Micro-CART
ONGO – 03
UNMANNED
AERIAL
VEHICLE
Microprocessor–Controlled Aerial Robotics Team
Advisors
Client
Dr. John Lamont
Iowa State University
Professor Ralph Patterson III
Department of Electrical and Computer Engineering
Primary Vehicle Team
2nd Semester
1st Semester
Tim Gruwell (Team Leader)
Andrew Larson
Erica Moyer
Maria-Cristina Olivas
Josh Robinson
Brian Baumhover
Bai Shen
Bill Hughes
Hassan Javed
Pankaj Makhija
Secondary Vehicle Team
1st Semester
Patrick Turner
Byung Kang
Interdisciplinary Members
Jeff Pries (ME)
Brett Pfeffer (ME)
Interdisciplinary Members
Kito Berg-Taylor (AerE)
Gustav Brandstrom (ME)
Fall 2006
Presentation Outline
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Definitions
Acknowledgment
Problem statement
Operating environment
Intended users and uses
Assumptions and limitations
End product requirements
Project activity
– Previous accomplishments
– Present accomplishments
– Future required activities
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Approaches considered
Project definition activities
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Research activities
Design activities
Implementations activities
Testing activities
Resources and schedules
Project evaluation
Commercialization
Suggestions for future work
Lessons learned
Risks and risk management
Closing summary
Fall 2006
Acronym Definitions
Attitude The orientation of an aircraft's axes relative to a reference line or plane, such
as the horizon
AUVSI Association for Unmanned Vehicle Systems International
CAD
Computer Aided Design
GPS
Global positioning system
GSS
Ground station system
IARC
International Aerial Robotics Competition
IMU
Inertial measurement unit
PC-104 x86-based controllable board
PIC
Programmable interface controller
PID
Proportional Integral Derivative
Pitch
Revolution of a vehicle forward and backward on a central axis
Pro/E
Professional Engineer CAD package
PWM
Pulse width modulation
RC
Remote control
Roll
Revolution around the longitudinal axis of a vehicle
SV
Secondary Vehicle
UAV
Unmanned aerial vehicle
WIKI
(What I Know Is) A public documentation repository
Yaw
Revolution around the vertical axis of a vehicle
Fall 2006
Acknowledgement
Iowa State University’s Microprocessor-Controlled Aerial Robotics Team would like to
give special thanks to the following people and organizations for their assistance:
Dr. John W Lamont and Assistant Professor Ralph Patterson III for sharing
their professional experience and guidance throughout the course of this
project.
Lockheed Martin Corporation for their technical expertise and generous
financial contribution to this costly endeavor. Without their assistance this
project would not be possible.
The Department of Electrical and Computer Engineering for creating MicroCART and providing the skills and knowledge required for this project.
Fall 2006
Problem Statement
• General Problem Statement
– To provide an entry into the International Aerial Robotics
Competition (IARC) Summer 2007 for Iowa State University
• General Solution Approach
– Develop an aerial vehicle to compete in IARC Level 1
– Develop a secondary vehicle for higher level IARC
– Main system components
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PC-104 embedded system
IMU
GPS unit
Battery power supply
Sonar array
Digital magnetic compass
Wireless modem
Fall 2006
Operating Environment
IARC (International Aerial Robotics Competition)
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Diverse indoor/outdoor environments
Obstacles defined by the competition mission
Temperature threshold (60o-100o F)
Possible wind, light precipitation, adverse topography of the
competition location
No extreme environments, e.g. fog, rain, etc.
