Field programmable gate array based altitude controller design for a four rotor unmanned aerial vehicle

In today's modern world, unmanned aerial vehicles mean vehicles that can move autonomously or can be controlled remotely by a human. Unmanned aerial vehicles are used in different areas and have different designs according to these areas. The fields where unmanned aerial vehicles are mainly used; military reconnaissance, border surveillance and attack. Other than military purposes UAV's are used for; in monitoring and spraying activities in agriculture, in transportation by commercial companies, in forest fire detection and extinguishing works, exploration activities and mapping in natural disaster areas. Microprocessors are generally preferred for autopilots of unmanned aerial vehicles. However, in applications requiring high speed, Field Programmable Gate Arrays (FPGA) can be preferred over processors. These processors read the incoming sensor and command control data and make the necessary decision mechanism. Unmanned aerial vehicles have proportional, integral and differential closed loop controllers for vehicle flight axes. These three elements are considered gains and their values must be tunned with the experiments. Four – rotor unmanned aerial vehicles, which are one of the unmanned aerial vehicles, are frequently preferred by researchers because they can take off and land vertically. They can also be used in indoor environments. Within the scope of this thesis non-linear mathematical model of a quadrotor was created. Quadrotor altitude model was implemented on Simulink. PID altitude controller was added to the realized model and simulations were made. In the next step, FPGA based altitude controller is presented. Altitude controller can be implemeted with different approaches and software design tools. At first method, FPGA based altitude controller was designed with Xilinx FPGA design blocks on Xilinx System Generator. Controller was tested with different referance altitudes and reference tracking also verified. At second method, altitude controller was implemeted on Matlab and reference tracking was verified. After reference tracking was verified, HDL codes were generated using HDL coder. At third method, altitude controller was implemented and tested with HLS which is growing in popularity recent years. Fourth and fifth methods were implemented on FPGA. At fourth method, PID altitude controller was implemented on FPGA using softcore microprocessor called "Microblaze". At fifth method, digital altitude controller IP was implemeted using VHDL and integrated with Zynq before testing functionality. At fourth and fifth methods reference tracking was verified using "Hardware in Loop" technique with Matlab Instrumentation Toolbox. Parameter uncertainty and noise parameters were added to design and alttitude controller functionality was tested. At final section of thesis, different approaches that were used at FPGA based alttitude controller, were compared to their performance, resource utility and power consumption.