Thesis (Ph. D.)--University of Sydney, 1992. / Includes tables. Bibliography: leaves 401-409. Also available in print form.

Thesis (M.S.)--University of Wisconsin--Madison, 1983. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 116-117).

Thesis (D.Eng.)--Cleveland State University, 2009. / Abstract. Title from PDF t.p. (viewed on Oct. 26, 2009). Includes bibliographical references (p. 78-89). Available online via the OhioLINK ETD Center and also available in print.

Predictive control has attracted much attention from both industry and academia alike due to its intuitive time domain formulation and since it easily affords adaption. The time domain formulation enables the user to build in prior knowledge of the operating constraints and thus the process can be controlled more efficiently, and the adaptive mechanism provides tighter control for systems whose behaviour changes with time. This thesis presents a fusion of technologies for dealing with the more practical aspects of obtaining suitable models for predictive control, especially in the adaptive sense. An accurate model of the process to be controlled is vital to the success of a predictive control scheme, and most the of work to date has assumed that this model is of fixed order, a restriction which can lead to poor controller performance associated with under/overparameterisation of the estimated model. To overcome this restriction a strategy which estimates both the parameters and the order of a linear model of the time-varying plant online is suggested. This Multiple Model Least-Squares technique is based on the recent work of Niu and co-workers who have ingeniously extended Bierman's method of UD updating so that, with only a small change to the existing UD update code, a wealth of additional information can be obtained directly from the U and D matrices including estimates of all the lower order models and their loss functions. The algorithm is derived using Clarke's Lagrange multiplier approach leading to a neater derivation and possibly a more direct understanding of Niu's Augmented UD Identification algorithm. An efficient and robust forgetting mechanism is then developed by analysing the properties of the continuous-time differential equations corresponding to existing parameter tracking methods. The resulting Multiple Model Recursive Least-Squares estimator is also ported to the δ-domain in order to obtain models for predictive controllers that employ fast sampling. The MMRLS estimator is then used in an adaptive multiple model based predictive controller for a coupled tanks system to compare performance with the fixed model order case.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references and index.

Thesis (M.S.)--Ohio University, June, 1995. / Title from PDF t.p.

This Thesis is concerned with model-based control, where models of linear nonminimal state-space (NMSS) and nonlinear state-dependent parameter (SDP) form are considered. In particular, the focus is on model-based predictive control (MPC) in conjunction with the linear NMSS model and on proportional-integralplus (PIP) pole-assignment control in conjunction with the SDP model. The SDP-PIP pole-assignment controller is based on a nonlinear SDP model, however, the approach uses a linear pole-assignment controller design technique. This ‘potential paradox’ is addressed in this Thesis. A conceptual approach to realising the SDP-PIP pole-assignment control is proposed, where an additional conceptual time-shift operator is introduced. This allows the SDPPIP, at each sampling time instance, to be considered as an equivalent linear controller, while operating, in fact, in a nonlinear overall context. Additionally, an attempt to realise SDP-PIP control, where the SDP model exhibits equivalent linear system numerator zeros, is proposed. Regarding the NMSS MPC, emphasis is on square, i.e. equal number of inputs and outputs, multi-input multi-output (MIMO) modelled systems, which exhibit system output cross-coupling effects. Moreover, the NMSS MPC in incremental input form and making use of an integral-of-errors state variable, is considered. A strategy is proposed, that allows decoupling of the system outputs by diagonalising the closed-loop system model via an input transformation. A modification to the NMSS MPC in incremental input form is proposed such that the transformed system input - system output pairs can be considered individually, which allows the control and prediction horizons to be assigned to the individual pairs separately. This modification allows imposed constraints to be accommodated such that the cross-coupling effects do not re-emerge. A practical example is presented, namely, a DC-DC boost converter operating in discontinuous conduction mode (DCM), for which a SDP model is developed. This model is based on measured input-output data rather than on physical relationships. The model incorporates the output current so that the requirements for the load, driven by the converter, is constrained to remain within a predefined output current range. The proposed SDP model is compared to an alternative nonlinear Hammerstein-bilinear structured (HBS) model. The HBS model is, in a similar manner to the SDP model, also based on measured input-output data. Moreover, the differences as well as the similarities of the SDP and HBS model are elaborated. Furthermore, SDP-PIP pole-assignment control, based on the developed SDP model, is applied to the converter and the performance is compared to baseline linear PIP control schemes.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references and index.

Thesis (Ph. D.)--Industrial and Systems Engineering, Georgia Institute of Technology, 2005. / Victoria Chen, Committee Co-Chair ; Kwok Tsui, Committee Chair ; Janet Allen, Committee Member ; David Goldsman, Committee Member ; Roshan Vengazhiyil, Committee Member. Vita. Includes bibliographical references.

