LinuxCNC S-Curve Accelerations

hi arvidb
I haven't been on the forum for a long time.
I wanted to know if it was possible to solve the problem that I understood on forum.linuxcnc.org/38-general-linuxcnc-q...elerations?start=210

If you are referring to installing ethercat, yes its solved by using a repository containing IgH Etherlabmaster maintained by them
I wrote a Sticky on it in the Ethercat section on how to do this.
forum.linuxcnc.org/ethercat/45336-etherc...-how-to-step-by-step
Everything else uses an obsolate version of the IgH source code on Mercurial when their repositories have moved to gitlab
Next on the agenda is a custom homing module for cia402 ethercat drives. 

I would suggest building linuxcnc on Debian Bullseye from source and follow that sticky using these instructions
www.qtpyvcp.com/install/bullseye.html
 

TheRoslyak wrote:

hi arvidb
I haven't been on the forum for a long time.
I wanted to know if it was possible to solve the problem that I understood on forum.linuxcnc.org/38-general-linuxcnc-q...elerations?start=210

Hi TheRoslyak,

The integration of my jerk limited jog planner is not done yet, no. I'm still working on it now and then, when I can find enough time and energy. I did get some significant preparatory patches into master recently. Lots of work still left to do though. Untangling the innards of motmod enough to enable modular jog planning is a large undertaking, and that's pretty much what I'm doing.

Grotius wrote:

Hi,

Now i can try to apply the the scurve algo to this working demo.

code
video
[/list]

Colleague, all the Githab links you cited above are dead, I can't download anything. Please share information about the current state of things.
I would like to implement the s-curve feature in my LinuxCNC2.8 example and would appreciate any help, guidance, instructions, links, etc.

abs32 wrote:

all the Githab links you cited above are dead,

Try github.com/grotius-cnc/scurve-pro

Hi,

To inform you all.
I designed a new scurve algoritme the past day's. Based on something bare simple.

Here a video of the scurve : video

This scurve has 3 periods for acceleration- and deceleration periods,

1. concave
2. linear acceleration
3. convex

The curve is based on the lineair acceleration formula :

v=vo+a*t

v=velocity, vo=velocity start, a=acceleration, t=time.

The implementation of the above formula makes it behave like a scurve.
Every cycle in the concave and or convex period the "a" is incremented
by a value "a_step". This simple thing makes it behave like a perfect scurve.

Let me know how you think about it..?

Source code : github.com/grotius-cnc/scurve_idea/blob/main/jog.h

Notes :

The source is working but not stable.

Trying to explanation why :

This is born out of a problem
with the scurve inplementation following
the science papers attached to the project where
Andy is pointing to in previous post.

The main problem in some scenario's is calculating the
jerk max. jm value. This value is based on a few inputs
like "velocity start" & "velocity end". It also relates
to acceleration start & acceleration end values.

In some cases, i found that the "velocity end" value can not
always be calculated on forehand.

In short, for full path calculation, that end with
acceleration end is zero, there is no problem.

The problem occurs when using acceleration end values and
recalculate a curve from there.

For example when releasing a jog button, machine will make a
controlled stop. Acceleration gets down. When then pressing the
jog button again, this is really a problem for calculating the
next curve i found out.