Fall 2006
Intended Users
Initial Users
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Spring 2007 Micro-CART team members
– Responsible for operating vehicle in summer 2007
IARC
Future Users
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Future Micro-CART teams
Researchers
Industry representatives
Hobbyists
Fall 2006
Intended Uses
Initial use
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Entry into Summer 2007 IARC
Future uses
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Search and rescue
Military and law enforcement reconnaissance
Environmental catastrophe control
Fall 2006
Assumptions and Limitations
Assumptions
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IARC Mission rules may change
Necessary funding remains available
Suitable hardware and software is available at an
affordable price
Onboard computing systems will be sufficient
Current vehicle able to carry necessary equipment
On-board memory sufficient
Sensor system will provide all necessary flight
software inputs
Attachment of secondary vehicle to primary vehicle
Fall 2006
Assumptions and Limitations
Limitations
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Physical limits of helicopter
Obstacle detection and avoidance
Power consumption limits
Competition maximum weight limit
Competition requirements
Team member expertise
Weather
Fall 2006
End Product Requirements
Primary Vehicle
IARC Level 1 Autonomous Functionality
• Take off
• Navigate to five waypoints with the fifth located three
kilometers away
• Maintain a stable hover at the fifth waypoint
Secondary Vehicle
Higher level IARC Functionality
• Communication with Primary Vehicle
• Image Recognition
• Obstacle Avoidance
Fall 2006
Presentation Outline
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Definitions
Acknowledgement
Problem statement
Operating environment
Intended users and uses
Assumptions and limitations
End product requirements
Project activity
– Previous accomplishments
– Present accomplishments
– Future required activities
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Approaches considered
Project definition activities
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Research activities
Design activities
Implementation Activities
Testing Activities
Resources and schedules
Project evaluation
Commercialization
Suggestions for future work
Lessons learned
Risks and risk management
Closing summary
Fall 2006
Project Activity
Previous Accomplishments
• Acquired helicopter, system components, and sensors
• Flight test stand modifications
Present Accomplishments
• First autonomously hovering flight on Sept. 26th, 2006
• Sonar developed and successfully implemented
• New Lithium Polymer battery purchased
• Testing procedures and Pre-Flight systems check list
created
Fall 2006
Previous Accomplishments
Fall 1999
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Purchased RC helicopter
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Purchased Dell PC
Fall 2000 – 2003
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Pilot training program
Spring 2002
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Acquired security box
Fall 2002
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Acquired and setup Linux PC
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Sonar circuit design
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Complete PIC programming for serial interfacing
Fall 2002 – Spring 2003
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Hardware acquisitions
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Serial software development
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PIC programming
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PC-104+ operating system
Spring 2003
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Power system
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Mounting platform
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Manual override switch
Fall 2004
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Replace PC-104+
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Purchased Dell PC
Spring 2005
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Acquired Wireless Data-link
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Acquired Magnetic Compass
Fall 2005
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WIKI
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Hardware enclosure
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New head block
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Flight test stand modifications
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Flight testing
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Onboard payload limitations
Spring 2006
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Untested altitude flight control code
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Flight simulator software ported to Linux
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Flight test stand modifications
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Developed exhaust shield
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GPS research and replacement
Fall 2006
Present Accomplishments
• Sonar
– A/D RS232 Module
– MINI-A Transducer
• New Lithium Polymer Battery
– Much higher Power-to-Weight Ratio
• New flight control software
• First autonomously hovering flight on Sept. 26th,
2006
• Testing procedures and Pre-Flight systems check
list created
Fall 2006
Future Activities
Compete in level one IARC
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Complete flight control code
Test fully autonomous flight
Research and plan trip to the competition
Fall 2006
Future Activities
Continue planning and development for higher
IARC levels
• Level 2
– Image recognition
– Object avoidance
• Level 3
– Deployment of the secondary vehicle
– Image recognition
– Object avoidance
Fall 2006
Approaches Considered
Activity
Approaches
Advantages
Disadvantages
Choice
Flight Control
Used C++ instead
of C language.
-Object Oriented
Programming is
easy for
modifications.
-Might be slower
Accepted
Code Comments on
Doxygen
-Nice Layout and it
does everything
automatically.
Writing data to the
CF card or to the
RF modem.
-Sends sensor logs
to RF modem and
that in turn sends it
to the Ground
Station for logging.
Accepted
-Write Speeds may
be limited.
-Might lose packet
information.
Accepted
Fall 2006
Approaches Considered
Activity
Approaches
Advantages
Disadvantages
Choice
Sonar
New circuit design
for Sonar
-Do not need the
Trigger Circuit and the
MUX.
-Implementing a
program can retrieve
the data from the
Sonar.
