On Wed, 22 Mar 2017, Sebastian Kuzminsky wrote: > Date: Wed, 22 Mar 2017 13:03:06 -0600 > From: Sebastian Kuzminsky <s...@highlab.com> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Subject: Re: [Emc-users] Different acceleration profiles - something that > would remove the discontinuity in the first derivative of the acceleration > ? > > On 03/22/2017 12:50 PM, Nicklas Karlsson wrote: >>> Hello, >>> >>> I want to ask if anybody has worked on different acceleration profiles >>> for linuxcnc ? I am looking for something that would remove the >>> discontinuity in the first derivative of the acceleration ? >>> >>> BR >>> Max. >> >> I guess to start with the DC motor model for example here >> https://www.electrical4u.com/torque-equation-of-dc-motor/ would be a good >> idea. Driving this with a limited voltage and current would probably be a >> good model for the limitations. > > I think Max is asking about changes to the LinuxCNC trajectory planner > that implement variable (non-constant) acceleration, aka "limited jerk". > > Currently when you start from a stand-still, command a move, and come to > rest at the end of the move, LinuxCNC implements a trapezoidal velocity > profile. This starts with a constant-acceleration phase until it > reaches the maximum speed for the move, then enters a constant-velocity, > zero-acceleration "cruise phase", and finishes with a > constant-deceleration phase back to zero velocity. Each phase > transition has an instant of infinite jerk, when acceleration goes from > one constant value to another in a single motion cycle. > > I think Yishin Li (https://github.com/yishinli) has done some work in > the area of jerk-limited trajectory planning, but AFAIK it has not shown > up as a pull request to our repo yet. > > > -- > Sebastian Kuzminsky
I think micges (Michael Geszkiewicz) also had an at least partially working Limited jerk profile TP, not sure if this was pre-CAB or not. > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
