MOET (More Open Elecrtical Technologies) is a European Funded research project for establishing a new industrial standard for the electrical system design of commercial aircraft, business and regional aircraft as well as rotorcraft. Within the scope of this consortium the department Safety Critical Systems und Systems Engineering is working on the design and analysis of condition monitoring systems for electromechanical flap actuation systems.
The goal of the MOET project is to define technologies for the realization of a more electrical aircraft and to develop, design and test necessary components. This includes the replacement of the nowadays used hydraulic actuators with electromechanical ones. The considered compact direct drive actuator is provided by Goodrich Actuation Systems France. Like all electromechanical systems, the actuator is carrying the risk of mechanical faults due to wear. Since it could not be precluded these faults leading to failures like actuator jamming, monitoring of the mechanical components of the actuator is mandatory. Therefore two approaches are feasible. Either by analyzing data from existing sensors already included in the actuator design, or by integration of dedicated monitoring sensors in the actuator.
Within the scope of this project the second approach was pursued by the department and a sensor technology based on pressure dependent and piezoresistive thin film sensors was developed. The sensor coating features a diamante like surface making it very durable while having a thickness of few µm and therefore not contributing to the systems weight. An array of these sensors was coated on the actuator components and placed within the load path hence allowing measuring the pressure distribution within the actuator. Analyzing the pressure distribution with nominal as well as defective bearings and screw drives proved this sensor concept being suitable for this kind of monitoring tasks.