Re: [Emc-users] Mill-Drill needs steppers and servos?
On Thu, Jun 04, 2009 at 09:42:21AM -0700, Dave Engvall wrote: > It may be possible to get more bang for your buck by purchasing a > better ball screw ( ebay or HIWin). Thank you for that. I'm not sure that I'd trust ebay on duch products, unless it's a recognised vendor using that means to advertise a warranted product. > On Jun 4, 2009, at 8:26 AM, Kirk Wallace wrote: > > Backlash compensation can improve your initial position, > > but the table or spindle can still have uncontrolled movement with > > in the backlash. With servos you can move the feedback closer to the > > cutter by having a linear scale on the table, but the backlash > > movement can be hard for the feedback system to deal with. ... > > Bottom line: steppers or servos, get rid of as much backlash as > > possible. (Has anyone used Turcite or other on leadscrews? > > http://www.moglice-turcite.com/ ) Ah, it's off with the quill feed pinion, capstan, and fine feed worm then, unless milling the 3 bolt holes to slots will allow the pinion to slip into pefect mesh with the rack on the quill. There's then room to fit a vertical ballscrew, clamped externally to the quill nose. It would only be 3-4 cm to the right of the quill circumference, but that would be about 8cm (3") from the quill centre. Yes, stopping to think it through, with the encoder on the motor or leadscrew, backlash after that isn't a feedback issue. > > One thing I have been thinking about recently is to make up an > > over-sized motor mounted so that I can measure torque, speed, > > voltage and current, mount it to the axis in question, run it > > through its paces, then use this data to determine how much smaller > > the real motor system can be. Yes, yes, yes! Maybe if I stop lazily looking for a motor with mounted encoder, instead fitting an encoder to the leadscrew, I can initially try the motors that I have, to sneak up on a solution. (A quick lash-up, mounted on the table T-slots, with the belt over the end, would suffice for a few laps of the pool.) > > Determine what is the single most objectionable issue and chose the > > shortest path to making it better. I often try to make something > > perfect on the first pass and end up doing something different in > > the long run, so jury rigging to prove a design may be a good thing. Yes, it is just that kind of analysis paralysis which results from having a purely manual machine, and thus no quantitative starting point for the conversion. I have some 100W and 300W motors, which will at least provide points from which to extrapolate. > > my2c But worth a great deal more than that! :-) -- I have yet to see any problem, however complicated, which, when you looked at it in the right way, did not become still more complicated. -- Poul Anderson -- OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] EMC slowing down after large program
Michael Jones wrote: > Rob, > > I've been noticing the same thing lately. Very similar hardware > setup.. very similar symptoms after a gcode file of about 20,000 lines > (fine line engraving). > > Has anyone seen anything like this? Is there a solution? > > Several people have reported such behavior in the last couple months. There may have been a recent update to Axis that may help this situation. I have a torture test program that commands a 2" diameter circle made up of 1 G01 moves at 60 IPM. The first time I run it, it often runs fine, after that it suffers motion queue starvation and begins to run in spurts and pauses. I'm not sure this is the same problem. I really ought to run this with TkEMC and see if there is a difference. The computer is a 600 MHz Pentium, so at the bottom range of CPUs, today. Jon -- OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Mill-Drill needs steppers and servos?
