On 5/7/2013 5:53 AM, andy pugh wrote: > This models a linear dependency of delta-torque to delta-time, which > seems like it should break down at some point. Absolutely, just as the small-angle analysis of a pendulum begins to break down as the angle increases beyond 30deg-45deg, say. Fred and Will were just trying to estimate the size of the effect.
--- On 5/7/2013 12:50 AM, Michael Haberler wrote: > Note this does_not_ address the (IMO more interesting) question how latency > impacts 'path tracking quality' of a real and complete motion/pid etc servo > setup; that would be worth a separate attempt, probably more based on control > theory than measurements plus some verification I share your desire. Not knowing how the work would proceed, I thought a bit instead about how it would end. A full minute later I decided I also don't know how one would devise a quality metric which would be useful to prospective CNC system buyers/integrators. We constantly run into these problems in devising rating schemes for equipment. Consider vehicle fuel economy ratings. In the USA the EPA three-number scheme (city mileage/highway mileage/combined) is constantly attacked as hopelessly simplistic yet the next step up in sophistication seems to be hopelessly complicated to non-technical people. I participated peripherally in similar endless arguments during the 1980s concerning rating schemes for such mundane items as HVAC equipment, solar-energy collectors, and the like. I'm hoping that work proceeds along the lines that Michael has indicated and some wisdom emerges out of the thicket of results. Regards, Kent ------------------------------------------------------------------------------ Learn Graph Databases - Download FREE O'Reilly Book "Graph Databases" is the definitive new guide to graph databases and their applications. This 200-page book is written by three acclaimed leaders in the field. The early access version is available now. Download your free book today! http://p.sf.net/sfu/neotech_d2d_may _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
