Structural control method research for MAV application

1. Structural control method research for MAV application Yao Lu Chairman : Prof. Dr. Fred van Keulen Supervisor: Dr. Hans Goosen, Hugo Peters

2. Content • Introductions • Introduction to the concept of MAV • Introduction to the task • Structural control methods and actuator screening • Tests • Conclusion and recommendation

3. Introduction to Micro Air Vehicle(MAV)

4. Introduction to the task • The aim of this thesis is to investigate approaches to modify the structure stiffness

5. Requirement approximation • The stiffness change requirement is done and it is supposed that the one that can serve more than 1% of stiffness modification is satisfied

6. Introduction to the task • It is hardly possible to investigate the problem on the vehicle currently • The research is based on a simplified model

7. Content • Introductions • Structural control methods and actuator screening • Tests • Conclusion and recommendation

8. Collection of stiffness change methods • Various methods can be used for the beam stiffness change • Before screening of these methods, actuators should be screened

9. Actuator screening • Actuators can be grouped into four groups according to different mechanisms Magnetic field Electric field Actuation Electro- Magnetic Temperature

10. Actuator screening • The generation of magnetic field requires too much additional weight

11. Actuator screening • Two groups of actuators are not favored in MAV application for the generation of magnetic field requires too much weight Magnetic field Electric field Actuation Electro- Magnetic Temperature

12. Criteria of methods screening • Piezoelectric material and Shape-memory-alloy material are representatives of the remained two groups of active materials • The stiffness change, the energy cost and the control time should be analyzed for each method. Piezo passive or SMA-two-state Piezo Piezo Piezo

13. Piezo passive stiffness method • The piezo passive stiffness method uses the mechanism that the stiffness of a short circuited piezo is lower than that in open circuit condition • The stiffness change is obtained by switching between two electrical conditions of electrodes.

14. SMA-two-state method mechanism • The Young’s modulus of SMA material depends on temperature

15. Screening of the methods • After screening using theoretical work and simulations, the piezo passive method is selected.

16. Piezo passive stiffness method • For a simplified model, the stiffness change depends on the Young’s modulus ratio and thickness ratio between beam material and piezo material

17. Piezo passive stiffness method • The stiffness change is about 20%

18. Piezo passive stiffness method • However, there are effects that will reduce the effectiveness of this method such as the effect of glue.

19. Piezo passive stiffness method • The effect of this method is greatly reduced, from about 20% to about 4%. Experiments should be done to verify the effectiveness of this method in practice.

20. Content • Introductions • Structural control methods and actuator screening • Tests • Conclusion and recommendation

21. Experiment set-up • Static test is performed

22. Experiment result

23. Experiment result • Limited by piezo patch numbers, limited tests are done • Tested stiffness change is less than expected

24. Content • Introductions • Structural control methods and actuator screening • Tests • Conclusion and recommendation

25. Conclusion and recommendation • It shows that the passive stiffness method can induce more than one percent of stiffness change for certain material. • For the future research, it is better to use material and manufacturing with more precision. • The integration of piezo ceramic material to the structural material without glue can be researched. • Future colleagues may work in the direction to enhance the effectiveness of the passive stiffness method by electronics.

26. 人法地，地法天，天法道，道法自然 Nature is a good teacher to human beings ---Laozi (571-471BC)