Analysis of Urban Air Taxi Inner Loop Controller Architectures Subject to Noisy Inertial Measurement Unit Input while Immersed in Empirically-Developed Urban Airflow Disturbances

Abstract

Interest in designing and operating commercial Urban Air Taxis (UAT) around the world has grown exponentially over the last decade. One of the many challenges that are unique to UATs is the urban airflow environment in which they are envisaged to operate in. The presence of high-rise buildings creates a highly turbulent urban airflow environment which requires UATs operating within it to be equipped with highly robust inner-loop controllers to maintain steady level flight. This study investigates the effect of Angular Random Walk (ARW) noise in four grades of Inertial Measurement Units (IMU) on the inner loop flight controller's ability to maintain steady level flight. Three types of control schema are examined, namely classical Proportional Integral Derivative (PID) control, Active Disturbance Rejection Control (ADRC), and Linear Active Disturbance Rejection Control (LADRC). Each control schema has a different method of overcoming ARW noise found in the IMU readings which impacts its performance. A total of three metrics are used to compare the performance of the different controllers: 1) command tracking performance; 2) control surface deflections; and 3) passenger comfort. The results of this study show promising potential for using ADRC-based control architecture in UAT inner-loop control applications by exhibting superior command tracking performance, lower control surface deflections, and increased passenger comfort compared to PID. It also provides insights to regulatory authorites and UAT manufacturers of the importance of accounting for IMU sensor noise and recommended IMU grades to be used in UAT applications. Finally, iv I would like to thank my family for their patience and support while I completed this work. To my parents who constantly supported my endeavor to complete this work, my wife who took on the extra load to free up my time, my brother who would make the 5-hour drive to Ottawa to help out with chores when deadlines were approaching, thank you for all you have done for me. To my four young children who never got bored of asking me whether I was done so I could play, I can now say that my work here is done and I now have time to play. It is my hope that my endeavor in completing this work serves as a source of motivation to you in the future that with dedication, determination and the right support you can achieve what may at first glance appear to be too difficult and out of reach. A special thank you to my co-supervisors Prof. Khouli and Prof. Atia for your constant support, motivation and patience when things weren't going in the right direction. Thank you to Dr. Wall and the extended research team at the NRC, RWDI and RMC for the opportunity to present my progress and the usefull feedback you provided throughout this work.