基于对象Petri子网模型的列车群分布式仿真

为提高效率,增强真实度和可信度,采用分布式仿真解决列车群行为的分析和验证问题,并基于列车群的对象Petri子网模型(TGOSOPS)实施分布式仿真系统。针对模型到仿真系统的逻辑映射、运行中的动态关联以及依靠模型处理仿真冲突和时间协调等问题,提出由终端上的列车仿真应用模块和服务器上的全局控制模块构成分布式仿真系统框架,并对TGOSOPS按照功能进行划分,使其和分布式框架有机结合和映射。根据系统结构,结合动态离散事件系统的仿真思想,明确系统中各类实体和事件间的逻辑关系,采用定时与主动对象(主动成分)扫描相结合的方法,建立分布式仿真策略,包括客户端和服务器端两部分,从而实现模型到系统的动态关联,并采用空消息算法消除策略死锁。采用一个统一的全局时钟来调整局部时钟的时间周期,以实现分布时钟的协调。路网图、运行图、模型库和各种信息库等都以全局数据库的形式存储在服务器上,在仿真过程中,根据实验推进的需要可以随时从服务器上读入所需信息和数据。

The Distributed Simulation of Train Group Operation Model Based on Object-Oriented Petri Subnet

In order to improve efficiency,strengthen reality and reliability,when solving the verification and analysis problems of train group behaviors,we can carry out distributed simulation system based on Trains Group Operation System with Object-oriented Petri Subnet(TGOSOPS).Aiming at such problems as how to map from the model to the simulation system,how to solve dynamic correlation problem between the model and simulation system in operation,as well as how to rely on model handling simulation conflict and time coordinative etc,we put forward distributed simulation system frame including the train simulation application modular on terminal and the overall control modular on server.In the frame,we divide TGOSOPS according to its functions and make it combine and map the distribution frame.Then,based on system frame,we combine the simulation thinking of discrete event dynamic system,make out logic relation between each kind of objects and events in system,adopt timing and active objects(active elements) scanning method,and establish distributed simulation strategy that through empty news eliminates dead locks including customer part and server part.We realize model dynamic combining from model to system.We adjust the time period of local clock with a unified overall clock in order to realize the coordination of distribution clocks.Road net pictures,timing charts, model bases and various information bases etc.are stocked in server as the overall database of situation.In the simulating,according experiment needs,information and data can be read in at any time from server.