DRC Atlas safety_controller URDF

asked 2013-07-08 09:02:15 -0500

Wally gravatar image

updated 2013-07-08 09:56:04 -0500


I looked into the URDF-File of Atlas. There, for example, you have:

<joint name="l_arm_shx" type="revolute"><origin rpy="0 -0 0" xyz="0 0.075 0.036"/>

<axis xyz="1 0 0"/><parent link="l_clav"/><child link="l_scap"/> <dynamics damping="1.0" friction="0"/> <limit effort="170" lower="-1.39626" upper="1.74533" velocity="12"/> <safety_controller k_position="100" k_velocity="100" soft_lower_limit="-11.3963" soft_upper_limit="11.7453"/>

What actually is the safety controller? I looked into http://www.ros.org/wiki/pr2controllermanager/safetylimits, but still I cannot figure out the soft_upper_limit and soft_lower_limit. There, they say " The upper soft limit is the upper hardware limit minus the safetylength_max"

My Hardware position limit for the l_arm_shx joint is [-1.3962 ... +1.74533]. So how do I account the softupperlimit with that? Is +1.74533 given in [rad], where softupperlimit given in [deg]? But this has to be wrong...1.74533 is somewhat 100°.

I'm sorry for this question, but I'm completly new to URDF, Gazebo and DRC

Thank you

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