Development of a small autonomous flying robot with four-rotor system

We discuss the development of a mini-quadrotor system for indoor application at Konkuk University. The propulsion system consists of X-UFO blade propellers and brushless direct current (DC) motors assembled on a very stiff airframe made of carbon fiber composite material. The attitude control system consists of a stability augmentation system as the inner loop control and a modern control approach as the outer loop. The closed-loop control is a PID controller, which is used for the flight test to validate our aerodynamic modeling. To perform an experimental flight test, basic electronics hardware is developed in a simple configuration. We used an AVR microcontroller as the embedded controller, a low-cost 100 Hz AHRS for inertial sensing, infrared (IR) sensors for horizontal ranging, and an ultrasonic sensor for ground ranging. A high performance propeller system is built on an X-UFO quadrotor airframe. The developed flying robot is shown to have an automatic hovering ability with aid of a ground control system that uses monitoring and a fail-safe system.