Comprehensive System Identification of Ducted Fan UAVs - Cal Poly

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CHAPTER 3 – VEHICLE IDENTIFICATION3.1 Areas of IdentificationAs mentioned in Chapter 2, the comprehensive identification of these vehiclesrequires modeling and testing of the bare-airframe dynamics as well as all of the systemsand components onboard which directly affect the flight characteristics of the vehicle.Figure 1.11 of Chapter 1 illustrates the areas of identification. The tools and techniquesoutlined in Chapter 2 will be applied to the bare-airframe of the vehicles with conclusionsbeing drawn for scaling and correlation. COTS actuators will then be analyzed for theredynamics and nonlinearities. Finally, all of the sensors and telemetry equipment used inobservation for the control system will be analyzed and modeled.- 16 -
3.2 Bare-Airframe IDThe bare-airframe dynamics are perhaps the most unique aspect of these vehiclesand the way they fly. A small inertia with a large concentration of mass near the center ofthe duct is inherent in the design. Combined with this, there is heavy coupling betweenpitch and roll due to the gyroscopic effects of the fast spinning propeller. All of thevehicles looked at utilize fixed pitch propellers. Figure 1.11 showed that the pitchingmoment characteristics together with the whole of the bare-airframe rigid body dynamicscharacterize the vehicle in uncontrolled flight.3.2.1 Aerovironment/Honeywell OAVThe goal of the CIFER ® system identification was to achieve an accurate Multi-Input Multi-Output (MIMO) state-space model to support flight control development andvehicle sizing for the DARPA Phase I test vehicle. The frequency range of interest was0.1 –10 rad/sec. Frequency response analyses show that the important dynamiccharacteristics in this frequency range are the rigid body dynamics.Examination of the eigenvalues of the identified model reveals low frequencyunstable periodic modes in both the pitch and roll degrees of freedom. Excellent matchesbetween the model and flight data for the on-axis time responses confirm the accuracy ofthe of the identified state-space dynamic model.- 17 -
Page 1 and 2: Comprehensive System Identification
Page 3 and 4: APROVAL PAGETITLE:AUTHOR:Comprehens
Page 5 and 6: ACKNOWLEDGMENTSThe author would lik
Page 7 and 8: 3.4.4 Magnetometer Identification..
Page 9 and 10: LIST OF FIGURESFigure 1.1 - Land Wa
Page 11 and 12: Figure 3.48 - Magnetometer Depictio
Page 13 and 14: CHAPTER 1 - INTRODUCTION AND MOTIVA
Page 15 and 16: The vehicles examined within the sc
Page 17 and 18: tunnel testing to study the charact
Page 19 and 20: Figure 1.8 - Helicopter Body Axes S
Page 21 and 22: GPSRate GyrosAccelerometersIMUInner
Page 23 and 24: CHAPTER 2 - METHODS AND TECHNIQUES2
Page 25 and 26: 2.2.1 Flight Test TechniquesThere a
Page 27: manufacturer specifications are mod
Page 31 and 32: Table 3.2 - OAV Frequency Range of
Page 33 and 34: ⎧ p⎫⎪ ⎪y = ⎨q⎬⎪ r ⎪
Page 35 and 36: Table 3.4 - OAV DERIVID Identified
Page 37 and 38: The identified state-space model yi
Page 39 and 40: Better sensors, at higher sampling
Page 41 and 42: Figure 3.3 - Yaw response frequency
Page 43 and 44: Figure 3.4 shows that even though t
Page 45 and 46: It can be seen that the Aerovironme
Page 47 and 48: 3.2.2 Allied Aerospace MAVFlight te
Page 49 and 50: 30MAGNITUDE(DB)-10-50250PHASE(DEG)5
Page 51 and 52: A 0th/2nd order transfer function i
Page 53 and 54: Figure 3.12 shows the same for the
Page 55 and 56: Techsburg) the pitching moment resp
Page 57 and 58: Table 3.11 shows that all of the di
Page 59 and 60: Figure 3.14 shows how increasing th
Page 61 and 62: the duct, the effects of the man ne
Page 63 and 64: ft-lbMu PLATFORM= 5.11ftsecThis dim
Page 65 and 66: apparent that the size of the duct
Page 67 and 68: adequate way to characterize the di
Page 69 and 70: actuators varied in size, weight, c
Page 71 and 72: It is noticeable from the figure th
Page 73 and 74: Table 3.17 - Actuator Calibration F
Page 75 and 76: Figure 2.1 shows an example frequen
Page 77 and 78: The test matrix is provided as Tabl
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frequency response curves shown in
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Table 3.22 shows that for the first
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The time delays all seemed to be ar
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400035003000250020001500y = -13429x
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higher data rates, and tighter tole
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esponse and the response obtained f
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The time histories show that the ou
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Figure 3.31 - Magnitude Comparison
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Performing the frequency response a
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Results from STI utilizing the exac
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The fact that the rate saturated du
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Table 3.23 for the maximum rates an
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Verification of the identified mode
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from testing (3.22), it was found t
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3.4.1 Accelerometer IdentificationM
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Figure 3.43 shows that gyros were m
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5 meter circle centered about the t
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Figure 3.46 shows the modeled fluct
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Figure 3.49 - Pressure Altimeter Mo
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Figure 4.1 - Simulink MAV ModelFigu
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Figure 4.3 - Simulink Sweep Generat
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cause a pitching moment to be exert
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Figure 4.6 - Cross Control Decoupli
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⎡ Lp Lq Lr Lu Lv Lw0 0 0⎤⎢MpM
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It can be seen right away that the
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Figure 4.8 shows that the coherence
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CHAPTER 5 - CONCLUSIONSThe need for
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6. Mettler, B., Tischler, M. B., an
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Appendix AOAV Proposal VehicleIdent
Page 137 and 138:
DS8417 - 5V- 125 -
Page 139 and 140:
HS512MG - 5V- 127 -
Page 141 and 142:
DS368 - 5V- 129 -
Page 143 and 144:
94091 - 5V- 131 -
Page 145 and 146:
CS-10BB - 5V- 133 -
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Appendix CActuator Generated Transf
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DS8417 - 100% - 5V- 137 -
Page 151 and 152:
DS8417 - 100% - 6V- 139 -
Page 153 and 154:
HS512MG - 100% - 5V- 141 -
Page 155 and 156:
HS512MG - 100% - 6V- 143 -
Page 157 and 158:
DS368 - 100% - 5V- 145 -
Page 159 and 160:
DS368 - 100% - 6V- 147 -
Page 161 and 162:
94091 - 80% - 5V- 149 -
Page 163 and 164:
94091 - 80% - 6V- 151 -
Page 165 and 166:
CS-10BB - 100% - 5V- 153 -
Page 167 and 168:
CS-10BB - 100% - 6V- 155 -
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Appendix DActuator Time Domain Veri
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94091 5V94091 6V- 159 -
Page 173 and 174:
DS368 5VDS368 6V- 161 -
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Comprehensive System Identification of Ducted Fan UAVs - Cal Poly

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