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 ------------------------------------------------------------------------------ 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
