The Design and Development of an Active Smart Wing Model

1
The Design and Development of an Active Smart
Wing Model

• ATAK Technologies

2
Team Structure

• Thomas Ayers
• Project Leader
• Robert Aguirre
• Senior Testing Research Specialist
• Kevin Mackenzie
• Senior Modeling and Design Specialist
• Vu Tran
• Senior Research Specialist
• Dr. R. O. Stearman
• University of Texas Faculty Consultant

3
Presentation Overview

• Project Objectives
• Aerodynamic Theory
• Model Design
• Model Testing Options
• Project Accomplishments
• Recommended Future Pursuits
• Summary
• Questions

4
Project Background

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

• Randall Bolding
• Wrote a masters thesis in 1978 in which a wing
  model was used to research the use of a
  stabilator as an active control to suppress
  flutter
• Lockheed Martin Corporation
• A research project on the benefits that an
  active wing can provide in contemporary aircraft
  design

5
High Airspeed Benefits

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

• At high airspeeds normally latent aerodynamic
  forces become powerful enough to affect the flow
  about the airfoil
• These changes cause torsional moments on the wing
• Theoretically, the use of active wing control on
  the leading edge flaps and ailerons can be used
  in order to better control these latent
  aerodynamic forces

6
Low Airspeed Benefits

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

• At low speeds airflow about the wing can separate
  from the wing causing a stall
• In natural flight, resonant flapping is used to
  sustain flight at low flight speeds
• Theoretically, oscillating the wings by using the
  control surfaces would create high lift
  conditions for short, low airspeed maneuvers

7
Project Objective

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

• To create an active wing model for the purpose
  of defining relationships between control surface
  oscillation and flight performance

8
Aerodynamic Theory

• Project Objectives
• Aerodynamic Theory
• Model Design
• Model Testing Options
• Project Accomplishments
• Recommended Future Pursuits
• Summary
• Questions

9
Desirable Flow Types
Attached-flow Difference of the circulations of
the upper and lower boundary layers create a lift
force near a quarter chord of the airfoil.
(figure a) Detached-vortex-flow rolled-up
leading edge vortices create additional lift.
(figure b) 4

• Background
• Theory
• Model
• Testing
• Work
• Summary
• Questions

10
Problems Encountered

• When a critical angle of attack achieved to
  create high lift, separated unsteady flow is
  unavoidable, and the vortices formed become
  uncontrollable once they leave the body.
  
• Unsteady separation
• Vortex shedding
• Vortex breakdown

• Background
• Theory
• Model
• Testing
• Work
• Summary
• Questions

11
Separation Control

• To control separation, essentially the boundary
  vorticity flux control, a relationship between
  pressure, inertial, and viscous forces must be
  utilized.
• Methods for controlling separation
• 1) Control tangential pressure gradient proper
  design of airfoil and wing geometry
• 2) Control skin friction field modify local
  skin friction field near critical points
• 3) Introduce local movable wall oscillating
  flaps

• Background
• Theory
• Model
• Testing
• Work
• Summary
• Questions

12
Reattachment Control

• When the boundary layer is already separated,
  control of its reattachment is also feasible by
  utilizing unsteady excitations.
• Example Small leading-edge oscillating flap was
  used to forced the shear layer separated from a
  sharp leading edge to attach to just the upstream
  of a round trailing edge, hence captured a strong
  vortex above a two-dimensional airfoil with angle
  of attack up to 27 degree. Lift was increased by
  60.
• 4

• Background
• Theory
• Model
• Testing
• Work
• Summary
• Questions

13
Reattachment Control
The inviscid vortex method can be used to compare
flow patterns with or without leading-edge
oscillation Case (a) leading-edge vortex moves
downstream as new vorticies start to form. The
leading edge vortex cuts off the trailing edge
vortex sheet. The main vortex will eventually
shed. Case (b) main vortex is stabilized and
stays close to the wing with nearly uniform
vorticity distribution 4

• Background
• Theory
• Model
• Testing
• Work
• Summary
• Questions

14
Reattachment Control

• An additional example
• Poly Vinylidence Flouride (PVDF) piezoelectric
  film was used on the surface of a NACA 0012
  airfoil to generate surface oscillation through
  polarization changes in the material
• 5
• Non-oscillated case Max lift coefficient
  0.72, stall angle 14 degree
• Oscillated case Max lift coefficient 0.76,
  stall angle 15 degree
• 5 5

• Background
• Theory
• Model
• Testing
• Work
• Summary
• Questions

15
Reattachment Control

• For a highly swept wing, unsteady surface
  excitations focus on delaying vortex breakdown,
  or can be used to maintain highly concentrated
  and stable leading-edge vortices
• Schematic of mini-upper wing
• 4

• Background
• Theory
• Model
• Testing
• Work
• Summary
• Questions

16
Reattachment Control

• Background
• Theory
• Model
• Testing
• Work
• Summary
• Questions

• Mini-upper Wing
• The wing has a larger incidence than the main
  wing, thus forcing the flow below it to converge.
  This implies an additional axial acceleration at
  the vortex core, and therefore delays its burst.
  However, the applicable angle of attack is
  limited, due to limitations created by the wing
  design

17
Model Design

• Project Objectives
• Aerodynamic Theory
• Model Design
• Model Testing Options
• Accumulated Project Work
• Recommended Future Pursuits
• Summary
• Questions

