MODEFLIER
Mode-Demonstrating Flying Laboratory:
Instruction and Experiment in Real-time
Preliminary Design Review
University of Colorado Boulder
October 14th, 2014
Riccardo Balin
Christian Ortiz-Torres Jeffrey Snively
Quinn Kostelecky
Matthew Slavik
David Thomas
Jas Min Ng
Tyler Smith
Hindrik Wolda
Agenda
Overview
10/14/2014
Project Overview
Jas Min Ng
Baseline Design
Henk Wolda
Aircraft
Matt Slavik
Control System
David Thomas
Ground Station
Tyler Smith
Logistics
Henk Wolda
Summary
Jas Min Ng
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
2
Project Background
• ASEN 3128 introduces natural modal response of conventional
aircraft
• Students spend semester analyzing these modes using a
MATLAB simulation
• Simulation is a good conceptual tool, but does not show
practical applications
Future ASEN 3128 Aircraft[1]
ASEN 3128 (2D) Simulation
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
3
Problem Statement and
Functional Requirements
Develop a small, low-cost system to exhibit phugoid, spiral, and
Dutch roll modes that are visible from the ground, downlink and
display real-time flight data, and record in-flight video.
FR1
FR2
FR3
Overview
10/14/2014
A fixed-wing, conventional aircraft will individually demonstrate the
phugoid, Dutch roll, and spiral modes in a manner visible to a ground
observer.
A ground station shall communicate with the aircraft at all times and
display live flight data of the aircraft state variables.
The aircraft will function autonomously, and commands from the ground
station will trigger mode demonstrations and allow for FAA required pilot
to directly operate the aircraft via RC in the event of an anomaly.
FR4
An onboard camera will capture video of the flight of the aircraft.
FR5
The aircraft shall be capable of controlled takeoff and landing without
requiring modifications to the flight environment and without suffering
any damage that will impair operational capabilities.
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
4
Concept Of Operations
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
5
Functional Block Diagram
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
6
Critical Project Elements
The baseline design must address the critical project
elements:
• CPE1: Phugoid, spiral and Dutch roll mode
demonstration
• CPE2: Autopilot design
• CPE3: Ground station electronics and communication
• CPE4: FAA Approval
• CPE5: Location
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
7
Baseline Design
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
8
Aircraft
The baseline design for the
conventional aircraft includes a
high-mounted wing and a T-tail.
Critical Project Elements
and Functional Requirements
High Wing T-Tail Aircraft[1]
addressed:
• CPE1, FR1: Phugoid, spiral, and Dutch roll mode
demonstration
• FR4: Onboard video
• FR5: Controlled take-off and landing
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
9
Control System
The baseline method of mode excitation is via an autopilot command.
Note:
• Autopilot commands will include surface singlets for the phugoid
and spiral modes and rudder oscillation for the Dutch roll mode
• The autopilot will not drive the dynamic response of the aircraft
Critical Project Elements and Functional Requirements addressed:
• CPE1, FR1: Phugoid, spiral, and Dutch roll mode demonstration
• CPE2: Autopilot Design
• FR3: Ground station commands and autonomous/RC toggle
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
10
Ground Station
The baseline ground station design will
have all components (data processor,
transceiver, display, aircraft controls)
housed in the same apparatus. The
Radio Controller will be handheld for
pilot use.
Critical Project Elements and Functional
Requirements addressed:
• CPE3: Ground station electronics
and communication
• FR2: Ground station communication
and data display
• FR3: Ground station commands and
autonomous/RC toggle
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Conventional Ground Station
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
11
Aircraft Design
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
12
Driving Requirements
The aircraft must meet the following critical project elements and
functional requirements:
• CPE1, FR1: Phugoid, spiral and Dutch roll mode
demonstration
• CPE5: Location
• FR4: Onboard video recording
• FR5: Takeoff and Landing
Feasibility Considerations:
• Determine if a Commercial Off the Shelf (COTS) aircraft with desired
configuration exists, satisfying budget and size constraints
• The COTS model considered must have static stability at trim, and
must perform the phugoid, Dutch roll and spiral modes
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
13
COTS Models Considered
HobbyUAV Techpod[1]
- Wing span: 2.59 m
- Length: 1.14 m
- Cost: $160 for Almost Ready to
Fly (ARF) kit
Overview
10/14/2014
Baseline
Design
Aircraft
HorizonHobby Icon A5 PNP[2]
- Wing span: 1.33 m
- Length: 0.87 m
- Cost: approx. $150 assembled by
parts
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
14
HobbyUAV Techpod
•
Advantages
– Rough Computer Aided Drawing
(CAD) model provided by
manufacturer[5]
– Airfoil types for wing and stabilizers
are known
– Easier and faster to model
– More accurate simulations and
results
– Greater confidence in feasibility
2.588 m
Proof of feasibility: Techpod aircraft
satisfies configuration requirement
•
Disadvantages
– Wing span does not meet size
constraint, will have to be
disassembled for storage
– Size and cruise speed (18 m/s) limit
possibility of flying indoors
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
1.14 m
Techpod Provided CAD Model[1]
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
15
Techpod CAD Model
Model Assumptions:
• Solid components can intersect
• Wing and Horizontal Stabilizer are not tapered nor
swept
• Servos, control linkages, wires, structural ribs and
additional internal components are negligible
• The is no glue/adhesive between components
• Material and internal component masses/densities were
approximated
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
16
Techpod CAD Model
2.44m
1.04m
Y
X
Z
Techpod Model Exterior
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
17
Techpod CAD Model
2.44m
1.04m
Y
X
Z
Techpod Model Interior
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
18
Techpod CAD Model
0.45 m
Y
X
0.1 m
Z
Techpod Model Internal Components
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
19
CAD Results
• Loaded Mass = 1.285 kg
• Center of Mass* = [0.0, 0.033, -0.357] m
• Moments of Inertia*
Volume Constraints:
Total Internal Space Available =
0.000922m3
Batteries = 0.000137m3
Autopilot = 0.000027m3
Video Camera = 0.000020m3
Total Used = 0.000184m3
– Ixx = 0.079 kg-m2
– Iyy = 0.268 kg-m2
– Izz = 0.198 kg-m2
*Coordinate system specific
to Solid Works model
Overview
10/14/2014
Baseline
Design
Total Remaining = 0.000738m3
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
20
AVL Model
•
Athena Vortex Lattice (AVL) simulation to determine static
stability of Techpod at trim and perform eigenmode analysis
– Uses a Vortex Panel Method to perform analysis
•
Assumptions made:
– Body has negligible effect on aerodynamic loads of aircraft
– Mass properties and Center of Gravity (CG) location as
specified by CAD model
– Trim condition is at 0 Angle of Attack (AoA) and V=18 m/s[1]
– Propulsion system and thrust not specified for simulation
– Leading Edge (LE) and Trailing Edge (TE) of wing are equally
tapered
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
21
AVL Model
Techpod AVL Model (Isometric-view)
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
22
AVL Model
Techpod AVL Model (Side-view)
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
23
AVL Model Eigenvalues
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
24
AVL Model Eigenvalues
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
25
AVL Simulation Results
•
Static Stability:
– Static margin = 0.02 m
– 𝐶𝑚𝛼 = -0.82 rad-1
– 𝐶𝑙𝛽 = -0.011 rad-1
Proof of feasibility: Phugoid, Dutch roll,
and spiral modes exist for the Techpod.
