本論文針對拍翼式微飛行器(FWMAV)或拍翼機，藉由結合延遲失速與機翼旋轉，展現較進階的空氣動力特性。本論文之伺服馬達建構具有兩組伺服系統的拍翼，一組用於拍撲，另一組則用於使機翼旋轉。伺服馬達組裝時使用的組件由CAD軟體設計，並以3D列印機進行製作，使用的列印材質為HIPS和ASA-PRO。機身採碳纖維桿製作以盡可能減少重量。並使用Arduino微處理晶片控制伺服馬達，方便隨時改寫控制指令以符合測試需要。拍翼機整體重量為121克，翼展達到96cm。 
	拍翼式微飛行器維持飛行所需升力與轉翼有極密切的關係。為驗證新型拍翼的性能，分別進行了2m尺寸的大風洞測試與繫繩懸吊飛行測試。測試結果顯示，有轉翼的升力比無轉翼的情形高出40%。此地使用脈衝寬度調變(PWM) 驅動之等效電壓值為2V ~ 8V，對應之拍翼頻率為1.4Hz ~ 2.7Hz。

This thesis presents the upgraded aerodynamic execution of flapping wing micro air vehicles (FWMAVs) or ornithopter results from a cooperation of the  delayed stall and wing rotation (or rotational circulation). Utilizing servo innovation to structure a flapping wing with two pair of servos. One pair is used for flapping and the other pair for wing rotation. Also, components used in the assembly of the servo-driven FWMAV are designed in CAD software and made by a 3D printer using materials like HIPS and ASA-PRO. Carbon fiber rods are used as fuselage in order to keep total weight as light as possible. Arduino microcontroller is used for control which makes FWMAV more customizable according to the need. The total weigh of the ornithopter is 121 g and the wing span is 96 cm.
The lift enhancement required to keep FWMAVs in the air has a strong relationship with wing rotation. For verifying the performance of the new FWMAV, the lift measurement in a wind tunnel with 2m test section size and a tethered flight test are both done. Total aerodynamic lift increment in case of the ornithopter with wing rotation was observed to be 40% when the results are compared to the ornithopter without wing rotation. The equivalent voltage of the pulse width modulation (PWM) driving is ranged as 2V, 5V, and 8V, and the corresponding flapping frequency is 1.4Hz, 1.6Hz, and 2.7Hz.

Contents
Acknowledgement	VI
Contents	VII
List of Figure	IX
List of Table	XII
CHAPTER 1: INTRODUCTION	1
1.1	Flapping wings and wing rotation	1
1.2	Literature Review	2
CHAPTER 2: SERVO – DRIVEN FLAPPING	7
2.1	Servo introduction	7
2.2	Importance of Servo Torque	8
2.3	Servo Flapping Mechanism	9
2.4	Wing Rotation	13
2.5	Advance and delayed wing rotation	15
2.6	3D printed parts	16
CHAPTER 3: FLIGHT CONTROL OF SERVO – DRIVEN FLAPPING	18
3.1	Arduino Flight System	18
3.2	Control Analogy	20
3.3	Tethered Flight	25
3.4	Wing Rotation servo ornithopter Tethered Flight	27
3.5	Wind Tunnel Testing	29
CHAPTER 4: WIND TUNNEL TESTING	32
4.1	Wind Tunnel Data Analysis	32
4.2	Wing Stress Analysis	44
CHAPTER 5: CONCLUSION	47
REFERENCES	49
APPENDIX A	53
A.1 3D Printing	53
A.2 Basic code for servo	54
A.3 Basic Servo knob code	55
A.4 Two servo flapping code	56
A.5 Wing rotation servo ornithopter Arduino code	60
APPENDIX B	64
B.1 Cut-off fft	64
B.2 FFT	66
APPENDIX C	67
C.1 With wing Rotation wind tunnel data	67
C.2 Without wing rotation wind tunnel data	70
Publication	73

List of Figure
Figure 1.1 Three axis wing rotation robotic fly apparatus 	3
Figure 1.2 Close-up view of robotic fly with force sensor and gear box 	4
Figure 1.3 Fruit fly Drosophila melanogaster wing rotation 	4
Figure 1.4 RoboBee on the tip of a finger .	5

Figure 2.1 Cross section of digital servo	7
Figure 2.2 Flapping wing servo	8
Figure 2.3 Wing rotation flapping mechanism	10
Figure 2.4 The 1st version of the main servo mount.	10
Figure 2.5 Servo ornithopter servo mount, fuselage and tail.	11
Figure 2.6 Main flapping servo mount	11
Figure 2.7 Front view of servo ornithopter	12
Figure 2.8 Isometric view of servo ornithopter	12
Figure 2.9 Top view of servo ornithopter	12
Figure 2.10 Front view of main flapping servo	14
Figure 2.11 Side view of wing rotation servo	14
Figure 2.12 Animation of the servo mechanism capable of wing	15
Figure 2.13 Servo mount CAD design	16
Figure 2.14 3D printed servo mount	16
Figure 2.15 Design of 3D printed tail part with servo	17
Figure 2.16 fixed tail 3D printed part	17
Figure 2.17 3D printed wing rotation servo parts	17

