A Design Procedure for Robust Actuator and Sensor Fault Detection

This paper considers the design of an integrated observer structure termed as Proportional Integral Fading Unknown Input Observer (PIFUIO). The advantages of PIO and UIO observers are used in robust fault detection. The UIO decouples the unknown input disturbance while PIO allows to estimates the faults. It is shown that the fading term of this observer plays a distinct role in reliable estimation of faults decoupled from the unknown disturbance or vice versa. The robust detection of sensor fault is also considered with the presence of unknown inputs. Indirect and direct design procedures for sensor fault detection are provided. Numerical examples are included to illustrate the advantage of PIFUIO