Researches On Time-Delay Control Systems Based On Neural Networks

From the points of view for practical uses, the theory and applications of time-delay control systems based on neural network are researched in this dissertation. The design theory of neural networks and the estimations of linear systems and nonlinear systems with dead time using neural network are discussed. Neuro-PID internal model control, adaptive PIP controller based on neural network and adaptive Smith Predictor using neural network are proposed for time-delay systems. The simulation experiments and the real-time temperature control of electrical furnace are made.The main research work and contributions of this dissertation are as follows:1. A survey of neural networks, neuro-control and time-delay systems is summarized, and the problems existing in time-delay control systems are also discussed.2. An introduction of the traditional design methods for time-delay systems is given, including a PID controller, a Smith Predictor and a PIP controller. And the pool robustness of these traditional design methods is pointed out by the simulation experiments.3. The design theory of neural networks is discussed, including the basis principles of neuron control and the design of Back-Propagation Network.4. To the identification of time-delay systems, the traditional identification methods are introduced. Two kinds of identification methods are put forward, including linear systems and nonlinear systems with dead time. The comparison between the traditional identification methods and the ways based on neural network is made.5. Combining internal model control method with Smith Predictor and single neuron controller, a neuro-PID internal model control method for time-delay systems is put forward. The real-time temperature control result of the electrical furnace shows that the control performance is very good.6. Adaptive internal model control and predictive PID control method are discussed, and the simulation experiments are made.7. According to the identification methods based on neural network, two kinds of compensative control strategies for time-delay systems are proposed, namely adaptive PIP controller based on neural network and adaptive Smith Predictor using neural network, and the simulation experiments show that the control performance is very good.