Aeronautics, Dynamics, and Control Laboratory

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Mission Statement

(1) interdisciplinary (multi-physics) modeling and analysis, (2) mathematical rigor, and (3) inspiration from Nature are our enabling factors to shape the future of aeronautical engineering.

Lab History

The ADCL was inaugurated in Sep 2014. Since then, it has produced 50 publications (20 journal articles and 30 conference papers); raised about $1.4 million; and supported two postdocs, seven PhDs, and 11 Masters.

Research Interests

1. Unsteady Aerodynamics
Unsteady aerodynamics emerges in various subjects such as the flapping wing, flutter analysis, and rotary blades. One of the most famous approaches in this field coming from the potential flow theory is the Theodorsen solution for the harmonically pitching-plunging flat plate which has been mainly devised for the flutter problem. Since lift generation and vorticity production inside are essentially viscous processes, we attempt to study the viscous unsteady aerodynamics rather than utilizing the conventional potential-flow-based solutions. To do so, we labor wind tunnel experimentation, computational fluid dynamics and analytical approaches to account for the viscous phenomenon. Recently, for the first time, we developed a theoretical viscous extension of the Theodorsen lift frequency response based on the triple deck boundary layer theory and validated it with high fidelity CFD simulations of a harmonically pitching airfoil. More phase lag at high reduced frequencies and low Reynolds numbers is the main outcome of the aforementioned study.

2. Geometric Control Theory
Linear Control has reached a mature stage of development and qualitative questions such as Controllability and Observability has been answered satisfactorily. For nonlinear systems, however, questions about fundamental structural properties such as Controllability are yet to be answered with the hope of reaching analogous results to linear systems. We aim at formalizing feedback-invariant necessary and sufficient conditions for Controllability of nonlinear systems and also we aim to develop a meaningful measure of degree of Controllability of nonlinear systems. If successful, the results of this project will hopefully revive interest in Geometric Control, a branch of control theory that is concerned with studying nonlinear systems using mathematical tools from Differential Geometry.

3. Engineering Applications
Geometric nonlinear controllability analysis sometimes leads to very interesting and non-intuitive results. A car with two controls (forward/backward and steering) is obviously not linearly controllable because of the inability to generate pure side motions. However, the nonlinear geometric analysis shows that the system is nonlinearly controllable and through some manipulation of the available two controls, one can generate side motions. This idea has been generalized to many nonlinear dynamical control systems, where the question is “Will the system still be controllable, if one or more actuators are missed?” One example is the attitude dynamics of a spacecraft (rigid body) where it has been shown that the system is still controllable even if one or two pairs of gas jets are removed, in spite of the system being linearly uncontrollable. In this research, we perform a geometric nonlinear controllability analysis for airplane flight dynamics to study whether the airplane will remain controllable if one or more of the control surfaces fail. Recently, we showed that a twin-engined airplane might still be controllable if it lost all control surfaces (thrust-only flight control system), despite the fact that it is linearly noncontrollable. From another perspective, if that control surface is not needed for control, then how can we use to improve efficiency or to execute unconventional maneuvers? One example is that we found that realizing the Lie bracket between the elevator and aileron deflections leads to a novel rolling mechanism that has a higher authority near stall than the conventional rolling mechanism (using aileron only). The reason is that the traditional mechanism depends on the value of the aileron sensistivity which vanishes near stall, whereas the novel mechanism depends on the rate of change of that sensistivity, which has a significant value near stall as shown in the figure. As such, this novel mechanism might be effective for near-stall or post-stall maneuvers.

