Study On Time-Delay NCS And The Application In Cement Mill Control System

Network control system (NCS) is a hot research issue of current control domain. While NCS could efficiently accomplish control tasks through networks, the network-induced delay is inevitably brought. Delay could cause performance degradation, and even the instability of control systems. Thus, the delay-related stability study of NCS is especially significant. In this paper, for a class of distributed multi input multi output (MIMO) delay NCSs, the delay-related stability conditions have been studied on the basis of the continuous-time model building of closed-loop NCS. Linking to practical project, the network design method based on MATI has been studied, and the network structure of cement mill control system has been devised with network configuration optimization. Consequently, the stability of control systems as well as the real time performance has been guaranteed.Firstly, considering the influence of delay factor, the discrete-time model of single input single output (SISO) delay NCSs based on augmented state has been built. On this basis, a distributed MIMO delay NCS has been partitioned into several single-loop subsystems. Using the state feedback controller with control constrains, the continuous-time model of MIMO closed-loop NCS has been set up.Furthermore, the delay-related stability issue of MIMO NCS has been studied using Lyapunov second method. By constructing a positive definite Lyapunov function with undecided matrix variables, the delay-related stability condition in LMI form has been deduced. Translated the determinant issue of system stability into feasible solution of LMI, new solutions of MATI under the system stabilization have been investigated.Finally, the information transfer delay of ControlNet has been computed quantitatively, to study the design method based on MATI. Combining the practical project, the design of node numbers need to satisfy the stability request of network structure of cement mill control system. Through the online test about the relationship of network parameters and the utility of network bandwidth, the network optimizing method to improve the system real-time performance has been proposed.