presents the technical routes and the innovations points.(2) Based on the theory of ship maneuvering motion, using the MMG model and considering various external influences, a model of ship’s motion equation referring to the water area near the bridge is established.According to the great effects from the wind¤t while the ships are navigating in the water near the bridge,a ship’s drifting model under those external wind¤t load is also established in the dissertaion.The established the track prediction model in waters areas near the bridge is based on the Navigation Standard of Inland Waterway, Two algorithms including the traditional empirical method and the ALE (Arbitrary Lagrangian Eulerian) technique used for calculation of the ship’s stopping engine stoke are compared, which provide the track pre-controlling algorithms for the active collision avoidance system.(3) The navigation simultation experiment is done according to the abome mentioned numerical model of shipinfluences, a model of ship’s motion equation referring to the water area near Yangtze river bridge is chosen as the water areas of simulation experimental and the3000DWT river-sea going ship from the National Twelfth Five-Year Plan for the Golden Waterway of Yangtze as the typical study ships. According to the various controlling methods by using the ship’s controlling equipments such as engines, steerings, anchors, moorings;considering the situation of malfunction of each controlling method based on those equipments,4main groups and9load case of typical numerical maneuvering simultation are set up. The time and displacement curves of those load cases are recorded and analyzed for the purpose of providing the comparison with the later physical model experiments.(4) According to each load case in the numerical experiment, a series of load cases in the physical model experiments are carried out. A physical model of the3000DWT river-sea going ship in a scale ration of1:40is made following the similarity criterion and considering the dimensions of the mother ship and the size of the existing experimental facility—the open-air ship performance maneuvering tank of our school.The simulation channel is set up with the same scale ratio.Considering the load cases of numerical experimental and the limitations of the physical model’s feedback channel,7load cases of pysical model experimental are carried out. An alalysis report is completed according to the experimental data. Following the similarity criterion the data of corresponding load cases of the numerical experimental are transformed and compared with the those of the physical model.A data correlation list is given.These results will give the support to the active collision avoidance system in determine the minimum distance parameter.(5) An active ship-bridge collision avoidance system based on computer vision detection is developed. At the beginning, the construct frame and the key technique of the ICAS (Intelligent Collision Avoidance System) are illustrated, Then, the target motion detection and the track correlation technique are studied under the dynamic complex background.In order to check the validation of the detection algorithm, we use video camera on the spot to get the video in manual and import a preset detection algorithm. The experimental results show that, in the case of ship navigating in normal situation in the water areas near the bridge, the algorithm has strong robustness.The author has built an active ship-bridge collision avoidance system based on the motion equations and the computer vision detection, through comparing and analyszing the data of particular load cases of numerical and physical experiments of the ships in typical water channel, and has checked the validation of the system by the on spot video from the bridge area.The present results could be used as a new method to improve the security of the bridge for the navigators and the bridge security ensurance department. |
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