Customer
Dr. Suzanna Diener
Northrop Grumman
Faculty Advisor
Team
Kyle Corkey
Devan Corona
Grant Davis
Nathaniel Keyek-Franssen
Robert Lacy
John Schenderlein
Rowan Sloss
Dalton Smith
Dr. Donna Gerren
1
Outline

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
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Project Description
Design Solution
Critical Project Elements
Design Requirements & Satisfaction
Project Risk & Mitigation
Verification & Validation
Project Planning
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
2
Motivation
 Northrop Grumman needs inertial wind data and
cloud observations to verify an atmospheric boundary
layer model
 Boundary Layer Wind Model Applications:
 Airborne pollution monitoring
 Prediction of forest fire advances
 Facilitating soldiers in battle
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
3
Project Deliverables
 A 3-Dimensional U-, V-, W-
inertial wind vector data inside
the measurement cylinder
 Cloud base altitude and cloud
footprint data above the
measurement cylinder
Measurement Cylinder
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
4
Concept of Operations
Airspace Test
Volume Subject
To Modeling
Within
Project
Scope
Legend
Project
Description
Design
Solution
200 m
200 m
200 m
200 m
Northrop
Grumman
Wind Model
Results
In-Situ Relative Wind
Velocity Data
Collection and Cloud
Imaging
Inertial Wind
from In-Situ
Data and Cloud
Base Altitude
Physical
Wind
Vector
NG model
wind vector
Critical Project
Elements
Requirements
100 m
100 m
100 m
100 m
200 m
100 m
Risks
Wind Vector and
Cloud Data Used
to Verify Northrop
Grumman Model
Wind Vector
of in-situ
data
V&V
Planning
5
Experimental
Setup
Cloud observations
constrained to the
measurement
cylinder’s vertical
projection
Legend
BLISS Measurement
and Delivery System
Data points –
Spaced at most
30m radially in 3D
space
Project
Description
100 m
Physical Wind
Velocity Vector Field
(u-,v-,w-)
200 m
≤ 30 m
Cloud Observation
System stereovision
cameras
Design
Solution
Critical Project
Elements
Atmospheric clouds
located high above
test volume
In-Situ relative wind
velocity data collection
Requirements
Risks
V&V
Planning
6
Design Overview
Delivery System
Measurement System
Cloud Observation System
Goal: Move the measurement
system through the cylinder
while meeting spatial (30 m)
and temporal (15 min)
requirements.
Goal: Deliver a 3-Dimensional
U-, V-, W- Inertial Wind Data
within accuracy of 1 meter per
second.
Goal: Determine cloud base
altitude and constrain cloud
footprint within 10% error.
Implementation:
 Rapid Prototyped 5-Hole
Probe
 Inertial Navigation System
 Post-Processing Algorithm
Implementation:
• Stereo Vision Camera
System
• Post-Processing Algorithm
Implementation:
 Autonomous Fixed Wing
UAV
 Ground Control Station
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
7
Delivery System Design
 Skywalker X8 airframe with Pixhawk
autopilot for autonomous control.
 Raspberry Pi micro-computer to
supply way-points to the Pixhawk
autopilot
 Contains and carries the
Measurement System throughout the
airspace.
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
8
Measurement System Design
 Collect in-situ pressure data
 Rapid prototyped 5-hole probe
mounted on Delivery System
 Transform pressure data to relative wind
 Calibration of probe to determine
relative velocity and direction
 Collect aircraft attitude and inertial GPS
data
 VECTORNAV VN-200 INS
 Convert relative wind to inertial wind
vector field
 Post processing using relative wind
from 5-hole probe and aircraft
orientation from INS
Project
Description
Design
Solution
Critical Project
Elements
[VWind]I = [VAir]I - [VInertial]I
UAV Inertial Velocity
Wind Velocity in Inertial Frame
[VAir]I
Air Relative Velocity in Inertial Frame
Requirements
Risks
V&V
Planning
9
Skywalker Layout
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
10
Functional Block Diagram
Northrop
Grumman Wind
Model
GPS
Power
Module
Inertial
U-,V-,WWind Vector
Field
GPS
Coordinates
14.8V
5V
Speed
Controller
Serial
Command
PWM
PWM
Pixhawk Flight
Controller
Flight Path
Waypoints
14.8V
Electrical Power
System
Post Processing
Algorithm
5V
Raspberry Pi
Aircraft
State &
Wind
Pressure
Motor
SD Card
Measurement System
Aircraft State
& Wind
Pressure
Design
Solution
Arduino Due
Electrical Power
System
Analog
Voltage
SPI
Inertial
Navigation
System
Thermistor
Analog
Pressure
Transducers
Air
Pressure
5-Hole Probe
Elevon
Servos
Relative
Wind
Manual
Commands
The Measurement
System is packaged
in the Delivery System
Antenna
Delivery System
Project
Description
9V
Critical Project
Elements
Requirements
Risks
V&V
Planning
11
Cloud Observation System
 Stereovision imaging system pointed
vertically in measurement cylinder
 Two Canon Powershot ELPH 150 IS
cameras with CHDK firmware hack

