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n4gix

PID Controllers in the .air file

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Some still insist that the PID Controller entries in the .air file are somehow different than those equivalent entries in the aircraft.cfg file.Here then is the definitive answer to the issue, taken directly from the ESP1 SDK (which all know is simply FSX with the GUI removed):

PID ControllersPIDs are only used to aid in the handling of AI (computer) controlled aircraft. PID stands for Proportional-Derivative-Integral controller, and is a feedback controller that takes an error for a controlled state and outputs a correction. For example, on an airspeed controller, the error would be the desired airspeed minus the current airspeed. The output is then determined by the sum of three factors using the error and the P, I, and D constants. The "P" factor is simply a factor proportional to the error. The "I" factor is an accumulated factor scaled by the error. The "D" factor is a factor based on the rate of change of the error."P factor" = P * error"Accumulated I factor" = "Accumulated I factor" + (I * error * deltaTime), in Calculus terms, this is simply an integral. The error must reverse its sign to drive this accumulated factor to 0. This is characterized as oscillations, but drives the error to zero."D factor" = D * error/deltaTime. As the error gets smaller, this drives the output to be asymptotic towards the desired value.
http://msdn.microsoft.com/en-us/library/cc526961.aspx

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Some still insist that the PID Controller entries in the .air file are somehow different than those equivalent entries in the aircraft.cfg file.Here then is the definitive answer to the issue, taken directly from the ESP1 SDK (which all know is simply FSX with the GUI removed):http://msdn.microsoft.com/en-us/library/cc526961.aspx
I do not agree. There was a previous thread on this subject in this forum in December. The quote you give here is the same as you gave then so what has changed? It was reported in that thread that changing these constants in the .cfg file had an observable effect. http://forums1.avsim.net/index.php?showtopic=236982The quotation is from the section of the SDK relating to the .air file However, as discussed previously, the section dealing with the .cfg file reads:"[autopilot]The following parameters determine the functionality of the aircraft

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I do not agree. There was a previous thread on this subject in this forum in December. The quote you give here is the same as you gave then so what has changed? It was reported in that thread that changing these constants in the .cfg file had an observable effect.
Did I state any differently?There are some who still believe that the .air file entries still have use in 'tuning' a user flown aircraft. This is false, as the SDK's statment makes clear.I am not in any way implying that the entries in the aircraft.cfg have no use for 'tuning' a user flown aircraft. The comments in the SDK as well as their use in the default aircraft.cfg files makes that clear.Once again you've read into what I've written something that simply isn't there.The only question then is why you're so intent in finding fault with whatever I write... :(

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You said:

Some still insist that the PID Controller entries in the .air file are somehow different than those equivalent entries in the aircraft.cfg file.
This has the nuance that Some still insist incorrectly... or despite being told otherwise. That is emphasised by including the word still, especialy as you did not mention the .cfg file.At least, there now seems to be agreement that the entries in the .air file are different than those equivalent entries in the aircraft.cfg file, and that .air file entries are used by AI aircraft and .cfg file entries by user-flown aircraft .

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The only autopilot section that in every aircraft that I see the effects in the cfg entry are the HDG ROLL RATE in 1199. changing from 530 (standard value in .air file) to 360 improves nav_proportional_control in cfg without changing the value in cfg.

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You said:This has the nuance that Some still insist incorrectly... or despite being told otherwise. That is emphasised by including the word still, especialy as you did not mention the .cfg file.
I didn't? What then -pray tell!- is that word (highlighted in red below) in the original sentence (which you even quoted)?"Some still insist that the PID Controller entries in the .air file are somehow different than those equivalent entries in the aircraft.cfg file."You are being deliberately obtuse...

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I didn't? What then -pray tell!- is that word (highlighted in red below) in the original sentence (which you even quoted)?"Some still insist that the PID Controller entries in the .air file are somehow different than those equivalent entries in the aircraft.cfg file."You are being deliberately obtuse...
You are correct. I should have said quoted the .cfg file.The substantive point is still that the PID Controller entries in the .air file are different to those equivalent entries in the aircraft.cfg file, despite your orginal obtuse statement.

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