State estimation and fault reconstruction with integral measurements under partially decoupled disturbances

This study is concerned with the state estimation and fault reconstruction problems for a class of discrete systems with integral measurements under partially decoupled disturbances. The considered integral measurements, as functions of the system states over a period of time, reflect the interval time between sample collections and real-time signal processing. Moreover, the process disturbances are allowed to be partially decoupled in the observer design. An augmented state vector is constructed, which consists of the current system state, the delayed system state and the additive fault, and the resultant augmented system is described in a singular form. Then, an unknown input observer is obtained that decouples partial disturbances and attenuates the effect from the remaining undecouplable disturbances. The existence conditions of the desired observer are thoroughly investigated and an algorithm for designing the observer gains is also provided. Finally, a numerical example is presented to show the effectiveness of the proposed method.