My understanding of the goal is that it is to have a minimum time subject to certain constraints.
The current constraints in LinuxCNC are to have certain acceleration and velocity limits. It has been suggested that it would also be appropriate to limit the jerk. Doing so could only make the time longer. For a variety of reasons (smaller error, less vibration, ...), some commercial machines add such constraints. I suggest that if enhance LinuxCNC to add the jerk constraints, that will be sufficient to "compete" with commercial solutions. =============== I've noticed that most of the papers I've looked at seem to discuss the problem of moving a single axis. Presumably, changing this to an N-axis solution is straight forward. LinuxCNC, though, handles both linear and circular interpolation. I've never looked closely enough at the design to understand how circular interpolation would change the problem. Regards, Ken On 5/1/2012 1:41 PM, Joachim Franek wrote: > Look at > http://www.roymech.co.uk/Useful_Tables/Maths/fourier/Maths_Fourier_transforms.html > and compare the fourier transform of: > 1. top hat (sinc) > 2. triangle (sinc^2) > 3. gauss (gauss) > > trapezoidal is inbetween top hat and triangle. > > for accaleration function > 1. top hat: jerc is unboundet > 2. triangle and trapezoidal: jerc is constant > 3. gauss: jerc is gauss > > _Conclusion:_ > gaussian accaleration gives the _lowest_ frequency components! > > Unfortunately gaussian jerk is impossible. You have to > wait infinite time to start the motion. > > Which function looks like a gaussian? > The sinusoidal type in > STR_V8_N1_07_MCH.pdf: Fig.1 (a) > or > 4267.pdf: page 8, upper trace > is a candidate! > > Joachim > > ------------------------------------------------------------------------------ > Live Security Virtual Conference > Exclusive live event will cover all the ways today's security and > threat landscape has changed and how IT managers can respond. Discussions > will include endpoint security, mobile security and the latest in malware > threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ > _______________________________________________ > Emc-developers mailing list > Emc-developers@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-developers ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
