On Thu, 3 May 2012 12:27:21 +0200 Lars Segerlund <lars.segerl...@gmail.com> wrote:
> I meant LVDT ! ....... sorry ! > > / Lars.... > > 2012/5/3 Lars Segerlund <lars.segerl...@gmail.com>: > > Buy some on sparkfun or similar, with the righte G force range, > > thera are a lot of them, and hooking one up on SPI or i2c is not > > complicated. > > > > The sensors for airbags are probably not right ... > > > > The DIY robotics guys use them a lot as far as I can understand. > > > > It will be a bugger to read though ....since you have machine > > vibration, tool acceleration and the stiffness of the machine ( > > resonance ? ) ... > > Check out Variax solution .... laser measurement in realtime of the > > lenght and deformations in the frame :-D ..... Coooool ...... > > > > I was thinking that hooking up a LIM or similar to a reference > > outside the machine might give better readings ? and simpler signal > > handling, since it gives absolute position ... > > It's not uncommon to have a LIM system with amplifiers lying > > around a machine shop . > > > > / regards, Lars Segerlund. > > > > > > 2012/5/3 EBo <e...@sandien.com>: > >> On Thu, 3 May 2012 12:39:15 +0300, Anders Wallin wrote: > >>>>> The spectrum is so full of noise all the way up and beyond the > >>>>> range > >>>>> of the chart, that it has to be measured on some kind of > >>>>> machine. Jon > >>>> I found the source of this pictures: > >>>> http://www.mmrc.iss.ac.cn/~xgao/papernc/jounce20111122.pdf > >>>> And I am not sure what was measured. From this motion > >>>> profile (0.1 to 0.2 s time to reach max. velocity) > >>>> I do not expect frequency components in the > >>>> 800 to 1200 Hz range. > >>>> Another point is that the spectrum does not look alike sinc. > >>>> But I may be totally wrong. > >>> > >>> The authors of that paper are not very clear on what exactly was > >>> measured, but I am sure it is not just an fft of the > >>> velocity-profile. > >>> Rather is a vibration measurement from somewhere on the machine. > >>> As such it might have components from the spindle, servo-drive, > >>> etc. > >>> > >>> If someone really wanted to get into this on a hobby level there > >>> might > >>> be acceleration-sensors (made for e.g. airbag-triggers on cars) > >>> which could be used? > >>> Simply HAL-scoping commanded/actual position and maybe looking at > >>> their spectra might be a good start too. > >> > >> Actually a high end smart phone with the new fancy nano gyros + > >> accelerometers might just do the trick. I think the first thing I'd try would be a mirror on the machine and a laser at an angle. The trick will be a sensor with enough sensitivity to get good signals. First step might be audio output, the ear is pretty good at frequencies a machine is likely to vibrate out. Just thinking out of the box. Dave > >> > >> ------------------------------------------------------------------------------ > >> Live Security Virtual Conference > >> Exclusive live event will cover all the ways today's security and > >> threat landscape has changed and how IT managers can respond. > >> Discussions will include endpoint security, mobile security and > >> the latest in malware threats. > >> http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ > >> _______________________________________________ Emc-developers > >> mailing list Emc-developers@lists.sourceforge.net > >> https://lists.sourceforge.net/lists/listinfo/emc-developers > > ------------------------------------------------------------------------------ > Live Security Virtual Conference > Exclusive live event will cover all the ways today's security and > threat landscape has changed and how IT managers can respond. > Discussions will include endpoint security, mobile security and the > latest in malware threats. > http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ > _______________________________________________ Emc-developers > mailing list Emc-developers@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-developers ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
