[Nicholas Rehm] works through the day on the Utilized Physics Laboratory at John Hopkins, Maryland, so has appreciable expertise with a wide range of UAV purposes. The query arose about how the perseverance mars rover touchdown labored, which prompted [Nicholas] to hold a rock underneath his drone, connected by way of a winch. This proved to be attention-grabbing. However what’s extra attention-grabbing for us, is what occurs while you attempt to connect an inverted pendulum to the highest of a drone in flight? (video embedded, beneath)
It is a basic management concept drawback, the place you should measure the angle of the pendulum with respect to the bottom, and shut the loop by calculating the mandatory acceleration from the pendulum angle. Sometimes that is demonstrated in a single dimension solely, however it is just a bit extra sophisticated to stability a pendulum with two levels of freedom.
[Nicholas] first tried to derive the pendulum angle by merely eradicating the centering springs from an analog joystick, and utilizing it to connect the pendulum rod to the drone physique. As is kind of apparent, this has a giant disadvantage. The pendulum angle from vertical is now the sum of the joystick angle and the drone angle, which with the related measurement errors, proved to be an unusable setup. To not be discouraged, [Nicholas] merely added one other IMU board to the underside of the pendulum, and saved the joystick mechanism as a pivot solely. And, as you may see from the video after the break, this certainly labored.
The flight controller is [Nicholas’] personal venture, dRehmFlight (GitHub), which is an Arduino library supposed for the Teensy 4.0, utilizing the ever present MPU6050 6-DOF IMU. [Nicholas] additionally made an intro video for the controller, which can show instructive for these wishing to go down this highway to construct their very own VTOL plane. The code for pendulum experiment shouldn’t be obtainable on the time of writing, maybe it’s going to hit the GitHub sooner or later?