Simulation and Initial Experiment of a Twist-Tilt Quadcopter for Fully Actuated Motion

Although conventional quadcopters are well developed and are used in many applications, they are limited to 4 degree-of-freedom motion. For instance, the underactuated quadcopters cannot hover with inclined roll or pitch angles. To achieve fully actuated 6 degree-of-freedom motion, this paper presents a design, construction, and initial experimental results of an overactuated twist-and-tilt quadcopter configuration proposed in the group's previous work. The copter is comprised of four rotors, where each rotor's twist and tilt angles are independently adjustable over one full rotation by servo actuators. The copter weighs 5.78kg and is designed to carry an additional 5kg payload. A comprehensive multi-body virtual plant simulation model was also created with identified parameters from the rotor-arm drive dynamics to verify the control, which is designed based on a lumped single rigid body model. Also, an experimental rig was constructed to facilitate flight testing in a small physical space with safety to both the copter and environment. The initial experimental results for 6 degree-of-freedom motion is then presented.