control science center of excellence overview 28 feb 2007 dr. david b. doman control design and...
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Control Science Center of Excellence Overview
28 Feb 2007Dr. David B. Doman
Control Design and Analysis Branch Air Vehicles Directorate
Air Force Research Laboratory
SAE Aerospace Guidance & Control Committee Meeting
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-DOCS15 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
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
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 controlOBJECTIVES
• Develop methods for increasing UAV effectiveness Develop methods for increasing UAV effectiveness for urban ISRfor urban ISR•Fault tolerant autonomous guidance, control and trajectory generation and support concept exploration for operationally responsive space
Cooperative Control of UAVs
Multivariable Control SystemsControl Science Center of Excellence
Air Force Research Laboratory, Dr. Siva S. Banda
Flow Control
Space Access and Hypersonic Vehicle Control
Cooperative Task Planning Incorporating 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
1700 ft
1700
ft
UAV Trajectories over Urban Terrain
M. Pachter AFIT, N. Ceccarelli and P.Chandler AFRL/VACA
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.
Micro UAV Path Planning for Reconnaissance in Wind
N.Ceccarelli, S.J.Rasmussen and C.J.Schumacher AFRL/VACA, J.J.Enright UCLA, E.Frazzoli MIT
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.
Fault Tolerant Control Allocation Stategies for Launch and Entry Vehicles
Mixed Integer Linear Programming Formulations for Nonlinear Control Effectors
• 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
D. Doman, M. Oppenheimer, A. Ngo, B. Gamble / AFRL / A. Hall /Northrop Grumman / P. Kubiatko / Boeing
• 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
-5 -4 -3 -2 -1 0 1 2 3 4 5-20
-15
-10
-5
0
5
10
15
20Pole-Zero Map
Real Axis
Imag
inary
Axis Unsteady
Steady
Multidisciplinary Control Oriented Modeling For Airbreathing Hypersonic Vehicles
D. Doman, M. Oppenheimer, M. Bolender \ AFRL \ Air Vehicles Directorate
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.
Truncated POD Basis Modes
Controllable and Observable Open-Loop Response Captured Tracking Control Achieved
S. Djouadi / University of Tennesse and AFRL/VACA (Summer 2006)
Snapshot Splitting Method Results in Improved Boundary Condition Accuracy and More Effective
Feedback Controllers
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
Identical snapshot ensembles, control formulation,POD basis energy requirements
Baseline and Actuator Modes
Off-design Boundary Condition Improvement
Snapshot Splitting Not Used
Snapshot Splitting Used