Modular Multirotors: From Quadrotors to Fully-Actuated Aerial Vehicles

Traditional aerial vehicles are constrained to perform specific tasks due to their adhoc designs. Based on modularity, we propose a versatile robot, H-ModQuad, that can adapt to different tasks by increasing its load capacity and actuated degrees of freedom. It is composed of cuboid modules propelled by quadrotors with tilted rotors. We present two families of module designs that bring scalable and versatile actuation to the aerial systems. By configuring multiple modules, H-ModQuad can increase its payload capacity and change its actuated degrees of freedom from 4 to 5 and 6. By modeling the actuation capability of H-ModQuad using actuation ellipsoids and wrench polytopes, we find the body frame of a vehicle that maximizes its thrusting efficiency. We also compare the vehicle capabilities against formally defined task requirements. We present the dynamics of H-ModQuad and integrate control strategies despite the vehicle design. The design and model are validated with experiments using actual robots, showing that H-ModQuad vehicles with different configurations provide different actuation properties. Note to Practitioners—This paper presents the H-ModQuad, a modular multirotor system designed to enhance the flexibility and versatility of aerial vehicles. Traditional drones often need to be specifically designed or modified for different tasks, but H-ModQuad allows for quick reconfiguration to meet varying operational needs. By adding or rearranging modules, users can easily increase the vehicle’s load capacity or improve its force and torque generation characteristics. This adaptability makes H-ModQuad particularly useful in industries such as logistics for transporting varying payloads, inspection and maintenance tasks in hard-to-reach areas, and uncrewed tool wielding. Our analytical tools provide pre-assembly vehicle capability assessment, and flight tests demonstrate that different modular configurations grant the vehicle with distinct actuation characteristics suitable for diverse tasks without redesigning the modules. Therefore, H-ModQuad offers a versatile aerial solution, making it a valuable tool for a wide range of autonomous applications.