Precise time-lapsing (Documented drift of
2ms/day)
 Turn off autofocus
2km
 Save images in .RAW format
 Disparity between images measures
cloud base altitude and constrains a
cloud footprint
80m
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
20m 20m
V&V
80m
Planning
12
Functional Block
Diagram
X
Cloud Base
Camera Field
of View
Camera Field
of View
Northrop Grumman
Wind Model
Battery
Cloud Base Altitude
& Footprint
Power
Power
.RAW Image
Battery
.RAW Image
Internal SD
Card
Internal SD
Card
Left and Right
.RAW Images
Computer with Post
Processing Algorithm
Vertical
Camera
Vertical
Camera
Cloud Observation System
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
13
Critical Project Elements
 Delivery System (DS)
 Measurement System (MS)
Obtaining a COA (REQ 4.1.1)
 Determining a flight path (REQ 1.1.1.1,
REQ 3.1)
Rapid prototyped 5-hole probe (REQ 1.2)
 Calibrated 5-hole probe to determine relative
wind angle to 1 degree(REQ 1.2.3)
 Aircraft state knowledge (REQ 1.2.2)
 Post processing software (REQ 1.2.1)


 Cloud Observation System (COS)
Camera mounting brackets (REQ 2.2.4)
 Post processing software (REQ 2.2.2)

 Interfacing (REQ 1.3)
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
14
Longmont
Obtaining a COA
● REQ 4.1.1: A Certificate of Authorization
(COA) shall be obtained to operate any
unmanned aerial system used to collect
data during this project.
● Table Mountain COA
Boulder
● Flight Ceiling of 400 feet (122 m)
● Pawnee National Grasslands COA
● Flight Ceiling of 1000 feet (305 m)
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Greeley
Risks
V&V
Planning
15
Previous flight path had
turning radiuses acceptable for
the aircraft, but too tight for
accurate data from the probe





Bank angles under 30° desired
New flight path created with
larger turning radius
Time of data collection was
increased to 13 minutes
Point distribution was done in
the same manner as the first
flight path
Helixes were the desired shape
for their simplicity and ease of
integration with the autopilot
Project
Description
Design
Solution
2D Point Distribution

