A self-powered sensor for drill pipe capable of monitoring rotation speed and direction based on triboelectric nanogenerator.

The rotation speed and direction of the drill pipe are the key parameters to control the drilling process, which need to be measured in real-time. Here, a self-powered drill pipe sensor that can measure the rotation speed and direction based on the triboelectric nanogenerators is proposed in this research. The basic working principle is that the single-electrode triboelectric nanogenerator will output the sawtooth signal during the rotation of the drill pipe, so the rotation speed can be measured by counting the signal pulse frequency, and then, the rotation direction can be realized by judging the direction of the tooth tip of the sawtooth signals. Test results show that the measurement range is 0-1000 rpm, the measurement error is less than 4%, the sensitivity is 0.0167 Hz/rpm, and the linearity is 3.5%. Further tests show that the maximum output voltage, current, and power are 21 V, 900 nA, and 3.35 μW, respectively, when a 107 Ω load resistance is connected in series. In addition, the working condition reliability tests show that the working temperature is less than 150 °C and the working relative humidity is less than 90%, with high reliability, which is very suitable for the drilling environments.