It seems that real motion and speeds are to be viewed from workpiece coordinate system since one of the main requirements in CNC is to have constant speed of tool over surface. Also there is a need to somehow define generic way of calculating real workpiece coordinates from dX, dY, dZ and dA, dB, dC dU, dV, dW since linuxcnc could not know, what is machine geometry or tool movement dependency on different axis.
Since change A,B,C and U,V,W axes each separately or in combination result in X,Y,Z movement would it be possible to put in INI a math expression that would be kind of: X(dA;dB;dC;dU,dV,dW) = dX + [name of radius A pin] * sin(dA*PI/180) + [name of radius A pin] * cos(dA*PI/180) + ... (formulas of X dependency from other axes) ... Y(dA;dB;dC;dU,dV,dW) = 0 Z(dA;dB;dC;dU,dV,dW) = dZ + [name of radius A pin] * cos(dA*PI/180) + [name of radius A pin] * sin(dA*PI/180) + ... (formulas of Z dependency from other axes) ... final movement would be then Xnew = X_from_queue + X(dA;dB;dC;dU,dV,dW) and similar for Y and Z axis. In this way user could define dependencies of main cartesian axes XYZ from angular ABC or linear UVW axis. It seems that would require adding some symbolic computation library... (check http://stackoverflow.com/questions/11715162/symbolic-computation-library-in-pure-c ). I hope I am not too much off topic and ideas are not too extreme to implement. Also if this is to be part of kinematics module of lcnc please somebody correct me or direct me how this is to be aproached... On Sun, Nov 6, 2016 at 6:48 PM, Robert Ellenberg <rwe...@gmail.com> wrote: > As of now, circular arc blending doesn't work with the ABC axes (which is > why it's running so slowly for you with short segments), but I'm working on > a fix. I had an extensive discussion with Andy Pugh a while back, which led > to some great ideas on how to solve this problem. There are two big reasons > it doesn't work now: > > 1) ABC units are degrees, whereas linear axes (XYZUVW) are in distance. A > spherical arc doesn't make physical sense between axes of different units. > > 2) "Velocity" as defined by the TP is actually velocity in either XYZ, ABC, > or UVW axes, depending on the context, but a spherical arc in general would > involve change in all 9 axes, so the arc length (and it's derivatives, TP > velocity and acceleration) needs to be expressed in terms of all axes. > > What I'm working on now is to treat ABC axis motion as an equivalent tool > tip motion in distance units. For example, if the tool is 10 inches above > the physical A axis, then the A axis has an effective radius of 10 inches. > Therefore it's easy to convert the angular motion to an equivalent tool top > motion. Ex: a 90 deg rotation would be similar to a linear move of pi / 2 * > 10 ~= 15.71 in. > > The good news is, if we assume some constant effective radius for all ABC > axes, I think it's possible to implement with the same basic structures as > the ones in my my experimental UVW axes blending branch > <https://github.com/robEllenberg/linuxcnc-mirror/ > tree/feature/uvw-blending-dev> > . > > The hard part is making the effective radius change with tool tip position. > That's my long-term goal with this fix, but it may still be a big > improvement to assume a constant effective radius. > > Best, > Rob > > On Sun, Nov 6, 2016 at 10:51 AM Tomaz T. <tomaz_...@hotmail.com> wrote: > > So for now there is no solution to speed this up till TP will be modified > in the way that it will take and "optimize" also moves with rotary axis > ...? > > > PS. yes I'm from Slovenia. > > > ________________________________ > From: klemenzivko...@gmail.com <klemenzivko...@gmail.com> on behalf of > Klemen Zivkovic <klemen.zivko...@gmail.com> > Sent: Sunday, November 6, 2016 2:10 PM > To: tomaz_...@hotmail.com > Subject: [Emc-users] max_velocity during execution - multiple axis > > Hello, > > > I think your problem is that linuxcnc have x,y,z trajectory planning. As > soon as you add rotary axis to have combined move you end up with single > lookahead in tp, so this limits velocity. > Check this out: > https://forum.linuxcnc.org/20-g-code/29662-coordinated- > motion-involving-rotary-axis > > > According to your name - I need to ask you are you native slovenian > speaker? > > > regards > KLemen > ------------------------------------------------------------ > ------------------ > Developer Access Program for Intel Xeon Phi Processors > Access to Intel Xeon Phi processor-based developer platforms. > With one year of Intel Parallel Studio XE. > Training and support from Colfax. > Order your platform today. http://sdm.link/xeonphi > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------ > ------------------ > Developer Access Program for Intel Xeon Phi Processors > Access to Intel Xeon Phi processor-based developer platforms. > With one year of Intel Parallel Studio XE. > Training and support from Colfax. > Order your platform today. http://sdm.link/xeonphi > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Developer Access Program for Intel Xeon Phi Processors Access to Intel Xeon Phi processor-based developer platforms. With one year of Intel Parallel Studio XE. Training and support from Colfax. Order your platform today. http://sdm.link/xeonphi _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
