Calibration of Tactile Pressure Sensors for Measuring Stress in Soils

This paper provides a method of properly calibrating tactile pressure sensors for the measurement of stress in soils subjected to short-term and long-term static loading. Tailor-made cells were used for the sensor calibration and examination of the calibration accuracy. It was found that if the calibration results for each sensing element on the sensor (i.e., each sensel) are used, the precision of the measured stress in soil under short-term static loading can be greatly enhanced. The sensor creep has to be quantified and removed from the measurement when the soil is subjected to long-term static loading. Because the creep response of each sensel depends on the applied pressure, the associated calibration also has to be carried out under different levels of pressure. This is time consuming and not feasible in reality. A quick method that can significantly shorten the calibration time is therefore proposed in this work. The examination results prove the accuracy of the quick method for calibrating sensor creep.