No, it's not currently possible. It would be a welcome topic for
improvement.
Right now, kinematics is confined to the realtime trajectory planner, so
nothing is known about it at the time soft limits are being enforced in
task.
A naive approach would be to put a copy of kinematics into task; for
each motion that task considers for soft limits, divide it up "finely"
and make sure each of the points along the motion, it has a kinematics
solution. However, this is probably going to be computationally
intensive, since you're doing the work of kinematics twice.
I think a plausible way to do this is to allow definition of arbitrary
working volumes using a standard format like .stl. Then, task would
have to answer a much simpler problem: whether any part of the motion is
outside this defined volume. However, it might be wise to use an
existing library to perform this test, rather than writing an original
implementation in LinuxCNC. For example, CGAL's Side_of_triangle_mesh
can tell you whether a particular point is on the interior or exterior
of the volume.
Of course, while thinking about this it will also be a good time to do
something about the related issue which can be seen on trivkins
machines: some arcs that go outside of soft limits aren't detected by
task. I think this is because only the two endpoints are tested (which
works fine with lines and convex working volumes, but doesn't work with
circular motion or non-convex working volumes):
https://github.com/LinuxCNC/linuxcnc/issues/80
For arcs which come near the edge (where the AABB of the arc is not
entirely inside the working volume), I suspect a strategy of dividing up
the arc will be neessary to fix this for the complex working volume
case. And remember, "arcs" now includes multi-turn helices which can
additionally be rotated. Oh yeah, and there are NURBs too, even if
nobody uses them.
Jeff
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