In the old days, building a quadcopter or drone required a lot of hacking together of various components from the motors to the batteries and even the control software. Not so much anymore, with quadcopters of all sizes ready to go literally out-of-the-box. While this has resulted in a number of knock-on effects such as FAA regulations for drone pilots, it’s also let us disconnect a little bit from the more interesting control systems these unique aircraft have. A group at Cornell wanted to take a closer look into the control systems for drones and built this one-dimensional quadcopter to experiment with.

The drone is only capable of flying in one dimension to allow the project to more easily fit into the four-week schedule of the class, so it’s restricted to travel along a vertical rod (which also improves the safety of the lab).  The drone knows its current position using an on-board IMU and can be commanded to move to a different position, but it first has to calculate the movements it needs to make as well as making use of a PID control system to make its movements as smooth as possible. The movements are translated into commands to the individual propellers which get their power from a circuit designed from scratch for this build.

All of the components of the project were built specifically for this drone, including the drone platform itself which was 3D printed to hold the microcontroller, motors, and accommodate the rod that allows it to travel up and down. There were some challenges such as having to move the microcontroller off of the platform and boosting the current-handling capacity of the power supply to the motors. Controlling quadcopters, even in just one dimension, is a complex topic when building everything from the ground up, but this guide goes some more of the details of PID controllers and how they help quadcopters maintain their position.

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