Designing, Modeling, and Control Allocation Strategy of a Novel Omnidirectional Aerial Robot

A novel omnidirectional aerial robot is introduced in this paper. It is driven by four 2-DOF tilting modules mounted at four vertices of a regular tetrahedron. This configuration ensures that at least three rotors remain on one horizontal plane while the frame rotates at any angle. The robot is thus capable of flying at any orientation in SE (3). This significantly expands application areas of the robot. Reliability is enhanced thanks the over-actuation design and configuration of the rotors. Dynamic equations of motion are derived based on the mechanical design. A control strategy is represented that allows decoupling of rotational and translational dynamics. A conceptual method for control allocation is also proposed. This takes into consideration the input saturation as well as other physical constraints. Furthermore, robustness is provided by re-configuration of rotors if some actuator encounters failures. Preliminary simulation and experiments demonstrate feasibility of the novel design and capability of this aerial robot.