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AP speed hold PID controller

Hi Bjoern,
Actually the integral of velocity is the distance while the derivative is acceleration. anyway, Wanted to share my approach perhaps someone would find it useful. Thanks for the feedback.
 
Hello. I wish I had come to this place before I attempted to write my own PID for FS. In any case, it's been done - for the most part but I have a few questions. My PID was "stolen" from some RC aircraft site and is extremely simple but seems to work. Although, as a pilot, I would find it insufficient for passenger comfort and an aircraft (at least the way I was taught) is properly flown. For example, when banking at 30°, the lead-in to level out would start about 15° from desired heading. But perhaps as a PID trainer, it might be useful. Here are my PID equations for a heading change:
P = error * Kp
I = (ErrorAccumulated + Error) * Ki
D =(Error - PreviousError) * Kd
anti-windup
Imax = some max value for I

Output = P + I + D

Notice that I do not have any time constants. The values above are just scanned at the gauge scan rate of 18Hz.

Question #1: What applicable formula would apply to the above?

I see that the aircraft.cfg (for my PID test, I set max bank at 40) has the following:
max bank = 25
max bank velocity = 3.5
max bank acceleration = 1.0

Question #2: How are these parameters applied in FS' PID's scheme?

Question #3: What percentage step change of a process variable would be considered extreme (i.e.: PV = 0° to 180°)?

I actually applied the above to a real-world application. I made a split serial cable and I used Excel (VBA) to talk to a GPS through my laptop's COM port. I then applied the above PID and then output through the COM port to a step motor board. I then attached it to my yoke (in a Cessna 182). In order to get it to have the correct amount of leverage to the links, I had to add an "arm" or "throw" value, so my actual output = throw * (P + I + D).

Question #4: What proper terminology would be applicable to the "throw" variable?

In the picture attached, it can be seen I'm using the Co50 PFD. In the gauge, a "tracking line" is used with the following formula:

(A:Velocity world X, m/s) (A:Velocity world Z, m/s) atg2 (A:Magvar, radians) - (A:Plane heading degrees gyro, radians) -

I see that it seems to trend what the ball does in a turn coordinator (A:TURN COORDINATOR BALL).

Question #5: What is being sought with the above formula?
 

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