Multi drone system models flexible cables for accurate load control
Dynamics Modeling of a Multi-UAV Slung Load System Using a Discrete-Link Cable Approach
Robotics
Summary
Controlling multiple drones carrying a shared load is tricky because the cables connecting the drones are flexible and behave in complex ways. The authors created a new model that represents these cables as a chain of rigid links, which lets computers simulate the motion more easily and accurately. They tested this model with real drone flights and found it closely matches actual movements. They've also shared the real flight data to help others improve cable models in the future.
What this means in practice
- •For multi-drone operators: Simulate and predict load behavior for safe multi-drone transport with flexible cables.
- •For robotics simulation developers: Integrate a discrete-link cable model into drone simulation tools to improve accuracy of slung load dynamics.
Authors
Harvey Merton, Ian W. Hunter
Abstract
A common assumption to simplify the problem of controlling a multi-UAV slung load system (MUSLS) is that the flexible cables can be modeled as massless rigid rods. In this work, we propose an alternative Euler-Newton derived dynamical model which uses a series of rigid links to model the flexible cables. The model is specifically designed to allow efficient simulation using Featherstone's articulated body algorithm. We perform real-world validation of this model on gentle, aggressive, and tension-engagement maneuvers and run a parameter sweep to determine the number of links, joint damping, and joint friction to achieve the greatest model fidelity. The model closely matches real-world flight data with mean load translation errors below 132 mm (5.5% of the cable length) and orientation errors below 11.4 degrees. We make the real-world flight data publicly available for the development of future cable models.