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Modeling And Control Of The Networked Control Systems

Posted on:2005-09-08Degree:DoctorType:Dissertation
Country:ChinaCandidate:W H FanFull Text:PDF
GTID:1118360152465797Subject:Control theory and control engineering
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The Modeling and Control of the Networked Control Systems (NCSs) are studied in this dissertation. The main parts are concluded as follow:(1) The models of the NCSs with delay shorter than one sample period are given. The NCS with time-driven sensor node, event-driven controller node and actuator node and uncertain delay is proved to be modeled as a class of uncertain discrete linear system. Based on the Lyapunov function and the Linear Matrix inequalities (LMIs), the sufficient condition for the NCS which is subject to the asymptotic stability and H∞ performance are derived. The design approach of the controller is given.(2) Supposing the controller node and the actuator node is event driven, the sensor node is time driven and uses multi-packets transfer; the model of the Multi-packets -transfer NCS (MNCS) is given. On condition that the sensor node using static scheduling strategy; the MNCS is modeled as a periodic system or an uncertain periodic system. The MNCS is modeled as a switched system when the sensor node using dynamical scheduling strategy. Based on the periodic Lyapunov function and LMIs, the sufficient condition for the periodic and uncertain periodic NCS which is subject to the asymptotic stability and H ∞ performance are derived, and the design approach of the controller is given. Based on the common Lyapunov function and LMIs, the sufficient condition for the switched NCS which is subject to the asymptotic stability and H∞ performance are derived, and the design approach of the controller is given.(3) The control problem of the MIMO NCSs with short delay is studied. At first, the model of the short-delay MIMO NCSs with time-driven sensor nodes and controller node is given. These sensors failed transferring the data packet in the sampling period are treated as invalidated temporarily, so the NCS is a system with sensors failure. In order to eliminate the effect of the network-induced-delay, the state observer is introduced. Based on the theory of the fault-tolerant control and the switched system, the sufficient condition for the MIMO NCSs which is subject to the asymptotic stability and H∞ performance are derived, and the cooperative design approach of the controller is given.(4) Firstly, the modeling of the long-delay NCSs is studied. Supposing the close loop system without network is asymptotic stable, the sufficient condition for the stability of the close loop system including network is derived based on the Lyapunov function andLMIs. And the approach to calculate the maximum time delay which guarantees the stability of the NCSs is given. For the NCSs with only control delay, supposing the sensor and the actuator node are synchronous, the storage is setup to fix the time-vary delay. The sufficient condition for the NCSs which is subject to the asymptotic stability is derived and the optimal controller is designed. Then supposing there are fixed time difference between the sensor and the actuator node, which takes the fractional time delay to the NCSs, the NCSs is modeled as a class of uncertain system with the conclusion in the chapter 2, and the sufficient condition for this NCSs which is subject to the asymptotic stability is derived and the optimal controller is designed. For the NCSs with only time varying output delay, an observer with delay compensation is introduced, and the design approach is studied using the theory of the switched system and LMIs. Finally, for the NCSs with both control delay and output delay, the storage is used to make the control delay fixed, and the observer is used to compensate the output delay, the design approach of the controller and the observer is derived based on the separate principle.(5) The NCSs with both data packet dropout and the delay are modeled as an Asynchronous Dynamical Systems (ADSs). Supposing the NCS without data packet dropout is stable, the sufficient condition for the exponential stability of the NCS with fixed data packet rate is derived. The design approach of the controller for the NCS with fixed data packet rate is studied. And the...
Keywords/Search Tags:Networked Control Systems (NCSs), network induced delay, multi-packets transfer, data packet dropout, Lyapunov function, Linear Matrix inequalities (LMIs), switched systems
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