Quadrotor Helicopter Flight Dynamics and Control: Theory and Experiment

TLDR

Quadrotor helicopters are a popular UAV platform because of their simple construction, ease of maintenance, hover capability, and VTOL performance, yet existing designs typically address only nominal operating conditions. This study aims to investigate control challenges that arise when operating far from the hover regime. The authors analyze three aerodynamic effects—vehicle velocity, angle of attack, and airframe design—that generate attitude‑ and altitude‑control moments, and validate a theoretical model with thrust‑stand measurements and flight tests on the STARMAC quadrotor. The validated model leads to improved controller performance.

Abstract

Quadrotor helicopters are emerging as a popular platform for unmanned aerial vehicle (UAV) research, due to the simplicity of their construction and maintenance, their ability to hover, and their vertical take o and landing (VTOL) capability. Current designs have often considered only nominal operating conditions for vehicle control design. This work seeks to address issues that arise when deviating significantly from the hover flight regime. Aided by well established research for helicopter flight control, three separate aerodynamic eects are investigated as they pertain to quadrotor flight, due to vehicular velocity, angle of attack, and airframe design. They cause moments that aect attitude control, and thrust variation that aects altitude control. Where possible, a theoretical development is first presented, and is then validated through both thrust test stand measurements and vehicle flight tests using the Stanford Testbed of Autonomous Rotorcraft for Multi-Agent Control (STARMAC) quadrotor helicopter. The results enabled improved controller performance.