Estimation and Control of Non-Linear Variables in a Continuous Fermentation Process using Sliding Mode Techniques

Rahman, A.F.N.A. and Spurgeon, Sarah K. and Yan, Xing-Gang (2012) Estimation and Control of Non-Linear Variables in a Continuous Fermentation Process using Sliding Mode Techniques. Transactions of the Institute of Measurement and Control, 34 (7). pp. 769-779. (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Biomass, substrate or metabolite concentrations are difficult to measure online in fermentation processes because of the lack of reliable, cheap and sterilizable transducers. Currently, many of the measurements required may be determined through offline analysis, which is costly and time consuming. Furthermore, the specific growth rate conditions involved in the fermentation are typically non-linear and uncertain. In this paper, a new variable, the substrate consumption rate, consisting of a combination of substrate concentration, biomass concentration, specific growth rate and yield production coefficient, is introduced to overcome these problems and simplify the non-linear differential equations of the fermentation process. A sliding mode observer, which only requires measurement of substrate concentration, is then developed to solve the estimation problem, providing a soft sensor to estimate the substrate consumption rate. It is shown that the sliding mode exhibited by the corresponding observer error dynamics is exponentially stable. This parameterization and the resulting estimate of biomass concentration are then utilized within a feedback control strategy. Non-linear simulation results in the presence of both parameter uncertainties and external disturbances illustrate the approach.

Item Type: Article
Uncontrolled keywords: biomass concentration estimation, non-linear process, sliding mode observer
Subjects: T Technology > TJ Mechanical engineering and machinery > Control engineering
Divisions: Faculties > Science Technology and Medical Studies > School of Engineering and Digital Arts > Instrumentation, Control and Embedded Systems
Depositing User: J. Harries
Date Deposited: 12 Nov 2012 14:46
Last Modified: 09 Jun 2014 13:42
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