Peter C. Wallace wrote: > > > One good sanity check on the velocity output is to setup your hardware step > generator for quadrature mode and set a constant velocity but randomly > changing directions(and ~infinite acceleration). Another good test is just a > slow velocity ramp. The advantage is the the hardware doesnt have the quirks > of a real encoder/motor. For example, quadrature phase error (signals not at > exact 90 degrees) will limit the improvement that a simple, all edge time > stamp can bring. > But, I WANT to see how it responds to all the vagaries of real encoders, especially dither and the quantizing noise. I was comparing against the software encoder component reading my MPG, with detents. I observed the phase error effect as the detents in the MPG severely affected the quadrature phasing. By gripping the knob tightly in my clenched fist I got most of the detent effect to disappear. That was an interesting effect to observe.
The software scheme that I copied has different modes depending on whether a count was recorded in the last servo cycle or not. I'm not convinced the code I produced is correctly blending between the two. I THINK I have checked all the scaling factors on paper and they seem to be right. But, at certain speeds, the velocity estimate seems to be jumpier than it should be. This could be the effect of the servo that is driving the encoder, I will have to back off on the servo tuning and see if it looks better. Jon ------------------------------------------------------------------------------ Nokia and AT&T present the 2010 Calling All Innovators-North America contest Create new apps & games for the Nokia N8 for consumers in U.S. and Canada $10 million total in prizes - $4M cash, 500 devices, nearly $6M in marketing Develop with Nokia Qt SDK, Web Runtime, or Java and Publish to Ovi Store http://p.sf.net/sfu/nokia-dev2dev _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
