Fault Diagnosis of Output-Induced Actuator Failures for a Flexible Beam with Collocated Input and Output

Abstract Nonlinear adaptive parameter estimation techniques are employed to detect changes due to actuator faults, in a plant described by a flexible beam actuated via a pair of piezoceramic patches. Changes in the input term, which provide a very simple and practical model of actuator failures whose magnitudes are functions of the output signals, are monitored via the implementation of an on-line estimator. Both abrupt and incipient time profiles of failures are considered in this note. Using Lyapunov redesign methods, extended and applied to distributed parameter systems, a stable learning scheme for fault diagnosis is proposed. The resulting scheme is able not only to detect the occurrence of a fault but also to identify the location and shape of the fault. A numerical algorithm is provided for the implementation of the detection scheme and simulation studies are used to illustrate the applicability of the theoretical results.