Design of Whisker-Inspired Sensors for Multidirectional Hydrodynamic Sensing

Aquatic robots can improve their state estimation and control by measuring relative water flow for tasks such as calculating speed, local currents, or wakes. This article presents a novel aquatic whisker-inspired flow sensor for accurate flow speed and direction prediction. Our sensor design addresses common waterproofing and corrosion issues through a magnetic transduction approach that isolates the Hall effect sensor and electronics from the aquatic environment. Flow-induced drag on a whisker element rotates an attached magnet, which is detected by the submerged waterproof Hall effect sensor. This design also provides modularity of the whisker drag element, and we demonstrate how changing the whisker profile can affect the sensor’s sensitivity and range. Finally, using both analytical and experimental models, we selected a sensor design to demonstrate the velocity measurement of a small, remote-controlled boat. The sensors predicted the boat’s velocity with a root-mean-square error (RMSE) of 0.08 ms ${}^{-{1}}$ , highlighting the potential of this sensor design for future aquatic robot applications.