Nowadays many people are interested in civil UAV’s, so called drones, which can be very helpful in many application areas. Fire-fighter drones, agriculture-sprayers, and flying cameras are very suitable for these tasks. This paper will carry through the design process of a multi-rotor helicopter. The target was to design and test a medium sized quadcopter, where the most important thing was the reliability and also the ability to be redesigned for a special purpose.
In the design process first I choosed the motors, that have enough thrust to lift the quadcopter, and then I designed a hardware which is able to spin the motors. These inverters use BLDC control scheme to spin the sinusodial motors, while the drone is flying. The design process of the inverters carry through the hardware design, soldering, testing, and also the software development. The design and testing process of the inverters took nearly 6 months.
The tests of the inverters showed that they are able to control the motor’s thrust, so I could start the development of the quadcopter. For the central control of the drone I designed a PCB (including hardware, soldering, software, testing), which is able to control the trajectory of the quadcopter, and able to estabilish a wireless connection between the drone and the ground.
The quadcopter would not be able to fly without a frame, so I designed a 3D printed body, which has more than 10 parts held together with different sized screws. To design the parts I used the Autodesk Inventor program.
The drone can be controlled via a wired (only for the development) and a wireless connection. For the wireless ground control I designed a remote controller, which also has a 3D printed body. The remote controller has 4 different switches, two joysticks and an OLED display to show the important flight data. The ground unit is controlled by an Arduino Nano development board.