Detecting temperature of small object using hybrid tactile sensor array and multi-parameter extraction analysis

Abstract

An artificial hybrid tactile sensor and a signal process which can detect precisely temperature and pressure were demonstrated. Although a resistive temperature sensor has been used widely due to the easy fabrication process for tactile sensors, it was hard to detect an exact temperature value and the sensor showed the slow response when an object smaller than the dimensions of the sensor structure touched the sensor. To measure the exact temperature for a small object, we conducted a signal process using two major factors, the change of resistance provided by the thermal sensor and the information on the contact dimensions acquired from piezoelectric multi-array sensors. The design of the temperature sensor was simplified by utilizing a single resistor placed on the top layer of the hybrid sensor structure to enhance the sensitivity of thermal detection. Furthermore, using the gradient of resistance change instead of a saturation value can provide more reliable data due to the minimization of thermal conductivity change among various contact situations on sensors and fast detection time. The hybrid sensor system provided area information by which the gradient values were modified, and then the actual temperature value was calculated using the two variables, slope and contact size. As a result, the hybrid sensor successfully classified temperature levels on objects up to 30 times smaller than the resistive sensor dimensions with a very fast response time of below 10 msec.