linuxcnc trajectory planner
16 Oct 2024 12:41 - 16 Oct 2024 12:41 #312253
by Lcvette
Replied by Lcvette on topic linuxcnc trajectory planner
awesome to see this active again!! glad you are ok and back at it
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16 Oct 2024 19:20 #312292
by Grotius
Replied by Grotius on topic linuxcnc trajectory planner
@Lcvette,
Thank you for your kind words !.
Had a weird experience. The scene was as follows.
1. Run linuxcnc with the "linuxcnc" splash gcode. Added G64 P1 to the top of gcode file. Then i pressed run.
2. Ok machine run's the file. In the background the traject optimizer was busy and a few moments later
was ready.
3. Then load the produced file : ~/cmake/ "validate.ngc". into linuxcnc.
4. The gcode preview shows that "arcs" where converted to "lines". So how is this possible. Did i made a typo in the code?
5. Then i was reading online :
link
when the maximum deviation of an arc from a straight line is less than the G64 Q- tolerance, the arc is broken into two lines (from start of arc to midpoint, and from midpoint to end).
Conclusion for the test environment :
The interpreter had transformed the G2 & G3's into G1's. And the optimizer was then reading this false information.
So now to avoid this mismatch the files to blend are loaded with a empty G64 P, Q value, ensuring a valid input to the optimizer.
Then inside the optimizer the G64 P & Q values are set for now.
Ok, Then finally :
The vertical lines are for testing. It are spline control points. I had to visualize them to track the previous error.
Ok for now this is looking better.
Thank you for your kind words !.
Had a weird experience. The scene was as follows.
1. Run linuxcnc with the "linuxcnc" splash gcode. Added G64 P1 to the top of gcode file. Then i pressed run.
2. Ok machine run's the file. In the background the traject optimizer was busy and a few moments later
3. Then load the produced file : ~/cmake/ "validate.ngc". into linuxcnc.
4. The gcode preview shows that "arcs" where converted to "lines". So how is this possible. Did i made a typo in the code?
5. Then i was reading online :
link
when the maximum deviation of an arc from a straight line is less than the G64 Q- tolerance, the arc is broken into two lines (from start of arc to midpoint, and from midpoint to end).
Conclusion for the test environment :
The interpreter had transformed the G2 & G3's into G1's. And the optimizer was then reading this false information.
So now to avoid this mismatch the files to blend are loaded with a empty G64 P, Q value, ensuring a valid input to the optimizer.
Then inside the optimizer the G64 P & Q values are set for now.
Ok, Then finally :
The vertical lines are for testing. It are spline control points. I had to visualize them to track the previous error.
Ok for now this is looking better.
Attachments:
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16 Oct 2024 21:45 #312303
by Grotius
Replied by Grotius on topic linuxcnc trajectory planner
Hi Lcvette,
I didn't know linuxcnc would do this. When coding and testing i got my head scratched and thought : alien obstruction
not sure how to get around linuxcnc applying the G64 rules pre optimizer
Yes, indeed. We are screwed.
Tested this in top off a linuxcnc gcode file :
G64 P10 Motion blending tolerance
G61 Exact Path Mode
This then resolves the issue.
Wich means this is not applied :
when the maximum deviation of an arc from a straight line is less than the G64 Q- tolerance, the arc is broken into two lines (from start of arc to midpoint, and from midpoint to end).
Another error i was getting:
"same Y word..".
Cause, when running the "validation.ngc" file, when start is pressed, the file overwrites itself.
To avoid this, the filename now get a random number attached.
In the mean time, we learned a lot today.
I didn't know linuxcnc would do this. When coding and testing i got my head scratched and thought : alien obstruction
not sure how to get around linuxcnc applying the G64 rules pre optimizer
Yes, indeed. We are screwed.
Tested this in top off a linuxcnc gcode file :
G64 P10 Motion blending tolerance
G61 Exact Path Mode
This then resolves the issue.
Wich means this is not applied :
when the maximum deviation of an arc from a straight line is less than the G64 Q- tolerance, the arc is broken into two lines (from start of arc to midpoint, and from midpoint to end).
