# Technical Note for "A Geodesic Approach for the Control of Tethered Quadrotors"

## TL;DR

This paper presents a novel cascade control scheme for tethered quadrotors that ensures stable, taut cable flight along geodesic paths, incorporating a reference governor for constraint enforcement.

## Contribution

It introduces a geodesic-based control approach with stability guarantees and constraint management for tethered UAVs.

## Key findings

- Control scheme maintains taut cable during flight.
- Ensures UAV follows geodesic trajectories.
- Stability proven using small gain arguments.

## Abstract

This technical note focuses on the control of a quadrotor unmanned aerial vehicle (UAV) tethered to the ground. The control objective is to stabilize the UAV to the desired position while ensuring that the cable remains taut at all times. A cascade control scheme is proposed. The inner loop controls the attitude of the UAV. The outer loop gives the attitude reference to the inner loop, and is designed so that (i) the gravity force is compensated, (ii) the cable is taut at all times, and (iii) the trajectory of the UAV follows the geodesic path. To prove asymptotic stability, small gain arguments are used. The control scheme is augmented with a reference governor to enforce constraints.