Modular Multi-Rotors: 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 different actuation characteristics to the system. By configuring multiple modules, H-ModQuad can increase its payload capacity and change its actuated degrees of freedom from 4 to 5 and 6. Using the concept of actua-tion ellipsoids, we find the body frame of an H-ModQuad that maximizes the thrust for hovering. By modeling the actuation capability of the vehicles using wrench polytopes, we examine them against formally defined task requirements. We present the dynamics of the vehicles and integrate control strategies despite 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.