On 16 August 2013 15:35, Chris Radek <[email protected]> wrote:
>  This means: just like you have
> to set AXIS LIMITS to be inside JOINT LIMITS, you must also set up
> your configuration so obeying AXIS CONSTRAINTS keeps you within your
> JOINT CONSTRAINTS.  This can be tricky, but you must do it.  I think
> your question is about this paragraph.

Yes, I think it is.
Unfortunately in some situations this could be painful. You would have
to choose your rotary axis constraint such that for the very longest
tool at the worst possible angle the linear axes can keep up. Then
when the tool is very short and the angle very small you will end up
with much slower than necessary motion. And this super-conservative
limit will also apply in G-code which does actually know better.

Would it be possible for the code to determine the instantaneous
relationship between current AXIS (trajectory?) velocity and the
associated JOINT velocities? I think in theory this is just two calls
to the kins module of a "now" and a "now + delta-t" point. The system
could then  "throttle back" the trajectory velocity accordingly. I
think that the relationships will always be continuous (as long as the
kins is continuous, and those kins with singularities are already a
problem). If the relationships are continuous then there may not be
any worries about simultaneously respecting accel limits.

-- 
atp
If you can't fix it, you don't own it.
http://www.ifixit.com/Manifesto

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