LABET
Low Altitude Balloon
Experiments in Technology
CPR E 491
ENGR 466
Team Introduction
ENGR 466 Team
Brian Walker
Richard George
CPR E 491 Team
Mike Svendsen
Steve Towey
Client Introduction
Client
Iowa State University Space Systems and Controls Lab
(SSCL)
Advisor
Matthew Nelson
Overview
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Client Statement of Needs
Functional Requirements
Non-Functional Requirements
Deliverables
Project Decomposition into Subsystems
Design Concepts
Testing and Evaluation
Work Plan
Client Statement of Need
 The SSCL has worked on several iterations of its
LABET platform which is a blimp platform used for
both research and for outreach events. Currently, all of
these have been limited to indoor use only which does
limit their functionality for some research based
projects. The need is to have an outdoor blimp
platform capable of carrying a small payload and able
to navigate in calm to light winds
Operating Environment
 Outdoor usage
 Maneuverable in winds up to 10 mph.
 Operate in temperatures between -20 and 100 F.
 Operate in humidity up to 90%
Functional Requirements
 Vertical lift capability up to 500 feet
 Wireless control/interface up to 1500 feet
 Additional payload lift of 7 ounces minimum
 System fly time of no less then 20 minutes
 Fly and maneuver in up to 10 mph
 Balloon lift potential between 80-90% entire system
weight
 GPS and pressure sensor to determine position
Non-Functional Requirements
 Durable and reusable design
 Controlled via computer interface
 Determine position via computer interface
Project Deliverables
 Complete balloon system meeting requirements
 Operating manuals
 Design documentation
Decomposition into
Subsystems
Decomposition into Subsystems
Software:
Propulsion
Balloon
Load
Electronics:
Frame:
System:
Includes
Systems:
Includes
Support
Provides
embedded
micro-controller,
for
Includes
control
majority
LABET
vertical
/ sensor
of software,
lift
wireless
and
of
systems
horizontal
base
station
thrust
the entire
and
communication,
payload,
motors,
communication,
system
while
propellers,
and
while
providing
all and
providing
sensors.
ESC’s,
GUI.
balance
and
stability.
main
weight.
battery use.
Work Breakdown
Design Concepts
Balloon System Design
Balloon Design Breakdown
Hybrid Latex Blimp System
Envelope
 1 mil plastic sheeting
 Seamed to form the blimp shape
Balloons
 Two individual 48” latex balloons
 Provides majority of entire system lift
 Easily replaced and interchangeable
Stiffeners
 Creates a rigid blimp shape in conjunction with balloons
 Foam core creates rigid yet light and inexpensive solution
Weight Distributor
 Foam core bars
 Distributes weight of frame to envelope and balloons
 Seals envelope shut when connected to frame
Final Design Decisions
Assembly
 Open seam prior to connection
 Stiffeners assembled inside envelope
 Balloons placed and blown inside envelope
Visual Presence
 Alternating color tip to determine front
 SSCL and LABET symbols for added visual
Benefits
 Breaks down to manageable sizes
 Envelope easily repaired
 Parts interchangeable and replaceable
Load Frame Research
Previous LABET Systems
 Load Frame Design
 Gen. III – Duel Fan Control
 Gen. IV – Direct Balloon Attachment
 Gen. V – Propeller Mounting
 Material Usage
Material Selection
 Weight
 Strength
 Durability
 Cost
Load Frame Design
Load Frame Design Breakdown
Cross Foam Core Load Frame
Foam Core Structure
 Rigid material yet light and inexpensive
 Cross design to minimize material
Wooden Motor Mounts
 Bass wood for rigidness and strength
 Built in sheer bracing which connects to frame
Propeller Shrouds
 Protects propellers from interference
 Provides some thrust funneling
System Box
 Contains/protects battery and circuits
 Weight supported by cross structure
 Removable/Replaceable to meet payload changes
Final Design Decisions
Structure
 Cross frame design
 Spaced separation to maximize strength
 Distributes weight through balloon connection
Visual Presence
 Minimal in design for weight and look
 Hides wires and electronics from view
Benefits
 Material is durable and light for size
 Materials locally and inexpensively obtained
 Direct connection to balloon system
Propulsion – Design Process
 Weight Constraints
 24 ounces
Battery Life Calculations
Thrust Calculations
Propulsion
 Ducted Fans vs. Propellers
 Brushless Motors vs. Brushed Motors
Propulsion – Design
Selections
Thrust
Battery Life
Electronics – Design Process
 Compile list of sensors
 GPS, Rate Gyroscope, Pressure Sensor, Fuel Gauge,
Digital Compass
 RF module
 Previous LABETs success with XBee
Electronics – Design Process
 PIC vs. Atmel
 Selecting PIC Processor
 Operating Voltage – 5.5V
 USART – 2
 I2C Bus
 Timer Counters – 5
 Program Memory – 48 KB
Electronics – Block Diagram
Software – Design Process
Software – Base Station
 Development Language and Platform
 C++ on Linux
Advantages
Disadvantages
Easy Serial Com
OS not as widely used
Easy File I/O
OpenGL GUI
Extensive experience
 C++ on Windows
Advantages
Easy File I/O
openGL GUI
Widely available OS
Disadvantages
Serial Com difficult
 Java
Advantages
Cross Platform
Swing GUI
Easy File I/O
Disadvantages
Serial Com difficult
 LabVIEW
Advantages
Cross Platform
Easy GUI
Built in threading
Disadvantages
Little Experience
Base Station – Frontend
Base Station- Backend
Software - LABET
Structural Testing
Balloon System
 Seam stress tests
 Lift potential test
 Assembly/Balloon fill test
Load Frame
 Drop test
 Motor mount sheer test
 Assembly/Balloon fill test
Electronics Testing
Hardware
 Simple test programs
Software
 Communication tests
 GUI interaction tests
 Ground tests
Risks
 Hybrid balloon system
 Encountering unforeseen setbacks
 Little experience with RC equipment
Costs/Resources
Task Breakdown
Current Status
 Load frame complete
 Balloon complete
 Propulsion system integrated
 Electronics selected and ordered
Spring Semester Gantt Chart
Questions