Les propriétés généralement demandées aux armatures pour béton armé doivent répondre à des exigences particulières précisées dans des normes nationales, européennes et internationales. Actuellement, dans la pratique de la production de l'acier à béton, on tend à substituer différentes nuances d'armature par une armature unifiée ayant une valeur de limite d'élasticité minimale de 500 MPa. Le remplacement des ronds à béton de nuance 400MPa par cette armature conduit à une économie de métal de l'ordre de 10-20 % d'après les estimations de différents spécialistes.Il existe, généralement, plusieurs techniques de fabrication des armatures, dont la déformation à chaud suivie d'un refroidissement accéléré sous flux d'eau (traitement thermomécanique ou Thermomechanical Control Process - TMCP), ainsi que la déformation à froid (tréfilage â travers une filière conique et une filière à rouleaux, microlaminage...), qui se heurte cependant â l'impossibilité de satisfaire aux exigences des Normes vis-à-vis des propriétés de résistance (Re > 500MPa) et de plasticité.Le présent travail a pour but le développement d'un procédé combiné de production d'acier à béton profitant des aspects positifs de deux types de déformation à chaud ainsi qu'à froid, sous forme du traitement combiné mécano-thermomécanique (post déformations à froid après le TMCP). et d'étudier la possibilité de production d'aciers à béton de qualité 500 MPa (B(A)500), de petits diamètres, en couronne, répondant aux exigences des Normes modernes. L'objectif scientifique de ce travail est d'étudier les mécanismes microstructuraux qui se produisent lors de la déformation à froid de l'acier préalablement traité thermomécaniquement et leurs conséquences sur l'évolution des propriétés mécaniques.Plusieurs nuances d'acier bas carbone de différents diamètres ont été étudiées. De nombreuses techniques de caractérisation macroscopique et microscopique de la structure de l'acier ont été utilisées: traction monotone, essais de microdureté, microscopie optique, microscopie électronique â balayage (MEB) et en transmission (MET), diffraction des rayons X. spectrométrie mécanique..Les résultats des essais montrent qu'il est possible d'obtenir avec assurance l’armature de qualité B(A)500, possédant des propriétés mécaniques qui dépassent les exigences des nonnes, à l'aide d’une déformation par torsion avec un cisaillement maximal de 22%, pour des aciers à 0.15 -0.2 % C(en poids), faiblement alliés en Mn et Si et traités themomécaniquement. La déformation par torsion provoque une augmentation de dureté en surface mais aussi au cœur de l'armature. Cette augmentation de dureté à cœur peut être amplifiée par le traitement thermique de vieillissement à 100°C correspondant à l'utilisation en Génie Civil. Cet effet, lié aux interactions dislocation-impuretés interstitielles, a été expliqué grâce â la MET et à l'étude du frottement intérieur. / Properties which are required from an armature for the reinforced concrete should satisfy the requirements of National, European and International standards. At the present time, in practice of armature production, there is a tendency of replacement of various classes of reinforcing steels by the unified armature with the minimum value of yield strength of 500 MPa. Replacement of the armature of the 400 MPa class by such reinforcing steel brings the economy of metal of an order of 10-20 % according to the estimations of various experts.In general, a set of production technologies of the armature exists, including hot deformation with the subsequent accelerated cooling in water - Thermomechanical Control Process (TMCP), and also cold deformation (drawing in conic die block, drawing in roller die block, microrolling) which nevertheless face the impossibility to provide the required strength (yield strength > 500MPa) and plastic properties.The technological purpose of the given work is:- development of the combined mechano-thermomechanical processing of armature's production which would combine positive aspects of hot and cold deformations (post deformation processing after TMCP);- examination of possibilty to manufacture the reinforcing steel of the class of 500MPa (B(A)500) of the small diameter, in coils, meeting the requirements of modem standards.The scientific objective of the work is the analysis of change of the microstructure of reinforcing steels after the cold deformation which is preliminary subjected to thermomechanical processing, and, also, the examination of the influence of microstructural effect on change of mechanical properties of steels.In the present study, a significant quantity of grades of low-carbon steels of various diameters has been investigated. Also, different techniques for macroscopical and microscopical characterization of the steel structures have been applied: tensile tests, micro-hardness test, optical microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray analysis and mechanical spectroscopy.Results of tests show that it is possible to obtain, with assurance, the reinforcing steel of the strength class B(A)500, with a complex of the mechanical properties surpassing the requirements of standards. For this purpose it is proposed to use the deformation by cold torsion with the maximum relative shear of 22 %, after thermomechanical processing, for steels with carbon content of 0,15...0,25% and alloyed with Mn and Si. Deformation by torsion provides an increase of hardness not only on the surface, but also in the core of armature. The effect of hardness increase can be strengthened by means of thermal ageing at 100°C corresponding to the use in Civil Engineering. This effect, related to the dislocations- interstitial impurities interactions, was explained thanks to MET and internal friction effect.