Non-fragile H_∞ Control For Networked Control Systems

With the continuous development of computer and network communication technology, the integration of control system and network communication system has become a hotspot in the field of control, therefore the concept of networked control system(Networked control systems, NCSs) is proposed. Since it’s a type of distributed control system, the components distributed in the different space exchange information through network in NCSs. NCSs is widely used in various fields of national defense construction and national economy with the advantages of convenient remote operations and high degree of resource sharing. This paper based on the Lyapunov stability theory developed mathematical model, then analyzed the stability of NCS under the condition of some non-ideal factors such as the networked induced delay, signal error and external noise disturbance. Considering the influence of the physical environment, controller parameter perturbation may exists, so this paper discussed the non-fragile H_∞ control of networked control systems with time-varying delay, the main contents are:(1) The non- fragile state feedback control problem is studied for the NCSs with network induced delay and the controller parameter uncertainties. By using Lyapunov stability theory and linear matrix inequality(Linear matrix inequality, LMI) techniques, a sufficient condition for the asymptotic stability and H_∞ stability of the closed-loop system is derived. And the controller gain can be obtained by solving the LMI toolbox. Finally, there are some numerical examples.(2) Aiming at networked control system with time-varying network-delay, the problem of state observer-based non-fragile H_∞ robust control for networked control system is studied. Considering the uncertainties exist not only in the gain of the observer but also the controller, by using Lyapunov stability theory and LMI method, a sufficient condition for the existence of the H_∞ asymptotic stability of the closed loop control system is derived, criteria for the existence of the non-fragile observer and robust controller are derived. The desired non-fragile observer and controller can be derived via a modified cone complementary linearization(Cone complementarity linearization, CCL) algorithm. Finally numerical simulation is given.(3) The research is about non-fragile H_∞ control of quantitative feedback control system with stochastic time-varying delay. Considering the influence of quantization error on the system performance, we use a dynamic quantizer, which consists of a dynamic adjusting parameter and a static quantizer. So that the scope of quantitative and quantitative error increase or decrease according to the dynamic adjusting parameter. Bernoulli distribution sequence describes the probability of network induced delay. Then design the non-fragile state feedback controller, so that the closed-loop system is exponentially mean-square stable and satisfies predefined H_∞ performance index. Finally a numerical simulation validates the effectiveness of the proposed method.