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Summary

  • Technical Group Lead of Advanced Control and Engineering Systems Group in the Intelligent System Division at NASA Ames Research Center
  • Senior research scientist with 32 years of aerospace engineering experience
  • PhD, MS, and BS degrees in mechanical engineering, and BS degree in mathematics
  • 214 publications and textbook Model-Reference Adaptive Control - a Primer
  • Recipient of NASA Exceptional Scientific Achievement Medal
  • Multidisciplinary research experience including advanced control theory (adaptive, optimal, distributed-parameter systems), structural dynamics, aeroelasticity, aerodynamics, aircraft multidisciplinary design, flight dynamics and control, flow control, turbomachinery rotor dynamics and aerodynamics, wind tunnel and modal vibration experimental methods.
  • Four US patents and two patents in pending
  • NASA ARMD (Aeronautics Research Mission Directorate) Project Scientist (2007-2010)
  • Chair of AIAA Intelligent Systems Technical Committee (2015-2017)
  • Adjunct professor at Santa Clara University (2006-present)
  • Consultant for intellectual property law office (2000-2005)
  • AIAA associate fellow

US Patents

  • Four US patents as primary inventor, two patents in pending, two provisional patent applications, and 16 NASA invention disclosures:
    • Aeroelastic Wing Shaping Using Distributed Propulsion
    • Control Systems with Normalized and Covariance Adaptation by Optimal Control Modification
    • Variable Camber Continuous Aerodynamic Control Surfaces and Methods for Active Wing Shaping Control
    • Blading System and Method for Controlling Structural Vibrations

Honors and Awards

  • 57 NASA career awards including:
    • NASA Exceptional Scientific Achievement Medal
    • NASA Exceptional Achievement Medal
    • Two NASA Ames Honor Awards for Excellence in Engineer Category
    • Four NASA Patent Awards
    • Ten NASA Ames Technology Transfer Awards
    • Six NASA Group Achievement Medal
    • NASA Ames Outstanding Achievement
  • External awards:
    • AIAA Distinguished Service Award
    • AIAA Intelligent Systems Technical Committee Distinguished Service Award
    • Santa Clara University Adjunct Lecturer of the Year Award
    • Best Paper Award AIAA Infotech@Aerospace Conference
    • Top-Ten-Best-Paper Award AIAA Guidance, Navigation, and Control Conference

