Optimal Control Algorithm And Performance Of The Network Control System Of The Communication Channel Is Limited

Networked Control System (NCS) is a full-distributed and networked real-time feedback control system, which has several advantages in low cost, easy maintenance, high reliability and so on. Due to the use of digital networks to transmit information, NCSs comes up against some special problems. Because the real-time transmitting capacity of networks are restricted by network bandwidth limitation and noise signal disturbance, communication channels constraints control problem comes into being. The problem may decrease control system performance, which is also the potential factors to influence system stability. Therefore, it is important to study on control strategy problem of networked control systems with limited communication channels.For multiple inputs and multiple outputs NCSs with limited communication channels, the system modeling, the selection of communication sequences, the design of the controller and the effects of limited communication channels on the control performances are studied. The main work lies in the following items:For NCSs with limited channels which are only permitted some of sensors and actuators access to networks at any time, system models of the zero control and the last available control are respectively built by introducing communication matrixes. Based on the controllability and observability of systems, the selection principle of the feasible periodic communication sequences is given. Then, the stable LQG (Linear Quadratic Gaussian) optimal networked controller is designed, and the simulation results verify the feasibility and validity of the methods.Based on the selection principle of the feasible communication sequences, the selection principle of the optimal communication sequences is given. Meantime, according to the features of the LQG optimal control problem, the ratio of cost functions with unlimited channels to limited channels is defined as control performance index to evaluate control action running stand or fall. The effects of different degrees of limited communication channels, different system models and communication sequences selection on the LQG optimal control performance are analyzed by a lot of simulation experiments.The predictive method is further proposed to estimate the dropped real-time information, and the system model of the predictive control is built. Then, the stable optimal predictive networked controller is designed. The numerical examples are given to demonstrate the feasibility of the method.Finally, the non-coupling second-order circuit control plant built in learning machine is directly connected to the Netcon networked controller. They are used to simulate the experimental environment of the NCSs with limited communication channels. The experimental results further prove the correctness and feasibility of the designed algorithms in the paper.