Sihem Tebbani

Université Paris-Saclay · Laboratoire des signaux et systèmes (L2S)

Microalgae biofilm emerged as a solid alternative to conventional suspended cultures which present high operative costs and complex harvesting processes. Among several designs, rotating biofilm‐based systems stand out for their scalability, although their primary applications have been in wastewater treatment and aquaculture. In this work, a rotati...

This paper considers the control of spacecraft's vibration testing system. This test system is used for the qualification of the dynamic behavior of spacecraft under severe launch environment. The vibration testing system shall cover the launcher's vibration frequency band with respect to the spacecraft limitations (notching around the eigen freque...

Fed‐batch cultures of Escherichia coli are commonly used for the production of biopharmaceuticals. However, productivity can be adversely affected by the production of acetate inhibiting the cell respiratory capacity. In this study, a nonlinear predictive control is developed based on a process model, and an unscented Kalman filter for estimating t...

Avoiding acetate accumulation is a major challenge in Escherichia coli fed-batch cultures, since it leads to an inhibition of the cell respiratory capacity. A closed-loop regulation ensuring a low acetate concentration offers a practical solution to maintain the cultures near the optimal operating conditions. In this work, a robust Generic Model Co...

Robust control of a lightly-damped system, such as the mechanical structure of a spacecraft, is a dilemma for control engineers. The shaker’s table used for satellite vibration tests for qualification uses a sine sweep acceleration signal to characterize the satellite’s frequency signature. The current control system presents strong oscillation whi...

Advanced control strategies proved to be promising tools to improve the performances of microalgae production systems, especially in the perspective of large scale cultivation plants. This paper proposes the validation of a nonlinear control strategy with experimental results. Additionally, the on-line estimation of the biomass concentration in a p...

This work proposes a Generic Model Control (GMC) strategy to regulate biomass growth in fed-batch cultures of Escherichia coli BL21(DE3). The control law is established using a previously validated mechanistic model based on the overflow metabolism paradigm. A model reduction is carried out to prevent the controller from relying on kinetics, which...

This work deals with the problem of trajectory tracking for a nonlinear system with unknown but bounded model parameter uncertainties. First, this work focuses on the design of a robust nonlinear model predictive control (RNMPC) law subject to model parameter uncertainties implying solving a min‐max optimization problem. Secondly, a new approach is...

Generic model control (GMC), a model-based adaptive control strategy, is applied to a fed-batch high cell density cultivation of Escherichia coli, with biomass production maximization as an objective. A macroscopic model based on the overflow metabolism assumption is used, considering two metabolic pathways (respirative and respiro-fermentative), a...

This paper proposes a novel strategy for completing a flight plan with a quadrotor UAV, in the context of aerial video making. The flight plan includes different types of waypoints to join, while respecting flight corridors and bounds on the derivatives of the position of the quadrotor. To this aim, non-uniform clamped B-splines are used to paramet...

The present work is an account of an ongoing work on biogas production from animal wastes at LEREA (Laboratoire d’enseignement et de recherche en énergétique appliquée) in Mamou, Guinea. The work consists of biogas production from anaerobic digestion and co-digestion of cow dung and droppings. We focus in this report on the determination of the phy...

Recent advances in modeling bacterial cell functioning have deeply renewed questions about bioprocess design and opens the way towards the development of computer aided design (CAD) for strains. This article aims at explaining and exploring the consequences opened by the new cell models, investigating the questions related to the biological impleme...

Resource allocation based models were shown to capture the main bacterial cell design principles in steady-state, thus managing the resource allocation between cell processes, and in fine growth rate. This paper introduces the basis of extension of resource allocation models to dynamical conditions. The framework is applied to a bioreactor operatin...

This work deals with the problem of trajectory tracking for a nonlinear system with unknown but bounded model parameters uncertainties. First, this work focuses on the design of classical robust nonlinear model predictive control (RNMPC) law subject to model parameters uncertainties implying solving min-max optimization problem. Secondly, a new app...

The rational bacterial strain design is a major challenge in synthetic biology. This paper deals with the optimization of a bacterial strain for specific processes taking place in a bioreactor. Such problems are namely maximizing the growth and the production of a product of interest. First, a model combining the internal behavior of the cells with...

Lactic acid is an important molecule for biopolymer production that can be obtained by biological processes. This work deals with the control of the lactic acid concentration in its production bioprocess using wheat flour as substrate. An adaptive control strategy for the simultaneous saccharification, proteins hydrolysis and fermentation (SSPHF) c...

