H_∞Control Of Networked Control Systems With Communication Energy Constraint

In recent years, with the rapid development of digital technology and information technology, network technology has been widely used in human life. Meanwhile, networked control systems (NCSs) are also gradually applied to the modern industrial control. Network control systems are also spatially distributed in different place. Its main components (sensors, controllers, actuators) are connected to each other through the shared communication network. Compared with the traditional point-to-point control systems, the technology of networked control systems increases the flexibility of the system, has a higher level of security and reliability and lower installation and maintenance costs. Therefore, the networked control system has become one of main research centers, not only in academic but also in industrial control. However, the intervention of the network also brings some new challenges, such as data packet dropout, random communication delay, communication energy constraint and so on. On the other hand, the energy of sensors is always provided by the battery in the wireless sensor network applications. Therefore, limited energy that the sensors only having can be used for the collection and transmission of information, so that the energy of sensor is very important and should be treat as scarce resources. We need to utilize the scarce resources reasonably and efficiently. Nowadays, most commercially available wireless sensor may adopt different energy levels of data transmission. Sensor adopting a higher energy level to transmit information will receive more reliable data streams, using a low energy lever to transmit information will lead to unreliable data stream, such as data packet loss and transmission delay. Litter researches on the control design, which not only utilizing the sensor energy rationally and effectively but also guaranteeing a better system performance, have been proposed. Therefore, the researches on network control system with communication energy constraint have important theoretical value and the value of industrial applications.The main research works are as follows:In the first chapter, this research works and practical significance, as well as domestic and foreign research status are introduced briefly.In the second chapter, the robust H∞state feedback controller design for networked control system with sensor energy constraint problems is discussed. Considering sensor communication energy constraints, general sensors provide different energy levels to transmit information, and selection of different energy level to transmit information will lead to a different random packet loss rate. Establishing networked control system as a random closed-loop system, using the Lyapunov function method, sufficient condition which guarantees random mean square exponential stability of the networked closed-loop system is given in terms of LMIs form. Meanwhile, robust H∞state feedback controller design method is given with a prescribed level of disturbance attenuation. Finally, taking the networked control of the uninterruptable power supplies (UPSs) for instance, the simulations by Matlab/Simulink toolbox illustrate the effectiveness of the proposed control method in this chapter.In the third chapter, the robust H∞dynamic output feedback controller design for networked control system with sensor energy constraint problems is discussed. In industrial systems, the system state is not measurable in many cases. In order to solve this problem, this paper take the observer-based controller design method. Based on the Lyapunov function method, sufficient condition which guarantees random mean square exponential stability of the networked closed-loop system is given in terms of LMIs form. Meanwhile, observer-based robust H∞dynamic output feedback controller design method is given with a prescribed level of disturbance attenuation. Finally, taking the networked control of the uninterruptable power supplies (UPSs) for instance, the simulations through Matlab/Simulink toolbox illustrate the effectiveness of the proposed control method in this chapter.In the fourth chapter, we summarize the research and show the prospect of this thesis.