Analysis of safety implications for SJA-based robust UAS flight control technology

Abstract

The cone of uncertainty of a small unmanned aerial vehicle's (UAV) flight trajectory induced by the aircraft's encounters with an upstream wake vortex or gust is addressed in the context of safety assessments for UAS operations. Such safety assessments will be a critical facet of the integration of unmanned aerial systems (UAS) into the National Airspace System (NAS), particularly in terminal airspace. This paper describes a predictive, robust feedback-loop flight control model that is applicable to various classes of UAVs and unsteady flight-path scenarios. The current test study investigates a new robust flight controller employing a ‘virtual’ control surface, which is generated using arrays of synthetic-jet micro-actuators (SJA). For a given amplitude of the flow disturbance and UAS parameters, the model employed in this paper allows us to estimate UAS flight-path deviations and recovery time, as well as to identify the limits of the control authority. In addition, the computationally simplistic structure of the proposed robust flight control method can operate at a faster sample rate, which can enable a UAS to recover more quickly from external disturbances due to wind gusts, while effectively minimizing deviations from the desired flight trajectory.