Adaptive Input-Output Linearization Control of pH Processes

Document Type : Research Article

Authors

1 Department of Chemical Engineering, Isfahan University of Technology, Isfahan, I.R. IRAN

2 Department of Chemical and Petroleum Engineering, Sharif University of Technology, P.O. Box 11365-9465 Tehran, I.R. IRAN

Abstract

pH control is a challenging problem due to its highly nonlinear nature. In this paper the performances of two different adaptive global linearizing controllers (GLC) are compared. Least squares technique has been used for identifying the titration curve. The first controller is a standard GLC based on material balances of each species. For implementation of this controller a nonlinear state estimator is used. Some modifications are proposed to avoid the singularity of the observer gain. The second controller is designed based on the reduced state equation. Through computer simulations, it has been shown that the performances of the second GLC is superior and it is more robust to process model mismatch. It should be also noted that the design of reduced state-based GLC is much easier and dose not need observer for implementation.
 

Keywords

References

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Iranian Journal of Chemistry and Chemical Engineering
Volume 27, Issue 3 - Serial Number 47
September 2008
Pages 25-35

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