Iterative higher order sliding mode observer for nonlinear systems with unknown inputs

Abstract : This paper deals with the problem of the design sliding mode observers for nonlinear systems subject to unknown inputs. In most approaches, sliding mode observers can be designed under the assumption that the system can be transformed into a specific canonical observable form. Then, the state and the unknown input of the system can be recovered in finite time. In this work, the class of systems for which unknown input sliding mode observers can be designed is enlarged by introducing an extended triangular observable form and a higher order sliding mode observers for which finite time convergence can be shown using Lyapunov stability arguments.