Design and Simulation-Based Flight Validation of a Synchronous Morphing Quadrotor

Abstract

The ability to navigate through confined and complex environments remains a significant challenge for standard rotary-wing Unmanned Aerial Vehicles (UAVs). This paper presents the design, dynamic modeling, and simulation-based flight validation of a novel synchronous morphing quadrotor. Utilizing a streamlined single-actuator planetary gear mechanism, the quadrotor can dynamically fold its arms during flight, successfully reducing its maximum diametric footprint from 280mm to 202mm. The hardware architecture revolves around the Pixhawk 6C Mini flight controller, ensuring robust low-level attitude stabilization. A comprehensive Software-In-The-Loop (SITL) simulation environment was constructed using Gazebo and PX4, accurately capturing the time-varying inertia and aerodynamic interactions during the morphing phase. Extensive offboard control experiments via MAVSDK-Python were conducted to evaluate the system’s trajectory tracking and disturbance rejection capabilities. Results from a Lissajous figure-8 tracking experiment demonstrate high spatial precision with negligible corner-cutting. Furthermore, dual disturbance rejection tests reveal that the attitude controller effectively mitigates a severe 5.0 Nm pulse wrench with only a 1.35-degree peak roll deviation, while continuous aerodynamic disturbances yield a steady-state error of merely 0.2 degrees. These findings validate the structural rigidity of the morphing mechanism and the robustness of the control framework, laying the groundwork for future fully autonomous confined-space navigation.