Optimal on-off control for fed-batch fermentation processes

Chen, Chyi Tsong; Hwang, Chyi

doi:10.1021/ie00105a019

Cited by 36 publications

(16 citation statements)

References 21 publications

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“…The proposed algorithm was used to ®nd the optimal feed-rate policy for maximization of secreted protein in a fed-batch bioreactor reported by Park and Ramirez [62], and was shown to result in a better pro®t function when the batch time was increased by a small quantity. The same approach is applied for ethanol production [69] and 4% improvement was reported over the results obtained by Chen and Hwang [56]. Iterative dynamic programming (IDP) was used together with suitable penalty functions of absolute error values and also with move suppression factors for control action minimization for biosynthesis of penicillin in a fedbatch reactor [70].…”

Section: Other Optimal Control Approachesmentioning

confidence: 98%

“…Further, it was shown that accurate kinetic constants are indispensable for an optimization study. For the same fermentation system, Chen and Hwang [56] proposed an optimal on-off control solution which was derived for a general process described by differential algebraic equations. A uni®ed algorithm was derived for computing the gradients of the cost function and constraints, which facilitates the solution of parameter selection problem resulting from on-off control parametrization by gradient-based optimization methods.…”

Section: Singular Control Approachesmentioning

confidence: 99%

See 1 more Smart Citation

Control of fermenters – a review

Rani¹,

Rao²

1999

Bioprocess Engineering

133

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Fermenter control has been an active area of research and has attracted more attention in recent years. This is due to the new developments in other related areas which can be exploited to overcome the inherent dif®-culties in fermenter control. Beginning with conventional regulatory control of operating variables such as temperature, pH and dissolved oxygen concentration, research in fermenter control has undergone signi®cant changes including the recent neural network based approaches. The objective of the paper is to focus the attention of the researchers to the developments in the control of batch, fedbatch and continuous fermenters over the past few years.

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Section: Other Optimal Control Approachesmentioning

confidence: 98%

Section: Singular Control Approachesmentioning

confidence: 99%

Control of fermenters – a review

Rani¹,

Rao²

1999

Bioprocess Engineering

133

View full text Add to dashboard Cite

show abstract

“…portamento dinâmico deste processo pode ser representado pelas seguintes equações de balanço de massa [1,4,7,8]: Do ponto de vista de controle, a trajetóriaótima da variável de controle que maximiza a produção de etanol ( pV ) consiste de arcos não singulares e singulares, caracterizando um Problema de ControleÓtimo Singular (PCOS), para o qual a sequência de arcos e os tempos nos quais ocorre a transição entre eles (eventos ou switching times) têm que ser determinados. Na literatura, inúmeras metodologias tem sido propostas para a resolução deste problema.…”

Section: Controleótimo Da Fermentação Alcoólica Usando Computação Biounclassified

Controle Ótimo da Fermentação Alcoólica em Reator Batelada Alimentada usando Computação Bio-Inspirada

Lobato

2015

Tend. Mat. Apl. Comput.

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Recebido em 15 abril, 2013 / Aceito em 24 janeiro, 2015 RESUMO. O modo de operação batelada alimentadaé reconhecido por amenizar os efeitos de inibição causados pelo produto e pelo substrato no processo de fermentação alcoólica. A otimização dinâmica deste processo para fins de maximização da sua produtividade, através do controle da vazão de alimentação do substrato, caracteriza um problema de controleótimo singular de difícil solução devido a flutuação dó ındice diferencial. Neste trabalho, este problema de otimizaçãoé resolvido usando o Algoritmo de Colônia de Morcegos, técnica bio-inspirada na natureza que se fundamenta no comportamento social de colônias de morcegos. Os resultados obtidos com este algoritmo são comparados a uma estratégia utilizada para a transformação do problema original em um de identificação de fases deíndice diferencial flutuante e de tempos de transição entre elas. Na aplicação proposta são consideradas restrições na produtividade, na variável de controle e no volume do fermentador, para operação com tempo livre. São analisadas o efeito das restrições operacionais e das condições iniciais sobre os perfisótimos.Palavras-chave: controleótimo singular, fermentação alcoólica, algoritmo de colônia de morcegos.

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“…On-off controllers are often used by engineering systems with only basic actuator capabilities, limited computation resources, and/or tight energy constraints. However, an additional obstacle to on-off control implementation is that most existing on-off control algorithms rely on accurate knowledge of system dynamics [4][5][6], for open-loop situations, or comparatively high-frequency sensing in order to implement decision rules on feedback measurements [7]. A sample prototype micro-robotic leg joint based on thin-film piezoelectric actuation is shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

On‐off iterative adaptive controller for low‐power micro‐robotic step regulation

Hahn

Oldham

2011

Asian Journal of Control

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A novel model-free iterative adaptive controller is presented for lowpower control of piezoelectric actuators. The controller uses simple adaptation rules based on known general behavior of piezoelectric actuators to adjust onoff switching times to drive piezoelectric actuators through a desired transient step motion. Adaptation rules are based on small numbers of measurements taken during each iteration of the actuator movement. Combined with the use of only on-off control inputs, controller implementation can be possible at much lower overall power levels than would be needed to implement a conventional control strategy such as through pulse-width-modulation (PWM) with real-time feedback. Such power savings are particularly important for the intended controller application to piezoelectric microactuators driving autonomous terrestrial micro-robots. A method for predicting convergence of systems with nominally linear dynamics and unknown, bounded nonlinearities is described, and applied to a sample target piezoelectric actuator. The controller is tested in simulation and experimentally on a piezoelectric cantilever actuator, and shows predicted convergence to the desired response.

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Optimal on-off control for fed-batch fermentation processes

Cited by 36 publications

References 21 publications

Control of fermenters – a review

Control of fermenters – a review

Controle Ótimo da Fermentação Alcoólica em Reator Batelada Alimentada usando Computação Bio-Inspirada

On‐off iterative adaptive controller for low‐power micro‐robotic step regulation

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