2D Point Determination
Flight Path Determination
𝑣2
𝑟=
𝑔 ∙ tan 𝜃
Critical Project
Elements
Requirements
Risks
V&V
Bank
angle, θ
Skywalker X8
Stall Speed
(m/s)
30°
10
45°
12
Planning
16
Flight Path
Radius
Small Helix (3X)
65 m
Large Helix
70 m
Helix Connection 1
(2X)
N/A
Helix Connection 2
N/A
Bank Angle
(θ)
25°
25°
0°
0°
Pitch
Angle
Time
17.2
𝑚
𝑠
3273 m
189.9
sec
3.25°
17.9
𝑚
𝑠
3524 m
197.0
sec
0°
17.2
𝑚
𝑠
60 m
3.5 sec
0°
17.9
𝑚
𝑠
35 m
2.0 sec
13,499.5
m
12.9
minutes
Provided
Thrust
4.06 N
7.06 N
1.7
Flight
Time
13 min
24.4 min
1.9
Design
Solution
Distance
3.50°
Required
Project
Description
Velocity
Safety
Factor
Critical Project
Elements
Totals
Requirements
200 m
Flight Path
200 m
Risks
V&V
Planning
17
Rapid Prototyped Probe
●
REQ 1.2: The measurement system shall collect
pressure measurements in order to determine 3dimensional inertial wind data accurate to 1 m/s
with a resolution of 0.1 m/s.
●
Commercial 5-hole probes are too expensive
●
Design Solution: Rapid prototype 5-hole probe
●
●
Limits risk due to machining so many miniature parts.
Outsourcing the job to Protogenic
●
CU’s 3-D printer was unsuccessful in printing the
probe.
●
Stereolithography technique of prototyping can meet
design specifications.
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
18
Calibrated 5-Hole Probe
●
REQ 1.2.2: The measurement system shall be calibrated
with a jet to determine how it interprets incoming wind.
●
Testing will not proceed if winds on the ground exceed
10 m/s
●
●
Aircraft cruise
velocity magnitude
Resultant air velocity
magnitude
Calibration points will cover flow angularities up to 42˚,
which correspond to a maximum perpendicular gust of 15
m/s at a cruise velocity of 17 m/s.
A calibration test stand will be designed and
manufactured and used to replicate these flow
angularities:
●
The calibration angle θ will be varied between -42 and +42
degrees
●
—The calibration angle φ will be varied between 0 and 180 degrees
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Wind gust
magnitude
Risks
V&V
Planning
19
Calibration Jet
● A air flow jet will be used to calibrate
the 5-hole probe
● Jet design based upon previous small
scale air jets as well as NASA wind
tunnel design
●
●
Designed to create laminar top-hat flow
profile
Reduces unknown flow angularities and
velocity anomalies
● Machined in house in five pieces from
5” stock
● Jet is connected to shop air (90 PSI)
with a pressure regulator used to
control air velocity
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
20
Aircraft State Knowledge
●
REQ 1.2.2: The measurement system shall
record the aircraft state data necessary to
determine the inertial wind vector from the
relative wind vector.
● REQ 1.2.2.1: The orientation shall be
known within 0.5 degrees in roll, pitch
and yaw.
● REQ 1.2.2.2: The aircraft velocity shall
be known within 0.1 meters per
second.
● REQ 1.2.2.3: The aircraft location shall
be known within 4 meters root mean
square.
Project
Description
Design
Solution
Critical Project
Elements
●
The aircraft state must be accurately known to
convert the relative wind data into inertial wind
data
●
The VECTORNAV VN-200 will provide the
following accuracies:
Requirements
●
0.3 degrees in yaw
●
0.1 degrees in pitch and roll
●
0.05 m/s velocity
●
2.5 m RMS in position
Risks
V&V
Planning
21
●
Post Processing Software
REQ 1.2.1: Relative wind data shall be post processed in order to determine the U-, V-,
W- inertial wind vectors at each point.
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
22
COS: Mounting Brackets

REQ 2.2.4: The orientation of each camera shall be within 5
degrees of final tested configuration in the X-, Y-, and Zaxis.

Bubble Level
Camera
Keeps total altitude error propagation to less than 10%.
 Brackets serve to align the cameras in a known,
repeatable configuration.
Decreases uncertainty of measurement
X, Y Orientation Control
 4 Adjustable Legs
 Built in 2 Axis Level
Z Orientation Control
 Guy wires between mounts