Dave Engvall wrote: > If you look at emc1 .ini files they had a set of parameters for at > least some of the > factors affecting axis motion. I think something was supposed to use > them to model > motion on the axis. I don't know it that ever worked. Maybe Ray H or > Matt S. can elucidate. > > All that motor inductance stuff, etc. was for a totally separate simulator that would generate predicted performance, assuming all your values were correct. I've never seen that simulator, so it wasn't distributed with the original NIST EMC. Jon -- OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] EMC slowing down after large program
Rainer, I am more talking in the range of 650.000 lines.so about 40 times as big as the program you tested. l am milling Large molds with high precision resulting in these very large programs. Rob Rainer Schmidt wrote: > 15K lines with 6 subsequent runs without exit or reboot and no issues... > I recommend stopping to watch THOSE movies while engraving ;) > Rainer > > > On Thu, Jun 4, 2009 at 12:43 PM, Michael Jones > wrote: > >> Rob, >> >> I've been noticing the same thing lately. Very similar hardware >> setup.. very similar symptoms after a gcode file of about 20,000 lines >> (fine line engraving). >> >> Has anyone seen anything like this? Is there a solution? >> >> - Michael >> -- OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] EMC slowing down after large program
Rainer, I am more talking in the range of 650.000 lines.so about 40 times as big as the program you tested. l am milling Large molds with high precision resulting in these very large programs. Rob Rainer Schmidt wrote: > 15K lines with 6 subsequent runs without exit or reboot and no issues... > I recommend stopping to watch THOSE movies while engraving ;) > Rainer > > > On Thu, Jun 4, 2009 at 12:43 PM, Michael Jones > wrote: > >> Rob, >> >> I've been noticing the same thing lately. Very similar hardware >> setup.. very similar symptoms after a gcode file of about 20,000 lines >> (fine line engraving). >> >> Has anyone seen anything like this? Is there a solution? >> >> - Michael >> -- OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Mill-Drill needs steppers and servos?
On Thu, 2009-06-04 at 09:42 -0700, Dave Engvall wrote: ... snip > > Direct engineering measurements are always nice but may not transfer > well to other machines. ... snip The plan was to have the test rig generic enough so it could be connected to each axis for each machine. The only part of the axis that would not be measured would be the final motor and driver. Without actually measuring how all of the axis parts perform together, its really just a guess. After my machines are done, I might be willing to ship the test rig to anyone wanting to figure out what size motors are needed for their new conversion, assuming I actually get something done. -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA -- OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] EMC slowing down after large program
Michael, Michael Jones wrote: > Rob, > > I've been noticing the same thing lately. Very similar hardware > setup.. very similar symptoms after a gcode file of about 20,000 lines > (fine line engraving). > > Has anyone seen anything like this? Is there a solution? > > - Michael I would run a script under cron to log a sample of system performance parameters into a file. Cron job would need to be set depending on how fast your system gets into "slow state." Programs to use are: vmstat, iostat, mpstat, and possibly others. You might need to install package sysstat. sysstat - sar, iostat and mpstat - system performance tools for Linux There is a sample of a script I successfully used in the past: http://www.linwin.com/sysadmin/bin/systat . Need to modify it for your particular use. I'm not sure at this point if RT kernel has other more suitable utilities to check it's performance. You can also change the script to run from a command line just before you start EMC. Script would run commands in the loop with a sleep of few seconds in between. Put the script in the background or open another terminal to monitor it's log file. Add gplot to get graphical output. Additionally you might want to check log files in /var/log directory. -- Rafael -- OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] EMC slowing down after large program
