Study On Fuzzy Dynamic Scheduling Algorithm And Variable Sampling Period Algorithm In NCS

NCS (Networked Control System) is a fully distributed, network-based real-time feedback control system, whose main characteristic is that information exchange of the different parts of the control system is achieved through network. The advantage of control system combined with that of network, NCS has extensive control range, less line connecting, strong adaptability and low operation cost, and therefore has wide application prospects. But unfortunately, introduction of network also brings a lot of new problems such as network-induced delay, data packet dropout and so on, which has limited full play of the system performance. How to solve these problems in order to effectively play the advantage of NCS has become a research focus.At present, research on NCS mainly focuses on either control or network scheduling. This dissertation focuses on the research of network scheduling, which objective is to minus the effect of those problems on NCS and improve the performance of NCS by designing proper dynamic scheduling algorithm and variable sampling period algorithm.First of all, development of NCS and the existing basic problems are introduced and research status of scheduling in NCS are analyzed ; Secondly, basic structure and function of TrueTime simulation toolbox used in the research are simply introduced, and a multi-loop NCS system model with schedulers is build based on TrueTime. The importance of scheduling to NCS is displayed by simulation; thirdly, considering the system error and the change rate of system error and using neural network fuzzy control theory, a fuzzy dynamic scheduling algorithm based on neural network is designed and then applied to the NCS model based on TrueTime ,which shows effectiveness in the simulation, while the basic principle of the algorithm is discussed in detail; eventually, taking the effect of sampling period on the performance of NCS into consideration, a variable sampling period algorithm under given network utilization requirements is designed ,and combined with scheduling algorithm and then applied to the NCS model based on TrueTime in the form of sampling period regulators, which shows effectiveness in the simulation, while the basic principle and realization process of the algorithm is discussed emphatically.