Ncs, The Network Delay Of The Pid Control Algorithm Performance Analysis And Experimental Research

As the result of combination of control technology and networked information technology, networked control systems have been researched widely in all kinds of control field. The process to be controlled and the controller are separated by network. The measurement and the controller output are transmitted via the network, and then network delay occurs. The typical network delay has stochastic behaviour and varies in a large range, which bring difficulties in the designing of NCS control strategy. So it is meaningful to analyze the influence of network delay on the performance of control system. This paper studies the influence of network delay on the control performance on basis of PID control algorithm.The main work of this paper lies in the following items. Fully -distributed NCS is taken as research object. Then analyzing the distributions of network delay firstly, giving the pictorialization and formula of the components of network delay in time-driven systems, and presenting a simulation method for varying time-delay. Discrete PID control algorithms with tuning methods of its parameters are introduced. Criterion of the evaluation for control performance is proposed to evaluate the effect of the control system.The hardware and software of NetCon control system are introduced. The configuration software is based on the platform of MATLAB, Simulink and Real-Time Workshop, which can integrate the Simulink seamlessly. It has the characteristic of accomplishment the generation, compile, link and download the code to the field network controller for running within several seconds with combination of Real-Time Workshop. A digital simulation for PID NCS on liquid level experiment device of first order water tank is done by True Time, and quantitative analysis applied in the influence of different network delay on the performance of control system is also done. .At last, NetCon controllers are used to form an actual NCS with the device and experiments for verifying the simulation are done. And the experiment results demonstrate the correctness and effectiveness of simulation analysis.