Hmm.. I didn't think THOSE movies would have such an impact ;-) On Jun 4, 2009, at 9:52 AM, Rainer Schmidt wrote: > 15K lines with 6 subsequent runs without exit or reboot and no > issues... > I recommend stopping to watch THOSE movies while engraving ;) > Rainer > > > On Thu, Jun 4, 2009 at 12:43 PM, Michael Jones > wrote: >> Rob, >> >> I've been noticing the same thing lately. Very similar hardware >> setup.. very similar symptoms after a gcode file of about 20,000 >> lines >> (fine line engraving). >> >> Has anyone seen anything like this? Is there a solution? >> >> - Michael >> >> >> On May 23, 2009, at 12:33 AM, Rob Jansen wrote: >> >>> Hi all, >>> >>> I am not sure if it is just me or my Linux machine but I have a >>> problem >>> that looks like memory leaks or something like this. >>> >>> After running a very large G-code program (like 655,000 lines of >>> code, >>> 14 MB filesize) EMC becomes real slow. A clear live plot (ctrl-K) >>> does >>> not help but after shutting down EMC and restarting again the >>> behaviour >>> is as expected. With real slow I mean that it takes 1 - 2 seconds >>> before >>> EMC responds on keypresses to move an axis. In a normal situation >>> the >>> response is instantaneous and a short push on the page up key moves >>> the >>> Z-axis a bit (1 mm or so) but after running a large program a short >>> press on page up results in a Z-axis move of 50 - 100mm. >>> I tried both the clear live plot and loading another (small, few >>> lines >>> of code) G-code file but that does not help. >>> Stopping and restarting EMC helps, then the system is in 'normal >>> mode' >>> again. >>> >>> The machines is a 1.8 GHz intel and has (only) 1 GB of memory >>> available. >>> I do see that there is about 1 MB of swap space being used but I >>> cannot >>> relate this to these slow response times. >>> >>> Regards, >>> >>>Rob >>> >>> -- >>> Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT >>> is a gathering of tech-side developers & brand creativity >>> professionals. Meet >>> the minds behind Google Creative Lab, Visual Complexity, >>> Processing, & >>> iPhoneDevCamp asthey present alongside digital heavyweights like >>> Barbarian >>> Group, R/GA, & Big Spaceship. http://www.creativitycat.com >>> ___ >>> Emc-users mailing list >>> Emc-users@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/emc-users >> >> >> -- >> OpenSolaris 2009.06 is a cutting edge operating system for >> enterprises >> looking to deploy the next generation of Solaris that includes the >> latest >> innovations from Sun and the OpenSource community. Download a copy >> and >> enjoy capabilities such as Networking, Storage and Virtualization. >> Go to: http://p.sf.net/sfu/opensolaris-get >> ___ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> > > > > -- > _ > Rainer M. Schmidt > Complex Consulting LLC > b...@complexllc.com > Mob (646)-275-0296 > VoIP (646)-233-1002 > FAX (646)-435-9216 > > -- > OpenSolaris 2009.06 is a cutting edge operating system for enterprises > looking to deploy the next generation of Solaris that includes the > latest > innovations from Sun and the OpenSource community. Download a copy and > enjoy capabilities such as Networking, Storage and Virtualization. > Go to: http://p.sf.net/sfu/opensolaris-get > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users -- OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] EMC slowing down after large program
