Spelling suggestions: "subject:"lyapunov stability"" "subject:"yapunov stability""
21 
Design of Model Reference Adaptive Tracking Controllers for Mismatch Perturbed Nonlinear Systems with Nonlinear InputsSu, TaiMing 03 May 2004 (has links)
A simple design methodology of optimal model reference adaptive control (OMRAC) scheme with perturbation estimation for solving robust tracking problems is proposed in this thesis. The plant to be controlled belongs to a class of MIMO perturbed dynamic systems with input nonlinearity and time varying delay. The proposed robust tracking controller with a perturbation estimation scheme embedded is designed by using Lyapunov stability theorem. The control scheme contains three types of controllers. The first one is a linear feedback optimal controller, which is designed under the condition that no perturbation exists. The second one is an adaptive controller, it is used for adapting the unknown upper bound of perturbation estimation error. The third one is the perturbation estimation mechanism. The property of uniformly ultimately boundness is proved under the proposed control scheme, and the effects of each design parameter on the dynamic performance is also analyzed. An example is demonstrated for showing the feasibility of the proposed control scheme.

22 
Design of the nth Order Adaptive Integral Variable Structure Derivative EstimatorShih, WeiChe 17 January 2009 (has links)
Based on the Lyapunov stability theorem, a methodology of designing an nth order adaptive integral variable structure derivative estimator (AIVSDE) is proposed in this thesis. The proposed derivative estimator not only is an improved version of the existing AIVSDE, but also can be used to estimate the nth derivative of a smooth signal which has continuous and bounded derivatives up to n+1. Analysis results show that adjusting some of the parameters can facilitate the derivative estimation of signals with higher frequency noise. The adaptive algorithm is incorporated in the estimation scheme for tracking the unknown upper bounded of the input signal as well as their's derivatives. The stability of the proposed derivative estimator is guaranteed, and the comparison between recently proposed derivative estimator of highorder sliding mode control and AIVSDE is also demonstrated.

23 
Formation control of mobile robots and unmanned aerial vehiclesDierks, Travis January 2009 (has links) (PDF)
Thesis (Ph. D.)Missouri University of Science and Technology, 2009. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed January 13, 2009) Includes bibliographical references.

24 
Stability of a Fuzzy Logic Based Piecewise Linear Hybrid SystemSeyfried, Aaron W. 01 June 2013 (has links)
No description available.

25 
Nonlinear dynamical systems and control for largescale, hybrid, and network systemsHui, Qing January 2008 (has links)
Thesis (Ph.D.)Aerospace Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Haddad, Wassim; Committee Member: Feron, Eric; Committee Member: JVR, Prasad; Committee Member: Taylor, David; Committee Member: Tsiotras, Panagiotis

26 
Análise de estabilidade de sistemas dinâmicos descontínuos e aplicações /Santos, Iguer Luis Domini dos. January 2008 (has links)
Resumo: Neste trabalho introduzimos uma classe de sistemas dinâmicos descontínuos com espaço tempo contínuo e analisamos Teoremas que asseguram condições suficientes para a estabilidade de Lyapunov utilizando funções de Lyapunov. Além disso, consideramos também Teoremas de Recíproca, que sob algumas condições garantem uma determinada necessidade para esses Teoremas de estabilidade de Lyapunov. / Abstract: In this work we introduce a class of discontinuous dynamical systems with time space continuous and we analyze Theorems that ensure sufficient conditions for the Lyapunov stability using Lyapunov functions. Moreover, we also consider Converse Theorems, which under some conditions guarantee a determined necessity for those Theorems of Lyapunov stability. / Orientador: Geraldo Nunes Silva / Coorientador: Luis Antônio Fernandes de Oliveira / Banca: Luis Antônio Barrera San Martin / Banca: Adalberto Spezamiglio / Mestre

27 
A study of a class of invariant optimal control problems on the Euclidean group SE(2)Adams, Ross Montague January 2011 (has links)
The aim of this thesis is to study a class of leftinvariant optimal control problems on the matrix Lie group SE(2). We classify, under detached feedback equivalence, all controllable (leftinvariant) control affine systems on SE(2). This result produces six types of control affine systems on SE(2). Hence, we study six associated leftinvariant optimal control problems on SE(2). A leftinvariant optimal control problem consists of minimizing a cost functional over the trajectorycontrol pairs of a leftinvariant control system subject to appropriate boundary conditions. Each control problem is lifted from SE(2) to T*SE(2) ≅ SE(2) x se (2)*and then reduced to a problem on se (2)*. The maximum principle is used to obtain the optimal control and Hamiltonian corresponding to the normal extremals. Then we derive the (reduced) extremal equations on se (2)*. These equations are explicitly integrated by trigonometric and Jacobi elliptic functions. Finally, we fully classify, under Lyapunov stability, the equilibrium states of the normal extremal equations for each of the six types under consideration.