Project
Description
Design
Solution
Critical Project
Elements
Adjustable legs
Requirements
Risks
V&V
Planning
23
Post Processing Software
•
•
REQ 2.2.2: Images from the stereovision cameras shall be post processed
to determine the cloud base altitude
REQ 2.3.2: Images taken during the test period shall be post processed to
overlay a projection of the clouds onto the 100-meter radius circle that
defines the base of the measurement cylinder.
• Read images to
Matlab
• Convert left and
right image to
grayscale.
Detect Distinct
Features
• Uses SURF edge
detection
algorithm
Load & Prep
Images
• Determine the
fundamental matrix
which defines the
stereo camera
Rectify
Images
• Align vertical
pixels to simplify
to a 1-D problem
Compute
Distance
Extract & Compare
Images
Project
Description
Design
Solution
Critical Project
Elements
• Disparity between
strongest SURF
features
• Using known
camera parameters
Requirements
Risks
V&V
Constrain
Footprint
• Find SURF point’s
distance from image
center
• Compute &
Illustrate Constraint
Planning
24
Post Processing Software
•
Test done with error prone method of simulating stereovision with one camera; due to lack of
available resources.
Outlying Errors
Median = 23 Ft
SURF Matches After
Filtering and
Rectification
SURF Matches Before
Filtering and
Rectification
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Distance of SURF
Features
Risks
V&V
Planning
25
Interfacing
● REQ 1.3: All interfacing components shall be verified for compatibility
before components are purchased.
● Three conditions must be satisfied:
● Compatible communication protocol
● Enough ports
● Sufficient power supply
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
26
Delivery System Interfacing
Delivery System
•
XT60 Connectors
•
•
•
•
RPi
•
•
•
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
4S LIPO
Power Module
ESC
Pixhawk
Telem2 Port
via Serial
MAVLink
Planning
27
Measurement System Interfacing
Measurement System
• Arduino
SD Card Header
• Serial Peripheral Interface (SPI)
• Arduino
Inertial Navigation System
• SPI
• TTL Serial (UART)
• Arduino
Transducers, Thermistor
• Analog
• 12-bit Analog Digital Converter
• Determination of Time Between Points
• Arduino Timing Library (timing interrupt)
• Transducer time constant 0.02 seconds
• 5o Hz for each measurement point
• ~39000 unique data points
• Read and Write Data < 0.02 seconds
• 84 MHz CPU clock
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
28
Delivery System Risk
Project
Description
Design
Solution
Unmitigated Risk Matrix
Mitigated Risk Matrix
Impact
1
2
Impact
3
4
1
4
A, B
3
E
C, F
D
2
4
3
4
E
C, D, F
Requirements
Risks
A, B
3
2
1
1
Critical Project
Elements
2
5
Probability
5
Probability
A - Propeller breaks on
landing
B - Servo breaks on landing
C - Transmission loss to UAV
D - UAV crashes
E – Speed controller burns
out
F – Measurement System
adversely affects flying
qualities
V&V
Planning
29
Delivery System Risk Mitigation
Risk
Mitigation Plan
Propeller breaks on landing
Purchase multiple propellers for testing.
Servo breaks on landing
Build servo arm protectors. Purchase multiple
servos.
Transmission loss to UAV
Program ‘return to home’ flight plan contingency.
UAV crashes
Pilot with experience with Skywalker X-8 on hand
for testing.
Speed controller burns out
Oversized the speed controller.
Measurement system adversely affects
flying qualities
C.G. has been found in CAD and the drag induced
by the probe is negligible.
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
30
Measurement System Risk
Project
Description
Design
Solution
Unmitigated Risk Matrix
Mitigated Risk Matrix
Impact
1
2
3
Impact
4
1
4
A
D
3
C
B
2
E
1
Critical Project
Elements
2
3
4
5
Probability
5
Probability
A – Unable to calibrate to
requirements
B – Unable to manufacture
calibration jet
C – 5-Hole probe hit on
landing
D – Unable to 3-D print 5hole probe
E – GPS velocity not
performing as expected
4
A
3
D
2
C, E
1
Requirements
Risks
V&V
B
Planning
31
Measurement System Risk Mitigation
Risk
Mitigation Plan
Unable to calibrate to requirements
Measuring mass flow at every point, high
resolution calibration
Unable to manufacture calibration jet
Decreasing the length/diameter of the
boring bar during manufacturing. Getting
CAD plans approved by Matt Rhode and
Bobby Hodgkinson.
5-hole probe hit on landing
Mount probe above nose, away from most
likely impact
Unable 3-D print 5-hole probe
Design the probe with 3-D printing
specifications in mind
GPS velocity not performing as expected
Testing INS
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
32
Cloud Observation System Risk
Project
Description
Design
Solution
Mitigated Risk Matrix
Unmitigated Risk Matrix
Impact
1
2
4
1
E
B
A
D
2
1
Critical Project
Elements
2
3
4
5
C
4
3
3
Impact
Probability
5
Probability
A – Uncertainty in
algorithm results
B – Unable to hack
cameras
C – Camera orientation
errors
D – No clouds during final
data collection
E – Batteries die/memory
card fills up during test
Requirements
Risks
4
3
C
2
E
A
1
B
D
V&V
Planning
33
Cloud Observation System Risk Mitigation
Risk
Mitigation Plan
Uncertainty in algorithm results
Full scale testing of final hardware and software by
targeting points of known distance
Unable to hack cameras
Use camera model supported by CDHK firmware
hack
Camera orientating errors
Build mounts with levels and guide wires
No clouds during final data collection
Write final test plans that include a check of Doppler
radar
Batteries die/memory fills up
Battery charge and memory checks in final test plan
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
34
Delivery System V&V Flow Chart
Autonomous Ground
Control Test
Manual Ground
Control Test
Preliminary Manual
Flight Test
Range Test
Preliminary Autonomous
Flight Test
Software in the Loop Test
Final Flight Path Test
Final Data Collection at
Pawnee National Grasslands
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
35
Ground Control Tests
● Goal: Test manual and autonomous control of elevons and motor.
Check for correct mixing of pitch and roll control in a static test.
● Requirement Verified: Building Block to 1.1.1.1
● Facilities: Senior Projects Lab
● Measurements: Elevon deflection, prop rotational direction
● Verification: Deflections are observed in the commanded direction
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
36
Software in the
Loop Test
Range Test
 Goal: Determine maximum range




