Degradation feature extraction method for piezoelectric ceramic of ultrasonic motor based on DCT-SV cross entropy

Abstract

Crack on piezoelectric ceramic is the main reason leading to failure of ultrasonic motors. A novel degradation feature extraction method based on discrete cosine transform (DCT)-singular value (SV) cross entropy was proposed in this paper. In order to improve the correlation with the crack, the DCT coefficients with the property of energy aggregation, were used to extract fault information. To avoid the influence of human factors in traditional DCT de-noising method, a matrix composed of DCT coefficients was constructed, and the SV cross entropy of the matrix was taken as the degradation feature for ultrasonic motor. A numerical simulated noise was added to the measured signal to verify the anti-noise performance of the feature. Analysis of the experimental results demonstrates that the proposed DCT-SV cross entropy is feasible and effective in indicating the degradation of piezoelectric ceramic in ultrasonic motor.

Design of a system for diagnosing the technical condition of a gas pumping unit based on the analysis of existing methods of processing vibroacoustic signals

“…У роботі [6] за допомогою швидкого перетворення Фур'є було визначено частоти та амплітуди вібраційних сигналів від пневматично спарених турбін (одна -компресор, другавільного ходу) із сигналу від усієї системи, однак подальший аналіз був неможливим, оскільки по номограмі Фельдмана співвідношення частот та амлітуд двох сигналів є таким, що не дозволяє чітко їх розділити, тому остаточний аналіз не було проведено, що є недоліком. За допомогою короткочасного перетворення Фур'є у роботі [7] було показано зміни при переході від робочого до неробочого стану, а саме відбулися зміни, що призвели до того, що найбільшою амплітудою стала володіти не перша гармоніка, а п'ята.…”

Intelligent fault diagnosis of ultrasonic motors based on graph-regularized CNN-BiLSTM

“…Ultrasonic motor (USM) is a kind of small and light piezoelectric actuator, which has been increasingly employed in * Author to whom any correspondence should be addressed. various high-end market segments like spacecraft, biomedical devices, optical instruments, etc [1,2]. Figure 1 presents a typical USM utilized in a micro-nano satellite control system for micro propulsion, and it mainly consists of piezoelectric ceramics, stator, rotor, encoder, and friction plate.…”

“…However, there are still two shortcomings in existing methods. (1) The geometric structure of the original distribution of multiple signals is rarely considered while the inherent topology and distance relationships among original data should be preserved in the transformation from high-dimension to one-dimension.…”