Optimization of the Discrete Structure in a Pressure Sensor Based on a Multiple-Contact Mechanism to Improve Sensitivity and Nonlinearity

Abstract

Pressure sensors based on discrete structure and multiple-contact mechanism (DSMM) have enabled high sensitivity and a wide range of nonlinear measurements in our previous work. In this work, we increased the density of the resistor array pixels and designed pixel patterns with varied separation distances to improve the sensing range and correct the sensing linearity, while maintaining the ultrahigh sensitivity of the DSMM pressure sensor. A refined calculation model was applied to simulate the multiple-contact mechanism and to optimize the sensing performance. The theoretical analysis and practical experiments agreed well. The ultrahigh sensitivity is 1.59/kPa for a small pressure range (<150 kPa) and 3.06/kPa for a large pressure range (150 kPa-230 kPa). High linearity (R <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> = 0.9565) and good repeatability(800 cycles) were achieved for pressure sensing. With the improved design, the DSMM pressure sensors and simulations exhibited steady performance, easy calibration and simple data processing. Moreover, we studied the effects of the pixel size and starting contact position on the sensor performance to further verify the feasibility of DSMM pressure sensors. The preferred range of thickness required for the support structure was analyzed from gravity deformation and threshold force. And the hardness of blueberries was detected to reflect its ripeness or rottenness and showed its potential applications.