Group Members Mike Svendsen – Computer Engineer Steve Towey – Computer Engineer Brian Walker – Architect Richard George – Industrial Technology Client – ISU Space Systems and Control Lab (SSCL) Advisor – Matt Nelson

Overview Client Statement of Need Project Requirements and Deliverables Project Plan Subsystem Designs & Implementations Testing Lessons Learned

Client Statement of Need The SSCL desires a blimp platform for research and outreach events. The need is to have an outdoor blimp platform capable of carrying a small payload and able to navigate in calm to light winds.

Requirements Non-Functional Durable and reusable design Controlled via computer interface Positional data displayed on computer Operating Environment Outdoors Winds up to 10mph Humidity up to 90% Functional Requirements Vertical lift feet Wireless control feet Carry 7 ounce payload Fly time of 20+ minutes Sensor to determine position

Project Deliverables Complete balloon system meeting requirements Operating manuals Detailed design documentation

Project Plan Work Breakdown Mike and Steve responsible for electronic components Brian and Richard for non electronic components Task Breakdown Gantt Chart

Communication / Collaboration Weekly meetings with team and advisor (client) At least a weekly meeting with just electronics team Frequent meetings in lab for implementation Used Dropbox to facilitate SVN like role Used GoogleDocs to facilitate sharing of information

Costs

System Overview

Balloon Design Hybrid Latex Blimp System

Balloon Implementation Initial implementation Struggled to achieve lift Weight calculation inaccuracies Propellers not performing as specified Redesign Remove stiffeners Remove latex balloons Increase to 2 mil plastic

Frame Design Cross Foam Core Load Frame Rigid material yet light, inexpensive Bass wood for motor mounts Propeller shrouds System box

Frame Implementation Difficulties attaching balloon around electronics box Shortened weight distributors Propellers not exact specified length, did not fit in vertical shroud Slightly trim propeller tips

Propulsion Design Weight constraint Battery life requirement 10 mph wind requirement Thrust CalculationsBattery Life Calculations

Propulsion Implementation Mount motors Attach propellers securely Attach easy to use bullet connectors Attach Deans plugs Connect motors to Electronic Speed Controllers

Circuit Design Compile list of sensors Select specific sensor Consider cost, voltage, accuracy Select processor capable of handling inputs

Circuit Implementation Package types ESCs raising voltage Solution – Diode Voltage drop during XBee Transmission Clean signal off of regulator pin Breadboard potential issue

Onboard Control Logic Design

Onboard Control Implementation Implemented each sensor separately Xbee ADC (gyro) I2C (compass, pressure) GPS Timers (ESCs) Simple, flexible message format Dealing with limited program space

Base Station Design C++ on Linux

Base Station Implementation Writing KML Files Implementing OpenGL GUI Serial communication Thread interaction

Testing Approach

Important Tests Individual module tests System lift Base station and onboard system interaction Assembly tests Battery Life Communication Range Indoor test flights (Uncooperative weather recently) Tests not carried out Outdoor tests – Fight winds

Lessons Learned Skills Basics of constructing practical circuits Basics of PIC Programming Be flexible - hold up in one area, work on another Test changes one at a time to isolate unknowns Budget enough time for documentation Interdisciplinary team

Questions?