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Non-linear on-line identifiers and adaptive control systems. Butler, Robert Ewart
Abstract
It is assumed that processes to be identified or controlled can be described by linear or non-linear differential equations with unknown coefficients aᵢ. For on-line identifications a model is constructed to have the same form of differential equation as the process, but with adjustable parameters αᵢ replacing the aᵢ. The parameters αᵢ are adjusted in a steepest descent fashion; they are shown to converge to the aᵢ as long as an adjustment gain K(t) is non-negative, and not identically zero. An approximate analysis is carried out to determine the best constant K which gives the fastest identification. Optimal control theory is introduced to find the best piecewise continuous K(t) in the interval 0 ≤ K(t) ≤ Kmax . From the exact solution in a special case, a switched suboptimal K which always gives fast identification is determined. Identification schemes are developed for processes which include an unknown non-linearity that, can be assumed to be piecewise linear. An adaptive control, system is developed to control processes with unknown time-varying coefficients. The system is shown to be stable as long as the process inverse is stable; the process need not be stable. Systems to control linear and non-linear unstable processes are designed and simulated. The limitations of the adaptive system are determined, and compared with the limitations of conventional feedback systems.
Item Metadata
Title |
Non-linear on-line identifiers and adaptive control systems.
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1966
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Description |
It is assumed that processes to be identified or controlled can be described by linear or non-linear differential equations with unknown coefficients aᵢ. For on-line identifications a model is constructed to have the same form of differential equation as the process, but with adjustable parameters αᵢ replacing the aᵢ. The parameters αᵢ are adjusted in a steepest descent fashion; they are shown to converge to the aᵢ as long as an adjustment gain K(t) is non-negative, and not identically zero.
An approximate analysis is carried out to determine the best constant K which gives the fastest identification. Optimal control theory is introduced to find the best piecewise continuous K(t) in the interval 0 ≤ K(t) ≤ Kmax . From the exact solution in a special case, a switched suboptimal K which always gives fast identification is determined.
Identification schemes are developed for processes which include an unknown non-linearity that, can be assumed to be piecewise linear.
An adaptive control, system is developed to control processes with unknown time-varying coefficients. The system is shown to be stable as long as the process inverse is stable; the process need not be stable. Systems to control linear and non-linear unstable processes are designed and simulated. The limitations of the adaptive system are determined, and compared with the limitations of conventional feedback systems.
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Genre | |
Type | |
Language |
eng
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Date Available |
2011-08-16
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0093632
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.