AA241X Summary

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AA241X Summary
AA241X - Design, Construction, and Testing of
Autonomous Aircraft
Stanford University- Fall 2003-04
Juan J. Alonso Ilan M. Kroo TA Andre C.
Marta Dept. of Aero/Astro

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Mission Statement

• To design, build, and fly an autonomous aircraft
  which can stay aloft within a three-dimensional
  box for as long a time as possible.
• Available battery, motor, control system will be
  provided and it is not subject to change.

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Constraints

• Motor ZAGI-FIXX kind
• Battery NiMh 370 mAh
• Control system GPS and actuators/servos only

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Flight Constraints

• Start anywhere within red box
• Size of box approx. 100 m
• Fixed penalty for each time the aircraft exits
  the box
• Both powered and gliding flight acceptable

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Start Here
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Flight Score, I

• Time of flight within box increases your score
  at a specified rate of a / sec
• Time of flight outside the box does not increase
  your score
• Each excursion outside of the box incurs a
  penalty of b
• Final score is the cumulative score of four
  attempts on two flight trial days (spaced a week
  apart)

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Control System Capabilities

• GPS receiver latitude - longitude - altitude
  (inaccurate)
• 4-channel micro servo actuation
• PIC microcontroller / on-board computer
• Flash memory
• C-like API with following functions
• Read GPS output through serial port
• Send angular position to each of 4 channels
• Write data to Flash memory
• Interrupts
• Approximate weight 1.5 oz
• Possibility of carrying a video camera downlink

Channel 4 (speed control)
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Construction Techniques

• Similar to AA241b lab section
• Foam and computer-controlled foam cutter
• Balsa, Basswood, Plywood
• Fiberglass / carbon / epoxy
• Model airplane construction techniques

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Three Teams

• 16 Students out of 24 in AA241a/b continued on to
  AA241x (Fall quarter)
• 5-6 Students per team
• Mix of expertise
• Electronics
• Manufacturing
• Aero and Stability Control

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Three Designs

• Flying wing design, pusher prop
• Conventional wing tail, tractor prop
• Wing twin boom, pusher prop

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They All Flew Under R/C

• Stability control is always the most difficult
  thing to get right
• Some aircraft had limited control authority and
  misplaced Center of gravity
• Limited R/C control surfaces

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Some Better Than Others
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The Electronics Were a Challenge
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And The Winner Is

• 13 min autonomous flight without ever leaving the
  boundary
• December 2003

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Lessons Learned

• Designing, building, and flying an autonomous
  airplane in one quarter is VERY challenging
• Electronics and software are a major portion of
  the effort (provided, mostly, to our students)
• Students need to be taught model manufacturing
  techniques
• It is a lot of funwe will do it again this
  FallAntarctica?