Ball-and-Socket joint produces longitudinal and lateral control with a horizontal feathered tail for small uncrewed aerial systems

This work presents the development of a novel, articulated small uncrewed aerial system (sUAS) tail with coupled twist-pitch motion via a ball-and-socket joint. The ball-and-socket joint is controlled by a five-bar linkage which allows two servos to work together in twist-pitch motion, as opposed to dedicated traditional elevator and rudder servo control. The articulated tail is constructed of synthetic feathers which slide over one another via a splay degree of freedom controlled by a third servo. Additive manufacturing is leveraged in the construction of all parts of a wind tunnel model with continuous carbon fiber (CCF) reinforcement, which increased the structural stiffness from 1–2 GPa for Nylon to 15–20 GPa with CCF reinforcement. Wind tunnel test results are presented for 5 and 7 m/s wind speed with body angles of-5° to 45° angle of attack and twist-pitch articulation of −30° to 45° and −45° to 45° respectively. This articulated tail design was capable of enabling fine five axis control (e.g., no roll moment control) via pitch and twist morphing across a broad range of angles of attack and airspeeds.