Second Order Step by Step Sliding mode Observer for Fault Estimation in a Class of Nonlinear Fractional Order Systems

This paper considers fault estimation in nonlinear fractional order systems in observer form. For this aim, a step by step second order sliding mode observer is used. By means of a fractional inequality, the stability of the observer estimation errors is analyzed and some conditions are introduced to guarantee finite time convergence of estimation errors. Finally, in a numerical example, effectiveness of this observer is demonstrated.