FPGA-Based Vibration Analyzer for Continuous CNC Machinery Monitoring With Fused FFT-DWT Signal Processing

Abstract

The industry of machine tools keeps a constant progress that responds to the most demanding market requirements, such as production-time decreasing and zero-defect manufacturing. As part of this progress, sensors and monitoring instruments have been integrated on machine tools, improving computer numerical control (CNC) and monitoring during the manufacturing process. The vibrations are one of the most significant variables to be monitored on machine tools since they directly affect the end piece finishing, tool life expectancy, general machine-tool condition, current consumption, etc. Time domain, fast Fourier transform (FFT), and discrete wavelet transform (DWT) are techniques often used for vibration analysis, because they are computationally efficient for online implementation; unfortunately, it is difficult to find an instrument for vibration analysis that allows individually applying the time, FFT, and DWT techniques, and their fusion. Moreover, the lack of instruments with characteristics such as open architecture, low cost, parallel processing, and continuous online monitoring is remarkable. The contribution of this work consists of developing a vibration-analysis instrument based on the time, FFT, DWT, and DWT-FFT fusion techniques. The instrument is implemented into a low-cost field-programmable gate array with proprietary hardware signal-processing cores in parallel for achieving real-time and continuous online analysis. Experimentation is done to show the proposed methodology efficiency and the developed-instrument versatility, focusing on industrial control applications for CNC machine tools.