Design Of Network Time Delay Compensation Controller Based On Implicit PIGPC

In the network control system, due to the introduction of network in the control circuit, it is inevitably to produce network time delay when the information is transmitting. The time delay will not only reduce the system control performance, but also cause instability. Particularly when the time delay is greater than the sampling period of the system, it can also cause the sequence disorder of transmission packet. Thus the time delay is one of the major problems of network control system. We should consider the time delay while we design a controller. Aiming at the problem of network control systems having random time delay, this article analyzes the network time delay, predicts the network time delay and designs the network time delay compensation controller.Firstly this article introduces the research background and significance. It reviews the existing method of network time delay prediction and network time delay compensation, and determine the principle and method of this article.Secondly, this article analyzes the structure and existing problems of network control system. Then we introduce the usage of 802.11 b network and True time toolkit. Finally we use True time toolkit to build a wireless network control system and use PID controller to analyze the influence of network time delay in the control system.Thirdly, because designing controller need to use the time delay, we introduce the components of the network time delay. The current time delay cannot be measured, thus we need to use the historical time delay data to predict the current time delay. We use the least squares support vector machine to predict the current time delay, and the particle swarm optimization to optimize the parameters γ and σ2 of the least squares support vector machine. Then we get the current time delay, and use the predict time delay instead of the actual time delay as the parameters of the network time delay compensation controller.Finally, the network time delay compensation controller is designed. This paper introduces the basic thought of predictive control and the principle of generalized predictive control. In order to reduce the online computation time of generalized prediction algorithm, we put forward the implicit generalized predictive control algorithm. Then we introduce the solution of the network time delay compensation, and use implicit GPC to verify the effectiveness of the solution. For improving the compensation effect of implicit GPC, this paper puts forward a implicit generalized predictive control algorithm with PI structure and uses implicit PIGPC to design controller and complete the design of time delay compensation controller based on implicit PIGPC. Through the simulation, we verify the effectiveness of this design.