I,m actually working on a unit to do exactly that Gene. Along with tool breakage sense Which is tending to be the pain, so I might make 2 units
Sarah Sent from BlueMail On 19 Oct 2016, 11:13, at 11:13, Gene Heskett <ghesk...@shentel.net> wrote: >On Wednesday 19 October 2016 01:01:18 Danny Miller wrote: > >> A friend showed me this today, not powered up yet: >> >> >https://www.kickstarter.com/projects/tropicallabs/mechaduino-powerful- >>open-source-industrial-servo-m >> >> At first I was confused, it says it's a stepper, but with an encoder, >> and lowers or disables drive current when not needed. Or you can >> freewheel it and it'll maintain the coordinate system. It cannot >> stall without the system knowing, and a stall won't corrupt the >> coordinate system. >> >> But there's no mechanical connection to the motor, it's this new >> AS5047D high speed, high resolution magnetic rotary position sensor: >> >> >http://ams.com/eng/Products/Magnetic-Position-Sensors/Angle-Position-O >>n-Axis/AS5047D >> >> You glue a magnet to the rear of the motor shaft, and keep the sensor >> like 1/4" away. Note it not only counts delta, it knows absolute >> rotor position. >> >> Gives 2000 counts/rev. That's enough that it could effectively show >> rotor phase through a single fullstep, which would allow for more >> stable electrical control of stepping. There's an initial >calibration >> phase that drives a phase so it knows where the TDC of Coil A is in >> absolute position. >> >> They set it up so it powers down and freewheels, except it will hold >> its position by powering coils when needed. It can also reduce >> current to product only the torque needed to follow the step >commands, >> instead of always operating at full current. >> >> Well, my mind is blown! >> >> Danny >> >That does indeed sound very handy for stepper users. But the sensor >magnet I do not envision as being on the motor, but on the ends of the >screws driving the machine. That will give 16,383 discrete positions of > >the screw per revolution of the screw, irrespective of any stepdowns >from belt drives etc between the motor and the screw. I did not see a >price for the completed board and magnet, just for the AMS device. >Ahh, >did find it on the pre-order button, $47 a copy for version 0.1. > >Did anyone else? If not too outrageous, I might be interested in a pair > >of them to put on this Sheldon conversion as a test bed. But I'll do >the >conventional way first & see where it falls over. > >What I would really like to see would be a light beam that a tool could > >be advanced into in order to both adjust the tool tip height, and set >the tools zero radius offset. Something whose shadow could be detected >by a 4 cell photodetector in the tailstock socket. Or even a low res >cmos imager would suffice for the detector. Almost anything to get us >into the +- .005" range for a first pass calibration cut. > >Comments? Gotchas? > >Cheers, Gene Heskett >-- >"There are four boxes to be used in defense of liberty: > soap, ballot, jury, and ammo. Please use in that order." >-Ed Howdershelt (Author) >Genes Web page <http://geneslinuxbox.net:6309/gene> > >------------------------------------------------------------------------------ >Check out the vibrant tech community on one of the world's most >engaging tech sites, SlashDot.org! http://sdm.link/slashdot >_______________________________________________ >Emc-users mailing list >Emc-users@lists.sourceforge.net >https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
