Agile and Cooperative Aerial Manipulation of a Cable-Suspended Load

TL;DR

This paper introduces an online kinodynamic motion planning framework for multi-quadrotor systems to manipulate cable-suspended loads with high agility, enabling fast, complex maneuvers and robustness without extra sensors.

Contribution

It presents a novel trajectory-based control approach that accounts for dynamic coupling, significantly improving agility over existing methods in multi-quadrotor load manipulation.

Findings

Achieves at least eight times greater acceleration than previous methods.

Enables complex maneuvers like flying through narrow passages at high speed.

Demonstrates high robustness without additional sensors on the load.

Abstract

Quadrotors can carry slung loads to hard-to-reach locations at high speed. Since a single quadrotor has limited payload capacities, using a team of quadrotors to collaboratively manipulate a heavy object is a scalable and promising solution. However, existing control algorithms for multi-lifting systems only enable low-speed and low-acceleration operations due to the complex dynamic coupling between quadrotors and the load, limiting their use in time-critical missions such as search and rescue. In this work, we present a solution to significantly enhance the agility of cable-suspended multi-lifting systems. Unlike traditional cascaded solutions, we introduce a trajectory-based framework that solves the whole-body kinodynamic motion planning problem online, accounting for the dynamic coupling effects and constraints between the quadrotors and the load. The planned trajectory is provided to the quadrotors as a reference in a receding-horizon fashion and is tracked by an onboard controller that observes and compensates for the cable tension. Real-world experiments demonstrate that our framework can achieve at least eight times greater acceleration than state-of-the-art methods to follow agile trajectories. Our method can even perform complex maneuvers such as flying through narrow passages at high speed. Additionally, it exhibits high robustness against load uncertainties and does not require adding any sensors to the load, demonstrating strong practicality.