James Turner wrote: > On 9 Sep 2009, at 03:01, dave perry wrote: > > >> Sorry, I misunderstood you concerning the animation edits. I will be >> glad to help with the xml edits and testing. Getting rid of the >> spurious 5x for the glide scope and adding the clamps is a good idea >> and >> adding the normalized CDI and GS could make the animators job >> easier. I >> will start by changing the vor.xml and vor2.xml in Instruments-3D that >> are used in the pa24 and pa28 and perhaps several other AC. >> > > I've already changed various aircraft locally, for testing: > > - the generic 2D and 3D instruments > - the Seneca, B1900d, 747-400, C172P and Aerostar > - the Primus-1000 suite > > I don't claim to have done this 100% correctly yet - especially, I > need to convince myself the that GS-ARM modes of the various > autopilots (eg, the KAP-140 in the default C172) are behaving > correctly, since this is generally implemented as Nasal scripts > testing the GS needle deflection. > > One area I do need help with is the autopilot PID laws: eg, here's the > relevant chunk for the B1900d: > > <pid-controller> > <name>Glideslop Hold</name> > <input> > <prop>instrumentation/nav/gs-needle-deflection-norm</prop> > </input> > <reference> > <value>0</value> > </reference> > <output> > <prop>autopilot/settings/target-pitch-deg</prop> > </output> > <config> > <Kp>-1.5</Kp> > <beta>1.0</beta> > <alpha>0.1</alpha> > <gamma>0.0</gamma> > <Ti>10.0</Ti> > <Td>0.0</Td> > <u_min> > <value>-10</value> > </u_min> > <u_max> > <value>5</value> > </u_max> > </config> > </pid-controller> > > Since I've switched the input to be the normalised prop, we've gone > from a unclamped input (swinging from sometimes -60 to 60!) to one > which is much 'smaller' in magnitude and clamped to [-1 .. 1]. I > *guess* the fix will be to increase the gain on the PID, otherwise GS > hold will tend to lag, but that's about the total of my knowledge of > tweaking the PIDs. > > > I have updated and tested the vor.xml, vor2.xml in Instruments-3D/vor as well as the century3.nas in Aircraft/Generic and the corresponding PID controllers. I will do the same for the AltimaticIIIC used in the SenecaII as I wrote the CenturyIII and AltimaticIIIC nasal and PID's which are very similar to the CenturyIII. I think we will have to change all the nasal GS arm entries. I also am familiar with the kap140 nasal, so I will update that also. I have found that the parameters in the PID controllers need to be optimised for each aircraft as the plant changes with a change in flight model optimisation. I am not using the normalized property. This made increasing the proportional gain <kp> by 5x a very good starting point for re-optimization. I will re-optimize the Cessna 172 PID file.
None of the above has been committed to CVS. Shall I send the diffs to you James for committing. Dave P ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
