how is everyone working out jerk / jolt? on a stepper motor you have a defined step or micro step (distance)
so if your acceleration is say 3000mm/s/s. (plasma cutter) and you are driving a 20T mod 1 rack and pinion with a 3:1 ratio drive, with a 200 step per rev stepper motor on 10uSteps the distance traveled per step is 0.01047197551 mm at 3000mm/s/s, the time that it takes from zero to the first step is sqroot ( 2x distance / acceleration) = 0.0026422182 seconds the jerk / jolt is therefore (acceleration X time for first step) >>> 3000 X 0.0026422182 = 7.92 mm/s/s/s without the 3:1 ratio drive reduction, the jolt or jerk is 13.72 mm/s/s/s. (or 1.73x greater than without a 3:1 ratio drive I used to have my same machine set up with a direct htd 5m 20T belt drive (ie each microstep was 0.05mm), with the same acceleration, the jolt or jerk was 17.32 mm/s/s/s..... although the belts were rubber and no doubt some compression of the teeth and movement in the belts took place Firstly I am trying to check my math is correct? On Thu, 26 Aug 2021, 09:44 andy pugh, <bodge...@gmail.com> wrote: > On Thu, 26 Aug 2021 at 00:34, Alexander Brock <a.br...@hhv-rheinklang.de> > wrote: > > > There is an elegant way to compute exact derivatives without computing > > analytical derivatives by hand. Here is a nice introduction: > > Is that applicable to the LinuxCNC kinematics functions? (Which are > kernel modules written in C). > > -- > atp > "A motorcycle is a bicycle with a pandemonium attachment and is > designed for the especial use of mechanical geniuses, daredevils and > lunatics." > — George Fitch, Atlanta Constitution Newspaper, 1912 > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