Figure 3.1 Connection diagram for one servo control	19
Figure 3.2 DEVO 10 channel transmitter for 2.4 GHz signal transmission	20
Figure 3.3 Basic servo control through Arduino Uno	21
Figure 3.4 Required components for servo ornithopter	22
Figure 3.5 Flow chart for flapping and wing rotation motion	24
Figure 3.6 Cruising trajectory of servo ornithopter tethered 	25
Figure 3.7  Servo ornithopter circular trajectory cursing (a), (b) and (c)	26
Figure 3.8 With wing rotation servo ornithopter tethered flight	27
Figure 3.9 Tethered flight of servo ornithopter with wing rotation 	28
Figure 3.10 Movable platform for experiment setup	30
Figure 3.11 Six-axis force sensor and servo ornithopter in wind tunnel	30
Figure 3.12 High-speed camera setup	31
Figure 3.13 Image from high speed camera	31

Figure 4.1 Lift signal form 20 cm wingspan MAV 	32
Figure 4.2 Lift signal (time domain) from servo ornithopter	33
Figure 4.3 Flapping lift (frequency domain) of the servo 	33
Figure 4.4 Double peak waveform in servo ornithopter with wing rotation	33
Figure 4.5 CL vs. Re 20 cm wingspan MAV 	34
Figure 4.6 Lift signal (time domain) from servo ornithopter	34
Figure 4.7 Flapping lift (frequency domain) of the servo	35
Figure 4.8 Thrust waveform of servo ornithopter with wing rotation	35
Figure 4.9 Thrust waveform servo ornithopter without wing rotation	35
Figure 4.10 Lift and thrust waveforms of servo ornithopter with wing rotation	36
Figure 4.11 Lift and thrust waveforms of servo ornithopter	36
Figure 4.12 CL vs. Re at 2V without wing rotation	37
Figure 4.13 CL vs. Re at 5V without wing rotation	37
Figure 4.14 CL vs. Re at 8V without wing rotation	38
Figure 4.15 CL vs. Re at 2V with wing rotation	39
Figure 4.16 CL vs. Re at 5V with wing rotation	39
Figure 4.17 CL vs. Re at 2V with wing rotation	40
Figure 4.18 CT vs. Re at 2V with wing rotation	41
Figure 4.19 CT vs. Re at 5V with wing rotation	41
Figure 4.20 CT vs. Re at 2V with wing rotation	42
Figure 4.21 CT vs. Re at 2V without wing rotation	43
Figure 4.22 CT vs. Re at 5V without wing rotation	43
Figure 4.23 CT vs. Re at 8V without wing rotation	44
Figure 4.24 Vertical deflection of different wings [45]	45
Figure 4.25 Vertical deflection of wings in servo ornithopter	46

Figure C.1 Lift vs. voltage at 1.5 m/s with rotation	67
Figure C.2 Lift vs. voltage at 1.7 m/s with rotation	67
Figure C.3 Lift vs. voltage at 2 m/s with rotation	68
Figure C.4 Lift vs. voltage at 2.25 m/s with rotation	68
Figure C.5 Lift vs. voltage at 2.5 m/s with rotation	69
Figure C.6 Lift vs. voltage at 2.7 m/s with rotation	69
Figure C.7 Lift vs. voltage at 1.5 m/s without rotation	70
Figure C.8 Lift vs. voltage at 1.7 m/s without rotation	70
Figure C.9 Lift vs. voltage at 2 m/s without rotation	71
Figure C.10 Lift vs. voltage at 2.25 m/s without rotation	71
Figure C.11 Lift vs. voltage at 2.5 m/s without rotation	72
Figure C.12 Lift vs. voltage at 1.5 m/s without rotation	72
List of Table
Table 2.1 Specification of wing rotation servo ornithopter	13
Table 2.2 Flapping angle, frequency and voltage	14

Table 3.1 Specification of Atmega328p 	18
Table 3.2 Connection pins	20
Table 3.3 Connections for servo	21
Table 3.4 Connection for servo ornithopter for wing rotation	23
Table 3.5 Specification of servo ornithopter without wing rotation	25
Table 3.6 Specification of wind tunnel	29

Table 4.1 Wing deflection	45
Table 4.2 Different material and parameters for the flapping wings	46

