A Wedge-Shaped Column Array-Based Self-Powered Vibration Sensor for Coal Mine Roof Fracturing Drilling

During coal mine roof fracturing drilling, vibration signals from the drilling tool can reflect both the drilling state and the structural response of the roof. However, traditional vibration sensors generally depend on batteries or wired power delivery, which hinders their long-term deployment in underground monitoring environments. To overcome this limitation, a self-powered vibration sensor featuring a wedge-shaped column array structure was developed, enabling vibration-induced electrical signal generation through the triboelectric effect. The sensor utilizes drilling-induced vibration to trigger cyclic contact–separation between the nanolayers, thereby converting vibration energy into electrical signals associated with the vibration frequency. In this way, the sensor can achieve both vibration frequency measurement and energy harvesting. The sensor was experimentally verified to enable reliable frequency detection across the 0–9 Hz range, with a measurement error of less than 3%. It also retained stable operational performance under temperatures up to 100 °C and relative humidity below 90%. Moreover, the output power reached a maximum value of 8 × 10−7 W with an external load of 108 Ω. The developed sensor enables self-powered vibration frequency measurement, while its redundant vibration structure enhances operational reliability. These features make it suitable for underground coal mine drilling environments characterized by limited space and strong mechanical vibration.