# First Experimental Demonstration of Natural Hovering Extremum Seeking: A New Paradigm in Flapping Flight Physics

## TL;DR

This paper presents the first experimental validation of Natural Hovering Extremum Seeking (NH-ES), a model-free, sensory-based control method enabling stable hovering in flapping flight using natural oscillations and local light measurements.

## Contribution

It demonstrates experimentally that NH-ES can achieve stable, autonomous hovering in a flapping-wing system without relying on detailed aerodynamic or morphological models.

## Key findings

- NH-ES enables a flapping body to gain altitude and stabilize autonomously.
- The method is robust against delays and noise in sensory feedback.
- The system successfully hovers around a light source using only local light intensity feedback.

## Abstract

In this letter, we report the first experimental demonstration of the recently emerged new paradigm in hovering and flapping flight physics called (Natural Hovering Extremum Seeking (NH-ES)) [doi.org/10.1103/4dm4-kc4g], which theorized that stable hovering flight physics observed in nature by flapping insects and hummingbirds can be generated via a model-free, real-time, computationally-basic, sensory-based feedback mechanism that only needs the built-in natural oscillations of the flapping wing as both the control and the propulsive input. We run experiments of moth-like, light source-seeking, on a flapping-wing body in a total model-free setting that is agnostic to morphological parameters and body/aerodynamic models. We show that the flapping body using NH-ES gains altitude and stabilizes autonomously the servos responsible for flapping, including with pitching dynamics (believed in literature to be a main reason of instability in open-loop hovering). The flapping body effectively/stably hovers about the light source, needing only feedback of local measurements of light intensity. Our results were also achieved under delay/noise effects, supporting earlier observations that NH-ES is robust against potential processing delays and noisy-sensations.