15K lines with 6 subsequent runs without exit or reboot and no issues... I recommend stopping to watch THOSE movies while engraving ;) Rainer On Thu, Jun 4, 2009 at 12:43 PM, Michael Jones wrote: > Rob, > > I've been noticing the same thing lately. Very similar hardware > setup.. very similar symptoms after a gcode file of about 20,000 lines > (fine line engraving). > > Has anyone seen anything like this? Is there a solution? > > - Michael > > > On May 23, 2009, at 12:33 AM, Rob Jansen wrote: > >> Hi all, >> >> I am not sure if it is just me or my Linux machine but I have a >> problem >> that looks like memory leaks or something like this. >> >> After running a very large G-code program (like 655,000 lines of code, >> 14 MB filesize) EMC becomes real slow. A clear live plot (ctrl-K) does >> not help but after shutting down EMC and restarting again the >> behaviour >> is as expected. With real slow I mean that it takes 1 - 2 seconds >> before >> EMC responds on keypresses to move an axis. In a normal situation the >> response is instantaneous and a short push on the page up key moves >> the >> Z-axis a bit (1 mm or so) but after running a large program a short >> press on page up results in a Z-axis move of 50 - 100mm. >> I tried both the clear live plot and loading another (small, few lines >> of code) G-code file but that does not help. >> Stopping and restarting EMC helps, then the system is in 'normal mode' >> again. >> >> The machines is a 1.8 GHz intel and has (only) 1 GB of memory >> available. >> I do see that there is about 1 MB of swap space being used but I >> cannot >> relate this to these slow response times. >> >> Regards, >> >> Rob >> >> -- >> Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT >> is a gathering of tech-side developers & brand creativity >> professionals. Meet >> the minds behind Google Creative Lab, Visual Complexity, Processing, & >> iPhoneDevCamp asthey present alongside digital heavyweights like >> Barbarian >> Group, R/GA, & Big Spaceship. http://www.creativitycat.com >> ___ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users > > > -- > OpenSolaris 2009.06 is a cutting edge operating system for enterprises > looking to deploy the next generation of Solaris that includes the latest > innovations from Sun and the OpenSource community. Download a copy and > enjoy capabilities such as Networking, Storage and Virtualization. > Go to: http://p.sf.net/sfu/opensolaris-get > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- _ Rainer M. Schmidt Complex Consulting LLC b...@complexllc.com Mob (646)-275-0296 VoIP (646)-233-1002 FAX (646)-435-9216 -- OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] EMC slowing down after large program
Rob, I've been noticing the same thing lately. Very similar hardware setup.. very similar symptoms after a gcode file of about 20,000 lines (fine line engraving). Has anyone seen anything like this? Is there a solution? - Michael On May 23, 2009, at 12:33 AM, Rob Jansen wrote: > Hi all, > > I am not sure if it is just me or my Linux machine but I have a > problem > that looks like memory leaks or something like this. > > After running a very large G-code program (like 655,000 lines of code, > 14 MB filesize) EMC becomes real slow. A clear live plot (ctrl-K) does > not help but after shutting down EMC and restarting again the > behaviour > is as expected. With real slow I mean that it takes 1 - 2 seconds > before > EMC responds on keypresses to move an axis. In a normal situation the > response is instantaneous and a short push on the page up key moves > the > Z-axis a bit (1 mm or so) but after running a large program a short > press on page up results in a Z-axis move of 50 - 100mm. > I tried both the clear live plot and loading another (small, few lines > of code) G-code file but that does not help. > Stopping and restarting EMC helps, then the system is in 'normal mode' > again. > > The machines is a 1.8 GHz intel and has (only) 1 GB of memory > available. > I do see that there is about 1 MB of swap space being used but I > cannot > relate this to these slow response times. > > Regards, > >Rob > > -- > Register Now for Creativity and Technology (CaT), June 3rd, NYC. CaT > is a gathering of tech-side developers & brand creativity > professionals. Meet > the minds behind Google Creative Lab, Visual Complexity, Processing, & > iPhoneDevCamp asthey present alongside digital heavyweights like > Barbarian > Group, R/GA, & Big Spaceship. http://www.creativitycat.com > ___ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users -- OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Mill-Drill needs steppers and servos?
