Digital controller design for sampled-data nonlinear systems

Download
2012
Üstüntürk, Ahmet
In this thesis, digital controller design methods for sampled-data nonlinear systems are considered. Although sampled-data nonlinear control has attracted much attention in recent years, the controller design methods for sampled-data nonlinear systems are still limited. Therefore, a range of controller design methods for sampled-data nonlinear systems are developed such as backstepping, adaptive and robust backstepping, reduced-order observer-based output feedback controller design methods based on the Euler approximate model. These controllers are designed to compensate the effects of the discrepancy between the Euler approximate model and exact discrete time model, parameter estimation error in adaptive control and observer error in output feedback control which behave as disturbance. A dual-rate control scheme is presented for output-feedback stabilization of sampled-data nonlinear systems. It is shown that the designed controllers semiglobally practically asymptotically (SPA) stabilize the closed-loop sampled-data nonlinear system. Moreover, various applications of these methods are given and their performances are analyzed with simulations.

Suggestions

Investigation of decoupling techniques for linear and nonlinear systems
Kalaycıoğlu, Taner; Özgüven, Hasan Nevzat; Department of Mechanical Engineering (2018)
Structural coupling methods are widely used in predicting dynamics of coupled systems. In this study, the reverse problem, i.e. predicting the dynamic behavior of a particular subsystem from the knowledge of the dynamics of the overall system and of all the other subsystems, is studied. This problem arises when a substructure cannot be measured separately, but only when coupled to neighboring substructures. The dynamic decoupling problem of coupled linear structures is well investigated in literature. Howev...
Model Updating of a Nonlinear System: Gun Barrel of a Battle Tank
Canbaloglu, Guvenc; Özgüven, Hasan Nevzat (2016-01-28)
Nonlinearities in a structural system make the use of model updating methods developed for linear systems difficult to apply nonlinear systems. If the FRFs of the underlying linear systems in a nonlinear system could be experimentally extracted, then the linear model updating methods could easily be applied to nonlinear systems as well. When there are complex nonlinearities in a structure together with frictional type of nonlinearity, linear FRFs cannot be accurately obtained by using low level forcing. In ...
Adaptive output feedback control with reduced sensitivity to sensor noise
Kutay, Ali Türker; Hovakimyan, N (2003-01-01)
We address adaptive output feedback control of uncertain nonlinear systems with noisy output measurements, in which both the dynamics and the dimension of the regulated system may be unknown, and only the relative degree of the regulated output is assumed to be known. Given a smooth reference trajectory, the problem is to design a controller that forces the system measurement to track it with bounded errors. A recently developed method proposes the use of a linear error observer that estimates the tracking ...
A Control System Architecture for Control of Non-Affine in Control, Open-Loop Unstable Underactuated Systems
Marangoz, Alp; Kutay, Ali Türker (2017-07-25)
In this paper, a control system architecture for control of non-affine in control, open-loop unstable underactuated system is discussed. Passivization of the unactuated (internal) system dynamics achieved through perturbation of trajectories of the actuated states, which are calculated through adaptive dynamic inversion technique, based on Tikhonov's theorem. Performance of the controller is shown through simulation of two open-loop unstable and locally uncontrollable example problems.
Distributed inelasticity planar frame element with localized semi-rigid connections for nonlinear analysis of steel structures
Sarıtaş, Afşin (2015-06-01)
A macro-element model with spread of inelasticity and localized nonlinear semi-rigid hinges is presented in this paper. The element is formulated through force-based approach. Spread of inelasticity along element length and section depth is captured by fiber discretization of monitoring sections, and introduction of localized connections enable representation of any type of linear or nonlinear semi-rigid (partially restrained) connection behavior along element length without any increase in number of degree...
Citation Formats
A. Üstüntürk, “Digital controller design for sampled-data nonlinear systems,” Ph.D. - Doctoral Program, Middle East Technical University, 2012.