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)

Video

Video

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

Video

Video