On Tuesday 09 Mar 2010, Curtis Olson wrote: > On Tue, Mar 9, 2010 at 12:15 PM, Torsten Dreyer wrote: > > Hi, > > > > I am about to commit a change that adds anti windup logic to > > the pi-simple- controller (FGPISimpleController) which > > currently lacks such functionality. > > > > The FGPIDController has some anti windup logic but that > > controller does not suit very well for some solutions and one > > might (I do) want to use the pi- simple-controller instead, if > > this just had some anti windup. > > > > My question is: should I add a switch to make the > > pi-simple-controller behave > > like it currently does, e.g. add something like > > <anti-windup>true</anti-windup> > > and default that switch to 'false'? > > This should be a good idea if some autopilots relied on wound > > up PISimpleController. Or is it oversized > > backwards-compatibility? I can't imagine a single case where > > wind-up is a good idea - but who knows... > > > > Comments? > > Torsten > > > > BTW. the patch is really simple: > > double output = prop_comp + int_sum; > > - output = clamp( output ); > > - set_output_value( output ); > > + double clamped_output = clamp( output ); > > + if( output != clamped_output ) // anti-windup > > + int_sum = clamped_output - prop_comp; > > + > > + set_output_value( clamped_output ); > > Speaking as the author of the original PISimpleController code I > think some anti-windup logic would be a good additive feature. I > don't think we would need a switch to maintain the old behavior > (unless we want to demonstrate to someone why anti-windup is a > good idea ... but in that case, the switch should be to turn it > off, not turn it on.)
[snip...] > > Regards, > > Curt. As this would be a new feature, and one which might affect existing behaviours, I _really_ think it ought to be off by default. Turning it on by default is almost guaranteed to break something, whereas because it is new nothing will be currently using it - this just seems a bit silly to me. LeeE ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