Another error i was getting:
"same Y word..".
Cause, when running the "validation.ngc" file, when start is pressed, the file overwrites itself.
To avoid this, the filename now get a random number attached.
In the mean time, we learned a lot today.
Attachments:
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18 Oct 2024 11:39 #312497
by Grotius
Replied by Grotius on topic linuxcnc trajectory planner
Hi Rob,
But probing is just a straight line feed that triggers a sensor event? How is this related to smoothing?
Attached a validation gcode file. You could test this in linuxcnc. It's result of a G64 P20 Q0.
To visualize this, the fillets are drawn as G1 linestrip.
This was hard work, because what you see is a filletized path using clothoids.
To use them in 3d space, i had to add logic to project 3d planes to xy planes and back to do the clothoid calculations.
At one point in the original gcode file it sees a transition from arc on xy plane to a line that goes z up.
This is a situation where segments points are not all in the same plane.
This situation is then reverted to use a bspline.
So far no tiny segments are filtered out.
For the source code, Clothoids-1 is added. This cmakelists file has to be reviewed as it is quite a mess now.
The clothoids lib integration was quite a lot off alien obstruction. But at least is works now !
repository
But probing is just a straight line feed that triggers a sensor event? How is this related to smoothing?
Attached a validation gcode file. You could test this in linuxcnc. It's result of a G64 P20 Q0.
To visualize this, the fillets are drawn as G1 linestrip.
This was hard work, because what you see is a filletized path using clothoids.
To use them in 3d space, i had to add logic to project 3d planes to xy planes and back to do the clothoid calculations.
At one point in the original gcode file it sees a transition from arc on xy plane to a line that goes z up.
This is a situation where segments points are not all in the same plane.
This situation is then reverted to use a bspline.
So far no tiny segments are filtered out.
For the source code, Clothoids-1 is added. This cmakelists file has to be reviewed as it is quite a mess now.
The clothoids lib integration was quite a lot off alien obstruction. But at least is works now !
repository
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18 Oct 2024 13:13 #312503
by Grotius
Replied by Grotius on topic linuxcnc trajectory planner
Hmm, ok.
Do you have the Eigen lib? : sudo apt-get install libeigen3-dev
In the next upload, there will be a check in the cmakelists for that.
So installing the clothoids-1 is for now a manual task. So it's annoying i know. I feel with you.
You can build the clothoids-1 in their own dir using a build dir. Then you can do a system wide: sudo make install.
Or copy the files over into the rtlib. Preferr to build the clothoids before the motion and planner.
I know this has to be changed soon.
Good luck. When spot install problems, let me know.
In the mean time i did some tests.
This are situations where the G64 P20 Q0 is used. Extreme situations to verify the blend algoritme for robustness.
Will show now a few pictures sets. Each set is before blending, and after blending with radius 20mm.
This are files using low dimensions so 20mm is just a incredible high value.
before:
after:
Here you can see the interpreter has given around 20.000 gcode lines. Not the entire file.
Therefore you see the buffered output is filletized as a result. When this then is machined, the next
load will occur.
before:
after:
before:
after:
Do you have the Eigen lib? : sudo apt-get install libeigen3-dev
In the next upload, there will be a check in the cmakelists for that.
So installing the clothoids-1 is for now a manual task. So it's annoying i know. I feel with you.
You can build the clothoids-1 in their own dir using a build dir. Then you can do a system wide: sudo make install.
Or copy the files over into the rtlib. Preferr to build the clothoids before the motion and planner.
I know this has to be changed soon.
Good luck. When spot install problems, let me know.
In the mean time i did some tests.
This are situations where the G64 P20 Q0 is used. Extreme situations to verify the blend algoritme for robustness.
Will show now a few pictures sets. Each set is before blending, and after blending with radius 20mm.
This are files using low dimensions so 20mm is just a incredible high value.
before:
after:
Here you can see the interpreter has given around 20.000 gcode lines. Not the entire file.
Therefore you see the buffered output is filletized as a result. When this then is machined, the next
load will occur.
before:
after:
before:
after:
Attachments:
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