Secondary Vehicle
Multi-rotor
-More lift capacity
-Very unstable
Rejected
Contra-rotation.
-Fewer components
and more stability.
-Less lift
Accepted
Accepted
Fall 2006
Project Definition Activities (SV)
IARC Requirements
- Fully autonomous
- Carried and launched by primary
vehicle
- 1m x 1m building entrance
-Safely navigate into the building
- Ability to obtain images
- Relaying images back to ground station through
primary vehicle
Fall 2006
Research Activities
Research Aims:
• Full understanding of vehicle and component behavior
• Minimize wasted development time
• Ensure suitability of components
Research Areas:
• Existing component performance
• Flight control algorithm design
• New Topics
– Debugging and Datalogging
– Code Documentation
– Optimal Control Frequency
Fall 2006
Research Activities
Existing Component Performance
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Operational Limits
Precision
Accuracy
Reliability
Quirks
Fall 2006
Research Activities - IMU
• Operational Limits:
– Missing spec. sheet limits precise knowledge
– Assumptions made based on mfg. manual
• ±2g Accelerometers
• ±100º/sec Rate Sensors
– Onboard Kalmann filter provides angular position
– Temperature Compensated
• Accuracy and Precision
– Precision to 0.01º and 0.01m/s2
– Angular position, rate and linear acceleration highly accurate
• Quirks
– Intermittent failure to initialize
– Mounted upside down on helicopter
Fall 2006
Research Activities - Compass
• Operational Limits:
– Compass must be level for accurate readings
– Cannot operate within 1.5' of main rotor shaft
• Accuracy and Precision:
– Lacked accuracy within the test environment
– Readings disputed by traditional compass
• Requires in-flight testing to ascertain reliability
• Magnetic interference around main rotor shaft
Fall 2006
Research Activities - PC-104
• HESC Power Supply
– Produces 5V and 12V power
– 6V to 40V input range
– High likelihood voltage fluctuations will cause power supply failure.
• Serial Port Add-on Board
– IRQ sharing creates massive delays
– To achieve parallel data streaming each port must be assigned
unique IRQ
Fall 2006
Research Activities - GPS
• Uses standard NMEA protocol
• Interface has to be reverse engineered from
proprietary software.
• Cannot obtain signal indoors
Fall 2006
Research Activities
Flight Control Algorithm
• Existing software was written in C and used a multilayered approach
• Large quantities of code were missing
• Control revolved around a PID
– PID is well-suited to onboard helicopter control
– PID was incorrectly and incompletely implemented
• Excessive threading contributed to complexity
• Hardware interfaces were buggy but mostly complete
• Code translated well to object-oriented design
Fall 2006
Research Activities
New Topics
• Debugging and Data logging
– Real-Time In-Flight feedback
– New debugging framework
– Unit Tests
• Code Documentation
– Doxygen
• Optimal Control Frequency
– Comparison with other vehicles
Fall 2006
Presentation Outline
•
•
•
•
•
•
•
•
Definitions
Acknowledgement
Problem statement
Operating environment
Intended users and uses
Assumptions and limitations
End product requirements
Project activity
•
•
•
•
•
Previous accomplishments
Present accomplishments
Future required activities
Approaches considered
Project definition activities
•
•
•
•
•
•
•
•
•
•
•
Research activities
Design activities
Implementations activities
Testing activities
Resources and schedules
Project evaluation
Commercialization
Suggestions for future work
Lessons learned
Risks and risk management
Closing summary
Fall 2006
Design Activities
Hardware
• New sonar hardware
– Serial I/O Board
– New Transducer
• Kill switch
• Wiring and mounting of
components
– sonar
– compass
– power supply wiring
Fall 2006
Design Activities
Sonar
• Ultrasonic transducer
– Downward facing
– 6” to 20' range
– Analog signal wired to I/O
Board
• I/O Board
– RS-232 interface
– Room to easily add up to 7
additional transducers
Fall 2006
Design Activities
Software
• Previously existing design
– Old design found to be unimplemented except for
basic hardware interfacing code
– Concluded that existing architecture was
inappropriate – too much threading added unneeded
