The Research And Application Of Networked Control Systems

Networked Control System is the novel frame of control system theories born with control,network and computer application technologies.The paper studied on control algorithms,scheduling strategies,simulation tools and engineering applications based on the existing theoretical achievements.The main contents are:1.Discussed in detail the main factors influencing networked control,such as transmission efficiency,network node drives,clock synchronization,and sampling period.Besides,according to the different combinations of controller,sensor and actuator drive methods,the discrete model of networked control system was deduced.2.Studied the application of GPC in NCS and built up the NCS distributional model.BP neural network was adopted to predict the errors between the controller and object outputs for their compensation and thus achieving the enhanced precision.Then the Implicit Generalized Predictive Control was adopted to identify the optimal controller parameters,therefore decreasing the online calculation and improving the efficiency.3.The State Space model was built up under certain specifications for the study of Predictive Functional Control applied in NCS.The network with uncertain transmission delay and data drop-off can be regarded as grey system.The paper adopted the GM(1,2) grey predictive control model to do research on the application of grey control theory in NCS.4.A mixed scheduling method was designed based on SSI in which the strategy combining RM static scheduling and MEF-TOD dynamic scheduling algorithm was introduced for QoS scheduling.Besides,a two-layer scheduling strategy was proposed based on BP neural network and fuzzy feedback,one layer being intended for decreasing network load through optimal system structure.Fuzzy feedback information scheduling was devised on the other layer in which the priority of information inputted into controllers was decided according to response error and the error differences while the priority of information entering sensors was made by testing sampling time and sampled value changes.5.Studied the characteristics and usage of TrueTime toolbox and designed the simulation platform of NCS based on Ethernet.The key techniques of structure building, working principles,program flow,clock synchronization,delay test and so forth were introduced and realized so that it would be helpful for the theoretical study of Ethernet-based NCS.6.A set of FCS which the author has developed as a participant was introduced by describing its basic functions and entire structure while emphasizing two key techniques. The event-clock driven way was explained in detail.The OPC server was designed using dynamic scheduling algorithm of complex task collection,attaining real-time data exchanges.This technique made the connection between different network control systems more convenient;besides,its openness would ensure the extensive the uses in practice.