Networked Control And Filtering For Nonlinear Systems Based On Fuzzy Models  Posted on:20150618  Degree:Doctor  Type:Dissertation  Country:China  Candidate:X B Chi  Full Text:PDF  GTID:1108330461985154  Subject:Basic mathematics  Abstract/Summary:  PDF Full Text Request  One of the development trends of an industrial control system is to integrate the digital sensors, communication devices, network, and intelligent computers into the closedloop control system. Comparing with conventional pointtopoint control systems, the advantages of the networkbased control systems are the lower cost, greater agility of control framework and ease of installation and maintenance, etc.. With the rapid development of digital sensing technology and network technology, networked control systems (NCSs) have been finding application in a broad range of areas, such as industrial control processes, intelligent transportation systems and so on. In the practical applications of NCSs, the controlled plant is usually nonlinear, there exist analog signals and digital signals simultaneously, the network bandwidth is limited, and networkedinduced delays and data packet dropouts often occur. Therefore, it is of theoretical significance to investigate these problems. In this dissertation, the design problems of control and filtering for the nonlinear NCSs will be investigated by using the TS fuzzy modeling method. The main contributions include the following two aspects:1) the networkresourcesaved eventtriggered transmission schemes are designed for improving the operating mechanism of NCSs; 2) by considering the effect the membership functions in NCSs on system performance, the membership function deviation approaches are proposed to design networked fuzzy controller and networked fuzzy filter for nonlinear systems, respectively. The research contents and results are as follows:(1) Networked stochastic Hâˆž control and networked tracking control are investigated for the nonlinear systems which can be described by discretetime TS fuzzy models, respectively. In the problem of stochastic Hâˆž control, the data packet dropouts are described by a stochastic sequence satisfying a Bernoulli distribution. Then, the nonlinear NCS is modeled as a TS fuzzy system with stochastic parameters. In the problem of tracking control, the networked tracking error system is modeled as a discretetime delay system by using the discrete input delay approach. Based on Lyapunov stability theory together with a improved Hâˆž performance, the design methods of the fuzzy controller and the fuzzy tracking controller are presented in terms of LMIs, respectively. The relation between the nonzero initial condition and the Hâˆž performance is established.(2) The design of sampleddata guaranteed cost fuzzy control is investigated for a class of nonlinear systems with control input constraints and the timevarying sampling way, where the nonlinear systems are described by continuoustime TS fuzzy models. Considering the control input constraints, a new lemma is presented to obtain the deviation bounds of the membership functions in the sampleddata fuzzy control system and to establish a quantitative relation between the deviation bounds and the upper bound of timevarying sampling intervals. Then, a membership function deviation approach is proposed to design the sampleddata fuzzy controller, and the membershipfunctiondeviationdependent condition for the existence of the sampleddata fuzzy controller is derived in terms of 1MIs. It is shown theoretical and numerically that the proposed membership function deviation approach can reduce the conservativeness of some existing results in the field of sampleddata fuzzy control design.(3) The design of static output feedback Hâˆž control is investigated for a class of nonlinear NCSs which can be described by continuoustime TS fuzzy models. The bilateral network channels with networkinduced delays and datapacket dropouts are considered. First, a novel lemma about the deviations of membership functions which are dependent on the system output in the NCSs is established in network environment, which formulates a quantitative relation between the deviation bounds and the maximum allowable equivalent delay bound of the NCSs. Secondly, a membershipfunctiondeviationdependent condition with a equality constraint is presented to design the static output fuzzy controller, and is transformed as an optimal problem for control design by using cone complementary linearization algorithm, which is easy to solved. In addition, by using relax lemma to decouple the Lyapunov matrices and system matrices, two new design methods of static output feedback fuzzy controllers are proposed in terms of quasi LMIs, where the one is shapedependent design method and the other is shapeindependent one. Finally, the relation between the two design methods is established by comparing their feasible problems.(4) The design of eventtriggered Hâˆž control is investigated for a class of nonlinear NCSs which can be described by continuoustime TS fuzzy models. A new eventtriggered transmission scheme is first proposed to reduce the network bandwidth utilization by reducing the amount of transmitting sampleddata. Under this scheme, the nonlinear NCS is formulated as a thresholderrordependent TS fuzzy system with asynchronous membership functions. Then, some codesign methods of the eventtriggered transmission scheme and the fuzzy controller are derived by using the deviation bounds of asynchronous membership functions which are dependent on system state in network environment. It is shown that the proposed design method can reduce the conservativeness of some existing results.(5) The design of eventtriggered Hâˆž filtering is investigated for a class of nonlinear networked systems which can be described by continuoustime TS fuzzy models. The system output is sampled with timevarying sampling periods. Firstly, a new eventtriggered transmission scheme on timevarying sampled outputs is proposed to reduce the amount of transmitting sampleddata. Notice that only the part of the hysteretic sampleddata are received to regulate the filter by a ZOH. To fire the fuzzy filter and to estimate system information in real time, a new synchronous fuzzy filter with the membership functions on filter state and the sampledstate of the filter is proposed, such that the clock in the filter and the one in nonlinear system are synchronous. Considering the fuzzy filter and the eventtriggered transmission scheme, the networked fuzzy filter error system with the asynchronous membership functions is modeled as a thresholderrordependent norm bounded uncertain TS fuzzy system. Third, a codesign method of the eventtriggered transmission scheme and the fuzzy filter is presented, and a membershipfunctiondeviationdependent condition for the existence of the parameters of the eventtriggered transmission scheme and the gain matrices of the fuzzy filter is derived.
 Keywords/Search Tags:  Networked Control Systems, Networked Filtering Systems, SampledData Control Systems, TakagiSugeno Fuzzy Model, Membership function deviation, Event triggered transmission scheme, Fuzzy Control/Filtering, H_∞ Control/Filtering, Tracking control  PDF Full Text Request  Related items 
 
