Demircioḡlu, Hüseyin (1989) Continuoustime selftuning algorithms. PhD thesis, University of Glasgow.
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Abstract
This thesis proposes some new selftuning algorithms. In contrast to the conventional discretetime approach to selftuning control, the continuoustime approach is used here, that is continuoustime design but digital implementation is used. The proposed underlying control methods are combined with a continuoustime version of the wellknown discrete recursive least squares algorithms. The continuoustime estimation scheme is chosen to maintain the continuoustime nature of the algorithms. The first new algorithm proposed is emulatorbased relay control (which has already been described in a paper by the author). The algorithm is based on the idea of constructing the switching surface by emulators; that is, unrealisable output derivatives are replaced by their emulated values. In particular, the relay is forced to operate in the sliding mode. In this case, it is shown that emulatorbased control and its proposed relay version become equivalent in the sense that both give the same control law. The second new algorithm proposed is a continuoustime version of the discretetime generalized predictive control (GPC) of Clarke et al (which has already been described in a paper by the author). The algorithm, continuoustime generalized predictive control (CGPC), is based on similar ideas to the GPC, however the formulation is very different. For example, the output prediction is accomplished by using the Taylor series expansion of the output and emulating the output derivatives involved. A detailed closedloop analysis of this algorithm is also given. It is shown that the CGPC control law only changes the closedloop pole locations leaving the openloop zeros untouched (except one special case). It is also shown that LQ control can be considered in the CGPC framework. Further, the CGPC is extended to include some design polynomials so that the modelfollowing and poleplacement control can be considered in the same framework. A third new algorithm, a relay version of the CGPC, is described. The method is based on the ideas of the emulatorbased relay control and again it is shown that the CGPC and its relay version become equivalent when the relay operates in the sliding mode. Finally, the CGPC ideas are extended to the multivariable systems and the resulting closedloop system is analysed in some detail. It is shown that some special choice of design parameters result in a decoupled closedloop system for certain systems. In addition, it is shown that if the system is decouplable, it is possible to obtain modelfollowing control. It is also shown that LQ control, as in the scalar case, can be considered in the same framework. An illustrative simulation study is also provided for all of the above methods throughout the thesis.
Item Type:  Thesis (PhD) 

Qualification Level:  Doctoral 
Subjects:  T Technology > TJ Mechanical engineering and machinery Q Science > QA Mathematics 
Colleges/Schools:  College of Science and Engineering > School of Engineering 
Supervisor's Name:  Gawthrup, Prof. P.J. 
Date of Award:  1989 
Depositing User:  Elaine Ballantyne 
Unique ID:  glathesis:19892174 
Copyright:  Copyright of this thesis is held by the author. 
Date Deposited:  12 Oct 2010 
Last Modified:  10 Dec 2012 13:52 
URI:  http://theses.gla.ac.uk/id/eprint/2174 
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