[Flightgear-devel] Re: FCS normalization

2004-12-15 Thread Jon S Berndt
On Wed, 15 Dec 2004 14:51:07 -0500
 "Norman Vine" <[EMAIL PROTECTED]> wrote:
Jon S Berndt writes:
This is irrelevant, also - at least for JSBSim. 
That is an excellent observation
FGFS is more then JSBSim though :-)
Norman
Absolutely. And JSBSim is used by more than FlightGear - which leads 
to part of the concern I have. FlightGear should not require the FDM 
to massage values that it should be massaging itself.

Abstraction in object-oriented design has been referred to as the "the 
elimination of the irrelevant and the amplification of the essential". 
All FDMs I have worked with or am aware of (except, perhaps YASim) 
output control surface deflections in degrees, and for good reason: 
it's natural, it's physical. From the point of view of JSBSim, 
"normalized" aerosurface deflections are unnatural and irrelevant. The 
overhead and baggage code causes confusion and obfuscates the 
operation of flight control code. It clutters the code. I have no 
problem with FlightGear doing whatever it wants to with the values we 
send, but I remain skeptical about using "normalized" values as a 
"common transport device" for the actual physical value.

Jon
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[Flightgear-devel] Re: FCS normalization

2004-12-15 Thread Jon S Berndt
On Wed, 15 Dec 2004 14:51:07 -0500
 "Norman Vine" <[EMAIL PROTECTED]> wrote:
Jon S Berndt writes:
This is irrelevant, also - at least for JSBSim. 
That is an excellent observation
FGFS is more then JSBSim though :-)
Norman
Absolutely. And JSBSim is used by more than FlightGear - which leads 
to part of the concern I have. FlightGear should not require the FDM 
to massage values that it should be massaging itself.

Abstraction in object-oriented design has been referred to as the "the 
elimination of the irrelevant and the amplification of the essential". 
All FDMs I have worked with or am aware of (except, perhaps YASim) 
output control surface deflections in degrees, and for good reason: 
it's natural, it's physical. From the point of view of JSBSim, 
"normalized" aerosurface deflections are unnatural and irrelevant. The 
overhead and baggage code causes confusion and obfuscates the 
operation of flight control code. It clutters the code. I have no 
problem with FlightGear doing whatever it wants to with the values we 
send, but I remain skeptical about using "normalized" values as a 
"common transport device" for the actual physical value.

Jon
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