SOPHIE: SOft and flexible aerial vehicle for PHysical Interaction with the Environment

TL;DR

This paper introduces SOPHIE, a soft, lightweight UAV made with 3D-printed flexible filament capable of full-body perching on complex surfaces, with a focus on its design, dynamics, and control challenges.

Contribution

The paper presents the first design and analysis of a soft, 3D-printed UAV capable of perching on irregular surfaces, including insights into its dynamics and control strategies.

Findings

Validates flyability at densities as low as 6%

Provides a static arm deflection model for control

Identifies non-linear elastic dynamics at low densities

Abstract

This paper presents the first design of a soft, 3D-printed in flexible filament, lightweight UAV, capable of performing full-body perching using soft tendons, specifically landing and stabilizing on pipelines and irregular surfaces without the need for an auxiliary system. The flexibility of the UAV can be controlled during the additive manufacturing process by adjusting the infill rate distribution. However, the increase in flexibility implies difficulties in controlling the UAV, as well as structural, aerodynamic, and aeroelastic effects. This article provides insight into the dynamics of the system and validates the flyability of the vehicle for densities as low as 6%. Within this range, quasi-static arm deformations can be considered, thus the autopilot is fed back through a static arm deflection model. At lower densities, strong non-linear elastic dynamics appear, which translates to complex modeling, and it is suggested to switch to data-based approaches.