Online natural frequency detection system

Abstract

The invention discloses an online natural frequency detection system, which at least comprises a signal acquisition unit, a sensor unit and a data processing unit, wherein the signal acquisition unitacquires time domain signals; the sensor unit is used for transmitting signals acquired by the signal acquisition unit and the sensor unit is connected with the signal acquisition unit; and the data processing unit is used for processing the acquired signals. In view of a modal intensive condition existing in actual test, an intensive mode is extracted independently and is indexed according to a frequency value. When pretest is carried out on a workpiece, a program finds out multiple peaks appear in a detection range, the section of frequency response function amplitude curve is extracted, andeach natural frequency in the section of curve is labeled. In the case of test, according to the label, the one-order natural frequency value is fixedly extracted.

Description

technical field [0001] The invention relates to an online natural frequency detection system, which belongs to the field of frequency detection. Background technique [0002] Natural frequency on-line detection system has great market demand. At present, there are mainly two natural frequency analysis methods on the market. The first method relies on the manual method to judge the natural frequency. Its advantage is that it has a better effect on dense modes and can judge the frequency value of small peaks adjacent to the main peak. However, it is analyzed manually, resulting in low efficiency. In many cases, it is offline analysis. It is difficult to trace unqualified products, and the accuracy is difficult to guarantee. The second is to carry out detection through the system. The detection through computer programs has high efficiency and good accuracy, and constant analysis avoids the project of data traceability. The disadvantage is that the current mainstream systems ...

AI Technical Summary

Problems solved by technology

The disadvantage is that the current mainstream multiple systems still rely on the search to see the maximum frequency value of the amplitude within the range for system judgment. If there are multiple peaks in the interval, only the maximum value can be taken, and it is difficult to obtain the first-order frequency fixedly.

[0003] Compared with the natural frequency detection system designed by the predecessors, the automatic natural frequency measurement system of the brake disc designed by Hu Lele (CN201520712770.9) is mainly designed for the brake disc. Values ​​are loose

As a result, dense modal identification is not possible and the additional mass caused by the use of accelerometers affects the measured values ​​of the workpiece

[0004] A workpiece natural frequency detection device designed by Ji Cheng (CN201110332097.2) also relies on hammer excitation, but it does not mention in the invention how to deal with unsatisfactory knocking. Offset can easily cause misjudgment of the workpiece

Moreover, the acceleration sensor is also used, which affects the accuracy of the test.

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