of Spektrum Dx6i and 3DR
Telemetry Radios
Requirement Verified: Building
Block to 1.1.1.1
Facilities: Kittredge Fields
Measurements: Range of link loss
Verification Method:
Loss Range > Max Range
Project
Description
Design
Solution
Critical Project
Elements
 Goal: Simulate flight plan on
autopilot code & record response
 Requirement Verified: Building
Block to 1.1.1.1
 Facilities: Linux Laptop
 Verification Method: UAV follows
desired flight plan and does not
crash
Requirements
Risks
V&V
Planning
37
Preliminary Flight Tests
● Goal: Test manual and simple autonomous flight capabilities of
Skywalker X8, tune autopilot PID gains
● Requirement Verified: Building Block to 1.1.1.1
● Facilities: Table Mountain Airspace
● Verification Method: Successful take off and landing by pilot,
autonomous tracking of simple waypoint, autopilot damping low
frequency oscillations
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
38
Final Flight Path Test
● Goal: Show the system can execute a reduced
ceiling flight path
● Requirement Verified: 1.1.1.1
● Facilities: Table Mountain Airspace
● Verification Method: Compare GPS location of
aircraft during flight to SITL simulations
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
39
Measurement System V&V
Flow Chart
Pressure coefficient
verification
Probe calibration
Angularity and velocity
determination testing
Final test at Pawnee
National Grasslands
INS GPS test
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
40
Probe Calibration
● Goal: Calibrate the probe and create a matrix of
reference pressure coefficients
● Requirement Verified: Building Block to 1.2.3
● Facilities: Bobby Hodgkinson’s lab with
compressed air lines
● Measurements: Pressure of each port on the 5hole probe, static pressure, and static
temperature
● Verification Method: Compare actual result to
analytical solution
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
41
Calibration Test Stand
● The calibration test stand
will be used to replicate
these flow angularities:
●
●
Roll Angle φ
The calibration angle φ will be
varied between 0 and 180
degrees
Yaw Angle ϴ
The calibration angle θ will be
varied between -42 and +42
degrees
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
42
Pressure Coefficient Verification
● Analytical solution is used to approximate
pressure values expected during calibration
 Derived from theory of 2-dimensional flow
around a circular cylinder
● Allows for the estimation of 3 of the 5
pressure ports lying along a 2-dimensional
cross-section of the hemispherical face
● Solution breaks down for flow angularity
angles past 30 degrees due to flow separation
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
43
Angularity and Velocity Testing
● Goal: Use the calibration stand and jet to verify the probe and
calibration data are capable of providing accurate measurements under
varying velocity and flow angularity conditions
● Requirement Verified: 1.2.3
● Facilities: Bobby Hodgkinson’s lab with compressed air lines
● Measurements: Pressure of each port on the 5-hole probe, static
pressure, and static temperature
● Verification Method: Compare measured & actual wind angle
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
44
COS Small Scale Testing
● Goal: Test image processing
algorithms with data from small to
medium scale stereo camera
● Requirement Verified: Building
Block to 2.2.3, 2.3.3
● Facilities: Large Room, Campus
buildings
● Measurements: Distance to target,
footprint constraint around target
● Verification Method: Compare
actual & measured distance
Disparity
Known
≈10-100m
Distance
Dist =
f *b
disparity
≈1-10 m
45
COS Final Configuration Test
● Goal: Verify the full scale COS meets all
system requirements
● Requirement Verified: 2.2.3, 2.3.3
● Facilities: NCAR parking lot
● Measurements: Distance to 2km target,
2km
footprint constraint around 2km target
● Verification Method: Compare actual &
measured distance, Cloud footprint overlaps
orange targets.
200m
40m
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
46
Organizational Chart
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
47
Work Breakdown Structure
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Risks
V&V
Planning
48
Work Plan
Mechanical Phase 1
Purchasing
Components
Measurement
System Test Phase
Software
Phase 2
Systems
Final Test
Phase 2
Phase
UAV Test
Phase
Systems
Phase 1
CDR
Electrical
Phase 1
Software Phase 1
Project
Description
Design
Solution
Critical Project
Elements
Hack
Cameras
Requirements
Mechanical
Phase 2
Risks
Cloud Observation
Test Phase
V&V
Planning
49
Cost Plan
Cloud System
7%
Shipping
10%
Margin
6%
Delivery System
25%
Measurement
System
52%
Project
Description
Design
Solution
Critical Project
Elements
Requirements
Component
Estimated Cost
Delivery System
Measurement
System
Cloud
Observation
System
Shipping
$1265
$2590
$355
$500
Margin
$290
TOTAL
$5000
Risks
V&V
Planning
50
Test Plan
Measurement
System Test Phase
•
Measurement System Test Phase
• Calibration requires use of the mass flow meter and
access to Bobby Hodgkinson’s lab
• INS test requires use of Doug Weibel's equipment
•
Cloud Observation Test Phase
• No special access required
Project
Description
•
•
Design
Solution
Critical Project
Elements
Cloud Observation
Test Phase
UAV Test Phase
Final Test
Phase
UAV Test Phase
• Requires access to Table Mountain.
• Scheduled for a week to plan around R/C pilot James Mack’s
schedule
Final Test Phase
• Requires access to Pawnee National Grasslands
• Scheduled for 2 weeks to plan around James Mack’s schedule but
should only take 1 day
Requirements
Risks
V&V
Planning
51
Acknowledgements
 We would like to thank all of the PAB, our advisor Dr.
Gerren, our customer Dr. Diener from Northrop
Grumman, Dr. Farnsworth, Trudy Schwartz, Matt
Rhode, Bobby Hodgkinson, and James Mack for their
help in preparation for this CDR.
52
Questions?
53
Back Up Slides
54
Design Solution-Delivery Components
Component
Chosen Product
Cost (USD)
Autopilot
Pixhawk
199
Digital Airspeed Sensor
3DR Airspeed Sensor
55
Telemetry Radios
3DR Telemetry Radios
100
GPS/Compass
Ublox GPS/Compass
80
Lipo Battery (x2)
ZIPPY Flightmax 8000mAh 4S1P 30C
62
ESC
Castle Creations Phoenix 50
100
Motor
Turnigy SK3 3542- 800
34
Prop (x4)
Master Airscrew 12”x6”
4
Servos (x4)
Hitec HS-225MG
25
Receiver
Spektrum DSM2 Remote Receiver
30
Transmitter
Spektrum DX6i Transmitter
160
Airframe
Skywalker X8
220
Micro-Computer
Raspberry Pi
40
Total Cost
1258
55
Pixhawk Autopilot
 3DR Pixhawk developed by the PX4 Open-Hardware
project.
 Open-Hardware reduces cost and allows for interface with
Raspberry Pi micro-computer.
 Pixhawk is the most current operational Open-Hardware
autopilot with an active development support community.
 $475 cost is significantly less than commercial small scale
UAV autopilots.
 Pixhawk Package from 3DR Robotics is sold with
accompanying Telemetry Radios (915 MHZ), Digital
Airspeed Sensor, and UBLOX GPS/Compass.
56
Lipo Battery
 ZIPPY Flightmax 8000mAh 4S1P 30C LIPO Battery
 Provides 13 minutes of flight at max motor thrust.
 Provides 24 minutes of fight at maximum thrust needed for data collection
flight path
 Will need 2 Batteries in order to collect 2 data sets in under one hour.
Battery
Trade
Capacity
(0.6)
ZIPPY
Flightmax
8000mAh
4S1P 30C
ZIPPY
ZIPPY
Turnigy
Turnigy
Flightmax
Turnigy
Compact
Lumenier
7200mAh 4S 6400mAh 4S 8400mAh 4S 6600mAh 4S 6200mAh 4s 8000mAh
40C
60C
2P 30C
14.8V 60C 40c
4s 25c
5
3
1
5
2
1
4
Weight (0.2)
2
2
3
1
2
5
3
Cost (0.2)
5
3
4
1
4
4
1
4.4
2.8
2
3.4
2.4
2.4
3.2
Total
57
Electronic Speed Controller
 Castle Creations Phoenix 50 ESC
 Unlikely to burn out with known data about max continuous and peak
current.
 Comparable to RECUV Skywalker X8 ESC.
 Selected because of known quality and effectiveness.
ESC Trade Study
H-KING 35A
Phoenix 50
X-40 SB
Cost-0.3
5
1
1
Quality-0.7
1
5
5
2.2
3.8
3.8
Total
58
Motor
 Turnigy SK3-3542 800KV Motor Selected.
 Motor must mount on same side as drive shaft because
of Skywalker X8 motor mount configuration.
 Turnigy SK3 motor currently in use on RECUV
Skywalker.
 Provides 720 grams peak dynamic dynamic thrust (413 g
required) at 17.24 m/s maximum flight speed with a
12”x6” Master Airscrew propeller for a Safety Factor of
1.7.
 Maximum Current draw 37A, less than 50A continuous
allowed by ESC.
59
Control Servos
 Hitec HS-225MG Mini Analog Servos




