Hierarchical control strategies for underactuated UAVs

Abstract

This talk discusses some control design challenges in Unmanned Aerial Vehicles, a rapidly growing technology with implementations in a variety of application fields. Starting from a description of the most common configurations (e.g., multirotor UAVs), novel platforms involving thrust-tilting mechanisms designed to increase maneuverability and interaction capabilities are described.
Salient features of the underlying mathematical models are highlighted, with particular emphasis to underactuation and nonlinear effects.  Limitations of existing control designs in addressing challenging operating conditions are presented together with some solutions based on hierarchical control ideas. Specifically, the talk covers the design of inner-outer loop attitude and position control laws for stabilization and trajectory tracking problems. We show how the hierarchical approach allows splitting the design challenges across different dynamic layers and simplifying the control law complexity with respect to classic backstepping-based approaches, enabling the
development of a modular framework wherein advanced control solutions, tailored to address specific conditions, can be considered in each layer. We present some experimental results, performed in the FlyART facility of Politecnico di Milano (ascl.daer.polimi.it/), concerning tilt-rotor UAVs, the testing of anti-windup designs for directionality compensation in quadrotors and the implementation of an autonomous strategy for the automatic landing of a quadrotor on a carrier drone.

Biosketch

Davide Invernizzi is an assistant professor at Politecnico di Milano, Department of Aerospace Science and Technology (DAER). After obtaining a MSc degree in space engineering in 2014, he received the Ph.D. degree in aerospace engineering in 2018, both at Politecnico di Milano, with a thesis on the control of underactuated Unmanned Aerial Vehicles. After two years as a Post-doc fellow at DAER, since 2020 he is an assistant professor (rtdA) at Politecnico di Milano. Since 2021, he is the lecturer for the MSc course ”Adaptive and Autonomous Aerospace Systems” and for the PhD course ”Advanced Aerospace Control”, both at Politecnico di Milano. He is a member of the Aerospace Systems and Control Laboratory at DAER and of the Observatory on Drones of Politenico di Milano. His main research interests lie in the area of aerospace control applications, with focus on nonlinear and robust control designs for unmanned systems and spacecraft.