||WING ROTATION EFFECT ON AN ORNITHOPTER USING SERVO CONTROL
||Department of Mechanical and Electro-Mechanical Engineering
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.
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
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
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
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
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