Selected
1.27”x 0.66”x 1.22” size fits Skywalker X8
servo mounting space cut into wing.
3.9 kg-cm torque at 4.8 V ample for flap
deflection.
Used on RECUV Skywalker X8 without
issue.
Metal Geared to prevent stripping and
increase component lifespan.
60
Dynamic Thrust Calculation
 d=12”
 pitch=6”
 RPM=9512
 V0=17.24 m/s
 Maximum dynamic thrust 7.06 Newtons
61
Skywalker X8 Center of Mass
 Coordinate System: Center
of Nose of Airframe
Configuration
X Center
of Mass
Y Center
of Mass
Clean
-16.66” 0.00”
0.55”
Loaded
-16.70”
0.01”
-0.01”
Z Center
of Mass
+Y
+
+Z X
6.9”
36.0”
81.9”
66
Calibrated 5-Hole Probe
63
Calibrated 5-Hole Probe
● Jet nozzle based off NASA wind
tunnel design theory
● Convergence ratio of 6
● Modeled with a fifth order
polynomial
Y(x)=6.35+31.8∗(6x^5 -15x^4+10x^3)
● Nozzle exit radius of 0.5”
● Roughly twice the radius of the
tip of the probe to ensure velocity
profile is large enough
64
65
Calibrated 5-Hole Probe
● Allows probe to roll 180 degrees and
yaw 50 degrees while maintaining tip
location
●
●
Yaw measured by markings on stand
Roll measured by rotary
potentiometer connected to Arduino
● Aligns jet with probe
●
●
Tip of jet less than 0.5” from probe tip
Jet is fixed in location
66
Calibrated 5-Hole Probe
●
By flying in conditions where wind gusts do
not exceed 10 m/s we ensure flow angularities
do not exceed 30 degree
Aircraft cruise
velocity magnitude
Resultant air velocity
magnitude
● Mitigating risk by preventing flow
separation
● Confidence in calibration accuracy
deteriorates at angularities greater than
30 degrees
Wind gust
magnitude
67
INS GPS Test
R

