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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Identification and self-adaptive control

Batur, Celal January 1975 (has links)
Identification requires assumptions about the unknown disturbance. For an open loop identification experiment, the disturbance and the input are physically independent. Therefore the most reasonable assumption is one of statistical independence. The estimation technique presented in the first part of the thesis exploits the statistical independence to reduce parameter estimation errors. The resulting algorithm is identical to that of the two stage least squares method [30].;Nevertheless it is believed that the original aspect of the approach is the treatment of the disturbance. In practice it is often desirable to avoid open loop experimentations due to economic and safety restrictions. In the second part of the thesis, the identifiability problem for the Box and Jenkins feedback control system is re-examined to extend the previous work of Turtle [52]. Based on a new estimation error equation, a self-adaptive optimization procedure is proposed. However due to doubts concerning stability and convergence, the procedure is not, at the moment, sufficiently well-developed for practical applications.;The final part of the thesis investigates the possibility of estimating the process and disturbance dynamics by use of an external perturbation signal while the process is operating under the Box and Jenkins control system. It is shown that a correlation analysis can produce consistent estimates. However for a limited amount of data these estimates are, in general, biased and hence do not always produce an optimum control system. Nevertheless further improvement can be achieved by applying the predictor updating procedure of Turtle [52] after the correlation analysis.
2

Distributed parameter theory in optimal control

Gregson, M. J. January 1979 (has links)
The main result of this work is the solution of open loop optimal control problems for counterflow diffusion processes, which occur very widely in chemical and mechanical engineering. In these processes two fluids pass each other moving in opposite directions separated by a membrane which is permeable to heat or a chemical solute. The membrane may also take the form of a liquid-gas interface. Subject to certain simplifying assumptions, the equations describing such processes are 01 (x,t), 02 (x,t) are the temperatures, or concentrations of solute, of the two fluids and u(t), v(t) are time dependent flow rates. k is a transfer coefficient which is assumed constant, and C1, C2 are thermal or solute capacities of the fluids per unit length of tube. h is an equilibrium constant; h = 1 for heat transfer. Possible controls are the inlet temperature or concentration of one stream and the flow rates, while possible objectives are the regulation of the outlet temperature or concentration of the other stream, or the maximisation of heat or solute transfer. Subsidiary results are the optimal control of simpler but related hyperbolic systems. One of these is the restricted counterflow problem in which the controlling stream is assumed to be so massive that it is unaffected by giving up heat or solute to the controlled stream, i.e. the system is described by the equations ; Another is the furnace equation in which u and w are possible controls. Different classes of problem arise according to whether the multiplicative controls u and v are subject to rigid constraints (frequently leading to "bang-bang" controls), or whether they are constants, functions of x and t, or functions of t only. Variational methods based on the maximum principle of A.I. Egorov are employed. Analytic solutions and numerical solutions using finite differences are obtained to the various problems. The simplifying assumptions made are probably too severe for many of the results to be directly applicable to industry. However the qualitative features of the optimal control of these processes are explained, and it is not too difficult to build more complex models.
3

Optimum shape problems in distributed parameter control theory

Girgis, Siham Boctor January 1979 (has links)
The work is concerned with optimum shape problems in the distributed parameter area and it consists of four parts. In Part I we consider first the basic variational theory due to Gelfand and Fomin emphasising the importance of the transversality condition in optimum shape situations; also in Part I we discuss an application of the basic theory in a particular problem where the state equations (the constraints) are hyperbolic in character. In Part II we consider a heat transfer problem between two streams of different temperatures, moving parallel to one another and with constant speeds, the aim being to choose the inlet conditions of one stream in order to achieve desired outlet conditions for the other stream. Two different aspects of the heat transfer problem are considered. In Part III we consider a hydrodynamic problem using shallow water theory in which we seek the optimum shape of a harbour boundary in order to redistribute the liquid energy in some desired way. Here one-dimensional and two-dimensional aspects of the problem are discussed, in the former fairly precise results are achieved, and in the latter the solution of the problem is shown to depend on the solution of coupled integral equations. In Part IV we consider the problem of optimum shape of an axially symmetric elastic body (subject to the classical equations of elasticity) in order to minimise the axial moment of inertia or the weight of the body. An approximate method for finding the optimum shape is presented though considerable work remains to be done in this problem.
4

Integrated process and control system design

Laing, D. Murray January 1995 (has links)
To support concurrent design a framework for hierarchical design of a <I>process operating system</I> is developed. A process operating system is defined as the complete collection of control schemes, alarms and operating procedures used for managing the process through all phases of operation. The design of an integrated operating system is approached by decomposing the problem into a hierarchy of operating tasks. Three classes of operating task are identified: regulatory tasks for optimising operation at a steady state, transition tasks for transferring the process from one regulatory state to another and executive tasks which manage the response to discrete events such as alarms and failures. Operating tasks define the requirements for optimisation and failure management. The implementation of an operating task is achieved by the design of a <I>control scheme</I> for which a generic structure has been developed. The structure emphasises the use of explicit models with <I>parameter estimation</I> and <I>control distribution</I> blocks providing the interface between the abstract model used for optimisation and the reality of the underlying system. A knowledge based representation has been developed to support operating system design. Particular attention has been given to the problem of supporting concurrent design of the process and operating system. A representation has been developed that links process design alternatives with operating system design alternatives by their association with a common operating task. A case study that considers the design of a hierarchical operating system for a hydrofluoric acid plant is included in this thesis. The study demonstrates how the operating system may be developed in step with the process design. The hierarchical development of the process is used to help formulate the operating tasks for the operating system design. Through design of the operating system it is possible to provide focused feedback on the process operability requirements. The final operating system structure demonstrates how failure management and optimisation are integrated together.
5

The computation of eigenvalues and eigenvectors of very large sparse matrices

Paige, Christopher Conway January 1971 (has links)
Several methods are avi1iible for computing elgenvalues and eigenveotors of large sparse matrices, but as yet no outstandingly good algorithm is generally known. For the synimetric matrix case one of the most elegant algorithms thetiretically is the method of m1rini1zed iterations developed by Lanczos in 1950 • This method reduces the origi1 matrix to tn-diagonal form from which the eigenaystem can easily be found. The method can be used iteratively, and here the convergence properties and different possible eigenvalue intervals are first considered assiinrtng infinite precision computation. Next rounding error pn1 yses are given for the method both with and without re-orthogonalization. It is shown that the method has been unjustly neglected, in fact a particular computational algorithm for the method without re-orthogoiiRl I zation is shown to have remarkably good error properties. As well as this the algorithm is very fast aM can be pronamined to require very little store compared with other comparable methods, and this suggests that this variant of the Lanczos process is likely to become an extremely useful algorithm for finding several extreme eigenvalues, and their eigenvectors if needed, of very large sparse symmetric matrices.
6

Resource allocation in systems of queues

Farrar, Timothy Martin January 1992 (has links)
No description available.
7

Modelling and multiarm robot manipulation of non-rigid materials

Lichon, Mariusz January 2001 (has links)
No description available.
8

The use of virtual environments in internet-based teleoperation

Tan, Jiacheng January 2001 (has links)
No description available.
9

Novel displacement sensing : towards robotic tunnelling

Dudeney, William Leonard January 2001 (has links)
No description available.
10

How manufacturing can learn from nature : exploration of ecological resilience

Wolfer, Stephan January 2006 (has links)
No description available.

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