Based On The Sampling Theory Of Wireless Sensor Network Analysis And Control Actuators

As a special wireless sensor networks,wireless sensor and actor networks (WSANs) integrate the functions of embedded computing,distributed information processing,wireless communication and collaboration. It has some advantages which the wireless sensor networks don’t own, such as long life service, good quality of real time etc. So, WSANs can bridge the physical world and the information world; realize the interaction between human society and nature. It also accomplishes several special missions intelligently in unattended environment.Especially,it makes network detection and control become possible in the place of installation difficulty or high-risk surveillance area where man can not operate. As a result,the emergence of WSANs does not only extend our ability for obtaining information, but also makes control application become more intelligent. In recent years, researches about wireless sensor and actor networks have primarily focused on network communication protocol,network security,real time of network,fault tolerance of network,network connectionsetc.There are few studies on its networks control. Moreover, the control systems are sampled with the same sampling period (that is single-rate control systems). However, as the deepening control applications of wireless sensor and actor networks, when many signals with different sampling period (such as flow signal and temperature signal) are needed to monitor and control simultaneously in the controlled area, it is not feasible with the method that can be used to single-rate control systems obviously.So,for monitoring and controlling multiple variable with different sampling periods,a method which can sample the systems with corresponding sampling period and holder (that is multirate control method) is required.Through this method,multiple variables with different sampling period can be controlled, at the same time, reliability of overall systems are also increased.The multirate control theory was introduced to study multiple variables control problems of WSANs in the paper in order to monitor and controll a variety of signal parameters in the monitor region.In addition.in the networks control system,the multirate control system has better robust performance than those of the single-rate control system. What’s more,the multirate control system decentralizes the control functions, which can increase the stability and reliability of the overall system. So it is significant to adopt the theory of multirate control in the study of control problem in wireless sensor and actor networks. The main parts of this paper are as follows:1.The structure, characteristics,application, background and research status of wireless sensor and actor networks were briefly described,and the research background and application of multirate control theory was overviewed.2. The equation of multirate output sampling was derived in detail for output multirate sampling control systems, and the entire design process of the multirate output feedback controller was described. The design of controller like state feedback was the same as any closed-loop pole placement, the controller itself has a specified stability margin,the effectiveness and feasibility of the solution were examined by some simulation examples.3. A new method of solving the static output feedback controller for input multirate sampling control systems was proposed,and the controller’s parameters were obtained by resolving the convex optimal problem with constrains on linear matrix inequalities. Compared with single-rate control method,the effectiveness and feasibility of the method were examined by some simulation examples.4. Multirate output feedback controller and static output feedback controller’s methods were used to wireless sensor and actor networks, modeling, control design and simulations were used for a cluster unit, and effectiveness were examined by simulation examples.