In a linear system, in order to estimate a state variable (e.g. biomass concentration, substrate and product concentration) a state vector (observer) is constructed based on the available outputs and inputs of the original system. The simplest observer described is the Luenberger observers. Several other types of observers comprise adaptive observers, interval observers, high gain observer, and asymptotic observers.

  • Benavides, M., Coutinho, D., Hantson, A.L., Van Impe, J., Wouwer, A.V., 2015a. Robust Luenberger observers for microalgal cultures. J. Process Control 36, 55–63.
  • Benavides, M., Mailier, J., Hantson, A.L., Munoz, G., Vargas, A., Van Impe, J., Vande Wouwer, A., 2015b. Design and test of a low-lost RGB sensor for online measurement of microalgae concentration within a photo-bioreactor. Sensors 15, 4766–4780.
  • Flores, G., Rodriguez-Mata, A.E., Amabilis-Sosa, L.E., Gonzalez-Huitron, V.A., Hernandez-Gonzalez, O., Lopez-Perez, P.A., 2020. A turbidity sensor development based on NL-PI observers: Experimental application to the control of a Sinaloa’s River Spirulina maxima cultivation. Open Chem. 18, 1349–1361.
  • Goffaux, G., Wouwer, A.V., Bernard, O., 2009. Continuous – Discrete interval observers for monitoring microalgae cultures. Biotechnol. Prog. 25, 667–675.
  • Mairet, F., Moisan, M., Bernard, O., 2014a. Interval observer with near optimal adaptation dynamics. Application to the estimation of lipid quota in microalgae. Int. J. Robust Nonlinear Control 24, 1142–1157.
  • Mairet, F., Moisan, M., Bernard, O., 2014b. Estimation of neutral lipid and carbohydrate quotas in microalgae using adaptive interval observers. Bioprocess. Biosyst. Eng. 37, 51–61.
  • Moisan, M., Bernard, O., Gouzé, J.-L., 2009. Near optimal interval observers bundle for uncertain bioreactors. Automatica 45, 291–295.

Specialist for obsevers

Dr.-Ing. Olivier Bernard

Inria centre at Université Côte d’Azur
2004, route des Lucioles – BP 93 06902
Sophia Antipolis Cedex, France
Tel: + 33 4 92 38 77 85
Fax: + 33 4  92 38 78 58