In the process of the system study , the knowledge in the domain of ship collision avoidance is analyzed and the collision mechanism , process and the tactic are studied firstly . and then , using the fuzzy mathematics theory , the fuzzy mathematical model of judging collision risk is built , which take into account of the factors such as ship maneuverability , visibility and so on . in addition , based on the expert system theory , a design method of ship intelligent collision avoidance expert system is put forward , and the frame of ship intelligent collision avoidance expert system is built 在系统的研究过程中，首先对船舶避碰领域知识进行分析，并研究了船舶碰撞的原理、过程及对策；然后运用模糊数学理论，建立了一种评判碰撞危险度的模糊数学模型，该模型考虑了船舶的操纵性能、能见度等多种因素；接着根据专家系统理论，提出了一种船舶智能避碰专家系统的设计思路，并构建了一种船舶智能避碰专家系统的框架；最后以visualbasic6 . 0作为软件开发平台，设计了一种具有良好的可视化人机交互界面的船舶智能避碰专家系统软件。
During last several years , the requirement to improve the maneuverability of ship has been increased among many international societies such as imo , impa ( international maritime pilot association ) and iacs ( international association of classification societies ) 很多国际协会比如国际海事组织( imo ) ，国际引水员协会( internationalmaritimepilotassociation ， impa )和国际船级社协会( internationaiassociationofclassificationsocieties ， iacs )对船舶操纵性能提出了越来越高的要求。
With the disturbance of random wave the ship will inevitably roll and result in the ship ' s incline , especially , for small ships which the most obliquity of the ship is likely to reach above degree 15 . in the actual combat the rolling movement of the ship will result in difficult control of the artillery for the artillerymen on the ship , reduce the artillery ' s probability of shots , and affect the power of the artillery by direct control of the object ( artillery ) fixed on the ship it can be kept horizontal state all the time 尤其是对大量的小型舰船，船体的最大倾角甚至可达到15以上。在实战中，船舶的摇荡将造成炮手对船载火炮的操纵性能降低，降低火炮的发射命中率，影响到船载火炮威力的发挥。通过直接控制固连于船体的火炮，使其始终保持在水平状态，可以提高实战中火炮的操纵性能，提高火炮的命中率。
Due to the limited underwater action scope of a submarine , and it must be provided well maneuver performance , not only the depth - keeping and directional steady motion but also quick elusion or entering the battle status , which brings forward a high demand to submarine control 由于潜艇在水下的活动范围有限，同时潜艇又必须具备良好的操纵性能，既要保证定深，定向的稳定运动，又要能机动灵活的规避或进入武器发射的战斗状态。这样就给潜艇的操纵控制提出了很高的要求。
Author processed a new method of establishing the point of the last minute action . the point of the last minute action is a dynamic model . the factors affection includes : ship maneuvering , ships speed , measure , in encounter situation , behaviour experienced , natural etc . first of all , these factors should be put in order according to the administrative structure . these factors are relativity experienced , fuzziness 本文认为最晚施舵点模型应当是一种动态的模型，影响最晚施舵点模型的因素包括：船舶的操纵性能、本船的速度、本船的尺度、来船与本船的会遇格局、人为因素、自然环境等因素的影响。
The research on the ship maneuverability in the wind , wave and current , can not only be used to optimize the maneuverability design in the ship design stage , help to understand the mechanics of ship collision and capsizal , but also guide the handling operator to improve the handling skill , guard against the sea accident . therefore , the study is significant both theoretically and practically 研究船舶在风、浪和流中的操纵性，不但能够在设计初始阶段，对船舶的操纵性能进行优化设计，而且有助于了解船舶碰撞与倾覆事故的产生机理，指导驾驶人员提高驾驶技术，预防海难发生，因而既有理论上的意义，又有很大的实用价值。
The study comes from two projects - " the practical experiment of ship navigation and the simulation study of the shu - tong yangtze river road bridge " and " the study on the ship navigation of the yichang yangtze river railway bridge " . the data is from these practical experiment which includes z - model experiment of sea - going vessel and fleet , turning motion experiment , stroke experiment and encounter experiment between sea - going vessel and fleet . based on those , it calculates the track of the ship in the navigational waters according to the maneuverability and the response equation 本文结合导师课题， “苏通长江公路大桥船舶通航实船试验及模拟研究” ，和“宜万铁路宜昌长江铁路大桥船舶通航问题研究”通过大量的实船试验：海船及船队的z型试验、旋回圈试验、冲程试验和海船及船队在桥区的航行会船试验等，以试验的数据为依据进行理论分析、计算，然后根据船舶的操纵性能及操纵响应方程，计算船舶在桥区的运动要素及航迹。
So , it is main problem that set up mathematic model for ship motion simulation . however , the calculating definition of maneuverability motion depends on the hydrodynamic derivatives . for this reason , the purpose of this article is : apply newly hydrodynamic derivatives formula to calculate hydrodynamic forces and offer the ship maneuverability index during the design stages 因此，本文的研究目的是：运用最近提出的水动力导数近似估算公式，获得较为精确的水动力计算，为船舶工程人员在船舶初始设计阶段提供使用工具，使他们在设计时就能较准确地获得实船操纵性能指标。
