Direct Shear Stress Mapping Using a Gallium Nitride LED-Based Tactile Sensor

An experiment was performed to calibrate the capability of a tactile sensor, which is based on gallium nitride (GaN) nanopillars, to measure the absolute magnitude and direction of an applied shear force without the need for any post-processing of data. The force's magnitude was deduced from monitoring the nanopillars' light emission intensity. Calibration of the tactile sensor used a commercial force/torque (F/T) sensor. Numerical simulations were carried out to translate the F/T sensor's reading to the shear force applied to each nanopillar's tip. The results confirmed the direct measurement of shear stress from 3.71 to 50 kPa, which is in the range of interest for completing robotic tasks such as grasping, pose estimation, and item discovery.

Automated summary

An experiment was conducted to calibrate a tactile sensor based on GaN nanopillars, which can measure the absolute magnitude and direction of applied shear force without requiring any data post-processing. The sensor's calibration utilized a commercial force/torque sensor, and numerical simulations were employed to convert the readings of the force/torque sensor into shear force applied on each nanopillar's tip. The results demonstrated the direct measurement of shear stress ranging from 3.71 to 50 kPa, which is important for various robotic tasks.