Signal processing and fabrication of a biomimetic tactile sensor array with thermal, force and microvibration modalities

We have developed a finger-shaped sensor array that provides simultaneous information about the contact forces, microvibrations and thermal fluxes induced by contact with external objects. In this paper, we describe a microprocessor-based signal conditioning and digitizing system for these sensing modalities and its embodiment on a flex-circuit that facilitates efficient assembly of the entire system via injection molding. Thermal energy from the embedded electronics is used to heat the finger above ambient temperature, similar to the biological finger. This enables the material properties of contacted objects to be inferred from thermal transients measured by a thermistor in the sensor array. Combining sensor modalities provides synergistic benefits. For example, the contact forces for exploratory movements can be calibrated so that thermal and microvibration data can be interpreted more definitively.