On Jun 4, 2009, at 8:26 AM, Kirk Wallace wrote: > On Thu, 2009-06-04 at 23:04 +1000, Erik Christiansen wrote: >> The mill-drill which I'm starting to convert to CNC has 0.2mm >> (0.008") >> backlash in the Z feed, making it a much better candidate for stepper >> control than servo, IIUC. There is though, sufficient in-built upward >> spring-loading for the quill to retract if the feed worm is >> disengaged. >> I wonder if that would permit servo control, without hunting? >> >> My brand new rotary table has almost 0.1° backlash, so I guess it >> has to >> be a stepper axis? > > In my opinion, the biggest issue with backlash has nothing to do with > the type of axis motor system. The problem is that your axis control > will put your table or spindle into position, you will start or change > your cut direction and the cutting forces will cause an uncontrolled > movement within the backlash, which the motor controller will usually > never see. Backlash compensation can improve your initial position, > but > the table or spindle can still have uncontrolled movement with in the > backlash. With servos you can move the feedback closer to the > cutter by > having a linear scale on the table, but the backlash movement can be > hard for the feedback system to deal with. IIRC JMK did a configuration for Stuart (MPM) which used a linear scale connected to the I in PID This drove final position. That said a linear scale when used alone on systems with backlash are difficult to tune. In addition the expense counts up quickly. Ask me how I know. ;-) It may be possible to get more bang for your buck by purchasing a better ball screw ( ebay or HIWin). > > Bottom line: steppers or servos, get rid of as much backlash as > possible. (Has anyone used Turcite or other on leadscrews? > http://www.moglice-turcite.com/ ) > >> It's a 970 kg machine, with a 1m long table, so even when I stump >> up for >> ballscrews, the thought of trying to drive X and Y with steppers is >> daunting, and I fear lost steps, so expect I'll have to go with >> servos >> there. > > I'm not a stepper fan, but they work well (not fast) on my Shizuoka: > http://www.wallacecompany.com/machine_shop/Shizuoka/00018-1a.jpg > http://www.wallacecompany.com/machine_shop/Shizuoka/ > > Both steppers and servos will miss steps or trip a following error if > overloaded. The key here is to size the axis motor system to fit the > load. Trying to evaluate the load is the hard part, which I haven't > figured out yet. It may be best to look at a similar machine that is > proven to work well and copy it. One thing I have been thinking about > recently is to make up an over-sized motor mounted so that I can > measure > torque, speed, voltage and current, mount it to the axis in question, > run it through its paces, then use this data to determine how much > smaller the real motor system can be. If you look at emc1 .ini files they had a set of parameters for at least some of the factors affecting axis motion. I think something was supposed to use them to model motion on the axis. I don't know it that ever worked. Maybe Ray H or Matt S. can elucidate. Direct engineering measurements are always nice but may not transfer well to other machines. > >> I've found some servos with attached encoders here: >> >> http://www.oceancontrols.com.au/motors/servo/servo_motors.htm >> >> but they look rather wimpy. On the other hand, I'd be amazed if I was >> outputting 150W when doing manual rapids, even with the acme >> leadscrew. >> Add some HTD pulleys, to increase the torque, and take what rapids I >> get, maybe? At least the motor compares favourably with the one Kirk >> found recently: >> >> http://www.cadcamcadcam.com/motorservoglobepm-dc.aspx >> >> giving 3.5 times the torque at 2800 RPM. Now, if only the >> appreciating >> A$ had brought the local price down. >> >> Erik > > If budget is the primary problem, I would try to make what you already > have work better, or buy what whatever is least expensive and will > still > work well enough, steppers or servos. Look at what other people are > throwing out and consider how parts might be used for a CNC. Determine > what is the single most objectionable issue and chose the shortest > path > to making it better. I often try to make something perfect on the > first > pass and end up doing something different in the long run, so jury > rigging to prove a design may be a good thing. > > my2c > > -- > Kirk Wallace > http://www.wallacecompany.com/machine_shop/ > http://www.wallacecompany.com/E45/index.html > California, USA > > > -- > > OpenSolaris 2009.06 is a cutting edge operating system for enterprises > looking to deploy the next generation of Solaris that includes the > latest > innovations from Sun and the OpenSource community. Download a copy and > enjoy capabilities such as Networking, Storage and Virtu
Re: [Emc-users] Mill-Drill needs steppers and servos?
