Delay estimation for nonlinear systems with unknown output delay

Quang Truc Dam (1) , Rihab El Houda Thabet (1) , Sofiane Ahmed Ali (2) , François Guérin (3)

1 IRSEEM - Institut de Recherche en Systèmes Electroniques Embarqués
2 IBISC - Informatique, BioInformatique, Systèmes Complexes
3 GREAH - Groupe de Recherche en Electrotechnique et Automatique du Havre

In this paper, the problems of delay identifiability and delay estimation for a nonlinear systems subject to constant unknown output delay are studied. Usually, the estimation of such delay is based on a monotonic condition which is hard to satisfy in the case of nonlinear systems. To deal with this open and interesting problem, a change of coordinates is introduced in this paper to transform the nonlinear system to the triangular form. Then, a high order sliding mode observer is designed based on implicit Lyapunov function to estimate the state and delayed-input, based on these estimation, the delay estimator is proposed. The convergence of the proposed observer is proved and the effectiveness of the proposed method is illustrated through simulation results of an Electro-Hydraulic Actuator (EHA) system.

Keywords: Delay identification; delay systems; nonlinear systems; state observers

Domains: Automatic

Quang Truc Dam, Rihab El Houda Thabet, Sofiane Ahmed Ali, François Guérin. Delay estimation for nonlinear systems with unknown output delay. IEEE Control Systems Letters, 2023, 7, pp.1219--1224. ⟨10.1109/LCSYS.2022.3232407⟩. ⟨hal-03921516⟩