dear Stevenson, LinuxCNC lacks jerk control and "G^2 blending". Without jerk control, the tangential acceleration jumps, without G^2 blending, the normal acceleration jumps. Both lead to an excitation of machine vibrational modes ... leading to bad surface quality.
No problem for hobbyist applications, but big problem for high end commercial applications. best regards, Raoul -----Message d'origine----- De : Stuart Stevenson <[email protected]> Envoyé : vendredi 22 novembre 2019 23:10 À : EMC developers <[email protected]> Objet : Re: [Emc-developers] announcement OpenCN, a new fork of LinuxCNC Just for my education would you tell me where LinuxCNC is so far behind today's commercial CNC controls? On Fri, Nov 22, 2019, 4:01 PM Herzog Raoul <[email protected]> wrote: > dear Andrew, > > thanks for your positive feedback. > > There were many reasons for us to develop OpenCN : > > 1) of course scientific curiosity ... I'm working for ~8 years in > this field > > 2) but, more important, I had and have customers having problems with > surface quality as feedrate increases. > I'm living in the "watchmaking" western part of Switzerland :-) We > found out that the cause of the bad surface quality problem stems from > the vibrational behaviour of the machine. > And we started to develop special trajectory planning algorithms coded > in Matlab for *precalculating* the setpoint values. > It turned out, that the machining time with our algorithms was ~5 > times lower compared to a high end CNC, while keeping the same surface > quality. > But then ... very difficult to get a commercial CNC manufacturer > interested in ... an industrialization seemed difficult. > We decided to make the important step from "offline precalculation" of > setpoint values to online calculation as any CNC does. > LinuxCNC and the IgH EtherCat Master were our starting points, but we > realized that LinuxCNC today is more a "hobbyist" solution, far from > the performance commercial CNC's can deliver today. > And for academic people, LinuxCNC, as it is today, is a code > labyrinth, especially in the trajectory planning part. > This motivated our development. > > 3) yes, we have immediate use : we are doing many machining tests on > our micro milling machine "m3" you can see in the video. > And next year we will have the "micro5" here ( > https://www.youtube.com/watch?v=hITTmdsiihY), and we'll move OpenCN to > 5 axis ! > > best regards, > > Raoul > > > -----Message d'origine----- > De : Andrew <[email protected]> > Envoyé : vendredi 22 novembre 2019 22:15 À : EMC developers > <[email protected]> > Objet : Re: [Emc-developers] announcement OpenCN, a new fork of > LinuxCNC > > Dear Raoul, > > I truly admire your and your team's efforts. > Let me ask you about the purpose of OpenCN. Why did you decide to > create it? > Was it mostly for science or you have immediate use for it? > > Sincerely, > Andrew > > > пт, 22 лист. 2019 о 09:48 Herzog Raoul <[email protected]> пише: > > > dear Linux developers, > > > > I'm pleased to announce a new fork of LinuxCNC, called "OpenCN* : > > > > OpenCN is an open source numerical control (CNC) for high end > > machining applications (high dynamics, high precision). > > > > OpenCN is originally based on LinuxCNC, but with strong enhancements : > > > > -) completely reworked trajectory planning (TP) including jerk > > control based on embedded optimization > > -) Xenomai asymmetric multiprocessing (AMP) for hard real time, low > > latency > > -) up to date Linux kernel > > -) EtherCat with 10 kHz frame rate and distributed clock (DC), mode > > B > > -) new Qt based GUI superseding "axis" > > > > The HW platforms are x86 (available) and ARM (in preparation). > > > > Software : gitlab.com/mecatronyx/opencnc/opencn< > > https://gitlab.com/mecatronyx/opencnc/opencn> > > Doc : mecatronyx.gitlab.io/opencnc/doc/< > > https://mecatronyx.gitlab.io/opencnc/doc/> > > Youtube : www.youtube.com/channel/UC8FQCu_fKYfK7QRDN0j_dBw< > > https://www.youtube.com/channel/UC8FQCu_fKYfK7QRDN0j_dBw> > > > > > > best regards, > > > > Raoul > > > > > > > > [http://correspondance.heig-vd.ch/assets/heig.png] > > > > Raoul Herzog > > Dr. > > > > Professeur > > Institut d'Automatisation Industrielle (iAi) Groupe mecatronYx Prof. : > > > > +41 24 557 61 93 > > > > Site web : > > > > http://www.iai.heig-vd.ch > > > > > > [email protected]<mailto:[email protected]> > > > > > > > > > > _______________________________________________ > > Emc-developers mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/emc-developers > > > > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers > > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers > _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