Goal: Verify the GPS performs as expected
 Facilities: Engineering Center Pavilion
 Measurements: GPS velocity compared to
velocity from motor measured using
V = ωR
 Issues: Use of Doug Weibel’s equipment. INS
GPS stated accuracy is such that it can not be
verified, however the GPS will be tested to
make sure it performs as expected.
ω
68
Measurement System Interfacing
● Record entire data set every 0.02 seconds
START
(50Hz)
○ ~39000 unique data points
New data
ready?
Yes
Read serial
data from
INS
Read analog
data from
thermistor
No
Read analog
data from
transducers
Legend
Data
Code
Read
internal
time
Flight path
finished?
No Yes
FINISH
Write data
to SD card
0 minutes
13 minutes
69
Risk Breakdown
 Probability
 1 - Highly unlikely (0-19%)
 2 - Unlikely (20-39%)
 3 - Probable (40-59%)
 4 - Likely (60-79%)
 5 - Highly Likely (80-100%)
 Impact
 1 - Negligible, no impact to project
success
 2 - Minor consequence, degradation of
results
 3 - Medium consequence, partial
subsystem failure
 4 – Critical, total subsystem failure
 Risk
 Low (1 – 6), acceptable risk
 Medium (7 – 12), risk needs attention
 High (13 – 20), urgent risk
1
2
3
4
5
5
10
15
20
4
4
8
12
16
3
3
6
9
12
2
2
4
6
8
1
1
2
3
4
70
Delivery System Break Down
Transmitter;
$160
Receiver; $30
Airframe;
$220
Servos (4);
$100
Propellers
(4), $16
Motor; $34
Autopilot;
$200
ESC; $100
Digital
Airspeed
Sensor; $55
LiPo Battery;
$130
GPS/Compas
s, $80
Telemetry
Radio; $100
Component
Estimated Cost
Airframe
$220
Autopilot
$200
Digital Airspeed
Sensor
$55
Telemetry Radio
$100
GPS/Compass
$80
LiPo Battery
$130
Electronic Speed
Controller
$100
Motor
$34
Propellers (4)
$16
Servos (4)
$100
Receiver
$30
Transmitter
$160
Micro-Computer
$40
TOTAL
$1265
71
Measurement System Break Down
Probe; $300
Miscellaneou
s ; $20
Differential
Pressure
Sensor; $303
Thermistor;
$22
Memory; $15
Absolute
Transducer;
$42
Microcontroll
er; $50
Inertial
Navigation
System; $1 811
Component
Estimated Cost
Differential Pressure
Sensor (5)
$303
Thermistor
$22
Absolute Transducer
$42
Inertial Navigation
System
$1,811
Microcontroller
$50
Memory
$15
Miscellaneous
$20
Probe
$300
TOTAL
$2560
72
Cloud Observation System Break Down
Battery; $11
Mounting
Hardware,
$25
Memory
Card; $20
Stereovision
Cameras;
$300
Component
Estimated Cost
Stereovision Cameras
$300
Battery
$11
Mounting Hardware
$25
Memory Card
$20
TOTAL
$355
73
74
Measurement System Accuracy
 All parts of the measurement system introduce some error







