Experimental and theoretical study of the electrical failures in a fault-tolerant direct-drive servovalve for primary flight actuators

Abstract

The current paper deals with the study of the electrical failures in fault-tolerant\ud flight actuators, with particular reference to the short circuits of the servovalve coils. A highfidelity\ud model of the servovalve of a modern fly-by-wire actuator is developed and validated\ud through experiments, focusing attention on the characterization of the component dynamics in\ud case of partial and total short circuits of the direct-drive motor coils. The servovalve model is\ud then used to simulate a typical on-ground built-in-test procedure to determine the limit\ud condition for the detection of a partial short circuit. Finally, once different possible\ud combinations of short circuits are injected, the degradation of performances of the whole\ud actuator is characterized through experiments, and the servovalve model is used to justify the\ud test results, highlighting and discussing the effects of the failures on the system dynamics

Dynamic Modelling and Experimental Characterization of a Self-Powered Structural Health-Monitoring System with MFC Piezoelectric Patches

“…The experimentally-validated model of the prototype was finally used to test a model-based condition-monitoring algorithm developed by the authors [40,[57][58][59][60][61], in order to assess the system applicability to SHM systems. In model-based condition-monitoring approaches, the detection of faults or anomalies is actually performed by evaluating the deviation of hardware responses from the predictions of a system model related to normal operating conditions.…”

Modelling and simulation of a fault-tolerant electrical motor for aerospace servovalves with Modelica

“…Previous works of the authors highlighted the role that the magnetic flux dispersion has in this type of system [6,7]. For this reason, the permanent magnet section of the motor has been modelled with the magnetic circuit network shown in Fig.…”

“…The Modelica model of the motor has been developed with reference to the fault-tolerant direct-drive motor of the servovalve of a modern fly-by-wire actuator, which has been experimentally characterised by the authors during previous research activities [6]. The model validation has been achieved by comparing the Modelica results with the experimental data in terms of current-to-force and current-todisplacement curves, with reference to both the normal operating condition (four active coils) and the worst-case fault-tolerant condition (only two active coils).…”

“…The model validation has been achieved by comparing the Modelica results with the experimental data in terms of current-to-force and current-todisplacement curves, with reference to both the normal operating condition (four active coils) and the worst-case fault-tolerant condition (only two active coils). In this section, the results of a Matlab-Simulink simulation of the motor [6] are also reported, in order to highlight the advantages of the objectoriented modelling with respect to a more classical approach.…”

“…The second part is focused on the main features of the Modelica model, mostly developed by using the components of the Modelica_Magnetic library [5], while the third section is dedicated to the model validation. In particular, the Modelica results are compared with both experimental data (obtained during previous research activities) and simulation results of a Matlab-Simulink model of the motor [6], in order to point the advantages of the objectoriented modelling for the study of complex electro-magnetic systems.…”