X4-MaG: a low-cost open-source micro-quadrotor and its Linux-based controller

• Manecy Augustin
• Marchand Nicolas
• Ruffier Franck
• Viollet Stéphane

The brand new open-source quadrotor platform called X4-Mag presented here was developed for academic and research applications. X4-MaG is a small, low-cost open quadrotor weighing only 307-grammes. This quadrotor offers two levels of controllers providing a manual mode and an automatic mode thanks to powerful Linux-based computational resources embedded onboard. The experiments presented here show the reliability of the open hardware and software embedded onboard the X4-MaG quadrotor, which is very easy to use. To estimate the robot's attitude, we developed a quaternion-based complementary filter requiring very few computational resources, which have been implemented on an 8-bit Arduino board. We have also established that the stabilization feedback system based on quaternions tracks the attitude setpoints with accuracy up to twice greater than a classical cascaded PI controller. The controllers and estimators were designed in the Matlab/Simulink environment and directly implemented onboard the tiny Linux-based autopilot board using a custom made toolbox (RT-MaG toolbox). The autopilot was tested in the brand-new Marseilles' Flying Arena with various 3-D flight trajectories and found to be highly reliable and accurate with errors of only 0.7cm in hover and less than 3.2cm at 1.2$m.s{-1}$). The X4-MaG quadrotor was able to reach speeds greater than 2 $m.s^{-1}$ and reject attitude disturbances as large as 20° within 0.8s.