Bug #138



Added by Quentin Sable over 6 years ago. Updated about 6 years ago.

Quentin Sable


For safety reasons, need to limit the range of joints angular positions q1, q2, q3.

The differential mechanism used for the transmission introduces relations between the motors angular positions m1 and m2. I don't know if it is feasible, but the best would be to verify that

q1 = (1/8)*(m1 + m2);
q2 = (1/8)*(m1-m2);
q3= m3

are in a given range, which is tunable.

Actions #1

Updated by Anthony Mallet over 6 years ago

  • Tracker changed from Pull request to Bug

Since this component is meant to be generic, i.e. it does not assume
anything special about the connected system, setting relative
constraints between joint angles seems difficult.

This would require to be able to pass a formal mathematical expression
that could be evaluated dynamically (so that nothing is hardcoded in
the code), which seems a bit overkill for this component.

What you really need in the long term is an "arm" component. I could
start developing this. In this component there would typically be a
kinematic model, joints limits as you want them, etc.

In the dynamixel component, setting static position limits for
individual joints would still makes sense, though. Would this be
helpful for your safety concerns or not at all?

Actions #2

Updated by Quentin Sable over 6 years ago

In my case it would not be helpful indeed. But maybe having a set_limits() for at least maximum velocities and accelerations in a limited range could be useful for safety concerns.

Actions #3

Updated by Anthony Mallet about 6 years ago

  • Status changed from New to Closed

Added set_limits() in 5f6c8e45


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