LinuxCNC S-Curve Accelerations

More
17 Jan 2026 20:30 #341494 by ruediger123
Replied by ruediger123 on topic LinuxCNC S-Curve Accelerations
I revised the NC program and made the number of corners and the radius parameterizable.
Attachments:
The following user(s) said Thank You: grandixximo, besriworld, endian

Please Log in or Create an account to join the conversation.

  • grandixximo
  • grandixximo's Avatar Topic Author
  • Away
  • Premium Member
  • Premium Member
More
17 Jan 2026 22:09 - 17 Jan 2026 22:12 #341503 by grandixximo
Replied by grandixximo on topic LinuxCNC S-Curve Accelerations
 
 Thats a dodecadon lol
I was planning to make rounded corners actually be radiuses in the gcode G2 G3, probably next week, unless you want to oblige, many thanks again Rüdiger!
Attachments:
Last edit: 17 Jan 2026 22:12 by grandixximo.
The following user(s) said Thank You: tommylight, besriworld, snowgoer540, endian, tiagounderground

Please Log in or Create an account to join the conversation.

More
18 Jan 2026 18:29 #341543 by ruediger123
Replied by ruediger123 on topic LinuxCNC S-Curve Accelerations
NC program.
square with parameterizable size and corner radius.
with G10 L2 R can be rotated around the C axis.
I don't have the knowledge to create an NC program with any number of corners and G2/G3 radiuses
Attachments:
The following user(s) said Thank You: grandixximo, besriworld

Please Log in or Create an account to join the conversation.

  • grandixximo
  • grandixximo's Avatar Topic Author
  • Away
  • Premium Member
  • Premium Member
More
21 Jan 2026 05:51 - 21 Jan 2026 06:56 #341630 by grandixximo
Replied by grandixximo on topic LinuxCNC S-Curve Accelerations
github.com/grandixximo/linuxcnc

For whomever would like to help me test the improvements, download and build, this is not in master yet, still waiting for the halcsope to get merged, I have only tested on the scope so far, will do some testing on real hardware before sending a PR to master.
Would love to have some help testing, thank you all!

still in fixing a few things, don't expect the git history to stay
Last edit: 21 Jan 2026 06:56 by grandixximo.
The following user(s) said Thank You: rodw, endian, Darium

Please Log in or Create an account to join the conversation.

  • grandixximo
  • grandixximo's Avatar Topic Author
  • Away
  • Premium Member
  • Premium Member
More
21 Jan 2026 10:09 #341637 by grandixximo
Replied by grandixximo on topic LinuxCNC S-Curve Accelerations
The arc interpolations need some work, G1 seems pretty good, will work on arcs next, maybe not ready for testing yet...
The following user(s) said Thank You: Todd Zuercher, endian, Darium

Please Log in or Create an account to join the conversation.

More
21 Jan 2026 16:52 #341656 by Aciera
Replied by Aciera on topic LinuxCNC S-Curve Accelerations
@grandixximo
Note the issues related to scurve code:
github.com/LinuxCNC/linuxcnc/issues/3719
github.com/LinuxCNC/linuxcnc/issues/3720

I'm not sure if pinging you on github works.

Please Log in or Create an account to join the conversation.

  • grandixximo
  • grandixximo's Avatar Topic Author
  • Away
  • Premium Member
  • Premium Member
More
21 Jan 2026 21:23 - 22 Jan 2026 07:26 #341668 by grandixximo
Replied by grandixximo on topic LinuxCNC S-Curve Accelerations
I get notifications, I do check on them when I am free...

Edit:

YangYang also replied, those will be fixed, but we have bigger fish to fry now, we are working on arc stopping, and some other arc blending related issues.
Last edit: 22 Jan 2026 07:26 by grandixximo.
The following user(s) said Thank You: rodw, zmrdko

Please Log in or Create an account to join the conversation.

More
22 Jan 2026 05:10 #341678 by yrsiddhapura
Replied by yrsiddhapura on topic LinuxCNC S-Curve Accelerations
Does it compatible with mesa based setup ??

Please Log in or Create an account to join the conversation.

  • grandixximo
  • grandixximo's Avatar Topic Author
  • Away
  • Premium Member
  • Premium Member
More
22 Jan 2026 07:18 - 22 Jan 2026 07:21 #341680 by grandixximo
Replied by grandixximo on topic LinuxCNC S-Curve Accelerations
it is compatible with mesa default setup, but you need add the jerk parameters in the ini file, look at the axis_mm_scurve.ini file


I wanted some feedback from the community about s-curve, there a few considerations to make, not just jerk spikes

I think there are some choices to make, when trying to respect jerk limits, we can:

1 - Slow down at curvature changes: reduce Vel so the centripetal acceleration change is manageable. (this defeats high-speed machining)

2 - Modify the geometry: insert transition curves (clothoids, Bezier, splines) that have gradually changing curvature. This eliminates the discontinuity but changes the path. (when G64 Px is too small you will see jerk spikes)

3 - Accept the spike: the programmed path has a curvature discontinuity, so the motion will too.

There is no fourth option. You cannot maintain velocity, follow the exact programmed path, AND have smooth jerk. we need pick two.
Last edit: 22 Jan 2026 07:21 by grandixximo.
The following user(s) said Thank You: rodw, besriworld, zmrdko

Please Log in or Create an account to join the conversation.

  • Todd Zuercher
  • Todd Zuercher's Avatar
  • Away
  • Platinum Member
  • Platinum Member
More
22 Jan 2026 12:12 #341694 by Todd Zuercher
Replied by Todd Zuercher on topic LinuxCNC S-Curve Accelerations
My personal opinion is to default to #1. But as G64P tolerance increases allow more path tolerance so that velocity deviation can decrees.
The following user(s) said Thank You: tiagounderground

Please Log in or Create an account to join the conversation.

Time to create page: 0.150 seconds
Powered by Kunena Forum