On Thu, 2009-06-04 at 23:04 +1000, Erik Christiansen wrote: > The mill-drill which I'm starting to convert to CNC has 0.2mm (0.008") > backlash in the Z feed, making it a much better candidate for stepper > control than servo, IIUC. There is though, sufficient in-built upward > spring-loading for the quill to retract if the feed worm is disengaged. > I wonder if that would permit servo control, without hunting? > > My brand new rotary table has almost 0.1° backlash, so I guess it has to > be a stepper axis? In my opinion, the biggest issue with backlash has nothing to do with the type of axis motor system. The problem is that your axis control will put your table or spindle into position, you will start or change your cut direction and the cutting forces will cause an uncontrolled movement within the backlash, which the motor controller will usually never see. Backlash compensation can improve your initial position, but the table or spindle can still have uncontrolled movement with in the backlash. With servos you can move the feedback closer to the cutter by having a linear scale on the table, but the backlash movement can be hard for the feedback system to deal with. Bottom line: steppers or servos, get rid of as much backlash as possible. (Has anyone used Turcite or other on leadscrews? http://www.moglice-turcite.com/ ) > It's a 970 kg machine, with a 1m long table, so even when I stump up for > ballscrews, the thought of trying to drive X and Y with steppers is > daunting, and I fear lost steps, so expect I'll have to go with servos > there. I'm not a stepper fan, but they work well (not fast) on my Shizuoka: http://www.wallacecompany.com/machine_shop/Shizuoka/00018-1a.jpg http://www.wallacecompany.com/machine_shop/Shizuoka/ Both steppers and servos will miss steps or trip a following error if overloaded. The key here is to size the axis motor system to fit the load. Trying to evaluate the load is the hard part, which I haven't figured out yet. It may be best to look at a similar machine that is proven to work well and copy it. One thing I have been thinking about recently is to make up an over-sized motor mounted so that I can measure torque, speed, voltage and current, mount it to the axis in question, run it through its paces, then use this data to determine how much smaller the real motor system can be. > I've found some servos with attached encoders here: > > http://www.oceancontrols.com.au/motors/servo/servo_motors.htm > > but they look rather wimpy. On the other hand, I'd be amazed if I was > outputting 150W when doing manual rapids, even with the acme leadscrew. > Add some HTD pulleys, to increase the torque, and take what rapids I > get, maybe? At least the motor compares favourably with the one Kirk > found recently: > > http://www.cadcamcadcam.com/motorservoglobepm-dc.aspx > > giving 3.5 times the torque at 2800 RPM. Now, if only the appreciating > A$ had brought the local price down. > > Erik If budget is the primary problem, I would try to make what you already have work better, or buy what whatever is least expensive and will still work well enough, steppers or servos. Look at what other people are throwing out and consider how parts might be used for a CNC. Determine what is the single most objectionable issue and chose the shortest path to making it better. I often try to make something perfect on the first pass and end up doing something different in the long run, so jury rigging to prove a design may be a good thing. my2c -- Kirk Wallace http://www.wallacecompany.com/machine_shop/ http://www.wallacecompany.com/E45/index.html California, USA -- OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] ld: no input files
Dear sir: Firstly, thank you Jeff! The following is the content in the file src/objects/hal/components/abs.mak abs-objs := objects/hal/components/abs.o ../rtlib/abs.ko: objects/rtobjects/hal/components/abs.o Now the error is disappeared. 在2009-06-02，"Jeff Epler" 写道： >I could cause the exact error you showed by corrupting the file >src/objects/hal/components/abs.mak, but never in normal circumstances. > >What is in your file src/objects/hal/components/abs.mak, which is >created by the build process? > >Jeff > >-- >OpenSolaris 2009.06 is a cutting edge operating system for enterprises >looking to deploy the next generation of Solaris that includes the latest >innovations from Sun and the OpenSource community. Download a copy and >enjoy capabilities such as Networking, Storage and Virtualization. >Go to: http://p.sf.net/sfu/opensolaris-get >___ >Emc-users mailing list >Emc-users@lists.sourceforge.net >https://lists.sourceforge.net/lists/listinfo/emc-users -- OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Mill-Drill needs steppers and servos?