Technical Leadership

  • Technical Group Lead of Advanced Control and Engineering Systems (ACES) group in the Intelligent Systems Division (current) - Direct and provide technical leadership to a 23-person research group with 14 PhD and 9 MS researchers. The ACES group capabilities include:
    • Research and development of advanced flight control, guidance, and trajectory optimization
    • Damaged aircraft resilient flight control, stall recovery guidance, adaptive aeroelastic wing shaping control for transport aircraft, UAS autonomy, NASA LADEE (Lunar Atmosphere Dust and Environment Explorer) spacecraft GNC, and adaptable deployable EDL (Entry Descent and Landing) system guidance, and flow control
    • Aerospace vehicle multidisciplinary aerodynamic-aeroelasticity-flight dynamic modeling and simulations
    • Flight simulations and experiments in NASA Ames ACFS (Advanced Concepts Flight Simulator), VMS (Vertical Motion Simulator), ACT (Advanced Control Technologies) lab, EAV (Experimental Aerial Vehicle) lab, SPHERES (Synchronized Position Hold, Engage, Reorient, Experimental Satellites) lab for NASA ISS (International Space Station), and flight test collaboration with NASA Armstrong
  • Research Lead of Performance Adaptive Aeroelastic Wing Research (current) - Lead a multi-division team of 16 researchers with a total budget of $15.6 million since 2011 to conduct MDAO (Multidisciplinary Design Analysis and Optimization) research to develop adaptive aeroelastic wing shaping control technologies for high aspect ratio flexible wing transport aircraft under the NASA Advanced Air Transport Technologies, Fixed Wing, and Subsonic Fixed Wing projects
  • Project Scientist of NASA Integrated Resilient Aircraft Control (IRAC) Project (2007-2010) - Served as NASA ARMD Project Scientist for IRAC Project responsible for establishing research portfolios across four NASA; Ames, Armstrong, Glenn, and Langley with duties:
    • Provided technical leadership for IRAC project with $21 million annual budget to advance adaptive flight control technologies and integrated aircraft modeling capabilities for NASA Aviation Safety Program
    • Responsible for technical execution and communication to NASA ARMD of project performance
    • Managed 24 funded projects at universities and companies competitively selected via NASA Research Announcement (NRA) opportunities
  • Deputy Principal Investigator of NASA IRAC Project (2005-2006) - Served as Deputy Principal Investigator for IRAC Project responsible for developing resilient flight control and integrated aircraft modeling research portfolio, and led the research planning at NASA Headquarters to develop technical plan for the integrated airframe modeling and simulations research area
  • Associate Technical Lead of NASA Fixed Wing Project (2012-2014) - Served as Associate Technical Lead for the Aerodynamic Efficiency sub-project under the NASA Fixed Wing Project to develop MDAO research portfolio to advance performance adaptive aeroelastic wing technology for transport aircraft and establish research collaboration with aircraft industry and academia
  • Subject Matter Expert (SME) in GNC at NASA Ames (2012-2013) - Selected by Director of NASA Ames Aeronautics Directorate as SME in GNC to represent NASA Ames in the planning of NASA Fundamental Aeronautics Program and NASA Aeronautics Research Institute (NARI)
  • Project Lead of Damage Adaptive Control System (DACS) Project (2004-2006) - Led research activities at NASA Ames to conduct multidisciplinary research in collaboration with NASA Langley to develop flight dynamic modeling of damaged aircraft and adaptive flight control for damaged aircraft recovery
  • Integrated Systems Test Manager of NFAC (National Full-Scale Aerodynamic Complex) Fan Blade Project (1997-1999) - Led a 10-person engineering team to conduct structural dynamic and aerodynamic measurements and perform engineering analysis to assess structural integrity of the NFAC 40-By-80-By-120-Ft Wind Tunnel fan blades before and after fan blade repair
  • Member of NFAC Fan Blade Investigation Board (1997) - Assigned by NASA Ames Center Director to the investigation board as resident expert in rotor structural dynamics and fan aerodynamics to conduct aerodynamic and fatigue analyses to identify root causes of the NFAC fan blade cracking
  • Principal Investigator of Ames Unitary 11-Ft TWT (Transonic Wind Tunnel) Three-Stage Compressor Rotor Blade Vibration (1989 - 1996) - In charge of developing a comprehensive project plan to conduct analysis and testing of the 11-Ft TWT three-stage compressor rotor blade vibration and mistuning problems and to develop solutions to address these problems resulting in the development of a highly effective patented passive structural vibration suppression control method that sharply reduces rotor blade dynamic stress amplitudes.

