Handheld Microtactile Sensor for Elasticity Measurement

This paper presents a novel MEMS tactile sensor that can provide elasticity measurement of a variety of target objects. This sensor can be integrated on a handheld probe or on minimally invasive surgical tools for in-vivo tissue elasticity measurement. The tactile sensor consists of a pair of contact bumps that have different values of stiffness. Two capacitive force gauges are integrated underneath the bumps. The sensor readout is composed of two channels of capacitance values and the ratio of these capacitance values can be used to calculate the elasticity of target objects. To obtain reliable measurement of capacitance ratios, an estimation algorithm is developed by using a recursive least squares method with adaptive forgetting factors. Experimental characterization of the sensor shows that this tactile sensor provides reliable elasticity measurement of polymer specimens and quickly detects changes in elasticity.