– 𝐶𝑛𝛽 = 0.054 rad-1
•
Proof of feasibility: The Techpod model is
statically stable at trim. Small static margin
indicates neutral stability which is
advantageous.
Dynamic Stability (Eigenmode Analysis):
Overview
10/14/2014
Eigen Mode
Natural Frequency,
[rad/s]
Damping Ratio
Time to Half, [s]
Phugoid
0.71
0.0028
350
Dutch roll
6.17
0.19
0.61
Spiral
0.051
-1.0
-13.7
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
26
Propulsion and Power
Model Assumptions:
• Prove feasibility by examining Techpod
recommended motor, batteries under worst
performance conditions:
– E-flite Power 10 Brushless Outrunner Motor
– Thunderpower Pro Light v2 3S 2600 mAh (two
batteries wired in parallel)
• Low propeller efficiency: 0.35[5]
• Boulder air density: 1.0419 kg/m3
• Mass, lift and drag coefficients, wing area, etc.
derived from AVL and CAD models
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
27
Motor Power Balance
Required
Effective Supplied
(Worst Case)
Safety Factor
Average Power
25.28 W
65.23 W
2.58
Max Power
46.5 W
114.14 W
2.45
Thrust
15.37 N
15.97 N
1.0385
Current
32 A continuous
42 A maximum
45.76 A
1.43
1.09
Flight Time
110 min
9.75 min / battery
set
N/A
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
28
Avionics Power Budget
Component
Estimated Max.
Voltage [V]
Estimated Max.
Current [A]
Estimated Max. Power
Capacity [W]
Electronic Speed
Controller (Battery
Eliminator Circuit)
5.5
3
16.5
Component
Estimated Max.
Voltage [V]
Estimated Max.
Current [A]
Estimated Max. Power
Consumption [W]
5
0.8
4
Camera
5.5
0.2
1.1
Autopilot
10
0.5
5
GPS RX
-
-
0.5
3DR Radio Link
-
-
0.5
Total
11.1
Servos (x 6 units)
Proof of feasibility: ESC supplies more
than sufficient power for all electronic
components on-board.
Overview
10/14/2014
Baseline
Design
Aircraft
Power = Current [I] x Voltage [V]
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
29
Total Aircraft Power Budget
• Power Supply:
1 2S 20C 2600mAh LiPo
• BOTE calculation:
Power = Current [I] x Voltage [V]
Total Battery Voltage
2 x 3.7V = 7.4V
Total Current Supply
2.6Ah x 20C= 52A
Total Battery Power
7.4V x 52A = 384.8W
Overview
10/14/2014
Baseline
Design
Aircraft
Components
Max. Power
Consumption [W]
Motor
114.14
ESC
16.5
Total Power
Consumption
130.64
Proof of feasibility: Battery power supply
is sufficient to power the entire aircraft.
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
30
Takeoff & Landing
Takeoff:
– Takeoff can be performed with a bungee launch system to
provide the Techpod with the angle of attack for max lift
and with a flight speed above stall speed (5.7 m/s)[1]
Landing:
– “With durable EPO foam construction the Techpod is
resistant to damage”[1]
– Material analysis software is being investigated to
determine the effects of (>1g) impact landings
• SolidWorks
• ANSYS
• NISA
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
31
Aircraft Design Summary
• Results:
– COTS models exist that fit design needs. Techpod is one
example
– AVL model indicated Techpod has static stability at trim
– Phugoid and Dutch roll modes are stable, while spiral
mode is unstable
– Even under low-efficiency conditions, engine and battery
models exist that are sufficient for use with the Techpod
• Future work:
– Improve software aircraft models
– Validate AVL and investigate other simulation methods
– Investigate alternative motor, propeller, avionics, and
battery options
– Model ground impact effects
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
32
Control System Design
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
33
Driving Requirements
Mode excitation must meet the following
critical project elements and functional
requirements:
• CPE1,FR1: Phugoid, spiral, and Dutch roll
mode demonstration
• CPE2: Autopilot Design
• FR3: Ground station commands and
autonomous/RC toggle
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
34
Mode Demonstrations
• Investigate feasibility of exciting each mode
individually
• Important assumptions:
–
–
–
–
Linear model of aircraft dynamics
Decoupled longitudinal and lateral responses
Ideal sensors and control surfaces
No external disturbances
• Simple control laws developed
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
35
Longitudinal Control Law
• Proportional-Derivative (PD)
pitch control with elevator
• Initial condition taken as real part
of phugoid mode eigenvector
Longitudinal Control Block Diagram
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
36
Lateral Control Law
• PD roll control with aileron and rudder
• Control law allows each mode to be displayed individually
– Display Dutch roll: only roll control
– Display spiral mode: only roll rate control
•
High-pass filter for roll rate control to allow for slow spiral mode
Lateral Control Block Diagram
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
37
Lateral Control Law
• Lateral responses to initial conditions of each eigenvalue
– Roll control (red)—suppress spiral mode and display Dutch roll mode
– Roll rate control (green)—suppress Dutch roll mode and display spiral mode
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
38
Control Surface Mode
Excitation
• Use control surfaces to excite each mode
– Phugoid—deflect elevator by 20° for 5 seconds
– Spiral—deflect rudder by 20° for 15 seconds
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
39
Dutch Roll Mode Excitation
Difficulty
•
Rudder oscillation with 20° amplitude at the Dutch roll mode frequency:
ωn = 6.17 rad/s
– Rudder oscillation failed to produce 5° oscillation in roll angle
•
Bode plot indicates that rudder input is attenuated by 24.6 dB
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
40
Model Validation
• The Techpod model was
compared to a model of the
RECUV Tempest aircraft
• The Tempest and Techpod
display similar modes
Spiral Mode Comparison
– The Techpod has less
damping in the phugoid
mode and more damping in
the Dutch roll mode
– Both display similar spiral
modes and similar
frequencies for the
oscillatory modes
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
41
Autopilot
• Autopilot characteristics to consider:
– Compatibility with software that enables the user to modify the
source code to create functions that will initiate each of the
modes via control surfaces
– Type of sensors included in the autopilot and their resolution
• State variables: inertial position, inertial velocity, Euler angles, angular rates
– Takeoff and landing capabilities
– Weight, size, and power needed
– Cost
• Autopilots taken into consideration:
– 3DR Pixhawk
– APM 2.6
– Autopilot in development by Dr. Lawrence
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
42
Autopilot
• 3DR Pixhawk Autopilot[7]
– Open source autopilot
– 14 servo outputs
– Sensors included:
• L36D20 gyroscope
• MPU-6000
accelerometer/gyroscope
• LSM303D
accelerometer/magnetometer
• M55611 barometer pressure
sensor
– Weight: 38 g
– Size: 8.15 cm x 5 cm x 1.55 cm
– Cost: $200 alone, $385 with sensors
and radio
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Pixhawk Autopilot dimensions[7]
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
43
Software Compatibility
•
•
Pixhawk is compatible with the open source software
QGround Control, which uses MAVLINK for
communication protocols
MAVLINK[8]:
– Is an open source
• Able to modify source code
• Will have to confirm reliability through testing
– Several commands available can be used for the
project:
• SET-SERVO: Uses Pulse-Width Modulation (PWM) to
control the pulse duration of a servo
• TAKEOFF[10]: Sets the throttle to maximum to climb to
the specified altitude
• LANDING[10]: Shuts down throttle and holds the current
heading as aircraft approaches its given location for
landing
• WAYPOINTS: Sets planned flight patterns
