Fall 2006
Advisors Client Dr. John Lamont Iowa State University Professor Ralph Patterson III Department of Electrical and Computer Engineering
Primary Vehicle Team Secondary Vehicle Team
2nd Semester 1st Semester 1st Semester Tim Gruwell (Team Leader) Brian Baumhover Patrick Turner
Andrew Larson Bai Shen Byung Kang
Erica Moyer Bill Hughes
Maria-Cristina Olivas Hassan Javed Jeff Pries (ME)
Josh Robinson Pankaj Makhija Brett Pfeffer (ME)
Kito Berg-Taylor (AerE)
Gustav Brandstrom (ME)
Interdisciplinary Members
Interdisciplinary Members
Micro-CART U N M A N N E D
A E R I A L
V E H I C L EONGO – 03 Microprocessor–Controlled Aerial Robotics Team
Fall 2006
Presentation Outline
• 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
• 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
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 DesignGPS Global positioning systemGSS Ground station systemIARC International Aerial Robotics CompetitionIMU Inertial measurement unitPC-104 x86-based controllable board PIC Programmable interface controllerPID Proportional Integral DerivativePitch Revolution of a vehicle forward and backward on a central axisPro/E Professional Engineer CAD packagePWM Pulse width modulationRC Remote controlRoll Revolution around the longitudinal axis of a vehicleSV Secondary VehicleUAV Unmanned aerial vehicleWIKI (What I Know Is) A public documentation repositoryYaw Revolution around the vertical axis of a vehicle
Acronym Definitions
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 Micro-CART 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
• PC-104 embedded system • IMU• GPS unit • Battery power supply• Sonar array• Digital magnetic compass• Wireless modem
Fall 2006
IARC (International Aerial Robotics Competition)• 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.
Operating Environment
Fall 2006
Initial Users• Spring 2007 Micro-CART team members
– Responsible for operating vehicle in summer 2007 IARC
Future Users• Future Micro-CART teams• Researchers• Industry representatives• Hobbyists
Intended Users
Fall 2006
Initial use• Entry into Summer 2007 IARC
Future uses• Search and rescue• Military and law enforcement reconnaissance• Environmental catastrophe control
Intended Uses
Fall 2006
Assumptions • 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
Assumptions and Limitations
Fall 2006
Limitations • Physical limits of helicopter• Obstacle detection and avoidance• Power consumption limits• Competition maximum weight limit• Competition requirements• Team member expertise• Weather
Assumptions and Limitations
Fall 2006
Primary VehicleIARC 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 VehicleHigher level IARC Functionality• Communication with Primary Vehicle• Image Recognition• Obstacle Avoidance
End Product Requirements
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
• 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 AccomplishmentsFall 1999• Purchased RC helicopter• Purchased Dell PC
Fall 2000 – 2003• Pilot training program
Spring 2002• Acquired security box
Fall 2002• Acquired and setup Linux PC• Sonar circuit design• Complete PIC programming for serial interfacing
Fall 2002 – Spring 2003• Hardware acquisitions• Serial software development• PIC programming• PC-104+ operating system
Spring 2003• Power system• Mounting platform• Manual override switch
Fall 2004
• Replace PC-104+
• Purchased Dell PC
Spring 2005
• Acquired Wireless Data-link
• Acquired Magnetic Compass
Fall 2005
• WIKI
• Hardware enclosure
• New head block
• Flight test stand modifications
• Flight testing
• Onboard payload limitations
Spring 2006
• Untested altitude flight control code
• Flight simulator software ported to Linux
• Flight test stand modifications
• Developed exhaust shield
• 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• 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.
Accepted
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.
-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.
Accepted
Secondary Vehicle Multi-rotor -More lift capacity -Very unstable Rejected
Contra-rotation. -Fewer components and more stability.
-Less lift 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
• 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 multi-
layered 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, object-oriented 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
• 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
• Quad-rotor design presents controllability issues
• Material availability
• Competition constraints
• XUFO test results not promising
• 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
• 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
ResourcesItem 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
Flight Controls
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
Vehicle Configuration
Power supply / battery $ 1,160.00 $ 629.95 $ 1,789.95
Helicopter / maintenance $ 6,437.00 $ 69.00 $ 6,506.00
Flight Augmentation Stand $ 185.00 $ 0.00 $ 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
Project Evaluation
Component TasksCurrent
StatusGPS software Test and verify Incomplete
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 Incomplete
Composite enclosureDesign, lay-out, and purchase composite
hardwareComplete
Fall 2006
Project Evaluation
Component Tasks Current StatusAutonomous hover Test and verify Complete
Autonomous flight Test and verify Incomplete
Helicopter electronics Test and verify Complete
Helicopter Determine center of mass Incomplete
Test stand Acquire Complete
Translational flight controller Complete, test, and verify Incomplete
Senior design Update website Complete
Senior design Fulfill reporting requirements Complete
Senior design Document on the Wiki 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– 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
Risk and Risk Management
Risk: Loss of team member Management: • Have proper documentation• Overlapping team member skills
Risk: Damage to components Management: • Create accurate testing procedures• Understand the “Big Picture”
Risk: Personal injury during testingManagement: • Stay alert• Maintain communication
Risk: Lack of expertise Management:• 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.