A bio-inspired artificial whisker for fluid motion sensing with increased sensitivity and reliability

Biological hair fluid motion sensors are found in a variety of animals such as arachnids and marine mammals. These sensors display a wide range of geometrical sizes and dynamic characteristics affecting their sensitivity. We report design revisions to improve sensitivity, wake detection capabilities, and reliability in a biologically inspired fluid motion/wake detection sensor. The design implements a cone-in-cone capacitance based sensing mechanism for monitoring fluid motion fluctuations in the wake of an object in four directions. The improved sensor design shows a gain range (the difference between peak output voltage amplitude divided by the peak input voltage amplitude) of up to 0.27 between whisker compression and deflection, a 300X increase relative to prior art. Improvements to the sensor include adjusting the deflection measurement modality, increasing the inner cone size, using silver epoxy for plating, shielding signal wires, and reducing parasitic capacitance that dampens the output voltage range.