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

3
Presentation Overview

• Background Information
• Aerodynamic Theory
• Model Design
• Past Group Work
• Present Group Work
• Summary
• Questions

4
Project Background

• Background
• Theory
• Model
• 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

• Background
• Theory
• Model
• 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

• Background
• Theory
• Model
• 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
Aerodynamic Theory

• Background Information
• Aerodynamic Theory
• Model Design
• Past Group Work
• Present Group Work
• Summary
• Questions

8
Aerodynamic Force Lift

• Air flows around the airfoil and create 2
  different velocity regions along the top and
  bottom surfaces of the wing.
• velocity increases pressure
  decreases
• Lift is generated due to pressure gradient along
  the surfaces of the wing.

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

2
9
Lift Coefficient vs. Angle of Attack
Lift Analysis Lift Coefficient Analysis The
amount of lift generated by the wings depends on
the shape of the airfoil and its inclination with
respect to the flow direction. The lift varies
almost linearly for small angles of attack
(within /- 10 degrees) 1.

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

2
http//www.centennialofflight.gov/essay/Dictionary
/angle_of_attack/DI5.htm Feb 2003
10
What is Stall?

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

• Stall occurs when the boundary layer separates
  from the surface of the wing, causing the lift
  dramatically decrease.
• Wing area exposed to the flow increases, thus
  increasing drag and decreasing velocity.
• Flow becomes highly unsteady behind the airfoil
  turbulence flow.

http//wright.nasa.gov/airplane/incline.html Feb
2003
11
What is Vstall?
The velocity of the aircraft when it stalls,
which determines the minimum velocity an aircraft
can fly. CLmax is the ideal parameter to
optimize in order to reduce stall speed How to
increase CLmax? - Trailing-edge flaps - Leading
edge slats - Oscillating flaps (New)

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

12
Lift-Enhancing Devices

• Flaps change the pressure distribution around the
  airfoil by changing its chord length and camber,
  also increase wing area to decrease stall speed.
• The effect of camber on lift can be explained
  qualitatively with Newtonian approach and Thin
  Airfoil Theory.
• Newtonian approach Lift is the result of
  pressure reactions that oppose the turning of
  flow higher lift is caused by greater turning
• Thin Airfoil Theory

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

http//www.desktopaero.com/appliedaero/airfoils2/h
ighlift.html Feb 2003
2
13
Lift-Enhancing Devices

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

• Slats an opening at the leading edge of the
  airfoil allowing high pressure air under the
  airfoil to pass.
• The high pressure air mixes with the air at the
  top surface and increases the energy of the
  boundary layer.
• By increasing the energy of the boundary layer
  the wing can sustain higher angles of attack and
  a higher maximum coefficient of lift 3

3
14
Lift-Enhancing Devices

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

• Oscillating Flap located near the leading edge
  of the wing to control the separation of the
  airflow from the wing delay the separation or
  reattach the separated flow onto the surface
• Vortices are created by oscillating flaps
  enhance the momentum transfer between the free
  stream and boundary layer, which makes the
  reattachment of vertices occur more upstream 3
  the further upstream the vertices are, higher
  Clmax can be achieved.
• Moreover, Clmax is further increased if
  excitation frequency of flap corresponds to the
  vortex shedding frequency 3

15
Model Design

• Background Information
• Aerodynamic Theory
• Model Design
• Past Group Work
• Present Group Work
• Summary
• Questions

16
Actuator Designs

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

• Hydraulic Actuator
• Electromechanical Actuator
• Electric Motor

17
Hydraulic Actuator System

• Available
• Dr. Stearman had a hydraulic unit for group use
• Fast response
• Can oscillate at required frequency
• Powerful
• Can easily drive the model control surfaces

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

18
How do Hydraulics Work?
Force that is applied at one point is transmitted
to another point using an incompressible fluid.
Varying the area of the pistons changes the
force output. In this example, the area of the
right piston is 9 times greater than the other
piston and the force output is thus 9 times the
force input.

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

http//science.howstuffworks.com/hydraulic.htm
Feb 2003
http//science.howstuffworks.com/hydraulic.htm
Feb 2003
19
Hydraulic System - Drawbacks

• Complex
• System requires power source, high pressure
  motor, fluid and tubing
• Expensive
• Available system lacked power source (500)
• Size
• System is awkward and not easy to set up
• Maintenance
• Pumps, filters need constant up keep

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

20
Electromechanical Actuation

• Size
• Overall system is much smaller
• Cost
• Motor and controller are available from Dr.
  Stearman for free
• Maintenance
• Does not require any form of maintenance

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

21
How does the controller work?

• A controller drives a motor coupled to a shaft
  that drives the flaps

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

2
2
22
Electromechanical Drawbacks

• Complexity of controller
• Circuit diagram is over 2 pages
• Size
• The controller alone weighs over 35lbs. and
  would be difficult to mount in the wind tunnel
• Limited applications
• Can only control leading edge flaps

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

2
23
ATAK Technologies 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

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

1
24
How will our control system work?

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

• Motor mounted to main spar
• Shaft drives slider crank assemblies that cause
  the flaps to oscillate
• Hand held tachometer will measure revolutions per
  minute of the flaps

2
1
25
Project Accomplishments

• Background Information
• Aerodynamic Theory
• Model Design
• Past Group Work
• Present Group Work
• Summary
• Questions

26
Past Accomplishments

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

• Project has been advanced in past three terms
• The Active Wing Group (AWG)
• Active Wing Technology (AWT)
• Active Wing Engineering (AWE)

27
The Active Wing Group

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

• AWG Work
• Recovered F-111 wing-tail from storage
• Investigated limit cycle oscillations
• Provided a strong foundation for Summer 2002
  group
• AWG Suggestions
• Prioritize system hardware recovery

28
Active Wing Technologies

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

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

29
AWT Suggestions

• Create a mathematical model of control system
• Create model using either Root Locus or Bode Plot
  in MatLab
• Create digital schematics of all drawings

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

30
Active Wing Engineering

• Research
• Aerodynamic Theory behind oscillating flaps
• Selected actuation system
• Constructed model wing with leading edge flaps

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

31
AWE Suggestions

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

• Add leading and trailing edge flaps to new design
• Create actuation system to control leading and
  trailing edge flaps
• Select wing type
• Swept, tapered Straight, non-tapered
• Incorporate Measuring tools for wind tunnel tests

32
Progress

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

• Research
• Aerodynamic forces involved in active wing
  technologies
• Control surface effect on lift
• Model Design
• Actuation and controller systems
• AutoCAD design of wing model
• Lab Maintenance
• Worked to clean WRW 316

33
Remaining Tasks

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

• Model Design
• Finalize wing model
• Construct wing model
• Incorporate testing system
• Perform wind tunnel test
• Reduce data for analysis

34
Projected Schedule

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

35
Presentation Summary

• Background Information
• Aerodynamic Theory
• Theory Behind the Model and Design Work
• Past Group Work
• Present Group Work
• Future work for ATAK Technologies

36
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.

37
Questions?