Programming The Gyro Settings; Programming Pid Correction - GRAUPNER 33575 Operating Instructions Manual

4. PROGRAMMING THE GYRO SETTINGS:

PID (Proportional Integral Differential) correction
The stabilising effect of the gyro sensors is based fundamentally on three parameters:
P factor: defines proportional correction
P = proportional: if the intended value is not the same as the actual value, then the difference is fed
proportionally into the corrective signal; in simple terms, the input value (e) is multiplied by a fixed
value: u(t) = Kp*e(t). Kp is termed the amplification value. The output value is therefore proportional to
the gyro's input value. Proportional correction cannot occur until a deviation from the intended value is
present; if the deviation is 0, then the product is also zero. If the amplification value is set too high, the
P factor causes the model to oscillate and become unstable.
I factor: integral correction (not currently implemented)
D factor: defines differential correction
D = differential: in this case the corrective output value is affected by the rate of change of the input
value, i.e. the faster the model tilts around the axis, the more pronounced the corrective response of the
gyro. If the model changes attitude very gently, then the D factor causes hardly any corrective action. It
also makes absolutely no difference how far the model has already changed attitude; the crucial value
is only the speed or rate of the movement. The rate of change is again multiplied by a factor (as with P
correction) to produce the output value. For this reason pure D correction is not used; it must always be
employed in combination with P correction.
4.1 Programming PID correction - Gyro settings display:
CAUTION: before you start entering settings for a new model, it is essential to select the
number of aileron servos in the Aileron servos menu point, and to define the gyro axes and
orientation in the New settings menu point.
Aileron / Elevator / Rudder: shows the programmable P factors for the corresponding control surface.
Note: the gyro axes must first be defined under New settings (see section 3.4).
If you wish to disable the gyro, enter the value OFF in the appropriate control function.
P factor:
The P factor should always be set first, followed by the D factor (adjustment range in each case 0 to 10).
A general rule is that the larger the control surface, the smaller the P factor required. Start with a factor
of 2 (default setting), and do not exceed 4 - 5 as maximum value for the normal flight phase, 2 - 3 for
speed, 3 - 6 for landing; the maximum value of 10 should be reserved for torque-rolls only.
WARNING: if you program separate flight phases, it is essential to select the appropriate
flight phase when the model is in the air, as inappropriate gyro settings may cause the control
surfaces to oscillate, possibly resulting in the loss of the model!
Note: the higher the model's speed, the more quickly oscillation may set in.
D factor: for a given P factor setting, the model's tendency to oscillate can be reduced by setting a lower
D factor. However, if you select a lower setting for the P factor, then you may be able to set a higher
D factor value before the onset of control surface oscillation. The gyro effect can be optimised by fine-
tuning the D factor.
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Manual Receiver GR-12+ 3xG Graupner HoTT 2. 4