News

Feb 2019 Professor Taha is awarded the prestigious NSF CAREER award. Congratulations!
Jan 2019 The ADCL group is presenting eight papers at the AIAA SciTech 2019 in San Diego. Great Effort!
Dec 2018 Amir has successfully passed his PhD Qualifying Exam. Congratulations Amir!
Nov 2018 Miquel Balta has successfully defended his MSc. Congratulations Miquel!
Nov 2018 Professor Taha is presenting at the APS DFD Meeting.
Nov 2018 Ahmed is presenting at the Socal Control Workshop.
Nov 2018 Ahmed Hassan has successfully defended his PhD. Congratulations Dr. Hassan!
Nov 2017 Ahmed Hassan has an accepted paper in the prestigious Journal of Nonlinear Science
Oct 2018 Professor Taha is giving an invited talk at the Aerospace Control and Guidance Systems Committee (ACGSC) on Vibrational Control of Flapping Flight.
Sep 2018 The ADCL welcomes four new PhD students: Moatasem Fouda, Nabil Khalifah, Dipan Deb, and Mahmoud Abdul Galil.
Aug 2018 Professor Taha is giving a talk at the University of Southern California.
Jul 2018 Imran and Sameh have their paper (Controllability Perspective of Dynamic Soaring) accepted at the Journal of Nonlinear Dynamics.
Jan 2018 Professor Taha is presenting papers at the AIAA Aviation and the IEEE ACC conferences.
Jun 2018 The Flapping MAV team won the first prize ($10,000) of the Beall and Butterworth competition. Yaay!
May 2018 The Flapping MAV team is selected to perform at the Ingenuity 2018 Showcase. Congratulations Flappers!
May 2018 Professor Taha is awarded the "AIAA OC 2018 Young Professional of the Year Award", for "high potential for continued professional engineering growth in teaching and for technical contribution to Advanced Flight Dynamics Research".
May 2018 Amir is awarded the "AIAA OC 2018 Student of the Year Award", for "demonstrated capability in his aerospace studies, for continued academic excellence and for developing CFD (Computerized Fluid Dynamics) code for solving unsteady aerodynamics". Congratulations, Amir!
May 2018 Ahmed and Amir are presenting at the AIAA OC ASAT Conference.
May 2018 Sameh and Imran have their paper accepted at the Journal of Aerospace Science and Technology.
May 2018 Sameh is presenting at the Socal Control Workshop.
May 2018 Professor Taha has a paper accepted at the Aerospace Science and Technology with his VT collaborators on the variational dynamics of unsteady vortices .
Apr 2018 Marco got married. Yaay! Congratulations, Marco!
Apr 2018 Ahmed and Amir are presenting at the Socal Fluids Workshop.
Mar 2018 The Flapping MAV team won the Dean's selection in the Winter Design Review. Congratulations Flappers!
Jan 2018 Professor Taha is giving a talk at NYU Abu Dhabi in the memory of the Benjamin Franklin medalist Ali Nayfeh.
Jan 2018 Mohammadali Kiani has an accepted paper in the IEEE American Control Conference (ACC).
Jan 2018 Mohammadali Kiani has an accepted paper in the prestigious International Conference on Robotics and Automation (ICRA).
Jan 2018 Professor Taha is presenting two papers at the AIAA SciTech conference.
Nov 2017 Mohammadali Kiani has an accepted paper in IEEE Robotics and Automation Letters on his demonstration of the vibrational stabilization phenomenon in flapping flight.
Sep 2017 Ahmed Hassan got married. Hooray!
Sep 2017 Professor Taha is giving a talk at the University of Michigan Ann Arbor.
Sep 2017 Ahmed Hassan is awarded Holmes Fellowship for the academic year 2017-2018.
Aug 2017 Professor Taha is giving a talk at NASA AMES Research Center.
Aug 2017 Dr. Sameh Eisa joins our research group as a post-doctoral fellow. Welcome Sameh!
Aug 2017 Mohammadali Kiani and Joel Navarro succeeded to experimentally demonstrate the Vibrational Stabilization phenomenon in flapping flight. Good job, indeed!
Jun 2017 Ahmed Hassan has an accepted paper in the prestigious journal of Guidance, Control and Dynamics.
Mar 2017 Professor Taha is giving a seminar at the University of Maryland College park.
Jan 2017 Ahmed Hassan has an accepted paper in the prestigious journal of Nonlinear Dynamics.
Jan 2017 Ahmed Hassan is among the six finalists for the Student Best Paper Award at the AIAA GNC, by his paper A combined Averaging-Shooting Approach ...
Jan 2017 Our research group is attending the AIAA SciTech 2017 meeting at Dallas Texas, presenting six papers.
Jan 2017 Professor Taha is awarded an NSF EAGER grant to revisit the Vibrational Control Theory.