LinuxCNC 2.7.3 Trajectory Planner, circle problem
12 Jan 2016 11:07 #68223
by matiq05
Replied by matiq05 on topic LinuxCNC 2.7.3 Trajectory Planner, circle problem
In sim is the same problem...
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13 Jan 2016 04:55 - 13 Jan 2016 12:11 #68285
by Rick G
Replied by Rick G on topic LinuxCNC 2.7.3 Trajectory Planner, circle problem
It seems to me there was some discussion during the testing of the new trajectory planner about the last or next to last move and acceleration because of the need to come to a complete halt at the end of the program.
What happens if you try this...
or this...
Rick G
What happens if you try this...
%
g64 p.05 q.05
G90G17G21
G00 X0.000 Y0.000 Z8.000 F34000
G00 X-0.000 Y-0.000 Z3.000
G01 X-0.000 Y-0.000 Z-5.000
G01 X0 Y200
G02 X400 Y200 R200
G02 X0 Y200 R-200
G01 X296.318 Y192.579
G02 X122.567 Y260.113 R-100.000
G02 X296.318 Y192.579 R100.000
G00 X647.090 Y435.084 Z10
G01 Z-5
G02 X299.587 Y570.151 R-200.000
G02 X647.090 Y435.084 R200.000
G01 Z.2
G01 Z0
%
or this...
%
g64 p.05 q.05
G90G17G21
G00 X0.000 Y0.000 Z8.000 F34000
G00 X-0.000 Y-0.000 Z3.000
G01 X-0.000 Y-0.000 Z-5.000
G01 X0 Y200
G02 X400 Y200 R200
G02 X0 Y200 R-200
G01 X296.318 Y192.579
G02 X122.567 Y260.113 R-100.000
G02 X296.318 Y192.579 R100.000
G00 X647.090 Y435.084 Z10
G01 Z-5
G02 X299.587 Y570.151 R-200.000
G02 X647.090 Y435.084 R200.000
G02 X299.587 Y570.151 R-200.000 Z0
%
Rick G
Last edit: 13 Jan 2016 12:11 by Rick G.
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18 Jan 2016 08:49 #68657
by matiq05
Replied by matiq05 on topic LinuxCNC 2.7.3 Trajectory Planner, circle problem
I can't test this program on machine right now, but on simulation is the same problem. You can see on graph that velocity slow down on last circle. I think if that slow down is on simulation then machine will behave the same.
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09 Oct 2018 13:15 #118583
by Pumuckl
Replied by Pumuckl on topic LinuxCNC 2.7.3 Trajectory Planner, circle problem
Hey Guys,
I would like to bump this topic because It is exactly the problem I am facing with the new trajectory planner and I could not find something newer. I have had this problem for a long time already and since I did a lot of circular cutouts last weekend I finally decided to investigate further.
So, I am on 2.8.0-pre1-3902 and whenever I go down in circles I get a stutter after the first segment because linuxcnc comes to a complete stop, then reaccelerates and continues. I sat down today at home and used the simulator. It shows the exact same behaviour. I did play around with G64 but that had no impact at all. Also what I did to the ARC_BLEND settings didn't have any impact.
When I disable the new planner and switch to 1 segment look ahead it behaves as expected. No slow down after the first segment!
Is this a known problem? Is there a solution (apart from using the old planner)? Since I could not find anything else but this thread, are there any other threads that deal with this problem and came up with a solution?
For my tests I used the "gantry_mm" sim config and changed the accelerations to 750mm/s^2, the g-code is below.
Cheers,
Christian.
I would like to bump this topic because It is exactly the problem I am facing with the new trajectory planner and I could not find something newer. I have had this problem for a long time already and since I did a lot of circular cutouts last weekend I finally decided to investigate further.
So, I am on 2.8.0-pre1-3902 and whenever I go down in circles I get a stutter after the first segment because linuxcnc comes to a complete stop, then reaccelerates and continues. I sat down today at home and used the simulator. It shows the exact same behaviour. I did play around with G64 but that had no impact at all. Also what I did to the ARC_BLEND settings didn't have any impact.
When I disable the new planner and switch to 1 segment look ahead it behaves as expected. No slow down after the first segment!
Is this a known problem? Is there a solution (apart from using the old planner)? Since I could not find anything else but this thread, are there any other threads that deal with this problem and came up with a solution?
For my tests I used the "gantry_mm" sim config and changed the accelerations to 750mm/s^2, the g-code is below.
Cheers,
Christian.
%
G90 G94 G17 G91.1
G21
G54
G0 X0 Y0 Z10
G1 X-100 Y0 Z0 F5000
G2 X100 Y0 Z-0.5 I100 J0
X-100 Y0 Z-1 I-100 J0
X100 Y0 Z-1.5 I100 J0
X-100 Y0 Z-2 I-100 J0
X100 Y0 Z-2 I100 J0
X-100 Y0 Z-2 I-100 J0
G0 Z10
G0 X0 Y0
M30
%
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- islander261
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09 Oct 2018 14:59 #118587
by islander261
Replied by islander261 on topic LinuxCNC 2.7.3 Trajectory Planner, circle problem
Hi
What you are describing sound like the bugs reported on GIT, 447 and or 426. They cause me no end of grief when plasma cutting.
John
What you are describing sound like the bugs reported on GIT, 447 and or 426. They cause me no end of grief when plasma cutting.
John
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- Todd Zuercher
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09 Oct 2018 15:27 #118593
by Todd Zuercher
Replied by Todd Zuercher on topic LinuxCNC 2.7.3 Trajectory Planner, circle problem
Personally I believe that it is a bug. But there are some others who may argue that it doesn't really exist.
If you play with the sequence of moves before or after the glitch. Sometimes you can make it go away. For example if you take your example code and change the g1 move before the 1st helical move to a g0 move, the pause goes away.
If you play with the sequence of moves before or after the glitch. Sometimes you can make it go away. For example if you take your example code and change the g1 move before the 1st helical move to a g0 move, the pause goes away.
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09 Oct 2018 16:29 #118597
by Pumuckl
Replied by Pumuckl on topic LinuxCNC 2.7.3 Trajectory Planner, circle problem
Thanks for pointing me to these issues. This is exactly what I am encountering. From what I read on git there should be fixes for both these issues but they don't seem to be merged because ARC_BLEND_FALLBACK_ENABLE doesn't seem to do anything in my case.
Strange things are happening when you play around with the code: If you set all the Z heights to 0 it will not slow down. If you set the Z height in the G2 line to 0 it will start to slow down a line further down in the codeā¦ And also not as much?? If something goes away by playing with what you do before or after I think it is safe to consider it a bug.
Someone commented on GIT an hour ago and asked if the fix for #426 is ready to be merged, so maybe something is going to happen... If you guys need anything to be tested feel free to contact me. I have quite a lot more circular cutouts to do this weekend.
Cheers,
Christian.
Strange things are happening when you play around with the code: If you set all the Z heights to 0 it will not slow down. If you set the Z height in the G2 line to 0 it will start to slow down a line further down in the codeā¦ And also not as much?? If something goes away by playing with what you do before or after I think it is safe to consider it a bug.
Someone commented on GIT an hour ago and asked if the fix for #426 is ready to be merged, so maybe something is going to happen... If you guys need anything to be tested feel free to contact me. I have quite a lot more circular cutouts to do this weekend.
Cheers,
Christian.
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