I am going to ask a stuid question.. If you have a velocity run step gen with pid. Couldn't you hook a limit3 between the pid and steghen. Because the input is velocity instead of position - wouldn't the acceleration limit in the limit3 be jerk instead of acceleration? I am sure it doesn't work that way.. I was just thinking you have moved the derivatives up one..
(I can tell you it doesn't seem to work in practice - probably because the pid will always try to correct the error. Like maybe you would need to negate the limit3 amount on the feedback side..) On Tue, Aug 17, 2021 at 1:28 PM Scott Harwell via Emc-users < emc-users@lists.sourceforge.net> wrote: > I haven't tried it yet, but this looks promising. > LinuxCNC S-Curve Accelerations > > > > Scott H > > > On Tuesday, August 17, 2021, 12:57:06 PM CDT, Ralph Stirling < > ralph.stirl...@wallawalla.edu> wrote: > > I've also been hoping to see this appear in a Linuxcnc update, > as it has been worked on by a number of people for years. > Here are the most recent threads about jerk-limited trajectory planning: > > > https://forum.linuxcnc.org/24-hal-components/40152-jerk-limited-trajectory-planner-hal-component > > > https://forum.linuxcnc.org/38-general-linuxcnc-questions/34666-c2-smooth-velocity-profile?start=0 > > -- Ralph > ________________________________________ > From: David Berndt [ber...@uberwin.com] > Sent: Tuesday, August 17, 2021 9:01 AM > To: Enhanced Machine Controller (EMC); andrew beck > Subject: Re: [Emc-users] jerk control > > CAUTION: This email originated from outside the Walla Walla University > email system. > > > I don't have a great need for it with my machines, or the time/brains to > implement it. It just seems like a feature we really should have. > > I'd be willing to participate monetarily in some sort of system to > incentivize the inclusion of jerk control. Perhaps an open-source feature > bounty? Does the community want to consider that sort of thing? > > -Dave > > On Mon, 16 Aug 2021 23:06:05 -0400, andrew beck <andrewbeck0...@gmail.com> > wrote: > > > hey guys > > > > I am sitting here watching my cnc mill atm its shaking quite a bit > > acceleration is 600mm/sec2 which is not that high i think. compared to > > every other cnc mill i have used with a commercial controller. they have > > jerk control and work much better. so looking forward to when we get > > jerk > > control here on linuxcnc! > > > > but in the mean time i need a poor mans jerk control and thinking of a > > limit on the pid output to chop down the initial acceleration for the > > first > > moment in time just so little moves don't shake it to death > > > > andy mentioned that I could maybe use a limit component to limit the > > initial acceleration for the first tiny moment in time to cut down on the > > vibrations. > > > > how do you guys think that could work? > > > > Regards > > > > Andrew > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > > https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.sourceforge.net%2Flists%2Flistinfo%2Femc-users&data=04%7C01%7Cralph.stirling%40wallawalla.edu%7C7457b9607a2d4747a1e508d961a1b508%7Cd958f048e43142779c8debfb75e7aa64%7C0%7C0%7C637648169423748846%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=ue%2BwIaVhfay08NBevlCAvyOoNp0qVz9ojUuigRuCOOs%3D&reserved=0 > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > > https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Flists.sourceforge.net%2Flists%2Flistinfo%2Femc-users&data=04%7C01%7Cralph.stirling%40wallawalla.edu%7C7457b9607a2d4747a1e508d961a1b508%7Cd958f048e43142779c8debfb75e7aa64%7C0%7C0%7C637648169423748846%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=ue%2BwIaVhfay08NBevlCAvyOoNp0qVz9ojUuigRuCOOs%3D&reserved=0 > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