REFERENCES
[1]	C. Zhang and C. Rossi, "A review of compliant transmission mechanisms for bio-inspired flapping-wing micro air vehicles," Bioinspiration & Biomimetics, vol. 12, no. 2, 2017, pp. 025005.
[2]	K. Karydis and V. Kumar, "Energetics in robotic flight at small scales," Interface Focus, vol. 7, no.1, 2017, pp. 20160088.
[3]	A. Magnan, "Le vol chez les insects," Hermann, 1934.
[4]	W. Shyy, H. Aono, S. K. Chimakurthi, P. Trizila, C. K. Kang, C. E. Cesnik and H. Liu, "Recent progress in flapping wing aerodynamics and aeroelasticity," Progress in Aerospace Sciences, vol. 46, no. 7, 2010, pp. 284-327.
[5]	S. Barbarino, O. Bilgen, R. M. Ajaj, M. I. Friswell and D. J. Inman, "A review of morphing aircraft." Journal of Intelligent Material Systems and Structures, vol. 22, no. 9, 2011, pp. 823-877.
[6]	C. K. Kang, H. Aono, C. E. Cesnik and W. Shyy, "Effects of flexibility on the aerodynamic performance of flapping wings," Journal of Fluid Mechanics, vol. 689, 2011, pp. 32-74.
[7]	J. Young, J. C. Lai and M. F.  Platzer, "A review of progress and challenges in flapping foil power generation," Progress in Aerospace Sciences, vol. 67, 2014, pp. 2-28.
[8]	S. Ramananarivo, R. Godoy-Diana and B. Thiria, "Rather than resonance, flapping wing flyers may play on aerodynamics to improve performance," Proceedings of the National Academy of Sciences, vol. 108, no. 15, 2011, pp. 5964-5969.
[9]	R. Ramamurti, and W. C. Sandberg, "A three-dimensional computational study of the aerodynamic mechanisms of insect flight," Journal of Experimental Biology, vol. 205, no.10, 2002, pp. 1507-1518.
[10]	S. P. Sane, "The aerodynamics of insect flight," Journal of Experimental Biology, vol. 206, no. 23, 2003, pp. 4191-4208.
[11]	Z. J. Wang, "Dissecting insect flight," Annu. Rev. Fluid Mech, vol. 37, 2005, pp. 183-210.
[12]	 A. Gilmanov and F. Sotiropoulos, "A hybrid cartesian/immersed boundary method for simulating flows with 3D, geometrically complex, moving bodies," Journal of Computational Physics, vol. 207, no. 2, 2005, pp. 457-492.
[13]	 M. S. Triantafyllou, A. H. Techet and F. S. Hover, "Review of experimental work in biomimetic foils," IEEE Journal of Oceanic Engineering, vol. 29, no. 3, 2004, pp. 585-594.
[14]	L. J. Yang, "The micro-air-vehicle golden snitch and its figure-of-8 flapping," Journal of Applied Science and Engineering, vol. 15, no. 3, 2012, pp. 197-212.
[15]	 S. Ho, H.  Nassef, N. Pornsinsirirak, Y. C. Tai and C. M. Ho, "Unsteady aerodynamics and flow control for flapping wing flyers," Progress in Aerospace Sciences, vol. 39, no. 8, 2003, pp. 635-681.
[16]	 S. A. Ansari, R. Zbikowski and K. Knowles, "Aerodynamic modelling of insect-like flapping flight for micro air vehicles," Progress in Aerospace Sciences, vol. 42, no. 2, 2006, pp. 129-172.
[17]	 S. P. Sane and M. H.  Dickinson, "The control of flight force by a flapping wing: lift and drag production," Journal of Experimental Biology, vol. 204, no. 15, 2001, pp. 2607-2626.
[18]	 S. P. Sane and M. H.  Dickinson, "The aerodynamic effects of wing rotation and a revised quasi-steady model of flapping flight," Journal of Experimental Biology, vol. 205, no. 8, 2002, pp. 1087-1096.
[19]	  D. J. Pines and F. Bohorquez, "Challenges facing future micro-air-vehicle development," Journal of Aircraft, vol. 43, no. 2, 2006, pp. 290-305.
[20]	 J. R. Usherwood and C. P. Ellington, "The aerodynamics of revolving wings I. model hawkmoth wings," Journal of Experimental Biology, vol. 205, no. 11, 2002, pp. 1547-1564.
[21]	 M. A. Ashraf, J. Young and J. C. S. Lai, "Reynolds number, thickness and camber effects on flapping airfoil propulsion," Journal of Fluids and Structures, vol. 27, no. 2, 2011, pp. 145-160.
[22]	 K. B. Lua, T. T. Lim and K. S.  Yeo, "Effect of wing–wake interaction on aerodynamic force generation on a 2D flapping wing," Experiments in Fluids, vol. 51, no. 1, 2011, pp. 177-195.
