Research on a friction-electromagnetic hybrid self-powered vibration sensor for geological drilling

Vibration signals of the drill string during drilling are crucial for optimizing drilling process parameters. However, existing downhole vibration sensors have limitations in power supply, which reduces drilling efficiency and increases drilling costs. This study proposes a friction-electromagnetic hybrid vibration sensor with self-powering capability based on the principles of triboelectric nanogenerators and electromagnetic generators. It utilizes vibration-induced triboelectric generation and electromagnetic generation and measures vibration frequency based on the pulse of the triboelectric generation output signal. Experimental results show that the sensor’s operating frequency range is 0–10 Hz, the operating temperature is less than 150°C, the operating humidity is less than 90%, and the measurement error is less than 3.8%. When external loads of 10 MΩ and 700 Ω are connected in series with the triboelectric generation unit and the electromagnetic generation unit of the sensor, respectively, the maximum output power generation is 16.9 μW and 36.2 mW, respectively. Compared with traditional downhole vibration sensors, this sensor has the function of power generation, and the redundant structure of the measurement unit effectively improves the reliability of the sensor, making it more suitable for actual downhole conditions.