**The D term** attempts to increase system stability by monitoring the rate of change in the error. If the error is rapidly converging to zero, the D term causes the strength of the correction to be backed off in order to avoid overshooting the target.
* At 3/4 throttle (1750), PIDs are reduced by approximately 25% (half way between 1500 and 2000 the dampening will be 50% of the total TPA value of 50% in this example)
* At full throttle (2000) the full amount of dampening set in TPA is applied. (50% reduction in this example)
If you are getting oscillations starting at say 3/4 throttle, set tpa breakpoint = 1750 or lower (remember, this is assuming your throttle range is 1000-2000), and then slowly increase TPA until your oscillations are gone. Usually, you will want tpa breakpoint to start a little sooner then when your oscillations start so you'll want to experiment with the values to reduce/remove the oscillations.
be. Note that the default value for P_Level is 90. This is more than likely too high of a value for most, and will cause the model to be very unstable in Angle Mode, and could result in loss of control. It is recommended to change this value to 20 before using PID Controller 1 in Angle Mode.
For the ALIENWII32 targets the gyroscale is removed for even more yaw authority. This will provide best performance on very small multicopters with brushed motors.
PID Controller 4 is an hybrid version of two MultiWii PID controllers. Roll and pitch is using the MultiWii 2.2 algorithm and yaw is using the 2.3 algorithm.
For the ALIENWII32 targets the gyroscale is removed for more yaw authority. This will provide best performance on very small multicopters with brushed motors.
The algorithm is leveraging more floating point math. This PID controller also compensates for different looptimes on roll and pitch. It likely don't need retuning of the PID values when looptime is changing. Actually there are two settings hardcoded which are configurable via the GUI in Harakiri:
## RC rate, Pitch and Roll Rates (P/R rate before they were separated), and Yaw rate
### RC Rate
An overall multiplier on the RC stick inputs for pitch, rol;, and yaw.
On PID Controllers 0, and 3-5 can be used to set the "feel" around center stick for small control movements. (RC Expo also affects this).For PID Controllers 1 and 2, this basically sets the baseline stick sensitivity
### Pitch and Roll rates
In PID Controllers 0 and 3-5, the affect of the PID error terms for P and D are gradually lessened as the control sticks are moved away from center, ie 0.3 rate gives a 30% reduction of those terms at full throw, effectively making the stabilizing effect of the PID controller less at stick extremes. This results in faster rotation rates. So for these controllers, you can set center stick sensitivity to control movement with RC rate above, and yet have much faster rotation rates at stick extremes.
For PID Controllers 1 and 2, this is an multiplier on overall stick sensitivity, like RC rate, but for roll and pitch independently. Stablility (to outside factors like turbulence) is not reduced at stick extremes. A zero value is no increase in stick sensitivity over that set by RC rate above. Higher values increases stick sensitivity across the entire stick movement range.
### Yaw Rate
In PID Controllers 0 and 5, it acts as a PID reduction as explained above. In PID Controllers 1-4, it acts as a stick sensitivity multiplier, as explained above.