Research Contributions

  • Develop wing shaping control technologies for flexible aircraft:
    • Adaptive aeroelastic wing shaping control concept for flexible aircraft and the Variable Camber Continuous Trailing Edge Flap (VCCTEF) system for aircraft drag reduction in 2010 - This multidisciplinary research led to on-going collaboration with Boeing since 2010 to mature performance adaptive aeroelastic wing technology for future transport aircraft. Wind tunnel experiments and CFD validation have confirmed the potential drag reduction of as much as 6% which could result in substantial fuel cost savings in future transport aircraft given that the global airlines spend more than $50 billion in jet fuel in 2012. Boeing expressed interest in flight validation of the VCCTEF on the future B777 ecoDemonstrator.
    • Aeroelastic wing shaping control using distributed propulsion for flexible wing aircraft in 2013 - This multidisciplinary research identifies a 2% potential fuel savings by aeroelastically tailoring thrust distribution along the wings to shape the lift distribution.
  • Lead and conduct research in the areas of aeroelasticity, aeroservoelasticity, coupled aeroservoelasticity-flight dynamics, and coupled aero-structural optimization of flexible wing transport aircraft:
    • Nonlinear aeroelasticity, aero-propulsive-elasticity, aeroservoelasticity, flutter analysis, and finite-element analysis
    • Integrated nonlinear aeroservoelasticity-flight dynamics of flexible wing NASA Generic Transport Model (GTM) and Boeing Truss-Braced Wing (TBW) aircraft
    • Coupled aerodynamics-structural analysis for optimization of the VCCTEF for drag reduction and maneuver load alleviation
  • Develop advanced aeroservoelastic control technologies for flexible aircraft:
    • Adaptive Linear Quadratic Gaussian flutter suppression control
    • Distributed-parameter flutter suppression control using Lyapunov method and differential-operator optimal control method in Hilbert space
    • Adaptive real-time drag optimization control using recursive least-squares model identification method
    • Multi-objective flight control method for simultaneous pilot command tracking, aeroelastic mode suppression, gust and maneuver load alleviation, and drag minimization using distributed multi-functional flight control surfaces such as the VCCTEF
  • Develop advanced adaptive flight control technologies:
    • Optimal Control Modification (OCM) method by combining optimal control with adaptive control theory
    • Bi-objective and multi-objective OCM
    • Performance optimizing multi-objective adaptive control with time-varying reference model
    • Least-squares model-reference adaptive control with Chebyshev orthogonal polynomial
    • Singular perturbation adaptive control for plants with slow actuator dynamics
    • Bounded Linear Stability Analysis (BLSA) and metric-driven adaptive control
    • Hybrid direct-indirect nonlinear dynamic inversion adaptive control
  • Conduct adaptive flight control experiments on NASA high-fidelity flight simulator and full-scale research aircraft:
    • Normalized OCM flight experiment on NASA F-18 research aircraft, tail number 853, at NASA Armstrong in 2010 and 2011
    • Normalized neural network intelligent flight control system flight experiment on NASA F-15 research aircraft, tail number 837, at NASA Armstrong in 2006
    • Pilot handling qualities evaluation of OCM, BLSA metric-driven adaptive control, and hybrid adaptive control in NASA Ames ACFS in 2009
  • Develop flow control technologies:
    • Distributed-parameter optimal control for flow separation control by stator air injection in gas turbine engines in collaboration with NASA Glenn
    • Distributed-parameter model predictive optimal control of Mach number regulation in NASA Ames 11-Ft TWT
  • Conduct trajectory analysis and optimization:
    • Minimum-time trajectory optimization of aircraft flight path in wind field
    • Minimum-fuel trajectory optimization using nonlinear optimal control and genetic algorithm
    • Range analysis for optimal cruise trajectory
  • Lead analytical and experimental structural dynamic characterization of rotor blades in NASA Ames 11-Ft TWT and NFAC:
    • Modal analysis testing of NASA Ames 11-Ft TWT compressor rotor blades and NFAC 40-By-80-By-120-Ft Wind Tunnel fan blades
    • Passive structural vibration control design, test, and implementation for 11-Ft TWT compressor rotor blades
    • Instrumentation, vibration measurements, and structural dynamic analyses of 11-Ft TWT compressor rotor blades and NFAC fan blades
  • Develop finite-element analysis codes and models:
    • Development of finite-element code for aeroelastic and flutter analysis of Boeing 757 wing and Truss-Braced Wing aircraft
    • Development of finite-element structural dynamic code for frequency and forced response analyses of NASA 11-Ft TWT compressor composite rotor blades
    • Finite-element analysis of the NFAC fan blades
    • Finite-element analysis of 11-Ft TWT motor drive shaft
    • Finite-element analysis of 11-Ft TWT semi-span model support
  • Lead and conduct aerodynamic analysis and experimental aerodynamics:
    • Development of unsteady mean flow CFD code for modeling transonic flow circulation of 11-Ft TWT using a mixed implicit-explicit wave-splitting scheme solution method in non-conservation form
    • Cascade aerodynamic analysis of 11-Ft TWT turning vanes
    • Wind tunnel testing of aerodynamic performance of NASA Ames 12-Ft PWT (Pressurized Wind Tunnel) and 11-Ft TWT
  • Conduct turbomachinery aerodynamic analysis and design optimization:
    • Turbomachinery aerodynamic analysis and design optimization of 11-Ft TWT three-stage compressor and rotor blades
    • Aerodynamic analysis of NFAC fan drive
    • Development of multi-stage axial-flow compressor design code
    • Turbomachinery aerodynamic analysis of 12-Ft PWT two-stage fan drive

