Futaba GY611 - Manual (Page 11)

11
B
EFORE
U
SE
trol signal larger than the signal from the gyro must be applied from
the transmitter. That is, the difference between the rudder control sig-
nal from the transmitter and the control signal that attempts to stop
this from the gyro becomes the actual amount of movement of the
tail. Ordinarily, the rudder control signal is amplified several times
over by the gyro amp and is balanced with the gyro control signal so
that the transmitter can be used at the normal steering angle.
The AVCS system uses a different rudder control method. As de-
scribed in the preceding section, it has additional functions that "at-
tempt to return movement by external force to the original position"
and that generate an angular velocity proportional to the rudder con-
trol signal. That is, it functionally controls the speed of rotation of
the tail. The original AVCS (Angular Vector Control System) came
from this.
· In the AVCS mode, when the transmitter rudder stick is moved when the heli-
copter was stopped, the rudder servo controls operation until the tail reaches
the specified rotational speed.
· Trim deviation of the rudder control signal also becomes a signal that causes
the tail to turn so that even a little trim deviation causes the tail to move.
Therefore, the rudder trim is made the same in all flight states and must
match the neutral reference signal at the gyro. The method of reading the
rudder neutral signal at the gyro will be described separately.
· Since the rudder mixing signals from the transmitter also become a tail rota-
tion signal, all the rudder mixing functions must be disabled.
· In the AVCS mode, the gyro automatically trims the rudder so that linkage
changes cannot be verified. Initially, the GY611 trims the rudder by flying in
the Normal mode to take the rudder linkage neutral position. This centers the
linkage. At this time, this rudder neutral reference point is read to the GY611.
Giving the gyro the rudder neutral reference signal and performing
tail operation by referring to this signal in the AVCS mode in this
way is how the AVCS system differs from the conventional system.