Anaerobic digestion is an effective biotechnological process for treatment of different agricultural, municipal and industrial wastes. Use of mathematical models is a powerful tool for investigations and optimisation of the anaerobic digestion processes and for softwere sensors design as well. In this paper a new version, conserning the gas phase m...

Controlling microalgae cultivation, i.e., a crucial industrial topic today, is a challenging task since the corresponding modeling is complex, highly uncertain and time-varying. A model-free control setting is therefore introduced in order to ensure a high growth of microalgae in a continuous closed photobioreactor. Computer simulations are display...

A kinetic model of the simultaneous saccharification, protein hydrolysis, and fermentation (SSPHF) process for lactic acid production from wheat flour has been developed. The model describes the bacterial growth, substrate consumption, lactic acid production, and maltose hydrolysis. The model was fitted and validated with data from SSPHF experiment...

This chapter proposes the optimization of batch microalgae cultures in artificially lighted photobioreactors . The strategy consists in controlling the incident light intensity so that the microalgae growth rate is maximized. Two approaches were developed and compared. In the first one, the ratio between the incident light intensity and the cell co...

In the context of radar applications using small UAVs (Unmanned Aerial Vehicles), this paper focuses on the dynamic modeling and the analysis of an octorotor in view of control design. As part of a research and educational project aiming at designing a VTOL (vertical take-off and landing) flying robot with an embedded radar system, this paper prese...

In this paper, the problem of trajectory tracking of a nonlinear system with unknown but bounded model parameters uncertainties is addressed. The proposed control strategy combines a robust model predictive control law with a proportional-integral (PI) regulator. The predictive controller guarantees the tracking of the reference trajectory, whereas...

This paper proposes the design of a hierarchical control strategy formed by a two-level controller: a Linearized Robust MPC (LRMPC) and an Integral Sliding Mode (ISM) control laws. The proposed strategy guarantees robustness towards parameters mismatch for a macroscopic continuous photobioreactor model, obtained from mass balance based modelling. F...

This paper proposes the design of a robust predictive control strategy which guarantees robustness towards parameters mismatch for a simplified macroscopic continuous photobioreactor model, obtained from mass balance based modelling. Firstly, this work is focused on classical robust nonlinear model predictive control law under model parameters unce...

This paper proposes the design of a robust predictive control strategy which guarantees robustness towards parameters mismatch for a simplified macroscopic continuous photobioreactor model, obtained from mass balance based modelling. Firstly, this work is focused on classical robust nonlinear model predictive control law under model parameters unce...

The key feature of this paper is the development of a control strategy for the lactic acid production process from wheat flour in a continuous bioreactor. As lactic acid has inhibition effects on bacterial growth and its own production, the regulation of its concentration is required. In this paper, a control strategy is proposed in order to maximi...

Advanced control strategies proved to be promising tools to improve the performances of microalgae production systems, especially in the perspective of large scale cultivation plants. This paper proposes the validation of a nonlinear control strategy with experimental results. Additionally, the on-line estimation of the biomass concentration in a p...

This paper proposes the design of a robust predictive control strategy which guarantees robustness towards parameters mismatch for a simplified macroscopic continuous photobioreactor model, obtained from mass balance based modelling. Firstly, this work is focused on classical robust nonlinear model predictive control law under model parameters unce...

This work presents a bioprocesses parameter estimation method based on heuristic optimization approaches. The identification problem is formulated as a multimodal numerical optimization problem in a high-dimensional space. Then, the optimization problem is split in simpler sub-problems that require fewer computational resources. The main results ar...

In this study, a control strategy for lactic acid production process from wheat flour is proposed. First, the process model to be used in the control strategy is chosen after performing an observability analysis of the system. Then, the optimal setpoint that maximizes the lactic acid productivity is determined based on this simplified model. Finall...

This paper deals with the design of a controller that maximizes the biomass production in an artificially lighted photobioreactor operated in batch mode, by maintaining the ratio between the incident light intensity and the biomass concentration (light-to-microalgae ratio) at targeted light regime. The controller acts on the incident light intensit...

This paper deals with the design of a predictive control law for microalgae culture process to regulate the biomass concentration at a chosen setpoint. However, the performances of the Nonlinear Model Predictive Controller usually decrease when the true plant evolution deviates significantly from that predicted by the model. Thus, a robust criterio...

This paper deals with the design of a predictive control law for microalgae culture process to regulate the biomass concentration at a chosen setpoint. However, the performances of the Nonlinear Model Predictive Controller usually decrease when the true plant evolution deviates significantly from that predicted by the model. Thus, a robust criterio...

