User`s manual

AscTec Hummingbird with AutoPilot User’s Manual
(front!) is pointing away from you, as in this case
the vehicle will move forward if you push your pitch
stick forward. Now, give a little throttle and the
vehicle should lift off. In manual mode, the throttle
stick on your remote directly controls the average
thrust of the rotors, the pitch/roll stick sets a desired
angle in these axes. Try hovering in a height of about
1m and concentrate on the red marking which is
the front of your vehicle. It is perfectly normal that
the vehicle drifts slowly in all directions without
GPS control enabled. Try to compensate for these
movements using the pitch/roll stick and try to hold
the height of about 1m by gently moving the throttle
stick up and down. After a while you will be able to
keep the vehicle hovering in one place. After a few
battery charges you will able to fly in any room, and
with some more practice you can even fly in small
spaces and land on tables etc.. Good luck!
3.4.3 Enabling height control
Once you feel comfortable controlling the vehicle
manually put the GPS/height control switch in center
position (”height control enabled”). Now, the vehicle
tries to hold its current height as long as the thrott-
le stick is centered. Moving the stick up and down
commands an ascending/descending rate. It is recom-
mended to use the height control mode only out-
doors. Please make sure you fly high enough above
the ground (at least at eye level) when using the height
control mode as turbulences or gusts might cause ra-
pid changes in air pressure which might make the ve-
hicle move up and down a bit without any command.
As long as the vehicle is standing on the ground make
sure you hold the throttle stick down (not in neutral
position!) to keep the motors idle. When taking off
from the ground in height control mode please make
sure you push the throttle stick all the way up until
the vehicle is at a safe height (at least eye level).
3.4.4 Flying in GPS mode
GPS operation in general
Flying the vehicle in GPS mode is very easy as
long as GPS receiption is good. However, as perfect
GPS receiption can never be guaranteed, the pilot
must be able to control the vehicle manually in
every situation. GPS mode is enabled by putting
the GPS/height control switch on the R/C in GPS
position. If the vehicle appears to become instable in
GPS mode or seems to not react to user commands
you need to push the GPS/height control switch to
manual mode immediately to take over control. As
I pilot you are responsible to control your vehicle in
a safe way, even if an electronic assistance like GPS
control fails.
Please note that in GPS mode height control is always
enabled, too.
It is perfectly normal that the vehicle is not absolu-
tely stationary when hovering in GPS mode without
any control command. The GPS position measure-
ments are supported by the inertial sensors on-board,
which makes the position estimate much more relia-
ble than what can be expected from a standard GPS
receiver. However, the inertial sensors can compensa-
te for short-term effects like a jump in the GPS po-
sition when a new satellite comes in view, but they
cannot compensate for long-term drift or position er-
rors.
How to determine weather the GPS fix is
valid
In all firmware versions LED 4 (
”
GPS status indica-
tor“) is flashing to warn the pilot, if there is no valid
GPS fix. It stays off if the GPS signal is OK. There is a
special firmware for the HighLevel-processor giving
an acoustic warning if the GPS signal is bad. This
firmware is usually not installed on the AscTec Hum-
mingbird with AutoPilot, as this vehicle is often used
for indoor research. Please note that the GPS control-
ler is automatically disabled if there is no valid GPS
fix. In this case, the vehicle reacts as if the GPS/height
control switch was in center position (height control
Ascending Technologies GmbH - 13 - www.asctec.de