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Waypoints example[9]
Logistics
Summary
44
Control System Sensors
Desired
variable
Required
Resolution
Position
(x, y, z)
1m
Velocity
(u, v, w)
1 m/s
Euler
angles
(ϕ, θ, Ψ)
Angular
Rates
(p, q, r)
Overview
10/14/2014
1°
1°/s
Baseline
Design
Measured Variable
Device
Measured variable
resolution
Desired variable
resolution
Position
GPS
_
Determined
through testing
Acceleration
Accelerometer
7.18 mm/s2
Determined
through testing
Angular Rates
Gyroscope,
Magnetometer,
Accelerometer
0.070 °/s
Determined
through testing
Angular Rates
Gyroscope,
Magnetometer,
Accelerometer
0.070 °/s
0.070 °/s
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
45
Control Design Summary
• Results:
– Linear models demonstrate that each mode can be displayed
individually
– Control surface deflections excite modes
– The Pixhawk autopilot software can be modified
– State variables of the aircraft can be obtained from autopilot
sensors
• Future work:
–
–
–
–
Overview
10/14/2014
Investigate alternative methods of Dutch roll demonstration
Improve control system gains for the Techpod aircraft
Develop non-linear model that includes external influences
Test Pixhawk autopilot to determine the resolution of the
sensors
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
46
Ground Station Design
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
47
Driving Requirements
Ground station design must
meet the following
requirements:
• CPE3: Ground station
electronics and communication
• FR2: Ground station
communication and data
display
• FR3: Ground station
commands and
autonomous/RC toggle
Conventional ground station design
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
48
Ground Station Components
Component
Purpose
Example
Data processor
Receives in-flight data and
analyzes it for the data display
Laptop
Data display
Receives and displays plots of
analyzed data from processor
External computer
monitors
RC controller
Allows an RC pilot to command
airframe
Spektrum DX7s
Autopilot
Controller
Controls current autopilot state
and tasking
QGroundControl
Radio/Transceiver
Sends autopilot commands and
receives raw in-flight data
3DR radio set
Generator
Supplies power to ground station
Rural King generator
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
49
Autopilot Controller and
Transceiver
Autopilot controllers software only, run through a computer
QGroundControl is open-source, so adapting the code to allow for on-demand
mode excitation is possible
• A calculation was performed for a high estimate of the required baud rate of
the radio transceiver:
20 8-Byte variables = 1280 bits for one transmission
10 Hz required
1280 bits * 10 Hz = 12.5 kbps
3DR radio set has standard baud rate of 64 kbps and exceeds requirements
•
•
3DR Radio[12]
QGroundControl Screenshot[11]
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
50
Data Processor
• All 12 variables provided by autopilot
• Data processor takes data from autopilot to plot to data
display
• 16-bit resolution provides resolution of 0.005 degrees
• A laptop is required for the autopilot system already;
modern laptops are greater than 16-bit systems
• Code written in MATLAB allowed plotting at 18 Hz
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
51
Data Display
• Not critical to decide on particular data display
• Potential data display design: two cloned-display
computer monitors, each with five observers to
examine state variables
• Why is this feasible?
– Computer monitors refresh at 60 Hz
– Monitors are compatible with most laptops
– If all 12 plots are on one 1920x1200 pixel screen allows 445x350
pixels for each plot
– 24” (61 cm) monitor provides 11 cm x 11 cm for each plot
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
52
RC Controller and
Transmitter
• Wide range of RC controllers
available off-the-shelf
• Choosing a controller is not a
critical element
• Spektrum DX7s is an example
– 7-channels is compatible with
PIXHAWK autopilot
– If signal is lost, autonomous
landing procedure can be
triggered
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Spektrum DX7s[13]
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
53
Power Estimate
Component
Power Estimate
Laptop
60 W max.
Two monitors
160 W max.
RC controller
Internal battery
Radio
0.1 W max.
Software
N/A
Total
220.1 W
Proof of feasibility: Generator can
supply enough power for ground
station system.
• A small gas-powered generator supplies 800 W with standard
120 V AC and 12 V DC outlets
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
54
Ground Station Summary
• Results:
– Ground station is feasible using these
components
– External power source will be required for
ground station
• Future work:
– Perform trades to determine specific
components
– Perform maximum range analysis for both the
radio and RC transmitter by CDR
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
55
Logistics
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
56
Driving Requirements
• CPE4: FAA Approval
– Public unmanned aerial system (UAS) in National Airspace requires a
Certificate of Authorization (COA)
– Need potential off-ramps in case COA is denied (ex. Indoor flight)
• CPE5: Location
– Cannot validate design without authorized flight location
– Design choices must be appropriate for location
• DR1.6: The aircraft shall not exceed $1000 reproducibility cost
• DR2.4: The ground station shall not exceed $2000 reproducibility
cost
• DR1.7, DR2.5: The full system must be stored in a cargo space no
greater than 150 cm x 100 cm x 90 cm
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
57
Certificate of Authorization
•
•
•
•
Key Needs:
Aircraft configuration, performance,
and communication characteristics
Planned operational uses for UAS
Planned flight location
~60 working days between submittal
and official response
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
58
Ease of Authorization
Characteristic
“Easy”* COA
Requirements
Baseline Design
Gross Weight (lb)
< 55.0
5.0
Max Speed (kts)
< 87.0
55.0
Flight Ceiling (ft)
< 400
-
Propulsion Type
Propeller
Propeller
• Location options have existing CU COA
*Numbers collected from Small UAS Aviation Rulemaking Committee, FAA UAS
Operational Approval document N8900.227, and James Mack experience with CU
COA applications
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
59
Outdoor Locations
Potential Options
• Arvada
Aeromodelers
– 15 mi from CU
• Table Mountain
– 18 mi from CU
• Pawnee National
Grasslands
– 120 mi from CU
Overview
10/14/2014
Baseline
Design
Aircraft
Logistics
• All have existing
CU COA’s for other
UAS
• Ample airspace
• Potential weather
effects
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
60
Budget Feasibility
Aircraft Part
Approximate Cost
(before Tax/Shipping)
Ground Station Part
Approximate Cost
(before Tax/Shipping)
Autopilot System
$385
Monitors
$400
Airframe
$160
RC Controller
$300
Control Servos
$130
External Power
$200
Propulsion System
$120
Autopilot Transceiver
$50
Batteries
$90
Laptop
$0
Camera
$20
Software
$0
Total
$905
Total
$950
Maximum
$1000
Maximum
$2000
• Need to take tax and shipping into account
• Will evaluate component options for cost-saving alternatives
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
61
Transport Volume Budget
Component
Maximum Dimensions, [m]
Techpod CAD Model*
Maximum Volume [m3]
-
0.02751*
0.46 x 0.38 x 0.35
0.059
Laptop
0.3 x 0.3 x 0.08
0.0072
Electronic Monitors (x2)
0.57 x 0.41 x 0.2
0.093
0.027 x 0.056 x 0.013
0.00002
DX7s
0.37 x 0.29 x 0.17
0.018
Total
-
0.205
Generator
Transceiver
SUV Space = 1.5m x 1.0m x 0.9m = 1.35m3
Extra Space Available = SUV Space – Total = 1.145m3 remaining
*Techpod CAD model volume is calculated with a safety factor of 2 to correct for the inaccuracy of the
current model.
