Stabilizing quadrotor altitude and attitude through speed and torque control of BLDC motors

This research presents a control structure that utilizes the speed and torque control of the brushless DC motors (BLDC) within the attitude altitude loops in order to attain flight stability and maneuverability of the quadrotor Quadrotor platform. Classical controllers were used drive each BLDC motor to compensate for the errors in altitude and attitude of the quadrotor during flight. The control system was implemented on a dsPIC33 microcontroller that used various feedback and instrumentation sensors. A complementary filter was used to incorporate the data of the accelerometer and gyrometer to arrive at usable attitude estimates. The experimental results revealed that when using the proposed control structure, the attitude varied by less than five degrees while the altitude deviates by 50 cm. This was attributed to the fact that the PID controllers were able to compensate for the electronic speed controller (ESC) and motor mismatches. During one experiment, Quadrotor platform was able to reach six meters within five seconds.