The mill-drill which I'm starting to convert to CNC has 0.2mm (0.008") backlash in the Z feed, making it a much better candidate for stepper control than servo, IIUC. There is though, sufficient in-built upward spring-loading for the quill to retract if the feed worm is disengaged. I wonder if that would permit servo control, without hunting? My brand new rotary table has almost 0.1° backlash, so I guess it has to be a stepper axis? It's a 970 kg machine, with a 1m long table, so even when I stump up for ballscrews, the thought of trying to drive X and Y with steppers is daunting, and I fear lost steps, so expect I'll have to go with servos there. I've found some servos with attached encoders here: http://www.oceancontrols.com.au/motors/servo/servo_motors.htm but they look rather wimpy. On the other hand, I'd be amazed if I was outputting 150W when doing manual rapids, even with the acme leadscrew. Add some HTD pulleys, to increase the torque, and take what rapids I get, maybe? At least the motor compares favourably with the one Kirk found recently: http://www.cadcamcadcam.com/motorservoglobepm-dc.aspx giving 3.5 times the torque at 2800 RPM. Now, if only the appreciating A$ had brought the local price down. Erik -- OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
Re: [Emc-users] Different structures PD IPD... Robust control
On Thu, Jun 04, 2009 at 01:15:01PM +0200, Jasiel Nájera wrote: > Hello to everybody. > > My questions are: > > 1- Is it posible to implement other types of controllers instead of PID? >If so, have some of you already done something regarding this? > I'm thinking on designing a compesator with QFT Robust Control, but the > problem is that the only compensator structure I find is PID, neither PI-D. If you want another kind of "controller", write it as a HAL realtime component. About the syntax of comps: http://linuxcnc.org/docview/html/hal_comp.html About compiling your own comps on your own system (section 1.3) http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?ContributedComponents I am not familiar with the specifics of "QFT Robust Control", but the emc motion controller really works very simply when it comes to commanding motor positions: Every servo period (typically 1ms) the realtime motion controller reads the motor's feedback position (e.g., from axis.0.motor-pos-fb) and if it is too far from the commanded position, it signals an error. then it computes a new commanded motor position and outputs it (e.g., on axis.0.motor-pos-cmd). What is done after this depends on the type of systems: on simulated systems without real hardware, motor-pos-cmd is simply connected to motor-pos-fb. On stepper systems, a pretuned loop uses velocity and error to control a frequency generator; the new feedback position is the old position plus the number of steps generated during the last period. On a PID servo system the command and feedback are used to compute a value that goes to a servo amplifier. Based on the little bit about QFT I could find not behind a paywall, it sounds like it's broadly similar to PID in terms of its inputs and outputs (but different in terms of the tuning parameters and computation method); if you understand the QFT algorithm then it's mostly a matter of transcribing the algorithm in to the subset of C that is available for realtime components, arranging for the tuning parameters to be set, and modifying a PID-servo hal configuration to use QFT instead of PID. We'd be interested in hearing about your results. Jeff -- OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] HighPoint RocketRAID 133
Does anyone know if HighPoint RocketRAID 133 is already supported in EMC or kernel together with drivers must be rebuild? -- OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
[Emc-users] Different structures PD IPD... Robust control
Hello to everybody. My questions are: 1- Is it posible to implement other types of controllers instead of PID? If so, have some of you already done something regarding this? I'm thinking on designing a compesator with QFT Robust Control, but the problem is that the only compensator structure I find is PID, neither PI-D. If it's not posible to do it now and some of you is interested in developing this in EMC contact me. We have build a Hexalgide. www.imac.unavarra.es/~cnc. This is a MIMO problem. 6 axis - 6 d.o.f. with non-trivial kinematics. By the moment we are doing independent joint controll so the main idea is to develop a good compensator for : First - reject disturbance in the joint from other part of the manipulator Second - avoid excitation of backlash non-linearities and vibrational modes 2- If it's not posible by the moment, how could we tune the PID parameters so to have: 1) peak response equal to zero 2) and the frencuency reponse of the output of the compensator U(s) limited to a specific band Thank very much for reading this mail. New ideas and help are welcome. Jasiel Nájera. -- OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get ___ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
