On May 6 2013 6:59 PM, Kent A. Reed wrote: > On 5/6/2013 5:00 PM, EBo wrote: >> does anyone remember the paper that was posted to the group that >> measured the loss in torque as a function of speed and jitter? That >> might give us a more principled start to develop guidelines. As a >> note, >> when you get anywhere close to the jitter threshold the apparent >> acceleration/deceleration is greater than what the motor can handle. >> >> hope that helps. >> >> > > Ebo: > > You may be thinking of this 2001 SPIE paper: > > Frederick M. Proctor and William P. Shackleford, "Real-time Operating > System Timing Jitter and its Impact on Motor Control", Proceedings of > the SPIE Sensors and Controls for Intelligent Manufacturing II, Vol. > 4563, pp. 10-16, October 28, 2001. > > Nevermind the SPIE paywall. NIST provides a pdf copy at > http://www.nist.gov/customcf/get_pdf.cfm?pub_id=824455 > > This is the work I alluded to in my earlier email.
Kent, I do not think this is the paper I was thinking of as I remember several velocities plotted for each motor. That being said this is an excellent reference. It looks like ~7.6% loss in torque at full speed (900RPM) with a jitter as little as 3.6us. As a note, this speed is nearly 3 times as fast as I sketched out before, and from the note on the second motor that is going half the speed only looses half the equivelent torque. So, lets assume for the moment that is scales linearly (which is very doubtful, but at least it gives us a starting place). So, the same motor might experience a 23% loss of torque if the jitter is bumped to 10us, and on the order of 50% if it is bumped to 20us. If we ran some real tests and generated some graphs of power loss we could com up with some guidelines. Anyway,that is what I was thinking before reading the appropriate literature. I am sure that the details are a lot more involved and specifically nonlinear. ------------------------------------------------------------------------------ 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 [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
