System Identification of Post Stall Aerodynamics for UAV Perching

Abstract

For a UAV to perch on a wire, aircraft control systems which operate far outside typical operating envelopes must be developed. The relevant transient aerodynamics at high angle of attack are not addressed today by control-accessible aerodynamic models. In this work, we present a set of physically-inspired basis functions which have enabled system identification of a nonlinear aerodynamics model along perching trajectories. Data is collected using a motion capture system which, critically, allows free-flight data from real system trajectories to be gathered. When simulated forward, the identified model accurately predicts the observed perching trajectories, making it an indispensable tool for designing feedback controllers that stabilize perching trajectories.

Identification of flight aerodynamics for flapping-wing microrobots

“…In [11], [17], it was shown that this method is capable of accurately predicting the aerodynamics of UAV perching under unsteady flight regimes.…”

“…It is straightforward to obtain an analytic solution to equation (11). Though, for the sake of simplicity and tractability, here we opt to replace the integration with a finite sum by dividing the damper into two pieces, separated by theẑ-axis.…”

“…This approach is, therefore, distinct from literature on aircraft system identification, where the models are typically linearized around cruising conditions [9], [10]. As a result, in this work, time domain identification techniques are employed [11], [12], [13], instead of frequency domain methods [9], [10], [14].…”

“…The physics-based approach taken here is unlikely to capture the dynamics of the vehicle as accurately as a model composed of best-fitted basis functions as presented in [10], [11], [13], nevertheless, it offers more insights into the interactions between aerodynamic forces and individual components of the vehicle. As a consequence, the learned model could serve as a guideline to iterate the design of the vehicle for better performance.…”

A Survey of Small-Scale Unmanned Aerial Vehicles: Recent Advances and Future Development Trends

“…Recently, promising results have been documented, regarding dynamics model identification for non-routine flight conditions or envelopes. Two successful cases can be founded in reports [40,44], in which system identification is applied to model take-off process (based on ARX/ ARMAX/BJ models) and perching (based on decoupled 6-DoF rigid-body dynamics model).…”