A UAS obstacle avoidance strategy based on spiral trajectory tracking

This article proposes a methodology for enabling Unmanned Aircraft Systems (UASs) to avoid obstacles. The strategy, which makes use of a Robust Exact Differentiation (RED), relies on spiral trajectory tracking maneuvers, and is based on a backstepping controller with disturbance compensation. The RED strategy has been adopted since it enables the exact estimation of disturbances from the first moment, a characteristic that may be useful for real-time UAS operations in environments with obstacles. Our research concentrates in one of the main components of a Sense and Avoid (SSA) system, specifically, conflict resolution, leaving as future work the sensing aspect. To demonstrate the performance of the proposed solution, we present a set of simulation results as well as a real-time experiment where a holonomic UAS makes use of the estimation and control strategy while evolving in an environment with obstacles.