Fault Feature Extraction Method For Local Defect In Friction Materials Of Ultrasonic Motor

Ultrasonic motors have gradually been used in many important fields due to their special excellent performance,such as the medical industry and aerospace.Therefore,the normal operation of ultrasonic motors is directly related to the safety of the entire system.In the traveling wave ultrasonic motor,the local peeling failure of the friction material directly affects the output performance of the motor,and will accelerate the motor failure.The working environment of the ultrasonic motor is relatively complicated.Although it is not affected by the magnetic field,it is inevitable that there will be other interferences.Aiming at the problem that the fault information is susceptible to noise,especially the difficulty in extracting the initial characteristics of the fault,an ultrasonic motor experimental platform is built in this paper to simulate different peeling degrees by changing the peeling width of the friction material.The advantages of using isolated pole voltage signal as the processing object are analyzed,and a fault feature extraction method based on the combination of LCD(Local Characteristic-scale Decomposition)and Teager energy operator is proposed.First,the original signal samples are decomposed by LCD to obtain different intrinsic scale components,and each component is reconstructed through autocorrelation analysis to achieve noise reduction preprocessing;secondly,the Teager energy operator is used to analyze the low frequency range of the reconstructed signal.The fault information is amplified;finally,the low-frequency fault frequency components are screened,and a fault feature calculation method based on amplitude and frequency information is proposed.Through sampling and processing of isolated pole voltage signals under different friction material peeling widths,the results show that this method can effectively characterize the amplification trend of local peeling of the friction material of the traveling wave ultrasonic motor,can accurately distinguish the early fault characteristics,and the calculation speed is faster At the same time,the fault feature also has applicability under a certain noise background.