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 The process control-related work present in this page concern the chromatography by Simulated-Moving Bed, the polymerization and the works linked to the ANR-project braise (saving energy in french bakery). Although cryogenic-related works can be included in the process control category, they are referred to in a dedicated page (see here) because of their specific importance. 

A hybrid nonlinear state observer for concentration profiles reconstruction in nonlinear simulated moving bed

In this paper, a state observer is proposed for the reconstruction of the concentration profiles in a simulated moving bed. The approach is based on a simple Luenberger-like correction term. The observer is used under the assumption that the flow rates are constant during each switching period. The matrix gain of the correction term may then be re-computed at the beginning of each switching period corresponding to flow rates being changed by the controller. Validating simulations are proposed to assess the effi- ciency of the proposed profile reconstruction and its robustness against uncertainties on modelling parameters. Comparisons are also done with open-loop simulation based-observer in order to strengthen the relevance of the correction term.


Corriou, J. P.; Alamir, M. A hybrid nonlinear state observer for concentration profiles reconstruction in nonlinear simulated moving bed. Journal of process control 16, No.4, 345-353 (2005) [download]

A flexible nonlinear model predictive control scheme for quality/performance handling in nonlinear SMB chromatography

In this paper, a new state feedback scheme is proposed for the control of simulated moving beds with strongly nonlinear iso- therms. The proposed scheme offers a unified framework enabling different performance criteria to be improved according to the active production constraints (achieving low cost, improving efficiency, respecting deadlines) that may unpredictably change during the production batch. The proposed scheme is illustrated through several examples showing the robustness of the closed-loop behav- ior against parameter uncertainties as well as its reactivity to changes in the active auxiliary criterion.


Alamir, M.; Ibrahim, F.; Corriou, J. P. A flexible nonlinear model predictive control scheme for quality / performance handling in nonlinear SMB chromatography. Journal of process control 16, No.4, 333-344 (2005). [download]

Diagnosis and on-line parametric estimation of simulated moving bed

In this paper, a recently developed graphical signa- tures generation tool is used for diagnosis and on-line paramet- ric estimation of simulated moving bed (SMB). The underlying diagnosis problem corresponds to variations affecting four of system’s parameters, namely, the two Langmuir coefficients, the extract and the feed flow rates. It is shown that this diagnosis method enables detection, isolation and parameter estimation even under simultaneous faults. Comparison with a simple least squares approach shows that the proposed approach needs drastically less iterations and therefore corresponds to a fast estimation results.


Youssef, B.; Alamir, M. and Ibrahim, F. Diagnosis and on-line parametric estimation of simulated moving bed. Proceedings of the 44th Conference on Decision and Control (CDC-ECC'05), Seville, Spain (2005) [download]

Measurement Based Modeling and Control of Bimodal Particle Size Distribution in Batch Emulsion Polymerization

In this paper, a novel modeling approach is proposed for bimodal Particle Size Distribution (PSD) control in batch emulsion polymerization. The modeling approach is based on a behav- ioral model structure that captures the dynamics of PSD. The parameters of the resulting model can be easily identified using a limited number of experiments. The resulting model can then be incorporated in a simple learning scheme to produce a desired bimodal PSD while compensat- ing for model mismatch and/or physical parameters variations using very simple updating rules.


Alamir M., N. Sheibat-Othman and S. Othman. Measurement Based Modeling and Control of Bimodal Particle Size Distribution in Batch Emulsion Polymerization. AiChE Journal, Volume 56, No 8, Pages 2122-2136 (2010) [download]

Constrained nonlinear predictive control for maximizing production in polymerization processes

In this paper, a new constrained nonlinear predictive control scheme is proposed for maximizing the production in polymeriza- tion processes. The key features of the proposed feedback strategy are its ability to rigorously handle the process constraints (input saturation, maximum allowed heat production, maximal temperature values and rate of change) as well as its real time implementability due to the low dimensional control parametrization being used. Simulations are proposed to show the effi- ciency of the proposed feedback as well as its robustness to model uncertainties.The controller performance is also validated experimentally on a laboratory scale reactor to control the emulsion polymerization of styrene.


Alamir, M.; Sheibat-Othman, N. and Othman, S. Constrained Nonlinear Predictive Control for maximizing Production in Polymerization Processes. IEEE Transactions on Control Systems Technology, Vol 15, No 2, March (2007). [download]

On The Use of Nonlinear Receding-Horizon Observers in Batch Terpolymerization Processes

In this paper, a nonlinear receding-horizon observer is proposed for state reconstruction in batch terpolymerization reactors. The related investiga- tions show that the state reconstruction problem may be quite ill conditioned in the sense that different states may exist that lead to roughly the same output. It seems however that when constrained receding-horizon estimation is used together with a dedicated crossing singularity heuristic, state reconstruction is possible even in presence of measurement noise and up-to 10% error on the r.h.s of the ODE’s describing the system’s dynamics. The efficiency and the real-time implementabil- ity of the overall scheme is shown through illustrative scenarios including both simulation and experimental validation.


Alamir, M., Sheibat-Othman, N. and Othman, S. On the use of Nonlinear Receding Horizon Observers in Batch Terpolymerization Reactors. International Journal of Modeling Identification and Control, Vol 4, No 1 (2008).[download]

Estimation of energy saving thanks to a reduced-model-based approach: Example of bread baking by jet impingement

n this paper, a reduced order mechanistic model is proposed for the evolution of temperature and humidity during French bread baking. The model parameters are identified using experimental data. The resulting model is then used to estimate the potential energy saving that can be obtained using jet impingement technology when used to increase the heat transfer efficiency. Results show up to 16% potential energy saving under certain assumptions.


M. Alamir, E. Witrant, G. Della Valle, O. Rouaud, Ch. Josset and L. Boillereaux. Estimation of energy saving thanks to a reduced-model-based approach: example of bread baking by jet impingement. Energy (Elsevier), vol. 53, pp 74-82, (2013).[download]

Estimation of temperature field during microwave tempering with unknown dielectric properties using CLPP: a generic user-friendly software sensor

The present study is dedicated to the estimation of internal temperatures within a foodstuff during microwave tempering, in the presence of unknown dielectric properties. The solution consists of a software sensor based on a model originating from the closed-form solutions of Maxwell’s equations coupled with the conduction heat equation solved by finite differences. The algorithm implemented enables convergence towards acceptable dielectric property functions while the temperature field is estimated simultaneously. This approach is carried out in simulation by considering the tempering of a block of raw beef located in a rectangular wave guide in order to consider a fundamental mode with perfectly known electromagnetic conditions.


Boillereaux L., M. Alamir, S. Curet, O. Rouaud and P. Bellemain Estimation of the temperature field during microwace tempering with unknown dielectric properties using CLPP: a generic user-friendly software sensor. Innovative Food Science & Emerging Technologies (Elsevier), Vol. 12, Issue 3, pp. 288-297 (2011). [download]