A flight control scheme for a quadcopter : implementation and validation

Abstract

A quadrotor is a type of rotorcraft composed of four equally-spaced rotors which provide the required lift and generated thrust from its xed-pitch propeller system. The attitude and position of the quadcopter is controlled by varying the angular speed of each motorised propeller. It provides the ability to move through six degrees of freedom, resulting in a multivariable underactuated nonlinear system. This complex system is an ideal platform for the development of several automatic control schemes and robotics research. The flight controller used in a custom built quadcopter uses the PX4 software architecture. This dissertation presents an in-depth analysis of the control schemes designed for the PX4 open source platform, mainly a cascade control architecture using several P/PID control loops. The flight controller has several flight modes, in which the degree of autonomy and type of user input response is varied. Lastly, this study includes both simulation and the experimental validation of the versatile control systems designed and implemented on a real quadcopter built specifically for the purpose of this project.