Multirotor Flight Leveling via PID Control Loops

by Ross Volenec

 

Submitted : Spring 2017

Unmanned multirotor “drones” generally operate using 3 or more motors oriented upwards to oppose gravity. Unlike a helicopter, they have no tail rotor to counter torque or cyclic control to influence angle of attack and unlike a fixed wing aircraft, they have no control surfaces for maneuvering. Additionally, while their relatively small size and low mass can be advantageous, it leaves them vulnerable to overcorrection and outside forces like wind. Most importantly, they don’t necessarily have a human acting as a pilot, remotely or otherwise.  

 

This is a problem that can be solved using applied calculus concepts. Using onboard sensors, it’s possible to determine actual position and relate that to desired position as an error function over time. This error function can be passed to the flight controller to determine corrections continuously in real time. One of the most common algorithms used to provide these corrections is the PID Controller – a closed-loop control system which has seen widespread use in a variety of fields for decades. 

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