oscillation during welding

I intend to weld with a 3-axis kinematics, but it must oscillate. How can I realize this with linuxcnc?

thank you for the quick reply, even if I did not fully understand.
I have also been programming robots for 30 years and here I only specify the movement type and the pendulum parameters.
But if I have now understood correctly, I must specify each point on the pendulum path individually. I can't imagine that, that would be stone age.

Its not really necessary to do the weave in cam.
You could use external offsets and calculate an appropriately scaled sine wave with siggen and apply it as an external offset.
the external offset is applied outside the motion controller so a straight line in CAM can be made to weave. (a Sine wave oscillates from -1 to 1)
Linuxcnc is really just designed for normal CNC machines .Welding is  special case. The tools are there, you just need to implement it.
Good luck!

For 3 axis welding, External offsets and siggen ( linuxcnc.org/docs/devel/html/man/man9/hm...FACE%20CONFIGURATION ) are pretty easy and for x and Y  directions, it would just involve some hal components and a couple of variables on the console for frequency and amplitude. Travelling diagonally would be harder as the weave needs to be apportioned between the X & Y axes. Linuxcnc lacks a heading value which tells you the angle of travel.

unfortunately not quite satisfactory so far. I can't really do anything with the oscillation of an axis, since the system works three-dimensionally in space and thus must also oscillate with all axes at the same time.
I know from a robot manufacturer that the path interpreter is used a second time to generate the pendulum movement, where any pendulum patterns are possible.
Furthermore, I need the possibility to influence the path via a sensor. In welding, the arc values are used as sensor variables. But also a displacement by operator intervention must be possible.
I assume that there are variables in LinuxCNC which contain the path tangent etc.?
Who deals with the path interpreter?

From my understanding, for normal kinematics, headings if they were supported could only be expressed in the xy, xz and yz planes.
The trajectory planner is deep witin the internals and does not have any  tangential parameters that can be read. They could be added and passed back via the state tags structure so they could be used. I did some work on this but the project was shelved.
My thought is the external offsets on the x,y,z axes would all need to be calculated to create the desired oscillation along the direction of travel.
This would likely be calculated in a custom component. This component would additionally receive your sensor variables and operator controls.

As an aside, Linuxcnc allows you to write custom components that once installed are treated as if they are part of the linuxcnc core.
linuxcnc.org/docs/devel/html/hal/comp.html
There are plenty of source examples in the /src/hal/components folder pick some easy ones like and2 and review some code
If voltage was a required input, this could be measured using a Mesa THCAD as used to monitor plasma torch voltage.
Actually dealing with the inputs will probably the easy bit!