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
62
Logistics Summary
• Results:
–
–
–
–
–
Flight locations have been identified
Likely to obtain COA
Aircraft cost is near, but within, budget
Well under ground station budget
Total volume estimated less than the available volume
• Future Work:
–
–
–
–
Overview
10/14/2014
Apply for COA within two weeks
Evaluate altitude loss from spiral mode
Firm up flight location off-ramps
Investigate cost-saving alternatives for the aircraft system
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
63
Summary
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
64
Feasibility
• Aircraft
 Statically stable and has three desired modes
 Can supply enough power and thrust
• Control System
 Each mode can be displayed individually
 Autopilot has modifiable software and measures state
variables
• Ground Station
 Discussed components satisfy ground station
requirements
 Power requirements satisfied by gas powered generator
• Logistics
 Likely to obtain COA at identified flight locations
 Budget and size constraints met
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
65
Future Work
• Aircraft
– More detailed software models
– Explore motor and battery options
• Control System
– Investigate alternative methods of Dutch roll
demonstration
– Non-linear model with external influences
• Ground Station
– Perform trades to determine specific components
– Perform maximum range analysis for both the radio and
RC transmitter
• Logistics
– Apply for COA within two weeks
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
66
Acknowledgements
• Customer: Doug Weibel
• Team Advisor: Dr. Gerren
• PAB Members, especially:
– Dr. Lawrence, Matt Rhode, Trudy Schwartz
• AES Faculty: Dr. Akos, Dr. Chu, Dr. Frew
• RECUV: James Mack
• Techpod Manufacturer: Wayne Garris
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
67
Questions?
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
68
References
[1] Wayne http://diydrones.com/
DVR/700/06P-MC-002-Portable-DVR-1.jpg
[2] http://www.horizonhobby.com/products/icon-a5-pnp-PKZ5875
[19]http://www.hobbyking.com/hobbyking/store/__31162__Arkbird_Autopil
ot_System_w_OSD_V3_1020_GPS_Altitude_Hold_Auto_Level_.html
[3]
http://www.hobbyking.com/mobile/viewproduct.asp?idproduct=45498&typ [20] Etkin, Bernard. Dynamics of Flight: Stability and Control. New York: Wiley,
e=&idparentcat=437
1982. Print.
[4] http://modelerc.pl/galeria/?falcon-epp-gotowy-samolot-szybowiec-rc[21] The Tempest UAS: The VORTEX2 Supercell Thunderstorm Penetrator --kamera
AIAA paper
[5] http://www.freecadweb.org/
[22] http://tornadochaser.colorado.edu/
[6] Motor and Battery pack CAD files courtesy Carl Marvin (DBF ‘13-’14)
[23] Roskam, Jan. Airplane Design Part 1: Preliminary Sizing of Airplanes.
Lawrence, KS: DARcorporation, 2003. Print.
[7] https://store.3drobotics.com/products/3dr-pixhaw
[24] http://usa.ioncamera.com/ion/iON-AIR-PRO-Wi-Fi_Lite.html
[8] https://pixhawk.ethz.ch/mavlink/
[25]
[9] http://copter.ardupilot.com/wiki/planning-a-mission-with-waypointshttp://www.bhphotovideo.com/bnh/controller/home?gclid=CNaPqO2QkcEC
and-events/
[10] http://plane.ardupilot.com/wiki/flying/automatic-takeoff-and-landing/ FQsSMwodhAUAfA&is=REG&sku=996553&Q=&O=&A=details
[11]http://2.bp.blogspot.com/_F0i917zfySk/THGdU2IfUbI/AAAAAAAAB3I/dz [26] http://www.vehouk.com/main/shop_detail.aspx?article=44&mode=specifications
mWhRgDfMc/s1600/2010-08-22-qgroundcontrol-improvements.png
[27] http://www.e-fliterc.com/Products/Default.aspx?ProdID=EFLM4010A
[12] http://api.ning.com/files/LqMVtloOMDw3nHIPr3E5S7EAmLXcCUyCvVhqLcpd6eJ8O83bxHSWNufAgEm*L [28] http://www.castlecreations.com/products/thunderbirds.html
J3Je8Au50r8ejpOJ*-dDmdAqQ7oP7w1C6O/Kit.jpg
[29] http://www.thunderpowerrc.com/Products/G8-Pro-Lite-RxLiPo/TP2700-2SPPRX
[13] https://www.spektrumrc.com/ProdInfo/Gallery/4SPM-DX7.jpg
[14] “Visual Acuity,” Encyclopædia Britannica, Encyclopædia Britannica Inc., [30] http://www.servocity.com/html/hs65hb_mighty_feather.html#.VDl_MvldV8F
2006.
[31] http://www.servocity.com/html/hs-82mg_servo.html#.VDl_fPldV8F
[15] http://ian.umces.edu/imagelibrary/displayimage-93-5195.html
[32] http://www.apcprop.com/ProductDetails.asp?ProductCode=LP11070E
[16] http://commons.wikimedia.org/wiki/File:Eye_symbol_lateral.svg
[17]http://www.researchgate.net/publication/41098859_Microstructure_ani [33]http://aerosciences.com.au/hidden/UAV%20Handling%20Qualities%20
Paper%20v1.pdf
sotropy_in_polyolefin_flexible_foams/links/00b49519bc824b3c7d000000
[18] http://www.hobbypartz.com/72p-80thumbcam.html#http://site.hobbypartz.com/pimages/06P-MC-002-Portable-
Overview
10/14/2014
Baseline
Design
Aircraft
Control
System
Ground
Station
University of Colorado Boulder
Aerospace Engineering Sciences
Logistics
Summary
69
Requirements Backup Slides
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
70
Design Requirements
FR1
DR1.1
DR1.2
DR1.3
10/14/2014
A fixed-wing, conventional aircraft will individually demonstrate the
phugoid, Dutch roll, and spiral modes in a manner visible to a ground
observer.
