Control Science Center of Excellence Overview

1. Control Science Center of Excellence Overview SAE Aerospace Guidance & Control Committee Meeting 28 Feb 2007 Dr. David B. Doman Control Design and Analysis Branch Air Vehicles Directorate Air Force Research Laboratory

2. Multivariable Control Systems Control Science Center of Excellence Air Force Research Laboratory, Dr. Siva S. Banda • Long-Term PAYOFF: Effective operator/multi-UAV interface for ISR in urban terrain/ Improved responsiveness and reliability for space access/Improved accuracy of reduced order flow models for more effective feedback flow control • OBJECTIVES • Develop methods for increasing UAV effectiveness for urban ISR • Fault tolerant autonomous guidance, control and trajectory generation and support concept exploration for operationally responsive space Cooperative Control of UAVs Flow Control Space Access and Hypersonic Vehicle Control • APPROACH/TECHNICAL CHALLENGES • Operation of small and micro UAVs in urban enviroment/variable wind fields, target tracking • Multidisciplinary first principles based controls modeling for scramjet vehicle analysis • ACCOMPLISHMENTS/RESULTS • Flight test of operator-assisted cooperative control of heterogenous UAVs in urban terrain • Snapshot splitting method improves accuracy leading to more effective control of aero flows • Integration of thermal, mass, and unsteady aero effects into controls oriented scramjet model • TRANSITIONS • 52 Publications, 1 patent application, 6.2 COUNTER Program, 6.2,6.3,6.5 IAG&C Programs for Space Access, 6.5 Programs for Flow Control • STUDENTS, POST-DOCS • 15 students/3 Post Docs at OSU Collaborative Center of Control Science, 20 Summer Researchers • LABORATORY POINT OF CONTACT • Dr. Siva S. Banda, AFRL/VA, WPAFB, OH

3. Cooperative Task PlanningIncorporating Operator Involvement Task modification and re-planning based on Operator Input Operator workload reduction and scheduling Control 5 UAVs from 1 Operator station Path Planning & Sensor Pointing Wind Compensation Target geo-location Direct Transition to AFRL/VA 6.2 program: Cooperative Operations in Urban Terrain (COUNTER) Demonstrated in Flight Test Oct 2006 Participant in Talisman Saber Joint US/Australian exercise summer 2007 Operator-Assisted Cooperative Control of Heterogenous UAVs in Urban Terrain UAV Trajectories over Urban Terrain 1700 ft 1700 ft

4. Vision based Target Geo-Localization Using Feature Tracking Problem: determining the location of a fixed ground target when imaged from the air using a camera equipped Micro Air Vehicle (MAV). Result: the target is accurately geo-located and the attitude sensors are calibrated. M. Pachter AFIT, N. Ceccarelli and P.Chandler AFRL/VACA

5. Micro UAV Path Planning for Reconnaissance in Wind Problem:obtaining video footage of a set of known ground targets with preferred azimuthal viewing angles, using fixed onboard cameras, in the presence of a known constant wind. Result: developed a waypoint path planner that explicitly takes the wind and the autopilot path following module into account. N.Ceccarelli, S.J.Rasmussen and C.J.SchumacherAFRL/VACA, J.J.Enright UCLA, E.Frazzoli MIT

6. MILP allocation of pulsed reaction control jets daisychained with LP allocation of aero-surfaces during reentry Quantized control stability analysis and design philosophy allows use of multivariable control techniques with pulsed effectors Sequential LP Allocation of gimbals and throttles on ascent (addresses bilinearity) Results targeted towards 6.2 IAG&C Ascent and Entry Programs Fault Tolerant Control Allocation Stategies for Launch and Entry VehiclesMixed Integer Linear Programming Formulations for Nonlinear Control Effectors D. Doman, M. Oppenheimer, A. Ngo, B. Gamble / AFRL / A. Hall /Northrop Grumman / P. Kubiatko / Boeing

7. Multidisciplinary Control Oriented Modeling For Airbreathing Hypersonic Vehicles • Continued development of first principles model of scramjet vehicle • Aero-thermo-servo-elasticity effects captured in multidisciplinary model suitable for control studies • Unsteady Aero Modeling via Piston Theory: • Accounts for Fluid-Structure Interaction as Vehicle Vibrates • Used to Compute Damping and Flex-body stability derivatives • Steady and Unsteady Aerodynamics in Model • Significant shifts in pole-zero locations • Heat transfer and thermal effects on structure modeled Unsteady Aero Terms – Move Unstable Zero & Pole to Right in S-Plane – Affect Stability and Closed-Loop Bandwidth Unsteady Steady D. Doman, M. Oppenheimer, M. Bolender \ AFRL \ Air Vehicles Directorate

8. Truncated POD Basis Modes Controllable and Observable Tracking Control Achieved Balanced Truncation Applied to POD Provides Reduced Basis Designed for Feedback Control • Shortcoming of Conventional POD: • POD modes selected from energy considerations. Modes may not be controllable • or observable. Open-Loop Response Captured Video Video S. Djouadi / University of Tennesse and AFRL/VACA (Summer 2006)

9. Snapshot Splitting Method Results in Improved Boundary Condition Accuracy and More Effective Feedback Controllers Baseline and Actuator Modes Off-design Boundary Condition Improvement • Challenges in Order Reduction for Boundary Control: • Boundary actuation energy small compared to baseline flow energy  important data from controls standpoint discarded during order reduction • Boundary input difficult to reconstruct from reduced model at off-design conditions Snapshot Splitting Not Used Video Snapshot Splitting Used Video Identical snapshot ensembles, control formulation, POD basis energy requirements