18
Actuator Designs

• Background
• Theory
• Model
• Work
• Summary
• Questions

• Hydraulic Actuator
• Electromechanical Actuator
• Electric Motor

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Benefits of ATAKs Design

• Size of Control System Electric motor and shaft
  will be half the size of the previous groups
• Ease of Operation Does not require
  understanding of complex controller
• Able to Test By taking wind tunnel dimensions
  into account when designing we make sure that we
  will be able to mount the wing in order to obtain
  Cl and Cd measurements
• Flexibility Leading and trailing edge flaps
  will be able to oscillate. Will be able to
  control angle of deflection and phase between
  flaps

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

20
Model Design

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

Overall Model Assembly
21
Model Design

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

Wing Spar, Engine and Rods
22
Model Design

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

Gearing Assembly
23
Model Design

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

Bevel Gears
24
Model Design

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

Actuation System Push/Pull Rods
25
Model Design

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

Actuation System including Control Surfaces
26
Model Design

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

Wing Model Without Modified Control Surfaces
27
Model Design

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

Wing Model With Deflected Control Surfaces
28
Model Design

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

Overall Model Assembly
29
Model Testing Options

• Project Objectives
• Aerodynamic Theory
• Model Design
• Model Testing Options
• Accumulated Project Work
• Recommended Future Pursuits
• Summary
• Questions

30
Model Testing Goals

• Background
• Theory
• Model
• Testing
• Work
• Summary
• Questions

• Take next step in project development
• Obtain and reduce data
• Conduct repeated tests to ensure quality data
  acquired

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Testing Data Acquisition

• Background
• Theory
• Model
• Testing
• Work
• Summary
• Questions

• Relationship between oscillation frequency and
• Variations of coefficient of lift
• Pressure distributions over wing
• Wing spar strain
• Wing tip flutter
• Relationships can be used to find optimum
  frequencies for
• Maximizing coefficient of lift
• Minimizing wing spar strain
• Minimizing wing tip flutter

32
Model Testing Equipment

• Background
• Theory
• Model
• Testing
• Work
• Questions
• Summary

• Smoke wire
• Pressure taps
• Strain Gauges
• Accelerometer

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Model Testing Suggestions

• Background
• Theory
• Model
• Testing
• Work
• Summary
• Questions

• Modify model as needed
• Start testing as soon as possible
• Be familiar with theory and equations needed to
  reduce data

34
Project Accomplishments

• Project Objectives
• Aerodynamic Theory
• Model Design
• Optional Testing Procedures
• Project Accomplishments
• Recommended Future Pursuits
• Summary
• Questions

35
Project Accomplishments

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

• Project has been advanced over the past four
  terms
• The Active Wing Group (AWG)
• Active Wing Technology (AWT)
• Active Wing Engineering (AWE)
• ATAK Technologies (ATAK)

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Active Wing Group

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

• Recovered F-111 wing-tail from storage
• Investigated limit cycle oscillations (LCO)
• Provided a strong foundation for Summer 2002
  project continuation

37
Active Wing Technologies

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

• Primarily Research on F-111
• Limit cycle oscillations (LCO)
• Increasing lift on fighter wings
• Implementation of control surfaces
• Digital and analog control systems

38
Active Wing Engineering

• Researched the aerodynamic theory behind
  oscillating flaps
• Selected actuation system
• Constructed model wing with leading edge flaps

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

39
ATAK Technologies

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

• Research
• Aerodynamic forces involved in active wing
  technology
• Control surface effect on lift
• Model Design
• Actuation system
• Structure design
• AutoCAD model
• Delivered spar design to machinist for
  construction
• Gathered all necessary model materials.
• Lab Maintenance
• Worked to clean WRW 316

40
ATAK Technologies

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

Wing Structure
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Recommended Future Pursuits

• Project Objectives
• Aerodynamic Theory
• Model Design
• Optional Testing Procedures
• Project Accomplishments
• Recommended Future Pursuits
• Summary
• Questions

42
Recommended Future Pursuits

• Objectives
• Theory
• Model
• Testing
• Work
• Summary
• Questions

• Complete the construction of the wing model
• Prepare for experimentation using the model
• Design testing equipment and conditions
• Place instruments on model design
• Use LabView software to coordinate data
  acquisition
• Conduct experiments using wing model
• Reduce acquired data and draw conclusions
  concerning the relationship between frequencies
  and the desired characteristics.

43
Presentation Summary

• Background Information
• Project Objectives
• Aerodynamic Theory
• Modeling and Final Design
• Proposed Testing Procedures
• Project Accomplishments
• Recommended Future Work

44
References

• 1 Aguirre, Robert, Thomas Ayers, Kevin
  Mackenzie, and Vu Tran. Design and Development
  of an Active Wing Model. ATAK Technologies,
  Austin, TX, Mar. 2003.
• 2 Garret, Carlos, Justin Gray, and Kevin Marr.
  Design of an Active Controlled Wing Model Using
  Flap Oscillation. AWE Engineering, Austin, TX,
  Dec. 2002.
• 3 Fuentes, David, Basil Philips, and Naoki
  Sato. Design and Control Modeling of an Active
  Variable Geometry Wing. Active Wing
  Technologies, Austin, TX, Aug. 2003.
• 4 Wu, J.M., Wu, J.Z., Vortex Lift at a Very
  High Angle of Attack with Massively Separated
  Unsteady Flow, Fluid Dynamics of High Angle of
  Attack, R. Kawamura, Y. Aihara ed.,
  Springer-Verlag, Berlin Heidelberg, 1993, pp.
  35-63.
• 5 Kobayakawa, M., Kondo, Y., Suzuki, H.,
  Airfoil Flow Control at High Angle of Attack by
  Surface Oscillation, Fluid Dynamics of High
  Angle of Attack, R. Kawamura, Y. Aihara ed.,
  Springer-Verlag, Berlin Heidelberg, 1993, pp.
  265-273.

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Questions?