Fault detection of ball screw-based electromechanical actuators using electrical, ultrasound and accelerometer sensors

Kurzfassung

Electromechanical actuators (EMAs) are considered a promising energy-efcient technology for actuating the flight controls of future aircraf. When it comes to aerospace systems, the degradation of EMAs should be checked during regular maintenance events or through condition-based maintenance. Ball bearings have a signifcant failure rate for flight control EMAs and are usually monitored by vibration noise. A challenge for detecting bearing faults, using state-of-the-art industrial methods, is the presence of a ball-screw mechanism that produces nominal vibration noise similar to that of faulty bearings. No prior research has investigated this problem. Tis paper explores vibration noise generated fom a set of healthy and faulty bearings included in a typical ball-screw EMA. In addition, a method is introduced for evaluating fault diagnosis performance for different time and fequency vibration features. Te technique has been validated on an EMA actuator at the German Aerospace Center (DLR).