Design And Implementation Of Pluggable Co-simulation Platform Based On FMI

Cyber Physical Systems(CPS)are systems which closely integrate information cal-culation with physical process,including the calculation part and the physical part,with a strong heterogeneity.In addition,CPS combine discrete system behaviors and continuous physical processes,are typical hybrid systems.CPS usually run in an open,uncertain en-vironment,which resulting in uncertain system behaviors.Based on the characteristics of CPS above,simulation,verification and analysis of the performance and security of CPS is challenging.co-simulation can solve the problem of heterogeneous system modeling and simulation to some extent,and existing technology,such as Functional Mockup In-terface(FMI),providing an unified standard specification for all tools to co-simulation,any tool can participate in co-simulation through implementing FMI,and therefore can promote the de-velopment of co-simulation.However,one side it is a complicated task to implement FMI standard and export FMU to participate in co-simulation which lim-its the number of tools supporting FMI;on the other side,the efficiency of the existing co-simulation algorithm needs to be improved.Firstly,we design and implement a hot-pluggable co-simulation platform based on FMI which supports three coupling modes:coupling by FMU,coupling by tool,cou-pling by plug-in.Coupling by FMU is the traditional coupling method;Coupling by tool is designed to provide a more efficient way to support the FMI-based co-simulation for any modeling tool,enabling more tools to support FMI-based co-simulation;Coupling by plug-in is designed to provide a more efficient way to support the FMI-based co-simulation for any code-customed model.Supporting three coupling modes make the hot-pluggable co-simulation platform has a strong simulation capability.Secondly,after analysing the existing co-simulation algorithm,we proposed a plug-gable co-simulation algorithm based on FMI,by dynamically changing the number of model participating in co-simulation and controlling the exchange times of coupling vari-ables to improve the efficiency of co-simulation.About the implementation way of hot-plug,in order to ensure the independence of each model during its modeling stage,we designed two types of plug-in situation:initiative plug-in and passive plug-in.For two different plug-in situations,we have proposed two ways to achieve:string-based initiative plug-in implementation,and configuration-based passive plug-in implementation.Finally,we use two co-modeling and co-simulation methods to analyse the classic case-study in CPS:Smart Building Systems,which fully demonstrate the advantages of the hot-pluggable co-simulation platform,and the performance of the co-simulation algorithm before and after the improvement is analysed by experiment,the results show that the proposed pluggable co-simulation algorithm can improve the efficiency of co-simulation to some extent.