Actuator Fault Estimation Technique Based on a Discrete-Time Observer Structure

In the paper is proposed a modified technique for actuator faults estimation in linear dynamic systems, which gives the possibility simultaneously estimate the system state as well as actuator faults. Using the discrete-time observer combined with fault estimation, the considered faults are assumed to be additive only, thereby the principle can be applied for a broader class of time-varying fault signals. An enhanced algorithm using H-infinity approach is provided to verify stability of the observer structure, giving a modified algorithm with improved performance of fault estimation. Exploiting this procedure the proposed technique allows to obtain signals that can be further used for thresholds setting in the fault residual scheme. The approach utilizes the measurable output vector variables and the design conditions are based on linear matrix inequality technique. Applied enhanced design conditions increase estimation rapidity and develop a general framework for additive fault estimation in discrete-time adaptive observer structures.