complexity and overhead
Fall 2006
Design Activities
Software
• Defined new architecture
– Simplified, tighter control loop and eliminated
unnecessary threading
– Rewrote much of controller code in a cleaner, objectoriented way
– Included integrated debugging and logging module,
unit tests, and software emulation of each hardware
sensor module
Fall 2006
Implementation Activities
• Divided components among team members
• Rewired helicopter
– prevent confusion
• Rewrote flight control code
– reuse hardware interface code
– control algorithm using PID
• Mounted remaining components
Fall 2006
Testing and Modification Activities
Software Tests
• Test individual components with new software
• Run software on helicopter
• Unit testing
• Reliability
– Code does not exhibit any reliability problems
• Error tolerance
– Program found to be tolerant of failures in everything but IMU
• Speed Issues
– 20Hz decided upon as minimum acceptable speed for control
loop frequency
– Hardware limit appears to be ~45Hz
Fall 2006
Testing and Modification Activities
Hardware Tests
• check functionality of all components being mounted on
helicopter
• check functionality of newly built components
• sensor interaction
– IMU initialization and polling code stress-tested
– Sensor input tested for helicopter 's full range of motion
Helicopter Control
• check servos
• have new team members learn controls
Fall 2006
Research Activities (SV)
• Previous Design
• Design Alternatives
– Alternative Solutions to IARC Criteria
• Components
– Necessary Components
– Previously Purchased Components
Fall 2006
Research Activities (SV)
Previous Design
• Function and advantages
• Missing documentation
• Requirements for
functionality
Fall 2006
Research Activities (SV)
Design Alternatives
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Ground based solutions
Wing-body options
Multi-rotor
Contra-rotation
Fall 2006
Research Activities (SV)
Necessary Components
– Size and weight
– Integration with other components
– Power requirements
• Microcontroller
• IMU
• Transceiver
– Bandwidth
– Range
Fall 2006
Research Activities (SV)
Current Components
– Function and operation
• Motors
– Power requirements
– Integration with speed controllers
• Speed Controllers
– Integration within current design
– Integration within test stand
Fall 2006
Design Activities (SV)
Test Stand
• Reason: Test lift capacity of contra-rotation.
• Design: Floating plate, spring tensioned design.
Fall 2006
Design Activities (SV)
Secondary Vehicle Frame
• Reason: New vehicle concept requires all new
layout
• Design: Coaxial, contra-rotating rotors create a
design similar to standard helicopter.
Fall 2006
Implementation Activities (SV)
Current Design Status
• Development of chassis CAD models
• Selected onboard components
• Development of test stand before
chassis construction
Fall 2006
Implementation Activities (SV)
BladeRunner R/C
Helicopter
• Contra-rotation proof of concept
• Study passive stability system
• Motivated by concerns regarding
control solution for current design
BladeRunner commercial model
Fall 2006
Testing Activities (SV)
Previous Secondary
Vehicle Design
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Quad-rotor design presents
controllability issues
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Material availability
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Competition constraints
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XUFO test results not promising
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Motivation for design alternatives
Current secondary vehicle design
Commercial XUFO
Fall 2006
Testing Activities (SV)
Contra-Rotation
Test Stand
• Evaluate lift capacity of two
motors
• Evaluate stability and yaw
control
• Evaluate battery life
Fall 2006
Presentation Outline
•
•
•
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•
•
•
•
Definitions
Acknowledgement
Problem statement
Operating environment
Intended users and uses
Assumptions and limitations
End product requirements
Project activity
•
•
•
•
•
Previous accomplishments
Present accomplishments
Future required activities
Approaches considered
Project definition activities
•
•
•
•
•
•
•
•
•
•
•
Research activities