The roll, pitch, and yaw angles of the aircraft will be distinguishable to a ground
observer with 20/30 vision at a resolution of 5°. This defines the maximum range of
demonstration as 200L for phugoid and spiral modes and 200b for Dutch roll mode,
where L is the length of the aircraft from tip to tail and b is the wingspan of the aircraft
(see Appendix A for derivation).
The aircraft shall exhibit a phugoid mode with a pitch oscillation amplitude of at least 5
degrees, meeting minimum visibility requirement.
The aircraft shall exhibit a Dutch roll mode with a roll oscillation amplitude of at least 5
degrees, meeting minimum visibility requirement.
DR1.4
The aircraft shall exhibit a spiral mode with a yaw rotation of at least 180 degrees, or it
shall reach a roll angle that approaches an unrecoverable attitude, within a safety factor.
The roll angle that is defined as unrecoverable will be determined through simulations.
DR1.5
The aircraft will be able to repeat the demonstration of all three modes in a period of
110 minutes (the duration of an ASEN 3128 lab) to at least 40 observers such that each
observer has the opportunity to view the ground station display at least 1 time.
DR1.6
The aircraft shall not exceed a reproducibility cost of $1,000.
DR1.7
The aircraft shall be stored in a container to be placed in an SUV with a cargo space no
greater than150 cm x 100 cm x 90 cm.
University of Colorado Boulder
Aerospace Engineering Sciences
71
Design Requirements
FR2
10/14/2014
A ground station shall communicate with the aircraft at all times and
display live flight data of the aircraft state variables.
DR2.1
The aircraft will measure and transmit flight data of its aircraft state in real-time
throughout its entire flight. The aircraft state measurements will abide to the following
resolutions: 1 m for position components, 1 m/s for velocity components, 1° for Euler
angles, and 1°/s for the angular rate components.
DR2.2
The ground station will process and output data of the aircraft state at a rate of at least
10 Hz.
DR2.3
The ground station will produce a real-time, on-screen display of the aircraft state data
that will be visible to at least 10 observers on the ground.
DR2.4
The ground station shall not exceed a reproducibility cost of $2,000.
DR2.5
The ground station must be stored in a conventional SUV with a cargo space no greater
than 150 cm x 100 cm x 90 cm.
University of Colorado Boulder
Aerospace Engineering Sciences
72
Design Requirements
FR3
The aircraft will function autonomously, and commands from the ground station will
trigger mode demonstrations and allow for a pilot to directly operate the aircraft via
RC in the event of an anomaly.
DR3.1
The autopilot will allow the aircraft to fly in steady, level flight on a predetermined path until it is
commanded otherwise.
DR3.2
The autopilot will return the aircraft to steady, level flight after the demonstration of each mode.
DR3.3
At any time during the flight, the RC pilot will be able to override the autopilot and give the pilot
direct control of the aircraft in case of an anomaly.
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
73
Design Requirements
FR4
An onboard camera will capture video of the flight of the aircraft.
DR4.1
The video will be stored onboard and downlinked after aircraft has landed.
DR4.2
The video will be able to be correlated with time such that the recorded flight data can be matched
to specific times in the video.
FR5
The aircraft shall be capable of controlled takeoff and landing without requiring
modifications to the flight environment and without suffering any damage that will
impair operational capabilities.
DR5.1
DR5.2
10/14/2014
The launch method will be appropriate for the test environment. The three methods being
considered are hand-launched, bungee-launched, and ground take-off with landing gear. This will
be highly dependent on the selected airframe.
The landing method will also be appropriate for the test environment. Methods considered will
include landing gear and controlled belly-landing. This will be highly dependent on the selected
airframe.
University of Colorado Boulder
Aerospace Engineering Sciences
74
Visibility Requirements
DR1.1: The roll, pitch, and yaw angles of the aircraft will
be distinguishable to a ground observer with 20/30
vision at a resolution of 5°.
• 20/20 vision is defined as “At 20 feet or 6 meters, a
human eye with nominal performance is able to
separate contours that are approximately
1.75 mm apart[14].” For 20/30 vision, the same
resolution can be seen at a distance of only 4 meters.
• Tip deflection, 𝑋, of the aircraft as a function of an Aircraft Euler Angle Visibility[15]
Euler angle rotation, 𝜃, and either the length of the
aircraft, 𝐿, or the wingspan, 𝑏 for small angles is:
𝑋 = 𝐿𝑠𝑖𝑛 𝜃 − 𝑂𝑅 − 𝑏𝑠𝑖𝑛(𝜃)
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
75
Visibility Requirements
(cont.)
•
The definition of 30/20 vision relates the distance and the minimum
resolution.
𝑋
𝐷
•
=
1.75𝑚𝑚
4𝑚
= 4.375 ∙ 10−4
Maximum distance can be:
𝐷
𝐷 = ∗ 𝑋 = (1/ 4.375 ∙ 10−4 ) ∗ 𝐿𝑠𝑖𝑛(𝜃)
𝑋
The minimum detectable angle of 5° gives three system constraints:
𝑃ℎ𝑢𝑔𝑜𝑖𝑑: 𝐷𝑚𝑎𝑥 = 200𝐿
𝑆𝑝𝑖𝑟𝑎𝑙: 𝐷𝑚𝑎𝑥 = 200𝐿
𝐷𝑢𝑡𝑐ℎ 𝑅𝑜𝑙𝑙: 𝐷𝑚𝑎𝑥 = 200𝑏
Angle Resolution vs.
