一类网络化串级控制系统的分析与建模

Analysis and Modeling of a Class of Networked Cascade Control Systems

针对基于现场总线的一类网络化串级控制系统,分析了其结构及系统模型,指出了网络诱导时延存在的位置,主控制器和副控制器均采用了增量式数字PID;在网络诱导时延常数小于、大于一个采样周期以及等于采样周期的整数倍的情况下,分别利用增广状态向量法,将系统建模为有限维离散时间线性时不变系统。最后,给出了网络化串级控制系统(NCCS)在不同时延的仿真实例。

Based on engineering practice, the concept of networked cascade control system （NCCS） is put forward. A class of networked cascade control system based on fieldbus is studied, in which the primary controller and the secondary controller are both incremental digital PID. And the location of the network-induced delay is pointed out. Using augmented state vector method, the model of the system is established as a finite-dimensional discrete-time LTI system, either the network-induced delay is shorter or longer than a sampling period, or equal to integral multiple of sampling period. The simulation examples of NCCS with different delays are given.