Gear Fault Diagnostics Integrated in the Motion Servo Drive for Electromechanical Actuators

This paper presents contributions made in gear fault diagnostics for motion servos with continuously variable speed as used for aerospace and automotive electromechanical actuators. As the first step for motion servo diagnostics, an observer-based kinematic error estimator is developed whereby this estimated kinematic error is proposed as an operating point-independent gear surface fault signature. As the second step, a signal processing method is developed for real-time implementation of spatial domain resampling of regular time domain samples, and this method is combined with spatial domain synchronous averaging methods, which are shown to be very effective in filtering out unwanted asynchronous signatures. Lastly, a motion servo actuator with a gear surface failure is tested, and the proposed methods are shown to successfully extract the kinematic error profiles of the defective gear during motion servo operation over a wide range of continuously varying velocity.