Frequency adaptive and frequency domain adjustable frictional electric vibration sensor and its application in CNC machine tools

Abstract

In the process of promoting the transformation of global manufacturing towards intelligence and green, vibration monitoring of CNC machine tools is crucial for ensuring machining quality and preventing failures. However, due to energy and wiring maintenance issues, traditional active sensors are difficult to match the requirements of highly integrated, high-precision, and wideband monitoring. This study introduces a frequency adaptive and frequency domain adjustable triboelectric vibration sensor (AR-TVS) integrated into the tool holder of a machine tool, as well as its supporting monitoring and early warning system. For machine tool spindles with dense energy gathering, it is proposed to use spindle vibration excitation and vibration coupling of AR-TVS nonlinear structure to broaden the frequency domain and adaptively adjust the speed frequency. The efficient frequency extension mechanism and stability mechanism of mixed nonlinear resonance phenomenon under multi-input excitation are revealed. The influence of the centrifugal hardening effect on the natural frequency of the structure under different speeds is analyzed. Combined with the beam collision frequency extension mechanism, the frequency response range of AR-TVS is widened to meet the monitoring needs of different working conditions. We established a collision dynamics model for AR-TVS and verified its comprehensive response capability under complex conditions such as simulated eccentricity, temperature rise, and iron chip impact. AR-TVS demonstrated excellent performance with frequency monitoring errors below 1% over a wide frequency range. This study provides reliable technical support for precise state monitoring and intelligent analysis of CNC machine tools under complex working conditions.