oscillation during welding
04 Nov 2022 11:01 #255904
by rodw
Replied by rodw on topic oscillation during welding
I think what Andy is aluding to is that motion by a welding torch can be defined on a continually changing plane normal to the weld. think of a ball rolling on the floor with the floor being the plane that has an infinite number of variations based on where the ball touches it. Linux has a finite number of planes as defined in canon.h
Which are derived from the g17-g19 commands linuxcnc.org/docs/devel/html/gcode/g-code.html#gcode:g17-g19.1
It is possible to hack the interpreter as I attempted to do here
github.com/rodw-au/linuxcnc/tree/arc-radius
and discussed here github.com/LinuxCNC/linuxcnc/pull/900
You can calculate the heading in real time and other data at the interpreter level and pass it back to motion by extending the state tags structure and then publish this data as motion pins. But the heading is only defined in terms of the gcode planes. So a straight line weld going from x=0,y=0,z=0 to x=100,y=100,z=100 is not traced on one of the linuxcnc planes.
There is another approach that may work for welding (as the weave does not need to be precise - my weaving certainly isn't
). I tried this but did not have any luck with it. A custom component could look at the x,y,z positions this servo thread cycle and the previous servo cycle and determine the heading based on simple? trig. I was only interested in motion on the XY plane. If the motion was mapped in this way on the XY, XZ and YZ planes, it would define the plane the motion was following and external offsets could be computed to define 3 dimensional weaving.
Good luck!
enum CANON_PLANE
{
CANON_PLANE_XY = 1,
CANON_PLANE_YZ,
CANON_PLANE_XZ,
CANON_PLANE_UV,
CANON_PLANE_VW,
CANON_PLANE_UW,
};
Which are derived from the g17-g19 commands linuxcnc.org/docs/devel/html/gcode/g-code.html#gcode:g17-g19.1
It is possible to hack the interpreter as I attempted to do here
github.com/rodw-au/linuxcnc/tree/arc-radius
and discussed here github.com/LinuxCNC/linuxcnc/pull/900
You can calculate the heading in real time and other data at the interpreter level and pass it back to motion by extending the state tags structure and then publish this data as motion pins. But the heading is only defined in terms of the gcode planes. So a straight line weld going from x=0,y=0,z=0 to x=100,y=100,z=100 is not traced on one of the linuxcnc planes.
There is another approach that may work for welding (as the weave does not need to be precise - my weaving certainly isn't
). I tried this but did not have any luck with it. A custom component could look at the x,y,z positions this servo thread cycle and the previous servo cycle and determine the heading based on simple? trig. I was only interested in motion on the XY plane. If the motion was mapped in this way on the XY, XZ and YZ planes, it would define the plane the motion was following and external offsets could be computed to define 3 dimensional weaving.Good luck!
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