LABET6 - Senior Design - Iowa State University

eyelashesnectarineSoftware and s/w Development

Nov 3, 2013 (3 years and 7 months ago)

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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


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

Balloon System
: Provides majority of lift of

the entire system while providing stability.

Load Frame
: Support for control / sensor systems

and payload, while providing balance weight.

Propulsion Systems
: Includes vertical and horizontal

thrust motors, propellers,
ESC’s
, and main battery use.

Electronics
: Includes micro
-
controller, wireless

communication, and all sensors.

Software
: Includes embedded LABET software, base
station communication, and GUI.

Decomposition into Subsystems

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


Development Language and Platform


C++ on Linux






C++ on Windows


Software


Base Station

Advantages

Disadvantages

Easy Serial
Com

OS not as widely used

Easy File
I/O



OpenGL
GUI



Extensive experience



Advantages

Disadvantages

Easy File
I/O

Serial Com difficult

openGL GUI



Widely available OS



Advantages

Disadvantages

Cross Platform

Serial Com difficult

Swing GUI



Easy File
I/O



Advantages

Disadvantages

Cross Platform

Little Experience

Easy GUI



Built in threading




Java






LabVIEW

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