Monitoring in torque-summed electromechanical actuators

The main aim of this paper is to address cross-monitoring techniques (lumped and hardware) in a single-type torque-summed architecture. In the lumped cross-monitoring technique, all lanes will be represented by their lumped models, while in hardware cross-monitoring, three-phase equivalents will model each motor. The analysis is based on a 4-lane actuation system capable of driving aerodynamic and inertial loads (with 2 lanes failed) acting on an aileron control surface similar to that of the Sea Harrier. The paper will start by giving an overview of the system, by briefly describing: (1) the fault detection and fault isolation, FDI, system, (2) threshold setting method, using the simulation graphical Monte Carlo, SGMC, and (3) For completeness, brief yet key models of the brushless DC motor and the aerodynamic load will also be given. Unscheduled thresholds values will then be evaluated from peak lane disparities (due to inherent parameter randomness) using the SGMC. The largest failure transient envelopes after failure isolations are then identified for different flight conditions, and their impact on the aircraft response in roll will then be assessed. The paper will conclude by showing that both actuator and aircraft requirements were met despite the use of two different cross-monitoring techniques.