The significance of unmanned aerial flying was increased dramatically in the past few decades both in military and civil sphere. The aerial vehicles are getting more and more complex systems and the development of advanced electronics, sensors and flight control algorithms leads us towards fully automated unmanned aerial vehicles (UAV). Within the frame of my MSc thesis I designed and built a quadrotor UAV, which is capable to follow the signals of an object autonomously, in the present instance a smartphone with the necessary sensors.
During writing my thesis I tried to present my work in a way to be understandable and reproducible for anyone with some technical experience. Therefore, after a short historical review and introduction, I give a comprehensive explanation for the built-up of the quadcopter. This chapter consists all the necessary information of the hardware, including the mechanical parts, the power electronics and the sensors. In order to get familiar with the quadcopter dynamics, in the third chapter I explain the basic concept of the maneuvering and the geometrical considerations. I investigated two mathematical models, the Euler-Newton and the Euler-Lagrange models, and I derived the equations of motion of the UAV based on the Lagrange’s equation, using Euler angles. These angles are calculated from the inertial measurement unit’s signals, therefore I present two sensor fusion algorithms, the direction cosine matrix and the Kalman filtering, which are able to accomplish the signal processing tasks. The last chapter of the theoretical backgrounds summarizes the theory of controls, in this case, the motor control algorithms and the PID controllers. At the end of this chapter, I try to give an estimation of the PID gains, based on the calculated equations of motion. Next, I summarize the process of the software development, where I show, how the control algorithms, the signal processing and the other parts of the system are implemented in the chosen microcontroller. This chapter covers the description of the application program interfaces (API) for calculating the orientation, the altitude and other necessary information of the system based on the sensor signals, furthermore the APIs to control the motors. Finally, I summarize the procedure of the effectuation, where I investigate the designed 3D printed parts and the results of the system testing.