• For the Techpod, these constraints are:
Distance from
𝑃ℎ𝑢𝑔𝑜𝑖𝑑: 𝐷𝑚𝑎𝑥 = 208 𝑚
Observer[16]
𝑆𝑝𝑖𝑟𝑎𝑙: 𝐷𝑚𝑎𝑥 = 208 𝑚
𝐷𝑢𝑡𝑐ℎ 𝑅𝑜𝑙𝑙: 𝐷𝑚𝑎𝑥 = 488 𝑚
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
76
Aircraft Backup Slides
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
77
Aircraft Configuration Trade
Study
• Needed to determine MODEFLIER
configuration
• Wing and Empennage studies were
carried out
• Baseline Design has a high wing with a
large span and a T-tail configuration
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
78
Wing Trade Study
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
79
Empennage Trade Study
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
80
CAD Assumptions Backup Slide
•
•
•
•
•
•
Expanded Polyolefin (EPO) foam has density of 45 kg/m3 (range is
20-60)[17]
Carbon-fiber rods have density of 1780 kg/m3
Batteries have mass of 0.137 kg (They are the ones DBF used in ‘13’14)
Motor has a mass of 0.159 kg (It is the one DBF used in ‘13-’14)
Video camera has a mass of 0.05 kg[18] and is located at the nose of
the aircraft (First Person View)
The autopilot package has a mass of 0.038 kg ,the casing is
approximated to 11 grams[19]
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
81
Techpod Provided CAD
•
•
Original CAD files provided by Wayne Garris
Techpod originally designed in FreeCAD (right) and converted to SolidWorks (left)
Techpod Provided CAD Model[5]
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
82
AVL Assumptions and
Limitations
• AVL assumptions and limitations:
– Airframe is composed of thin lifting surfaces at
small AOA and sideslip
– Lifting surfaces are represented as single layer
vortex sheets, discretized into horseshoe vortex
filaments
– Slender bodies are modeled as source + doublet
filaments
– Quasi-steady flow
– Compressibility effects are treated using PrandtlGlauert transformation
– Viscous effects neglected
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
83
Phugoid Mode
Approximation
Natural frequency approximation:
𝜔𝑛 =
𝜌𝑆𝐶𝑊0 𝑔
𝑚
Damping ratio approximation:
1 𝐶𝐷0
𝜁=
2 𝐶𝐿0
Given the stability data provided by AVL
𝜔𝑛 = 0.77 and 𝜁 = 0.0036.
These results have a percent difference with AVL results of
10% for 𝜔𝑛 and 28% for 𝜁.
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
84
Dutch Roll Mode
Approximation[20]
Dutch Roll eigenvalue approximation:
𝒴𝑣 + 𝒩𝑟
𝜆=−
± 𝑖 𝑢0 𝒩𝑣
2
From given stability information in AVL:
𝜔𝑛 = 𝑅𝑒 𝜆
2
+ 𝐼𝑚 𝜆
2
1
2
= 6.17 rad/s
𝑅𝑒 𝜆
𝜁=−
= 0.19
𝜔𝑛
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
85
Spiral Mode
Approximation[20]
Spiral eigenvalue approximation:
𝑔 ℒ𝑣 𝒩𝑟 − ℒ𝑟 𝒩𝑣
𝜆=
𝑔ℒ𝑣 + 𝑢0 ℒ𝑝 𝒩𝑣 − ℒ𝑣 𝒩𝑝
From given stability information in AVL:
𝜔𝑛 = 𝑅𝑒 𝜆
2
+ 𝐼𝑚 𝜆
2
1
2
= 0.044 rad/s
𝑅𝑒 𝜆
𝜁=−
= −1.0
𝜔𝑛
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
86
Dutch Roll and Spiral Mode
Validation[19]
•
•
•
Stability derivatives from AVL and mass properties from CAD model were used
as input to the Matlab code developed in ASEN 3128.
In this code, the lateral stability matrix was computed according to Etkin, and
the eigenvalues, λ, were calculated with the eigen() function.
The natural frequency is defined as
𝑅𝑒(λ)2
•
•
1
+ 𝐼𝑚(λ)2 2
𝜔𝑛 =
The damping ratio is then computed as
𝜁 = −𝑅𝑒(λ)/𝜔𝑛
Dutch roll mode:
– 𝜔𝑛 = 6.17 rad/s
– 𝜁 = 0.19
– both within 1% error of AVL results
•
Spiral mode:
– 𝜔𝑛 = 0.044 rad/s
– 𝜁 = -1
– 𝜔𝑛 has 14% error difference compared to AVL results
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
87
HobbyUAV Techpod Specs
Cruise speed: 16 m/s
Max speed: 28 m/s
Stall speed: 6 m/s
Wingspan: 2.59 m
Wing area: 0.390 m2
Length: 1.14 m
Dry weight: 1.25 kg
EPO wings and
fuselage, carbon fiber
tail boom and wing
spar
• Requires 6 channels
•
•
•
•
•
•
•
•
10/14/2014