Pressure transducers: ±7 Pa (differential)
Thermistor: ±0.1o C
Static pressure transducer: ±400 Pa (absolute)
Euler Angles: ±2o yaw, ± 0.5o roll and pitch
Euler Angle rates: ± 0.05o /s
Inertial velocity: ±0.05 m/s
Calibration angles: ±1o
 Through standard error propagation equation, we are able to achieve an
accuracy of ±
0.3
0.1
0.9
m/s
75
Measurement System Calibration

The 5 pressure readings from the probe (one from each
port) can be related to the orientation of the probe
through non-dimensional coefficients
To do this:

𝑝=
Independent coefficients
 Independent non-dimensional coefficients are
•
calculated as a function of the 5 recorded pressure
values from the probe
 dependent non-dimensional coefficients are
calculated as functions of total pressure and static
pressure. Coefficients are stored in a matrix.
During testing, the independent coefficients act as
look-up tables, which allow determination of
orientation, total pressure and static pressure.
𝑝2 + 𝑝3 + 𝑝4 + 𝑝5
4
𝐶𝑝𝛼 =
𝑝4 − 𝑝5
𝑝1 − 𝑝
𝐶𝑝𝛽 =
𝑝2 − 𝑝3
𝑝1 − 𝑝
Dependent coefficients
𝑝1 − 𝑝𝑡𝑜𝑡𝑎𝑙
𝐶𝑝𝑡𝑜𝑡𝑎𝑙 =
𝑝1 − 𝑝
𝐶𝑝𝑠𝑡𝑎𝑡𝑖𝑐 =
𝑝 − 𝑝𝑠𝑡𝑎𝑡𝑖𝑐
𝑝1 − 𝑝
76
Measurement System: Pressure Transducers,
Thermistor
 Differential Pressure Transducer – Honeywell HSC – 010MG
 Measurement range -1 to 1 KPa differential
 Accurate to 0.25% of total range -> ±5 Pa
 Resolution of 0.03 m/s
 Absolute Pressure Transducer – Honeywell SSC-MRNN
 Measurement range 0 to 160 KPa Absolute
 Accurate to 0.25% of total range -> ±400 Pa
 Thermistor Omega 44030 (3000 Ohm)
 Measurement range 0° to 75° C
 Accurate to ± 0.1° C
77
Measurement System Error Propagation
δP0 δT δΔP → δV
Pressure
measurements
from each hole
δu
δV δФ δΘ → δv
δw
Calibration
𝑢
𝑣
𝑤
𝑏
δu
δv
δw
𝑏
𝑢
𝑣
𝑤
𝐼
𝑏
δφ
δu
δθ → δv
δψ
δw
𝑢
= 𝑇𝑏𝐼 𝑣
𝑤
𝑏
Euler Angles
𝐼
δu
δv
δw
𝐼
δ𝑥
δ𝑦 → δ𝑊𝑖𝑛𝑑
δ𝑧
𝑢
𝑥
𝑊𝑖𝑛𝑑𝐼 = 𝑣 − 𝑦
𝑤 𝐼
𝑧
GPS Velocity
78
Calibration Diagram
79
Cloud Observation System Requirements
 Requirements created by studying wind conditions at
12,000 ft ASL (approx. 2 km AGL) at Denver
International Airport
 Avg. Velocity: 5.54 m/s Std. Dev.: 2.89 m/s
 Assume Normal Distribution: 95th Percentile Strongest
Wind Velocity = 11.32 m/s
 Cloud will move across measurement cylinder in about
17 seconds
80
Cloud Observation System Camera
81
Calibration Jet Drawing
82
Five Hole Probe Drawing
83
Arduino Due with SD Card Shield
 ARM Cortex-M3 CPU
 84 MHz clock
 32-bit processor
 12-bit ADC
 Extended SPI library
 SD Card Shield
 Compatible w/ Due
 SPI
 Header Pins
 Two devices on same SPI pins
84
Raspberry Pi A+
85
COS Orientation Error
Error reduction by averaging 2 points means
altitude error can be up to 283m and to meet REQ 2.2.3
D
D=
DRequired ≈ 364m
1-Axis Error Required ≈ 210 m
ThetaMax= Maximum Alignment Angle Error =5.9°
86
Mechanical Phase 1
87
Software Phase 1
88
Electrical/Systems Phase 1
89
Measurement Test Phase
90
Phase 2’s
91
Final Tests
92