Aiaa 2008 6490

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Aiaa 2008 6490

  1. 1. AIAA-2008-6490 Transition Point Displacement Control on a Wing Equipped with Actuators A. Popov, M. Labib, J. Fays and R. Botez, ETS, Montreal, Quebec, Canada
  2. 2. SUMMARY <ul><li>Project context </li></ul><ul><li>Simplified model </li></ul><ul><li>SMA model in open loop </li></ul><ul><li>SMA model control in close loop </li></ul><ul><li>Bench test </li></ul><ul><li>Conclusion </li></ul><ul><li>Future work </li></ul>
  3. 3. Project context <ul><li>CRIAQ Project 7.1 </li></ul><ul><li>Laminar Flow Improvement on an Aeroelastic Research Wing </li></ul><ul><li>Partners </li></ul><ul><li>Objectives </li></ul><ul><li>To develop a system for active control of wing airfoil geometry during flight. In-flight modification of aircraft wing airfoils will make it possible to maintain laminar flow over the wing as flight regime changes </li></ul>
  4. 4. Project context Morphing wing schematic concept
  5. 5. Project context <ul><li>2 actuations line with 5 actuation points (Shape Memory Actuators) </li></ul><ul><li>32 pressure sensors </li></ul><ul><ul><li>16 optical sensors </li></ul></ul><ul><ul><li>16 Kulite sensors </li></ul></ul><ul><li>Thermocouples, Load cells and Displacement sensors </li></ul><ul><li>Horizontal moves of the SMA for vertical moves of the flexible skin </li></ul>
  6. 6. Simplified model <ul><li>WTEA laminar airfoil </li></ul><ul><li>Between 7% - 65 % installed a flexible skin with 1 control point at 36% with deflections of ±20, ±16, ±12, ±8, ±5, ±3, ±1.5, ±0.5 et 0 mm by use of B-splines . </li></ul><ul><li>Aerodynamic study of transition point variation with the airfoil shape in XFoil </li></ul><ul><li>M = 0.2 & 0.3 </li></ul><ul><li>Re = 2.29 mil & 3.6 mil </li></ul><ul><li>Alpha = -2,-1,0,1,2,3,4 deg </li></ul>
  7. 7. Simplified model
  8. 8. SMA model in open loop Shape memory and super-elasticity properties of Ni-Ti alloys Shape memory actuators principle
  9. 9. SMA model in open loop <ul><li>Transfer function parameter identification </li></ul>Delay due to phase transformation :
  10. 10. SMA model in open loop
  11. 11. SMA model control in closed loop <ul><li>Find the critical gain Kc and critical period for the TF </li></ul><ul><li>Ziegler-Nichols method for designing a PID </li></ul>
  12. 12. SMA model control in closed loop <ul><li>Internal model control method (IMC) </li></ul>K P = 144.28, K I = 11.10 K D = 332.96
  13. 13. SMA model control in close loop <ul><li>Disadvantages </li></ul><ul><ul><li>PID has a time delay for both heating and cooling </li></ul></ul><ul><ul><li>To decrease the delay in cooling we need to disconnect the PID </li></ul></ul><ul><li>Improvement with an algorithm </li></ul><ul><ul><li>If y d -y > 0 then cooling PID = 0 </li></ul></ul><ul><ul><li>Else heating PID ≠ 0 </li></ul></ul>
  14. 14. SMA model control in close loop
  15. 15. Aerodynamic simulation of the simplified model controlled by SMA in close loop <ul><li>simulation with deflection commanded by step input,  , M, Re constant </li></ul><ul><li>simulation with deflection commanded by step input,  given by a sinusoid function and M, Re constant </li></ul><ul><li>simulation with deflection and  given by sinusoid function and M, Re constant </li></ul>
  16. 16. Aerodynamic simulation of the simplified model controlled by SMA in close loop Simulation results
  17. 17. Bench test Charging spring Linear variable differential transducer Force transducer Wheel Potentiometer error < ± 0,005 mm Heating generated by PID Cooling current = 0
  18. 18. Conclusion <ul><li>Easy implementing way of controlling the deflection on a morphing wing airfoil equipped with actuators, sensors and flexible skin which ultimately has an effect on the transition point position. </li></ul><ul><li>The SMA has a non-linear behavior with a slow dynamics. The IMC method has been preferred to the ZN method as it provided better results. Once the closed loop inside the ‘SMA’ block has been controlled, we had to control the whole closed loop. The whole closed loop has a very fast dynamics, because of the real time controller located in the ‘Determination of the pressure coefficients versus chord and transition point position’ block. </li></ul><ul><li>The simulations validated our choice of design, as we obtained fast and precise responses. The main advantage of this method is its simplicity and its incorporation in experimental applications, such as in the controller of a morphing wing model. </li></ul>
  19. 19. Future work <ul><li>Simulation of the mechanical system control with aerodynamic forces in the same conditions as wing tunnel </li></ul>
  20. 20. Future work <ul><li>Implementing the controller into the physical model </li></ul><ul><ul><li>Connecting Simulink with the power supplies and acquisition cards </li></ul></ul><ul><li>Bench tests & wind tunnel tests </li></ul>

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