The nonlinearity of the biotechnological processes and the absence of cheap and reliable instrumentation require an enhanced modelling effort and estimation strategies for the state and the kinetic parameters. This work approaches nonlinear estimation strategies for microbial production of enzymes, exemplified by using a process of lipase productio...

The paper addresses the design and the analysis of adaptive and robust-adaptive control strategies for a complex recycled wastewater treatment bioprocess. The design procedures are developed under the realistic assumptions that the bacterial growth rates are unknown and the influent flow rates are time-varying and uncertain, but some lower and uppe...

Algae are photosynthetic organisms that develop in varied habitats, predominantly in aquatic environments, capable of converting light energy and carbon sources into “biomass”. Depending on their size, algae can be classified into two broad categories: “macroalgae” and “microalgae”. The microalgae have a size measured in micrometers and are conside...

Microalgae growth modeling represents a scientific challenge due to the very complex phenomena to be considered. In fact, a biological system interacts with many physical and biological factors. In a culture, microalgae behavior depends strongly on the surrounding environmental and operational parameters. Various models of different complexity have...

Recent works show that CO2 biofixation by microalgae can be coupled with biofuel production, which allows us to increase the efficiency of the process and to obtain better production performance. In this case, the CO2 produced by the combustion of biofuel can be recycled to be absorbed by the microalgae, and again be converted into biofuel. Various...

Microalgae culture for CO2 sequestration must be maintained at optimal operating conditions in order to maximize CO2 biofixation. In the case of the microalgae culture, some recent studies have focused on the optimal control of cultures in a photobioreactor. These studies concern either pH regulation, or concentration regulation in the bioreactor....

This chapter is dedicated to the estimation of biomass concentration through different estimation strategies. It gives a state of the art of the biomass estimation strategies used in the field of biotechnology and more particularly in the case of the microalgae culture. Three types of estimator are presented and explained in detail: the Kalman filt...

Due to the consequences of global warming and large emissions of greenhouse gases, solutions for the sustainable development and the safeguarding of land resources are currently the focus of reflection and international actions. One of the major lines of action relates to the stabilization or reduction of greenhouse gases concentrations in the atmo...

Due to the consequences of globa l warming and significant greenhouse gas emissions, several ideas have been studied to reduce these emissions or to suggest solut ions for pollutant remov al. The most promising ideas are reduced consumption, waste recovery and waste treatment by biological systems. In this latter category, studies have demonstrated...

The objective of this study is to design a Nonlinear Model Predictive Controller for a microalgae culture process to regulate the biomass concentration at a chosen setpoint. The optimization problem is discretized and transformed into a nonlinear programming problem, solved by Control Vector Parametrization technique. How-ever, the performances of...

ISBN : 978-1-78405-040-5 (papier) ISBN : 978-1-78406-040-4 (ebook)

Microalgae culture is used in various biotechnological applications. Optimisation of the system productivity needs reliable sensors. However, physical sensors for biomass and dissolved dioxide carbon concentrations are expensive and not accurate, especially for online measurements. In this context, robust and efficient software sensors have to be d...

In this paper, a robust nonlinear receding-horizon observer is proposed for the estimation of cellular concentration in a bioreactor. In the presence of uncertainties on the model parameter or on the initial state of the system, this estimation problem can lead to poor estimation performance. A min-max optimization solution can be used to increase...

The application of white biotechnological processes to produce biopolymers has been increasing recently. In this study, a mathematical model describing the lactic acid production from wheat flour using lactic acid bacteria is presented. The model considers the kinetics degradation of maltose into glucose and the inhibitor effect of substrate and pr...

In the framework of environment preservation, microalgae biotechnology appears as a promising alternative for CO2 mitigation. Advanced control strategies can be further developed to maximize biomass productivity, by maintaining these microorganisms in bioreactors at optimal operating conditions. This article proposes the implementation of Nonlinear...

In the framework of environment preservation, microalgae biotechnology appears to be a promising alternative for CO2 mitigation. Implementation of advanced control strategies can be further considered to improve potential performances of these organisms. In this context, this paper proposes the implementation of predictive control combined with an...

As a result of different environmental issues, especially global warming and the greenhouse effect, biotechnology using microalgae has become a very promising alternative for carbon dioxide mitigation. Indeed, these unicellular microorganisms reduce efficiently carbon dioxide emissions through their photosynthetic activity. In order to maximize the...

Microalgae present a very promising alternative for carbon dioxide mitigation strategies. These unicellular photosynthetic microorganisms fix carbon dioxide efficiently, converting it into biomass and high-value compounds. One of the control system challenges is to maximize carbon dioxide consumption by maintaining the cellular concentration to an...

