Output Feedback Regulation For Several Classes Of Feedforward Nonlinear Systems  Posted on:20160426  Degree:Doctor  Type:Dissertation  Country:China  Candidate:W Y Yu  Full Text:PDF  GTID:1108330461485541  Subject:Control theory and control engineering  Abstract/Summary:  PDF Full Text Request  In the real world, since many physical systems, for instance, the ball and beam system and the cartpendulum system, can be transformed to feedforward nonlinear systems, which are also called uppertriangular systems, the regulation or stabilization problems of feedforward nonlinear systems have attracted much attention from the nonlinear control community. This dissertation is concerned with the problem of output feedback regulation for several classes of uncertain nonlinear systems whose structure is more general form than feedforward nonlinear systems. The main contents of the dissertation are as follows:1. Adaptive output feedback regulation for a class of uncertain nonlinear systemsThe problem of global state regulation by output feedback is investigated for a class of uncertain nonlinear systems satisfying some relaxed uppertriangulartype condition. The uncertainties of the considered systems are bounded by unmeasured states with growth function of input multiplying an unknown constant. Based on a linearlike observer with two dynamic gains, the linearlike output feedback controller is explicitly constructed. It is proved that the proposed adaptive controller guarantees that all the states of the closedloop system are globally bounded and the states of the original systems converge to zero. It is worth pointing out that, By redefining an unknown constant and a known function, the continuous function of the dynamic equation of the gain can be appropriately chosen such that the amplitude values of the states of the closedloop system are acceptable.2. Disturbance attenuation via output feedback for nonlinear systems with output and input depending growth functionThe problem of output feedback disturbance attenuation is addressed for a class of uncertain nonlinear systems. The uncertainties of the considered systems are bounded by unmeasured states with growth function of output and input multiplying an unknown constant. The uncertainties associated with the disturbance are bounded by an unknown constant multiplying growth function of output and input. Based on a dynamic gain observer, an adaptive output feedback controller is proposed such that the states of the closedloop system are globally bounded, and the disturbance attenuation is achieved in the L2gain sense. Furthermore, if the disturbance is uniformly bounded and square integrable on the infinite interval, then the states of the original systems converge to zero. Compared with the previous works, the stability analysis of the closedloop system is more complicated due to the presence of the disturbance and a growth function depending on the input and output.3. Global output feedback regulation of uncertain nonlinear timedelay systemsThe problem of global output feedback regulation is studied for two classes of nonlinear systems with unknown time delay. Firstly, for a class of nonlinear timedelay systems, the adaptive output feedback controller is explicitly constructed. Strictly speaking, the uncertain delay is not included in the inputs of the considered timedelay systems. By using the dynamic gain scaling technique and choosing an appropriate LyapunovKrasovskii functional, it is proved that the proposed controller can make all the states of the considered timedelay systems converge to zero while maintaining global boundedness of the closedloop system. Then, by using the appropriate state transformation, the output feedback regulation problem is also solved by the preceding controller for a class of more general uncertain nonlinear systems with delay in the input.4. Adaptive output feedback regulation for largescale uncertain nonlinear systems with time delaysThe problem of adaptive output feedback regulation is considered for largescale uncertain nonlinear systems with time delays in the states and inputs. The systems are assumed to be bounded by a class of feedforward systems satisfying a linear growth condition in the unmeasurable states multiplying by unknown growth rates and continuous functions of the inputs or delayed inputs. Under two dif ferent assumptions, the delaydependent output feedback controller and the delayindependent output feedback controller design approaches are proposed. Firstly, by using a series of coordinate transformation and choosing the appropriate LyapunovKrasovskii functionals, the delaydependent adaptive controller is explicitly constructed such that all the states of the closedloop system are globally bounded and the states of largescale uncertain systems converge to zero. Then, under a strict assumption, it is proved that the adaptive output feedback problem of the considered timedelay systems can be solved by a delayindependent adaptive controller.To sum up, the output feedback regulation problem is solved by using the dynamic gain scaling technique for several classes of uncertain nonlinear systems in this dissertation, which promote the development of theoretical research of feedforward nonlinear systems.  Keywords/Search Tags:  Output feedback regulation, timedelay systems, adaptive control, un certain nonlinear systems, feedforward nonlinear systems, largescale systems, dy namic gain scaling technique  PDF Full Text Request  Related items 
 
