Differential heat-flow-type warmth sensor for object material discrimination with reduced sensor output error due to object temperature

Abstract

This paper presents a differential heat-flow-type warmth sensor for highly accurate material discrimination by robots. In the previous study, we demonstrated a warmth sensor that identifies the material of a contacted object by its heat-flow-peak value. However, the previous heat-flow-type warmth sensor had a sensor output error in which the heat-flow-peak value changed depending on the temperature of the contacted object. In the present effort, to reduce the sensor output error, we propose a differential-type sensor composed of the two warmth sensors, based on the thermal equivalent circuit. First, the transient thermal equivalent circuit model was simulated to confirm the principle that it cancels the sensor output error. Then, a differential heat-flow-type warmth sensor with dimensions of 10.0 × 24.0 × 5.0 mm3 was fabricated by integrating two warmth sensors with thermal insulators. Finally, experimental results successfully demonstrated that the sensor output error can be reduced to − 0.17 mW/°C or less, which is almost 1/16 the error of the previous sensor.