Microalgae consume carbon dioxide for their growth and to produce secondary metabolites. One of the control system challenges is to maximize this carbon dioxide consumption by controlling microalgae growth, and by maintaining its growth rate at an optimal value. However, there is no such thing as a microalgae growth rate sensor. This paper proposes...

The microalgae biotechnology is a very promising solution for environmental applications. In particular, these photosynthetic microorganisms have a great capacity to fix the carbon dioxide converting it into biomass and other secondary metabolites. Therefore the biological CO 2 fixation by microalgae has attracted much attention. The optimization o...

A strategy for controlling a fed-batch Escherichia coli culture is described to maintain the culture at the boundary between oxidative and oxido-fermentative regimes. A nonlinear predictive controller is designed to regulate the acetate concentration, constraining the feed rate to follow an optimal reference profile which maximizes the biomass grow...

This paper presents the control strategy of a fossil-fuel power plant. In previous work, an advanced coordinated controller was synthesized to achieve stability with satisfying performances. This controller was implemented on-site leading to satisfactory results. However, mainly because of modeling uncertainties, the obtained performances could be...

This paper presents a nonlinear predictive control (NMPC) strategy applied to the continuous microalgae cultivation process in a closed photobioreactor. The photo-bioreactor system is programmed to operate in a constant biomass density mode, in order to maintain the culture at the optimal population density and sustain high biomass production level...

This paper proposes an off-line procedure which enables the robustification of an initial stabilizing controller for multivariable systems using the convex optimization of a Youla parameter. This robustification must provide stability robustness towards unstructured uncertainties for the nominal system, while guaranteeing stability properties over...

Microalgae have many applications such as the production of high value compounds (source of long-chain polyunsaturated fatty acids, vitamins, and pigments), in energy production (e.g. photobiological hydrogen, biofuel, methane) or in environmental remediation (especially carbon dioxide fixation and greenhouse gas emissions reduction). However, the...

This paper deals with the adaptive retuning of a feed-forward controller, under the normalized lattice form, for a parameter-varying closed-loop system. The objective is to tune the controller in real-time during specific flights so that it does not need the adaptive part in nominal operation. The method was developed to help aeronautical design en...

This paper addresses a study of the regulation of the biomass density in a closed microalgal photobioreactor by using a linearizing control approach. The photobioreactor system was programmed to operate in a constant biomass density mode, in order to maintain the culture at the optimal population density and sustaining high biomass production level...

This paper deals first with the open-loop optimization of a fed-batch bioreactor, using an approach combining direct transcription and collocation techniques. The proposed strategy avoids taking into account singular arcs as it transforms the optimization problem into a nonlinear programming problem (NLP). The state and control variables are both d...

This paper presents a nonlinear predictive control strategy for maximizing the biomass growth in fed-batch cultures of E. Coli. This objective is achieved by regulating the acetate concentration at a low measurable value, while tracking (in a compromising way) an optimal glucose feed-rate trajectory determined off-line. Robustness with respect to m...

Microalgae biotechnology has been focusing on the use of algae in the production of high value compounds. During the last few decades, the intense research effort has been aiming at improving new controls and supervising tools as well as on a good process understanding. This requirement involves a large diversity and a better accessibility to proce...

This paper deals with the synthesis of an open-loop control law of a civilian aircraft for the compensation of the pitching moment generated by the extension of airbrakes. The proposed method uses in-flight recorded data and is based on impulse response identification and inverse simulation, whose results are used to design the controller upon qual...

This paper proposes a nonlinear model predictive control scheme with particular application to the regulation of acetate concentration in order to maximize the biomass growth during fed-batch cultures of E. Coli. A reference feed rate which enables to maintain the acetate concentration at a specified level is first determined by means of optimal co...

In this paper, a new optimisation strategy for the solution of the classical Unit Commitment problem is proposed. This problem is known to be an often large scale, mixed integer programming problem. Due to high combinatorial complexity, the exact solution is often intractable. Thus, a metaheuristic based method has to be used to compute a very ofte...

This paper proposes the design of a nonlinear model predictive control (NMPC) scheme for the regulation of the acetic acid concentration (leading to the biomass growth maximization) during high cell density fed-batch cultures of Escherichia coli . For NMPC purposes, an unstructured model for the growth is first derived with respect to the major met...

In this paper, an enhanced genetic algorithm for the Unit Commitment problem is presented. This problem is known to be a large scale, mixed integer programming problem for which exact solution is highly intractable. Thus, a metaheuristic based method has to be used to compute a very often suitable solution. The main idea of the proposed enhanced ge...