User`s manual

AscTec Hummingbird with AutoPilot User’s Manual
enabled), even with the switch in GPS mode.
Hand control in GPS mode
When in GPS mode, the yaw and throttle/height
control stick on the R/C still has the same function
as in height control mode. The pitch and roll stick
still controls the same axes, but the vehicle behaves
different as in manual mode. When flying in GPS
mode the vehicle always is in a speed controlled
state. This means, no matter how far you push the
pitch/roll stick, the vehicle will not travel faster than
defined in its control parameters. In windy conditions
it will travel at almost the same speed going up-wind
and going down-wind. The moment you push the
stick from center to any direction the vehicle will
change its tilt in that direction rapidly to accelerate
until it has reached the desired speed. Then it will
tilt back to an angle at which it travels at the desired
speed in the current wind conditions. The further you
push the stick, the faster the vehicle goes. If you put
the stick back to center the vehicle will stop at its
current position. With the standard parameter set the
vehicle will not move faster than about 2 meters per
second in hand controlled GPS mode.
In GPS mode it is possible and also recommended
to control one function of the vehicle at a time,
e.g. first fly to a desired height, then move to a
desired position, then turn the heading to a desired
orientation.
Starting and landing in GPS mode
It is possible to launch the vehicle directly in GPS
mode, but it has to be done with care as the vehicle
might move a bit into any direction during the launch.
If you do want to launch directly in GPS mode ma-
ke sure that there is enough free space surrounding
the vehicle and that persons are standing at least 10m
away from it. After turning on the motors make sure
you hold the throttle stick down (not in neutral posi-
tion!) to keep the motors idle. When you are ready,
you should start immediately by pushing the throttle
stick all the way up until the vehicle hovers in a safe
height, at least at eye level. For the landing you also
need to make sure that there is enough free space sur-
rounding the vehicle, as especially close to the ground
the GPS position might drift quite a bit due to signal
reflections. For starting and landing in tight spots it is
recommended to launch and land the vehicle in ma-
nual mode and switch to GPS mode once it is in a safe
height.
Waypoint navigation
The vehicle only accepts waypoint commands by a
PC or an external control computer mounted to it (e.g.
a GumStix processor board) when the switch on the
R/C is in GPS position. Any stick input on the R/C
will override a waypoint command. For safety rea-
sons it is absolutely necessary that there is always a
safety pilot standing by with the R/C in his hands to
take over control if something is not working as ex-
pected.
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