Comparison between unit vector and super-twisting sliding mode FDI design for actuator faults

In this paper a comparison between a first order sliding mode and a super-twisting based observer is made for a nonlinear benchmark satellite system subject to uncertainties and sensor noise. Fully open and fully closed thruster faults are applied to both the rigid body and flexible mode models. The performance of a first order sliding mode observer based on the unit vector approach, and a second order super-twisting observer are compared using Monte Carlo simulations.