Many Researches On Robust Filtering Problem  Posted on:20080106  Degree:Doctor  Type:Dissertation  Country:China  Candidate:H Y Li  Full Text:PDF  GTID:1118360215498562  Subject:Control theory and control engineering  Abstract/Summary:  PDF Full Text Request  State filtering has been attracting much attention as one of important fields in controltheory and engineering application. In many practical applications, however, the statisticalproperties of exogenous noise signals are rarely known and there are perturbations insystem model, that is, exogenous disturbances and uncertainties in system model, so therehas been rapidly growing interests in robust filtering. In the past decades, robust filteringwas studied and amount of meaningful results were obtained, but, the delaydependentrobust filtering for timedelay systems and robust filtering for nonlinear systems have notbeen fully investigated.The main content of this thesis can be briefly described as follows:The history and research status of robust filtering are introduced systematically, theemphasis is focused on the representative algorithms and results in the development ofrobust filtering theory and we forecast the problem and development in the future.We developed a robust filtering algorithm for a class of timevarying delayuncertainty linear systems, a new LyapunovKrasoviskii functional is given andboundedreal lemma is used in order to design a delaydependent H_âˆžfilter.The Riccati equation method is used for uncertain neutral delay system, the suitablefilter can be obtained by solving a pair of Riccati equation, the cycle of solving andjudging is omitted. Considering the convenient and effective algorithm of LMI, we use itas a design tool. A sufficient condition for the existence of H_âˆžfilter is given andformulated in terms of linear matrix inequalities.The study of neutral delay systems with distributed delays is not sufficient, so it is stillessential to study this system. Some overbounding techniques of inequality were proposedthat reduces the conservativeness coming from the derivative of Lyapunov function. Thenorm bounded uncertainty in system is regarded as exogenous disturbance, so theconservativeness is degraded in the proof of BRL and better H_âˆžindex is obtained, what'more, the filtering problem is solved when there are distributed delays in measurementequation. An approach introduces a slowtype state transformation and is based onrepresenting the augmented system by a descriptor system and designing a H_âˆžfilterwhich guarantees the performance level for the descriptor model. The numerical exampleis provided to demonstrate the effectiveness of the proposed method.The other important content is about robust filtering for nonlinear system. TS fuzzy model is used to describe kinds of nonlinear systems. The delaydependent H_âˆžfilter forcontinuous time delay TS fuzzy model and discrete time delay uncertainty TS fuzzymodel are studied respectively, the sufficient condition is given, and the method isdeveloped by considering time delays. We studied robust H_âˆžfiltering for a descriptornonlinear timedelay system based on TS fuzzy model. The fuzzy filter can insure theerror filtering system is regular, impulsefree and asymptotically stable.  Keywords/Search Tags:  timedelay system, nonlinear system, neutral system, distributed delay, TS fuzzy model, parameter uncertainty, robust filtering, robust control, H_âˆžcontrol, linear matrix inequality (LMI), Riccati equation, timevarying system, Lyapunov function  PDF Full Text Request  Related items 
 