Design activities
Implementations activities
Testing activities
Resources and schedules
Project evaluation
Commercialization
Suggestions for future work
Lessons learned
Risks and risk management
Closing summary
Fall 2006
Resources
• Estimated and actual personal hours
• 1223.75 Total Hours
• Average 80 hours per team member
Hours Category
Estimated Hours
Actual Hours
Team Leader
324
254.75
Software Subteam
671
405
Ground Station Subteam
188
140
Hardware Subteam
553
421
Secondary Vehicle Subteam
396
333
Total
2132
1553.75
Fall 2006
Resources
Item
Previous Total Cost
Actual Cost for Fall 2006
Total Project Cost to Date
Sensor Systems
GPS
$
5,000.00
$
31.00
$
5,031.00
IMU
$
5,500.00
$
0.00
$
5,500.00
Sonar
$
618.00
$
172.78
$
790.78
Magnetic compass
$
400.00
$
0.00
$
400.00
Wireless comm link
$
500.00
$
0.00
$
500.00
Ground station PC
$
0.00
$
20.00
$
20.00
PC/104
$ 1,217.00
$
0.00
$
1,217.00
Servo controller
$
100.00
$
0.00
$
100.00
Manual override switch
$
50.00
$
0.00
$
50.00
Emergency shutoff switch
$
59.85
$
0.00
$
59.85
Power supply / battery
$ 1,160.00
$
629.95
$
1,789.95
Helicopter / maintenance
$ 6,437.00
$
69.00
$
6,506.00
Flight Augmentation Stand
$
$
0.00
$
185.00
Flight Controls
Vehicle Configuration
185.00
Total Hours
10,771
1,223.75
11,994.75
Labor ($10.50 per hour)
$ 113,095.50
$
12,849.75
$ 125,945.25
Total Costs (w/o labor)
$ 21,226.85
$
922.73
$ 22,149.58
Total Costs (w/ labor)
$ 134,322.35
$ 13,772.48
$ 148,094.83
Fall 2006
Schedules
Fall 2006
Schedules
Fall 2006
Project Evaluation
Current
Status
Component
Tasks
GPS software
Test and verify
Mounting scheme
Implement, test, and verify
Complete
Sonar
Purchase, test, and verify
Complete
Sonar software
Develop, test, and verify
Complete
Compass software
Test and verify
Complete
Wireless data link
Test and verify
Complete
Flight Control Software
Debug, test, and verify
Design, lay-out, and purchase composite
hardware
Composite enclosure
Incomplete
Incomplete
Complete
Fall 2006
Project Evaluation
Component
Tasks
Current Status
Autonomous hover
Test and verify
Complete
Autonomous flight
Test and verify
Incomplete
Helicopter electronics
Test and verify
Complete
Helicopter
Determine center of mass
Test stand
Acquire
Translational flight controller
Complete, test, and verify
Senior design
Update website
Complete
Senior design
Fulfill reporting requirements
Complete
Senior design
Document on the Wiki
Incomplete
Complete
Incomplete
In Progress
Fall 2006
Commercialization
• At this time, the project will not be
commercialized
– Too large, too fragile for military applications
– Too expensive for civilian applications
• Future
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Military
Reconnaissance and surveying
Hazardous site clean-up
Search and rescue
Traffic control and enforcement
Fall 2006
Recommendations
• Continue as originally envisioned
– Automated helicopter is close to flying
– Project will no longer suffer “memory loss”
– Micro-CART is a worthwhile learning
experience
Fall 2006
Lessons Learned
• Take care when testing
• Document thoroughly
• Start deliverables early
Fall 2006
Risk and Risk Management
Risk: Loss of team member
Management:
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Have proper documentation
Overlapping team member skills
Risk: Damage to components
Management:
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Create accurate testing procedures
Understand the “Big Picture”
Risk: Personal injury during testing
Management:
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Stay alert
Maintain communication
Risk: Lack of expertise
Management:
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Consult advisors
Research and learn
Fall 2006
Closing Summary
• Project has had it’s hurdles, but progress is still being
made and we will be ready to compete in Summer 2007.
• Micro-CART is a challenging project encompassing
control systems, mechanical systems, hardware, and
software.
• It also gives students an excellent way to broaden their
experiences, build problem solving skills, and learn
responsibility.
• Bottom Line: Micro-CART is a valuable and interesting
project and should be continued in Senior Design.
Fall 2006
Questions?
Fall 2006