28 
On the use of fuzzy logic to control paralleled DCDC convertersTomescu, Bogdan 25 October 2001 (has links)
The objective of the thesis is to introduce a new fuzzy logic control application, develop the associated mathematical theory and prove the concept and its advantages through comparative simulation with existing, classical, methods. A stable fuzzy logic controller for the masterslave current sharing loop of a paralleled DCDC system is presented that exhibits a considerably improved large signal performance over the presently employed, small signal designed compensators, both in terms of system response and control effort. Because of high system complexity, the present small signal designs are unable to give a good response for large load changes and line transients. Fuzzy logic, by dealing naturally with nonlinearities, offers a superior controller type, for this type of applications. The design uses a PID expert to derive the fuzzy inference rules, and simulation results show a good parameter insensitive transient response over a wide range loadstep responses, e.g., from 25% to 75% of the nominal load. Current sharing control is formulated as a tracking problem and stability is ensured through adaptation or supervisory control on a Lyapunov trajectory. The technique benefits also from the heuristic approach to the problem that overcomes the complexity in modeling such systems and, hence, offers a practical engineering tool, amenable to both analog and digital implementations. / Ph. D.

29 
The paradox of enrichment in predatorprey systemsSogoni, Msimelelo January 2020 (has links)
>Magister Scientiae  MSc / In principle, an enrichment of resources in predatorprey systems show prompts
destabilisation of a framework, accordingly, falling trophic communication, a phenomenon
known to as the \Paradox of Enrichment" [54]. After it was rst genius postured by
Rosenzweig [48], various resulting examines, including recently those of MougiNishimura
[43] as well as that of BohannanLenski [8], were completed on this problem over
numerous decades. Nonetheless, there has been a universal none acceptance of the
\paradox" word within an ecological eld due to diverse interpretations [51].
In this dissertation, some theoretical exploratory works are being surveyed in line with
giving a concise outline proposed responses to the paradox. Consequently, a quantity of
di usiondriven models in mathematical ecology are evaluated and analysed.
Accordingly, piloting the way for the spatial structured pattern (we denote it by SSP)
formation in nonlinear systems of partial di erential equations [36, 40].
The central point of attention is on enrichment consequences which results toward
a paradoxical state. For this purpose, evaluating a number of compartmental models in
ecology similar to those of [48] will be of great assistance. Such displays have greater
in
uence in pattern formations due to diversity in metapopulation.
Studying the outcomes of initiating an enrichment into [9] of Braverman's model,
with a nutrient density (denoted by n) and bacteria compactness (denoted by b)
respectively, suits the purpose. The main objective behind being able to transform [9]'s
system (2.16) into a new model as a result of enrichment. Accordingly, n has a logistic
type growth with linear di usion, while b poses a Holling Type II and nonlinear
di usion r2 nb2 [9, 40].
Five fundamental questions are imposed in order to address and guide the study in
accordance with the following sequence:
(a) What will be the outcomes of introducing enrichment into [9]'s model?
(b) How will such a process in (i) be done in order to change the system (2.16)'s stability
state [50]?
(c) Whether the paradox does exist in a particular situation or not [51]? Lastly,
(d) If an absurdity in (d) does exist, is it reversible [8, 16, 54]?
Based on the problem statement above, the investigation will include various matlab
simulations. Therefore, being able to give analysis on a local asymptotic stability state
when a small perturbation has been introduced [40]. It is for this reason that a bifurcation
relevance comes into e ect [58]. There are principal de nitions that are undertaken as
the research evolves around them.
A study of quantitative response is presented in predatorprey systems in order to
establish its stability properties. Due to tradeo s, there is a great likelihood that the
growth rate, attack abilities and defense capacities of species have to be examined in line
with reviewing parameters which favor stability conditions. Accordingly, an investigation
must also re
ect chances that leads to extinction or coexistence [7].
Nature is much more complex than scienti c models and laboratories [39]. Therefore,
di erent mechanisms have to be integrated in order to establish stability even when a
system has been under enrichment [51]. As a result, SSP system is modeled by way of
reactiondi usion di erential equations simulated both spatially and temporally.
The outcomes of such a system will be best suitable for realworld life situations which
control similar behaviors in the future. Comparable models are used in the main
compilation phase of dissertation and truly re
ected in the literature. The SSP model
can be regarded as between (20182011), with a stability control study which is of an
original.

30 
Design of Adaptive Block Backstepping Controllers for Perturbed Nonlinear Systems with Input NonlinearitiesChien, ChiaWei 01 February 2012 (has links)
Based on the Lyapunov stability theorem, a design methodology of adaptive block backstepping control scheme is proposed in this thesis for a class of multiinput perturbed nonlinear systems with input nonlinearities to solve regulation problems. Fuzzy control method is utilized to estimate the unknown inverse input functions in order to facilitate the design of the proposed control scheme, so that the sector condition need not to be satisfied. According to the number of block m in the plant to be controlled, m−1 virtual input controllers are designed from the first block to the (m−1)th block. Then the proposed robust controller is designed from the last block. Adaptive mechanisms are also employed in the virtual input controllers as well as the robust controller, so that the least upper bounds of perturbations and estimation errors of inverse input functions are not required. The resultant control system is able to achieve asymptotic stability. Finally, a numerical example and a practical example are given for demonstrating the feasibility of the proposed control scheme.

Page generated in 0.1117 seconds