Controller Design for Attitude and Position Control of Quadrotor

Abstract

This thesis discusses the development of detailed mathematical model for specific type of UAV, which has Vertical Takeoff and Landing (VTOL) ability, known as quadcopter. Mathematical model of quadrotor in state space form is derived; it utilizes Newton and Euler equations for three dimensional motions. This mathematical model is nonlinear and accurate enough including the aerodynamic effects and rotor dynamics. Quadrotor dynamics can be divided into two subsystems; translational subsystem and rotational subsystem. Translational subsystem is an under actuated system as it depends on roll, pitch, yaw angles and the translational state variables. The rotational subsystem is fully-actuated and only depends on the rotational states. Then development of two control approaches to control the attitude and position of the quadrotor in space is discussed. In first approach, Four PID controllers are designed to control the roll angle, pitch angle, yaw angle and altitude respectively. Strategy to implement PID controllers on nonlinear quadrotor model is discussed along with simulation results. In second approach, Backstepping controllers are designed to control the roll angle, pitch angle, yaw angle, altitude and positions. Simulation results after implementation Backstepping controllers on MATLAB are presented.