User`s manual

AscTec Hummingbird with AutoPilot User’s Manual
B Troubleshooting
This chapter holds solutions to problems which might
occur during the operation of your AscTec Humming-
bird w/AutoPilot.
B.1 Slight tilt in pitch/roll with
the pitch/roll stick in
neutral position
Due to unavoidable measurement errors or the
unbalance of mechanical parts it is perfectly normal
that the AscTec Hummingbird w/ Autopilot is not
always 100% levelled during flight with the control
sticks in neutral position. A slight tilt can easily be
compensated by the trimmers on your remote control.
B.2 Considerable tilt in pitch
or roll
There are some situations where the measured angle
can considerably differ from the real angle, which re-
sults in big tilt-angles in pitch and/or roll while the
pitch/roll stick on your remote is centered. This can
have the following reasons:
• Shaking during initialization: It is very import-
ant that the vehicle is not moved at all during the
initialization phase. Calibration errors caused by
shaking during startup can affect the system per-
formance in many ways. If the vehicle tilts more
and more after starting the motors it is very li-
kely that it was moved during the initialization.
In this case, please turn it off and on again and
make sure that it is not moved until the AutoPi-
lot displays the Ready to flyLED-pattern (LED 1
(red) off, LED 2 (green) blinking).
• Teach-in of your transmitter was not correct:To
check if your transmitter was taught-in correctly,
please refer to section ??.
• Rapid change of the ambient temperature or ope-
ration under extreme temperature conditions:
Temperature compensation is applied to all sen-
sors of the AscTec AutoPilot. We have not en-
countered any problems with temperature yet.
However, in theory it is possible that you might
get drift effects and therefore unwanted tilt in
pitch or roll if you for instance fly directly from
a warm room into a very cold outdoor environ-
ment. If this happens, please turn the vehicle off,
let the electronics adopt to the ambient tempera-
ture and try again.
• Extremely fast maneuvers: Fast maneuvers,
which result in high accelerations interacting
with your aircraft, can cause faulty measure-
ments. If you fly several circles in a row in high
speeds it can happen, that the measured angle
differs several degrees from the real angle. If this
is the case, you simply have to fly gently or ho-
ver for a few seconds until the unwanted tilt is
gone, as the data fusion system usually is able to
recover very quick.
• Flying on a circular path in always the same di-
rection for a longer period of time: The centri-
petal force affecting your vehicle when flying on
a circular path prevents the sensors from measu-
ring the earth’s gravity vector. In this case, the
other sensors on-board the vehicle are used by
the on-board software to estimate the real tilt of
the vehicle. This works for quite a long time, but
at some point the errors may become significant.
Therefore it is recommended that after flying a
full circle in one direction the pilot should fly
straight for a couple of seconds or a circular path
in the other direction. If you experience such a
problem simply keep the vehicle hovering until
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