Juan J. Alonso
Aeronautics & Astronautics
Associate Professor
Durand Building, Room 252
Stanford University
Stanford, CA 94305
AA 241X Problem Set 3
Due Wednesday May 20, 2015, before class starts
This is the last problem set in AA241x. Beyond PS3, your only remaining assignments are
(a) to complete and fly an autonomous aircraft during the flight trials (first week of June
2015) and (b) to turn in a final report by June 10, 2015, noon. Of course, obtaining a high
score in the flight trials will ensure your spot in the UAV hall of fame!
The outcome of this problem set is supposed to be a report, contributed to by all members of
the team, and placed on your team’s website with password protection. Each of the sections
of the report must have a small identifier stating who was responsible for that section. If
more than one person (or the entire team) was responsible for any particular section, please
state it so. The actual organization of the report (PDF, HTML, embedded images/videos, etc,
etc) is entirely up to you: all that we require is that the information be logically organized on
your website.
For this last problem set, we would like you to use, as much as possible, your own aircraft. If
your own aircraft is not up to the task, you can fall back on using the Bixler 2. Your score in
the PS will be 10% lower if you use the Bixler 2 for all tasks, and will be prorated if you use
a combination of the Bixler 2 and your own aircraft for various tasks.
Task 1. Acquisition of a line.
Demonstrate your capability (see Figure below) to “acquire” a line in space (at constant
altitude) from different starting headings. In other words, given a line (with an orientation) in
3D space that is parallel to the ground, and given that your aircraft is flying at the
corresponding altitude but with a different heading, show the capability of your control
algorithm to “acquire” that line and follow it for approximately 100 m. In your write-up,
please include the XY flight trajectory and the time histories of position, attitude, altitude,
and airspeed, as well as the errors (relative to the line) and the control inputs.
Phone: 650.723.9954 • Fax: 650.725.3377 • E-mail: [email protected] • Web: http://adl.stanford.edu
Task 2. Transition between lines
As a way to ensure that you can begin to follow specified paths in the air (guided by your
mission planning strategy), and after you have completed Task 1 in this PS, demonstrate the
ability to transition to a second intersecting line (while maintaining altitude and airspeed, but
changing heading) as is suggested in the Figure below. Demonstrate this capability with at
least 2 transitions where the lines change heading by 15 deg and 45 deg. As in Task 1, in
your write-up please include the XY flight trajectory and the time histories of attitude,
position, altitude, and airspeed, as well as the errors (relative to the line) and the control
inputs.
Task 3. Update the mission plan / strategy
Describe any updates (from PS2) to the thinking and/or analysis that your strategy is based
on. For this task, your team is expected to include the final MATLAB-based simulations of
the mission plan that you are planning on using for your demonstration flights. As in PS2,
please make sure that you repeat your simulations multiple times with different fire
scenarios. Report your expected scores as statistical averages (mean and variance) based on
the simulations you perform. State clearly all your assumptions for performance and provide
an estimation of how accurately you believe you will be able to realize the scores presented
in this Task.
Task 4. Aircraft characteristics: theory vs. experimental data.
For the aircraft you designed provide the predicted values and the analysis used to make
these predictions. For each estimate in this section, provide a suitable error estimate. These
should include but not be limited to:
1. Aerodynamic performance: CL vs α, drag polars, lift to drag ratio vs. CL, maximum
climb rate, turning performance, required power in level flight vs airspeed, required
power in climb vs climb rate.
2. Flight dynamics: Stability derivatives, frequencies and damping ratios for your
optimal cruise and climb rate.
3. Weight and CG statements.
Phone: 650.723.9954 • Fax: 650.725.3377 • E-mail: [email protected] • Web: http://adl.stanford.edu
Compare all of the above-predicted values with those measured experimentally. Also
include details of your design and manufacturing approach, choices made during fabrication,
and a report on the achieved flight performance of the aircraft. Include a three-view drawing
(and any CAD renderings you think would be useful) and make sure to provide summary
tables and drawings that, at least, include quantities such as:
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Total weight
Wing area and wing loading
Wing weight
Fuselage weight
Tail & boom weight
Payload weight
CG location
Horizontal and vertical tail areas, position, and relative incidence to the wing (where
applicable).
Lifting surface parameters (including span, root & tip chords, taper ratio of the
various sections, dihedral / polyhedral angles, control surface spans and chord
fraction, etc). Task 5. Minimum turn radius (extra credit)
Demonstrate in flight the minimum turn radius that can be achieved with your aircraft, both
flying in RC and autonomous modes. Measure and report the turn radius, bank angle,
airspeed, CL, g-loading, trim controls surfaces, power settings, and power consumption.
Task 6. Goals & Plan of Action:
i.
Describe briefly your goals and plan of action between now and the Fly-offs. Include
any schedules / diagrams if needed.
ii.
Discuss how the plan of action you set out to achieve in PS2 differed from what you
actually did and why.
Phone: 650.723.9954 • Fax: 650.725.3377 • E-mail: [email protected] • Web: http://adl.stanford.edu