Research On NS2-Based Integrated Simulation Platform For Networked Control System

Networked Control System (NCS) is a kind of new developing direction of Control Science, which integrates control, computer science and network communication. Intergrating computer network has emormous advatanges, such as lower cost, reduced weight and power,simpler installation,high reliability,ease of system diagnosis and maintenance,and increased system agility. On the other hand, network induced delay, packet losing and other factors have advers effects on overall system operation and performance. In order to study the influences which the features of the network impose upon the NCS, a integrated simulation platform is designed, which based on a special network simulation software Network Simulator V2 (NS2). Upon this network, we can do many simulations to verify our assumptions and conclusions about NCS. Quality of Service (QoS) greatly affects the performance and stability of NCS. After introducing the research and development situation of NCS, two stability theorems are introduced and the evaluation method of control performance is discussed in the first two chapters. This paper focuses on the general design of the simulation platform hierarchy and each module. As a integrated simulation platform, it should embody the features such as open, scalable,real-time,ease to use and true to reality,besides integrates network and control system simulations. With this in mind, this paper completes the general design and partial implementation of the simulation platform. DDE and Socket are used in the Matlab Data interface module and Network Interface module design, which realizes the ability of Matlab to access the network in real-time without using real-time targets. And the special network simulation tool NS2 is used to implemente the network model. This approach combinded the virtues of NS2 and Matlab. Network module is the most important and difficult part.In this part, we explain why NS2 is selected at first. Then, we introduce NS2 and how to use the emulation ability of NS2. At last, two typical network models are emulated. At the end of this paper, a networked DC servo system simulation example is given on the simulation platform. After analyzing the infuences imposed by the time delay, some suggestion are given on how to reduce the effect.