Javier Hernando Pardo MayorgaAlain Sellier2026-03-222026-03-22200610.16924/revinge.23.1https://doi.org/10.16924/revinge.23.1https://andeanlibrary.org/handle/123456789/61949In the dynamic systems a fail can occur in any moment, the fail can be present for variations in one or more parameter of the dynamic system. This paper present a fail detection in a non linear system compose by two tanks in parallel one with constant transversal area and the other one with variable area, the work is develop with adaptive observers and LAMDA classification. The application on this paper is in a non linear system, the level control in the two tank system.esMoment (physics)Transversal (combinatorics)Computer scienceConstant (computer programming)Variable (mathematics)Control theory (sociology)Work (physics)Mathematicsarticle