Publications

  • 214 publications in many engineering disciplines including adaptive control, optimal control, distributed parameter control, flow control, aeroelasticity, flight dynamics, structural dynamics, aerodynamics, computational fluid dynamics, turbomachinery fluid dynamics, and optimization:
    • Textbook Model-Reference Adaptive Control - a Primer, ISBN 978-3-319-56393-0, Springer, March 2018
    • 33 journal articles
    • 171 conference papers
    • 5 NASA reports
    • 4 book chapters
    • Co-editor of 100-page AIAA document “Roadmap for Intelligent Systems in Aerospace”
  • Work on flexible wing aircraft drag reduction control appears on the aerospace industry magazine Aviation Week & Space Technology in January 28, 2013 issue

Invited Talks and Seminars

  • Invited keynote speaker by German Aerospace Center (DLR) at the inauguration of the Robotics and Mechatronics Center in Oberpfaffenhofen, Germany in April 2016 "Progress in NASA Flight Control Research for Improved Safety and Performance of Next-Generation Aircraft"
  • Invited speaker at AIAA SciTech Forum in January 2018 "Verification and Validation Challenges for Adaptive Flight Control of Complex Autonomous Systems"
  • Invited speaker by Bombardier Aerospace, Wichita, KS, in August 2017 “Performance Adaptive Aeroelastic Wing Research”
  • Invited speaker at NASA Engineering Safety Center GNC committee meeting at NASA Ames in January 2017 on “Flight Control of Flexible Aircraft”
  • Invited speaker by Yale University at the Eighteenth Yale Workshop on Adaptive and Learning Systems in New Haven, CT in June 2017 “Performance Optimizing Adaptive Control with Time-Varying Reference Model Modification”
  • Invited speaker by Boeing at the Aircraft Multidisciplinary Design Analysis and Optimization (MDAO) Workshop in Seattle, WA in October 2016 "MDAO and Control of Performance Adaptive Aeroelastic Wing"
  • Invited panelist by MIT at AIAA Robust Tactical Planning and Mixed Initiative Control for Aircraft Initiative Control for Aircraft and Spacecraft Workshop in Arlington, VA in September 2005 “Tactical Planning and Intelligent Control of Degraded Flight Performance”
  • Seminar at TU Delft in the Netherlands in April 2016 "Progress in NASA Flight Control Research for Improved Safety and Performance of Next-Generation Aircraft"
  • NASA Aerospace Modeling and Simulations Seminar in April 2014 "A Framework for Adaptive Aeroelastic Wing Shaping Control"
  • Carnegie-Mellon University Seminar in May 2012 "NASA Adaptive Control Research - Progress and Challenges"
  • NASA Aeronautics Technical Seminar in April 2010 "NASA Adaptive Control Research - Progress and Challenges"
  • Santa Clara University Seminar in February 2009 "Adaptive Control Research - Progress and Challenges for NASA Aviation Safety Program"

Professional Activities

  • Chair of AIAA Intelligent Systems Technical Committee in 2015-2017 with 50 professional members from the government, industry, and academia
  • General chair of AIAA Infotech@Aerospace Conference in 2012
  • Chair of AIAA Intelligent Systems Workshop in 2015
  • Member of AIAA Nomination Board for AIAA President and Board of Technical Directors Election in 2016
  • AIAA associate fellow
  • Adjunct professor at Santa Clara University in mechanical engineering department since 2006 teaching graduate courses in adaptive control, aircraft flight performance and dynamics, advanced dynamics, and aeroelasticity
  • Consultant for intellectual property law office in San Jose, CA in 2000-2005 on 33 US patent cases
  • Member of 6 PhD thesis committees at Georgia Tech, UC Davis, UC Santa Cruz, Carnegie-Mellon University, University of Washington, and University of South Florida; and 3 MS thesis committees at Technical University Delft in the Netherlands and Oklahoma State University
  • Journal reviewer:
    • Control journals: IEEE Transaction on Automatic Control, IEEE Transactions on Control Systems Technology, IEEE Transactions on Aerospace and Electronic Systems, Elsevier Journal of Systems and Control Letters, International Journal of Robust and Nonlinear Control, Automatica, Journal of the Franklin Institute, IET Control Theory & Applications, AIAA Journal of Guidance, Control, and Dynamics, AIAA Journal of Aerospace Information Systems
    • Aerospace engineering journals: AIAA Journal of Aircraft, AIAA Journal, Elsevier Journal of Aerospace Engineering, Elsevier Aerospace Science and Technology, Acta Astronautica, Aircraft Engineering and Aerospace Technology, Chinese Journal of Aeronautics, Aeronautical Journal

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