Stabilizing Aerodynamic Dampers for Cooperative Transport of a Suspended Payload with Aerial Robots

Abstract

The current paper addresses the problem of stabilizing multiple aerial robots cooperatively transporting a cable-suspended payload by an aeromechanic method. Instead of relying on global navigation satellite systems (GNSS) or vision and communication for agents to actively estimate and control the state of the multibody dynamics, lightweight air dampers to make the multiagent system inherently stable at its equilibrium state, permitting the robots to safely carry a load at a constant velocity are employed. This is achieved without additional state estimation or active correction. The proposed framework is proven stable and verified by simulations and extensive flight experiments. Lightweight mechanical dampers (under 7 g) are shown to be effective in attenuating undesired oscillations and overcoming disturbances. To this end, a team of four robots cooperatively transporting a payload over 20 m in open space is demonstrated, and three robots safely transporting a point-mass payload over a distance of 45 m outdoors. The promising outcomes highlight the benefits of the passive strategy, which demands minimal hardware components and computation to realize the sophisticated aerial transport task.