Multiple quadrotors carrying a flexible hose: dynamics, differential flatness and control

TL;DR

This paper models and analyzes the dynamics of multiple quadrotors transporting a flexible hose, demonstrating differential flatness and designing a linear control strategy validated through simulations.

Contribution

It introduces a generalized coordinate-free dynamic model for multi-quadrotor systems carrying flexible hoses and explores their differential flatness for control design.

Findings

Derived a coordinate-free dynamic model for the system

Identified configurations exhibiting differential flatness

Validated control approach through numerical simulations

Abstract

Using quadrotors UAVs for cooperative payload transportation using cables has been actively gaining interest in recent years. Understanding the dynamics of these complex multi-agent systems would help towards designing safe and reliable systems. In this work, we study one such multi-agent system comprising of multiple quadrotors transporting a flexible hose. We model the hose as a series of smaller discrete links and derive a generalized coordinate-free dynamics for the same. We show that certain configurations of this under-actuated system are differentially-flat. We linearize the dynamics using variation-based linearization and present a linear time-varying LQR to track desired trajectories. Finally, we present numerical simulations to validate the dynamics, flatness, and control.