HobbyUAV Techpod[1]
University of Colorado Boulder
Aerospace Engineering Sciences
88
HorizonHobby Icon A5 PNP
Specs
Wingspan: 1.33 m
Length: 0.875 m
Loaded weight: 1.23 kg
Horizontal CG location:
30-35 mm behind LE of
wing
• Landing gear is optional
• Z-Foam construction
• Requires five channels
•
•
•
•
10/14/2014
HorizonHobby Icon A5 PNP[2]
University of Colorado Boulder
Aerospace Engineering Sciences
89
HobbyKing Skywalker 1900
Specs
Wingspan: 1.90 m
Wing area: 0.355 m2
Length: 1.18 m
Loaded weight: 1.31.8 kg
• EPO wings and
fuselage
• Requires four
channels
•
•
•
•
10/14/2014
HobbyKing Skywalker 1900[3]
University of Colorado Boulder
Aerospace Engineering Sciences
90
HobbyKing FPV/UAV 168
Specs
•
•
•
•
•
•
Wingspan: 1.66 m
Length: 1.18 m
Dry weight: 1.3 kg
Fiberglass fuselage and
Landing gear
Requires five channels
10/14/2014
HobbyKing FPV/UAV 168 1900[4]
University of Colorado Boulder
Aerospace Engineering Sciences
91
FAA Handling Qualities
• Level 1: Perfect handling
• Level 2: Decent handling, increased control system
workload
• Level 3: Poor handling, high control system
workload[33]
Mode[23]
Phugoid
Dutch roll
Spiral
10/14/2014
Level I
Level II
Level III
𝜁 ≥ 0.04
𝜁≥0
𝑇2 ≥ 55𝑠
𝜁 ≥ 0.08
𝜁𝜔𝑛 ≥ 0.15
𝜁 ≥ 0.02
𝜁𝜔𝑛 ≥ 0.05
𝜁≥0
𝑇2 > 20𝑠
𝑇2 > 8𝑠
𝑇2 > 4𝑠
University of Colorado Boulder
Aerospace Engineering Sciences
92
Aircraft Average Power
Requirements
𝑃𝑟𝑒𝑞𝑎𝑣𝑔
𝑊
2𝑊
=
= 𝟐𝟓. 𝟐𝟖 𝐖
(𝑐𝑙 𝑐𝑑 ) 𝜌∞ 𝑆𝑐𝑙
𝜂𝑝𝑟𝑜𝑝 = 0.28
𝜂𝑚𝑜𝑡𝑜𝑟
𝐼𝑎𝑣𝑔 𝑅
(32 A)(0.043 Ω)
=1−
=1 −
= 0.8089
𝑉
7.2 V
𝑃𝑠𝑢𝑝𝑝𝑙𝑖𝑒𝑑𝑎𝑣𝑔 = 𝐼𝑎𝑣𝑔 𝑉 = 230.4 W
𝑃𝑠𝑢𝑝𝑝𝑙𝑖𝑒𝑑𝑒𝑓𝑓 = 𝑃𝑠𝑢𝑝𝑝𝑙𝑖𝑒𝑑𝑎𝑣𝑔 𝜂𝑝𝑟𝑜𝑝 𝜂𝑚𝑜𝑡𝑜𝑟
𝑷𝒔𝒖𝒑𝒑𝒍𝒊𝒆𝒅𝒆𝒇𝒇 = 𝟓𝟐. 𝟏𝟖 𝐖 > 𝑷𝒓𝒆𝒒𝒂𝒗𝒈 = 𝟐𝟓. 𝟐𝟖 𝐖
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
93
Aircraft Maximum Power
Requirements
𝑃𝑟𝑒𝑞𝑚𝑎𝑥
𝑊
12.61 N
m
=
𝑉
=
28.29
= 𝟒𝟔. 𝟓 𝐖
(𝑐𝑙 𝑐𝑑 ) 𝑚𝑎𝑥 (0.2394 0.0312)
s
𝜂𝑚𝑜𝑡𝑜𝑟 = 1 −
𝐼𝑚𝑎𝑥 𝑅
(42 A)(0.043 Ω)
=1 −
= 0.8495
𝑉𝑚𝑎𝑥
12 V
𝑃𝑠𝑢𝑝𝑝𝑙𝑖𝑒𝑑𝑚𝑎𝑥 = 𝐼𝑚𝑎𝑥 𝑉𝑚𝑎𝑥 = 504 W
𝑃𝑠𝑢𝑝𝑝𝑙𝑖𝑒𝑑𝑚𝑎𝑥 = 𝑃𝑠𝑢𝑝𝑝𝑙𝑖𝑒𝑑𝑚𝑎𝑥 𝜂𝑝𝑟𝑜𝑝 𝜂𝑚𝑜𝑡𝑜𝑟
𝑒𝑓𝑓
𝑷𝒔𝒖𝒑𝒑𝒍𝒊𝒆𝒅𝒎𝒂𝒙
10/14/2014
𝒆𝒇𝒇
= 𝟏𝟏𝟒. 𝟏𝟓 𝐖 > 𝑷𝒓𝒆𝒒𝒎𝒂𝒙 = 𝟒𝟔. 𝟓 𝐖
University of Colorado Boulder
Aerospace Engineering Sciences
94
Force Balance
1
𝐿 = 𝜌∞ 𝑉∞2 𝑆 𝑐𝑙
2
1
kg
𝐿=
1.0419 3
2
m
𝑳 = 𝟏𝟕. 𝟐𝟕 𝐍
m
18
s
𝑊 = 𝑚𝑔 = 1.285 kg
𝑾 = 𝟏𝟐. 𝟔𝟏 𝐍 < 𝑳
10/14/2014
2
0.42730 m2 0.23943
m
9.81 2
s
University of Colorado Boulder
Aerospace Engineering Sciences
95
Force Balance
1
𝐷 = 𝜌∞ 𝑉∞2 𝑆𝑐𝑑
2
𝐷=
1
2
kg
1.0419 3
m
m 2
18
s
0.42730 m2 0.00121 + 0.03
𝑫 = 𝟐. 𝟐𝟓 𝐍
𝑇=
𝑃𝑠𝑢𝑝𝑝𝑙𝑖𝑒𝑑𝑒𝑓𝑓
𝑉
𝑻 = 𝟐. 𝟗𝟎 𝐍 > D
10/14/2014
52.18 𝑊
=
𝑚
18
𝑠
University of Colorado Boulder
Aerospace Engineering Sciences
96
Aircraft Energy
Requirements
𝐶 = 2600 mAh ∗ 2 = 5.2 Ah
𝐸𝑠𝑡𝑜𝑟𝑒𝑑 = 3600𝑉𝐶 = 3600
sec
hr
7.2 V 5.2 Ah = 𝟏𝟑𝟒 𝐤𝐉
Nominal Discharge Rate: 16C
𝐷𝑖𝑠𝑐ℎ𝑎𝑟𝑔𝑒𝑚𝑎𝑥 = 16 ∗ 𝐶 = 𝟖𝟑. 𝟐 𝐀
𝜂𝑏𝑎𝑡𝑡𝑒𝑟𝑦 = 0.55
𝐷𝑖𝑠𝑐ℎ𝑎𝑟𝑔𝑒𝑒𝑓𝑓 = 𝐷𝑖𝑠𝑐ℎ𝑎𝑟𝑔𝑒𝑚𝑎𝑥 ∗ 𝜂𝑏𝑎𝑡𝑡𝑒𝑟𝑦 = 𝟒𝟓. 𝟕𝟔 𝐀
𝐹𝑙𝑖𝑔ℎ𝑡 𝑇𝑖𝑚𝑒 =
𝐸𝑠𝑡𝑜𝑟𝑒𝑑
= 585 s = 𝟗. 𝟕𝟓 𝐦𝐢𝐧
𝑃𝑠𝑢𝑝𝑝𝑙𝑖𝑒𝑑
𝐶ℎ𝑎𝑟𝑔𝑒 𝑇𝑖𝑚𝑒 =
10/14/2014
𝐶ℎ𝑎𝑟𝑔𝑒𝑚𝑎𝑥 3𝐶[Ahr] 15.6 Ahr
=
=
= 0.5 hr = 𝟑𝟎 𝐦𝐢𝐧
𝐼𝑐ℎ𝑎𝑟𝑔𝑒𝑚𝑎𝑥
6𝐶[A]
31.2 A
University of Colorado Boulder
Aerospace Engineering Sciences
97
Performance Constraint
Assumptions
•
•
•
•
•
•
•
Cd0 = 0.03 (Drag coefficient at 0 lift)
W = 3 lb = 1.36 kg (Weight)
𝜂𝑝 = 0.28 (Propeller efficiency)
𝜂𝑚 = 0.84 (Motor efficiency)
e = 0.8 (Oswald’s efficiency rating)
E = 0.5 hrs (Endurance)
CLmax = 1.86 (1.06 from AVL at 10° which
is wing stall point with CLflaps = 0.8)
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
98
Performance Chart
= Design
Space
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
99
Performance Constraint
Results
Value
Design Point 1
(Black Diamond)
Design Point 2
(Blue Diamond)
Power Required [W]
244.4
275.4
Batter Capacity Required
[A-hr]
4.97
5.60
Surface Area Required [m2]
0.42
0.65
The Techpod base design has a surface area of ~0.70 m2 which means
either design point can be satisfied by the current aircraft geometry.
