AEROBULL: A Center-of-Mass Displacing Aerial Vehicle Enabling Efficient High-Force Interaction

Abstract: In various industrial sectors, inspection and maintenance tasks using UAV (Unmanned Aerial Vehicle) require substantial force application to ensure effective adherence and stable contact, posing significant challenges to existing solutions. This paper addresses these industrial needs by introducing a novel lightweight aerial platform (3.12kg) designed to exert high pushing forces on non-horizontal surfaces. To increase maneuverability, the proposed platform incorporates tiltable rotors with 5-DoF (Degree of Freedom) actuation. Moreover, it has an innovative shifting-mass mechanism that dynamically adjusts the system's CoM (Center of Mass) during contact-based task execution. A compliant EE (End-Effector) is applied to ensure a smooth interaction with the work surface. We provide a detailed study of the UAV's overall system design, hardware integration of the developed physical prototype, and software architecture of the proposed control algorithm. Physical experiments were conducted to validate the control design and explore the force generation capability of the designed platform via a pushing task. With a total mass of 3.12kg, the UAV exerted a maximum pushing force of above 28N being almost equal to its gravity force. Furthermore, the experiments illustrated the benefits of having displaced CoM by benchmarking with a fixed CoM configuration.