Modelling and Control of the Crazyflie Quadrotor for Aggressive and Autonomous Flight by Optical Flow Driven State Estimation

Abstract: The master thesis seeks to develop a control system for the Crazyflie 2.0 unmanned aerial vehicle to enable aggressive and autonomous flight. For this purpose, different rigid-body models are considered, differing primarily in their parametrisation of rotation. The property of differential flatness is explored and several means of parametrising trajectories in at output space are implemented. A new method of rotor control with parameter estimation is developed and geometric controllers are implemented for rigid-body control. Finally, state estimation is accomplished through a scalar-update extended Kalman filter, where information from the internal measurement unit is fused with positional information from camera systems, ultra-wide band systems, optical flow measurements and laser ranging measurements. Capable of sustaining flight with any combination of the previously mentioned sensors, the real-time implementation is showcased using polynomial motion-planning to avoid known obstacles.