[23]	 K. B. Lua, S. M. Dash, T. T. Lim and K. S. Yeo, "On the thrust performance of a flapping two-dimensional elliptic airfoil in a forward flight," Journal of Fluids and Structures, vol. 66, 2016, pp. 91-109.
[24]	M. H. Dickinson, F. O. Lehmann and S. P. Sane, "Wing rotation and the aerodynamic basis of insect flight," Science, vol. 284, no. 5422, 1999, pp. 1954-1960.
[25]	 F. O. Lehmann, "The mechanisms of lift enhancement in insect flight," Naturwissenschaften, vol. 91, no. 3, 2004, pp. 101-122.
[26]	  T. Maxworthy, "The fluid dynamics of insect flight," Annual Review of Fluid Mechanics, vol. 13, no. 1, 1981, pp. 329-350.
[27]	 T. J. Mueller, (Ed.), "Fixed and flapping wing aerodynamics for micro air vehicle applications,” American Institute of Aeronautics and Astronautics, 2001.
[28]	 P. Zdunich, D. Bilyk, M. MacMaster, D. Loewen, J. DeLaurier, R. Kornbluh and D. Holeman, "Development and testing of the mentor flapping-wing micro air vehicle," Journal of Aircraft, vol. 44, no. 5, 2007, pp. 1701-1711.
[29]	 J. Murua, R. Palacios and J. M. R. Graham, "Applications of the unsteady vortex-lattice method in aircraft aeroelasticity and flight dynamics," Progress in Aerospace Sciences, vol. 55, 2012, pp. 46-72.
[30]	Y. Lu, G. X. Shen and G. J. Lai, "Dual leading-edge vortices on flapping wings," Journal of Experimental Biology, vol. 209, no. 24, 2006, pp.5005-5016.
[31]	D. Viieru, J. Tang, Y. Lian, H.  Liu and W. Shyy, "Flapping and flexible wing aerodynamics of low Reynolds number flight vehicles," 44th AIAA Aerospace Sciences Meeting and Exhibit, 2006.
[32]	  D. Garmann and M. Visbal, "Three-dimensional flow structure and aerodynamic loading on a low aspect ratio, revolving wing," 42nd AIAA Fluid Dynamics Conference and Exhibit, 2012.
[33]	D. Floreano and R. J. Wood, "Science, technology and the future of small autonomous drones," Nature, vol. 521, no. 7553, 2015, pp.460.
[34]	K. Y. Ma, P. Chirarattananon, S. B. Fuller and R. J. Wood, "Controlled flight of a biologically inspired, insect-scale robot," Science, vol. 340, no. 6132, 2013, pp.603-607.
[35]	C. P. Ellington, "The aerodynamics of hovering insect flight. I. the quasi-steady analysis," Philosophical Transactions of the Royal Society of London. B, Biological Sciences, vol. 305, no. 1122, 1984, pp. 1-15.
[36]	T. A. Ward, M. Rezadad, C. J. Fearday and R. Viyapuri, "A review of biomimetic air vehicle research: 1984-2014," International Journal of Micro Air Vehicles, vol. 7, no. 3, 2015, pp.375-394.
[37]	J. M. McMichael, "Micro air vehicles-toward a new dimension in flight," http://www. arpa.gov/tto/MAV/mav_auvsi.html, 1997.
[38]	M. Keennon, K. Klingebiel and H. Won, "Development of the nano hummingbird: A tailless flapping wing micro air vehicle, " In 50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition, 2012, pp. 588.
[39]	 Z. Khan, K. Steelman and S. Agrawal, "Development of insect thorax based flapping mechanism," In IEEE International Conference on Robotics and Automation, 2009, pp. 3651-3656.
[40]	M. Ryan and H.J. Su, "Classification of flapping wing mechanisms for micro air vehicles," In International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 2012, pp.105-115.
[41]	C. Schubert, M. C. Van Langeveld, and L. A. Donoso, "Innovations in 3D printing: a 3D overview from optics to organs." British Journal of Ophthalmology, vol. 98, no. 2, 2014, pp. 159-161.
[42]	S. F. Barrett, "Arduino microcontroller processing for everyone!," Synthesis Lectures on Digital Circuits and Systems, vol. 8, no. 4, 2013, pp. 1-513.
[43]	O. Barth, "Harmonic piezodrive—miniaturized servo motor," Mechatronics, vol. 10, no. 4-5, 2000, pp. 545-554.
[44]	L. J Yang, C. K Hsu, J. Y Ho, & C. K Feng. "Flapping wings with PVDF sensors to modify the aerodynamic forces of a micro aerial vehicle." Sensors and Actuators A: Physical 139.1-2 (2007): 95-103.
[45]	 L. J Yang, A. F Ko, & C. K Hsu. "Wing stiffness on light flapping micro aerial vehicles." Journal of Aircraft 49.2 (2012): 423-431.