A review on the use of angle measurements in gear condition monitoring and fault detection

Condition monitoring is crucial for the predictive maintenance of gear transmissions to avoid unexpected failures with downtimes, costly repairs, or dangerous incidents. While vibration-based condition monitoring is widespread in industry and research, using angle measurements as a primary source still offers much potential. This review provides insights into current methods of angle-based condition monitoring for gear transmissions – from sensors, data acquisition, and algorithms to condition evaluations. It shows how current research applies measurement principles with various resolutions and sampling frequencies at stationary and dynamic operating conditions. It includes one or multiple angle measurements (instantaneous angle, instantaneous angular speed, instantaneous angular acceleration, or transmission error), electric current measurements, or the combination with acceleration measurements. Next to rotation as an auxiliary quantity for vibration order tracking, the review, in particular, focuses on algorithms with angle-based condition indicators. It summarizes the state of research of preprocessing, feature engineering, and automatic condition evaluation methods. Using angle measurements for gear condition monitoring is a promising approach to improve fault detection capabilities. Therefore, a summary of the identified gaps and needs recommends future research for further enhancing angle-based gear condition monitoring.