Flow Shadowing: A Method to Detect Multiple Flow Headings using an Array of Densely Packed Whisker-inspired Sensors

TL;DR

This paper introduces 'flow shadowing,' a sensor array technique inspired by whiskers, to distinguish multiple simultaneous airflow sources around a drone by analyzing occlusion patterns.

Contribution

The study presents a novel method using densely packed sensors to identify multiple flow directions simultaneously, advancing airflow detection capabilities.

Findings

Flow shadowing predicts flow source occlusion based on sensor array data.

A 2x2 sensor array detects asymmetrical responses to multiple flow sources.

The method accurately predicts flow directions from multiple sources.

Abstract

Understanding airflow around a drone is critical for performing advanced maneuvers while maintaining flight stability. Recent research has worked to understand this flow by employing 2D and 3D flow sensors to measure flow from a single source like wind or the drone's relative motion. Our current work advances flow detection by introducing a strategy to distinguish between two flow sources applied simultaneously from different directions. By densely packing an array of flow sensors (or whiskers), we alter the path of airflow as it moves through the array. We have named this technique ``flow shadowing'' because we take advantage of the fact that a downstream whisker shadowed (or occluded) by an upstream whisker receives less incident flow. We show that this relationship is predictable for two whiskers based on the percent of occlusion. We then show that a 2x2 spatial array of whiskers responds asymmetrically when multiple flow sources from different headings are applied to the array. This asymmetry is direction-dependent, allowing us to predict the headings of flow from two different sources, like wind and a drone's relative motion.