Flexible, Equipment-Wearable Piezoelectric Sensor With Piezoelectricity Calibration Enabled by In-Situ Temperature Self-Sensing

Abstract

Flexible piezoelectric sensors have attracted much attention due to good dynamic response, high sensitivity, and self-powered sensing advantages. However, piezoelectric outputs are usually affected by temperature variation, thus limit their applications on industrial intelligent equipment. Here, a new flexible piezoelectric sensor with <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in situ</i> temperature sensing and piezoelectricity calibration function is developed. The sensor can calibrate the piezoelectric output based on temperature to achieve high-accuracy sensing capability. It consists of a flexible polyimide substrate, S-shaped platinum interdigital electrodes and aligned piezoelectric fibers. The designed S-type electrode with thermosensitive effect measures the temperature <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in-situ</i> , and then the piezoelectric strain output from P(VDF-TrFE) fibers is calibrated according to the temperature. The temperature sensor has a high sensitivity of 19.2 Ω/°C with good linearity, and keeps good accuracy under bending deformation. When the working temperature range is 25 °C–60 °C, the sensor has a good piezoelectricity calibration effect, so that it maintains a stable sensitivity of 244 mV/μϵ without being affected by temperature. Furthermore, this article systematically studied the influence of temperature on piezoelectric output, and established a calibration method to improve the accuracy of piezoelectric output under temperature changes. Finally, the flexible integrated sensor was conformally attached on the bearing surface to <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in situ</i> sensing temperature and micro-strain. The structural design and piezoelectricity calibration method can promote the application of flexible piezoelectric sensors in the industrial field.