Empirical Study of Ground Proximity Effects for Small-scale Electroaerodynamic Thrusters

TL;DR

This empirical study investigates how ground proximity affects the performance of small-scale electroaerodynamic thrusters, revealing significant thrust enhancements at close distances and dependencies on geometric parameters, aiding indoor robot propulsion.

Contribution

First empirical analysis of ground proximity effects on small electroaerodynamic thrusters, identifying key geometric factors influencing thrust enhancement for indoor robotic applications.

Findings

Peak thrust increased by 300-600% at 0.2 mm ground distance.

Thrust increased by up to 20% at centimeter distances.

Ground proximity effects depend on thruster geometry and configuration.

Abstract

Electroaerodynamic (EAD) propulsion, where thrust is produced by collisions between electrostatically-accelerated ions and neutral air, is a potentially transformative method for indoor flight owing to its silent and solid-state nature. Like rotors, EAD thrusters exhibit changes in performance based on proximity to surfaces. Unlike rotors, they have no fragile and quickly spinning parts that have to avoid those surfaces; taking advantage of the efficiency benefits from proximity effects may be a route towards longer-duration indoor operation of ion-propelled fliers. This work presents the first empirical study of ground proximity effects for EAD propulsors, both individually and as quad-thruster arrays. It focuses on multi-stage ducted centimeter-scale actuators suitable for use on small robots envisioned for deployment in human-proximal and indoor environments. Three specific effects (ground, suckdown, and fountain lift), each occurring with a different magnitude at a different spacing from the ground plane, are investigated and shown to have strong dependencies on geometric parameters including thruster-to-thruster spacing, thruster protrusion from the fuselage, and inclusion of flanges or strakes. Peak thrust enhancement ranging from 300 to 600% is found for certain configurations operated in close proximity (0.2 mm) to the ground plane and as much as a 20% increase is measured even when operated centimeters away.