Abstract: A method for estimating actuator and sensor faults in linear dynamical systems is presented in this paper. The method is based on the use of proportional integral (PI) observer which can simultaneously estimate the actuator and sensor faults as well as the states of the system. In this paper, we use PI observer incorporated with strong tracking filter (STF) to estimate the states and faults. When faults arise in the control systems, PI Strong Tracking filter can detect, locate and estimate the faults at the same time. This method is used to estimate the thrusters and gyroscopes faults of a satellite. The simulation results demonstrate the effectiveness of this approach.

Key words: proportional integral observer, strong tracking filter, fault estimation