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
100
Performance Constraint Equations[23]
• [W/S]stall = (1/2)*𝜌*(Vstall2 )*CLmax
• [W/P]maneuver =
(√((2n)*(W/S)/(𝜌*CL)) * (q*CD0/(W/S)+n2/(K*q)))-1
• [W/P]cruise= (W/S)/(q*V*(CD0+CL2/K))
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
101
Control System Backup
Slides
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
102
Control System Trade Study
Facet
Weight
(%)
APM 2.6
Autopilot in
development
3DR Pixhawk
Complexity to modify
source code
30
3
4
3
Sensors available
20
4
4
4
Takeoff/Landing
capability
15
3
2
3
Availability
20
4
3
4
Cost
15
4
3
4
Total
100
18
16
18
3.55
3.35
3.55
Weighted Total
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
103
Backup Slide: Mode Excitation Trade
Study
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
104
Control Surface Responses for
Modes from Initial Conditions
• The control surfaces can easily suppress the phugoid and
spiral modes
• The rudder cannot suppress such a large Dutch Roll
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
105
Control Surface Responses
for Mode Excitation
• Reasonable control surface deflections occurred for
the phugoid and spiral modes
– A reasonable rudder oscillation failed to produce a 5° roll
angle oscillation for the Dutch roll mode
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
106
Tempest vs. Techpod
Techpod[1]
Tempest[21][22]
Mass (loaded) = 2.25 kg
Cruise Speed = 16.5 m/s
Mass (loaded) = 5.4 kg
Cruise Speed = 30 m/s
Dimensions of images are in meters
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
107
Comparison of Tempest and
Techpod Modes
• The Tempest and Techpod
display similar modes
– The Techpod has less damping
in the phugoid mode and
more damping in the Dutch
roll mode
– Both display similar spiral
modes and similar
frequencies for the oscillatory
modes
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
108
Comparison of Tempest and
Techpod Modes
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
109
Ground Station Backup
Slides
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
110
Data processor memory
requirements
Assuming 20 8-byte variables at 200 Hz:
20*8*200 = 32000 bytes per second
For a 2-hour lab period:
32000*3600*2= 230400000 B
230400000 B = 230.4 MB
This memory requirement is much smaller
than modern laptop hard drives, so
memory is not a concern
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
111
Data processor speed
requirements
• MATLAB code written followed the following structure
to simulate receiving, performing calculations, and
plotting:
– Generate one data point for 12 variables each
– Calculate mean and standard deviation for last 50 data
points of each variable
– Plot last 50 data points on screen
– Repeat the process
• Performing this process 500 times took 27 s, allowing for
plotting at 18 Hz.
• If a compiled programming language were used, this
would be quicker
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
112
Ground Station Trade Study
• Good communication – only one link between aircraft and data processor
• Lapse time – fastest for displaying data in real-time because only one link required
• Reproducibility cost – cheapest because it doesn’t require internet routers,
additional cables
• Visibility – dependent on size of monitors, but still can display well with 10 audience
at maximum
• Ease of Assembly – least amount of equipment/components
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
113
Logistics Backup Slides
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
114
Indoor Locations (Off-ramp)
Potential Options
• Fleming Flight
Facility
• Balch Fieldhouse
• Athletic Bubble
•
•
•
•
•
•
10/14/2014
Logistics
Do not need COA
Need Proper
Permissions
Space Restriction
Not subject to
weather effects
GPS difficulties
Will need to analyze
the Icon UAS
University of Colorado Boulder
Aerospace Engineering Sciences
115
Fleming Flight Facility
• Used for testing of quadcopters
• Dimensions: 30 ft x 70 ft
Pros
Cons
Do not need COA
Speed and Mode Size Constrained
Dedicated Flight Facility
Spiral Mode not Feasible
Not Subject to Weather Effects
No Feasible UAS Available
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
116
Balch Fieldhouse
• Potential location for ASEN2004 rocket launches
• Dimensions: ~156 ft x 238 ft
• Have reached out to Athletic Dpt. and waiting for
response
Pros
Cons
Do not need COA
Spiral mode is constrained
Less constraints on flight speed
than Fleming
Need Permission
Not subject to weather effects
Difficult to schedule
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
117
Athletic Bubble
• Dimensions: ~160ft x 360ft
• Less constraints on flight speed
• Have reached out to Athletic Dpt and waiting for response
Pros
Cons
Do not need COA
Spiral mode is constrained
Less constraints on flight speed than
Fleming and Balch
Potential bubble rupture from contact
with propeller
Not Subject to Weather Effects
Need Permission
Difficult to Schedule
Expensive to Use (~$100/hr)
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
118
Misc. Backup Slides
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
119
Onboard Video Options
iON Air
Pro[24]
Mini DV[18]
Contour
ROAM2[25]
MUVI Micro
Camcorder[26]
Battery
Capacity
19.8 kJ
3.73 kJ
(3.5 hours)
4.7 kJ
Power
2.2 W
(@ 5 V)
0.9 W
(@ 3.7 V)
(N/A)
(@ 5 V)
0.9 W
(@ 5 V)
Size
(40x40x108)
mm
(20x20x60)
mm
(61x33x99)
mm
(55x18x20)
mm
Weight
130 g
50 g
145 g
50 g
Resolution
1080p @ 30
fps
720x480 @ 30
fps
1080p @ 30
fps
640x480 @ 25
fps
Price
$200
$20
$150
$42
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
120
Electronic Speed Controller
(ESC)
Turnigy Trust 45A Brushless Speed Controller[27]
Features:
• Integrated Switching Battery
Eliminator Circuit (SBEC)
• Capable of dissipating heat efficiently
due to large heat sink
Specifications
Front
Max. Motor Current
45 A
Max. BEC Current
3A
BEC Voltage
5.5V
Compatible with
2S – 6S LiPo
10/14/2014
Back
University of Colorado Boulder
Aerospace Engineering Sciences
121
Servos
Need 6 units at most: aileron, rudder, elevator, flaps
Specifications
Hitec HS-65B Servo[28]
10/14/2014
Weight
11g
Torque @ 4.8V
1.8kg.cm
Speed
0.14s @ 60deg
Dimensions
24mm x 12mm x 24mm
Max. Current
500mA @ no load
University of Colorado Boulder
Aerospace Engineering Sciences
122
GPS Receiver
Features:
• Centimeter accurate relative
positioning with Real Time Kinematics
(RTK)
• Capable of differential positioning
• Built-in antenna
Specifications
Dimensions
53mm x 53mm x 13mm
Weight
32g
Supply voltage
3.5V – 5.5V
Power consumption
500mW
Front
Back
Piksi GPS RX[29]
10/14/2014
University of Colorado Boulder
Aerospace Engineering Sciences
123
Radio Telemetry
Features:
• Compatible with Pixhawk/APM
• Air data rates up to 250kbps
• Can correct up to 25% data bit errors
MicroUSB
Cable
Antenna
Specifications
Range
~ 4.5km @ 64kbps
Supply Voltage
3.7V – 6V
Transmit/Receive
Current
25mA – 100mA
Power Consumption
100mW
Dimensions (without
antenna)
26.7mm x 55.5mm x
13.3mm
10/14/2014
Android
Cable
Connector
Cable
Radio
3DR Radio Link Kit[30]
University of Colorado Boulder
Aerospace Engineering Sciences
124