Application of Feedback Linearization to Bioreactor Control
ABSTRACT This paper presents the procedures and results of Using the input-output linearization technique in the design of a controller for a generic nonlinear continuous bioreactor. Of special interest is the existence of singular points which renders direct application of the input-output linearization theory infeasible. In this paper, we present a modified scheme which allows us to approximately extend the input-output linearization technique across the singular points. The feasibility and effectiveness of the proposed method are demonstrated through computer simulation. This modified method provides a more intuitive insight into the nonlinear system control.
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ABSTRACT: Recent developments in nonlinear systems theory combined with advances in control system hardware and software make the practical application of nonlinear process control strategies a reality. This review article surveys nonlinear control system techniques ranging from ad hoc or process-specific strategies to predictive control approaches based on nonlinear programming. The capabilities of these techniques to handle the common problems associated with chemical processes, such as time delays, constraints, and model uncertainty are discussed. Although the recent progress in nonlinear control is encouraging, a significant number of goals for future research in nonlinear control of chemical processes are detailed.Industrial & Engineering Chemistry Research 04/2002; 30(7). DOI:10.1021/ie00055a001 · 2.24 Impact Factor
Conference Paper: Optimization approach to controlling constrained nonlinear systems[Show abstract] [Hide abstract]
ABSTRACT: The authors discuss the results of using the input-output geometric transformation method in the development of an efficient controller for nonlinear systems with constraints, while being easy and intuitive to tune and requiring minimal computational effort. While dynamic matrix control (DMC) and quadratic DMC (QDM-C) have been successfully applied in optimal control of industrial processes, they are restricted to linear/near-linear processes. An approach combining the transformation method with DMC for nonlinear systems with constraints that require low computational effort is reported. Using input-output linearization, a pseudolinear model of the system is derived that is valid for the entire region of operation. DMC is designed on this system, ignoring constraints. The DMC-computed input is checked for constraint violation, and a pointwise optimal feasible input is generated if such violation occurs. The performance of the proposed control scheme is demonstrated via simulation of two processes: a continuous stirred tank bioreactor (CSTBR), and an exothermic continuous stirred tank reactor (CSTR)Decision and Control, 1992., Proceedings of the 31st IEEE Conference on; 02/1992
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ABSTRACT: An internal model control (IMC) strategy for nonlinear single-input single-output systems is proposed. The controller is designed to provide nominal performance, and a nonlinear filter is added to make the controller implementable and to account for plant/model mismatch. An important advantage of the new approach is that the assumption of full-state feedback inherent in most input-output linearization schemes is eliminated. However, the proposed IMC strategy is restricted to open-loop stable systems with stable inverses. Under mild assumptions, the closed-loop system possesses the same stability, perfect control, and zero offset properties as linear IMC. Simulation results for a continuous fermentor illustrate the advantages of the nonlinear IMC strategy.AIChE Journal 07/1991; 37(7):1065 - 1081. DOI:10.1002/aic.690370711 · 2.58 Impact Factor