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Planning requests counting collisions between robot links that should be ignored?

asked 2019-07-02 12:43:32 -0500

ssnover gravatar image

I'm using Moveit in ROS Melodic and am currently attempting to have it create a trajectory for a move group. However planning is failing, here's output below:

[ INFO] [1562088292.033876171, 130.937000000]: Planning request received for MoveGroup action. Forwarding to planning pipeline.
[ INFO] [1562088292.037457241, 130.940000000]: Found a contact between 'housing_back' (type 'Robot link') and 'housing_inner' (type 'Robot link'), which constitutes a collision. Contact information is not stored.
[ INFO] [1562088292.037527012, 130.940000000]: Collision checking is considered complete (collision was found and 0 contacts are stored)
[ INFO] [1562088292.037581084, 130.940000000]: Start state appears to be in collision with respect to group arm
[ WARN] [1562088292.076473969, 130.978000000]: Unable to find a valid state nearby the start state (using jiggle fraction of 0.050000 and 100 sampling attempts). Passing the original planning request to the planner.
[ INFO] [1562088292.079769807, 130.981000000]: Planner configuration 'arm' will use planner 'geometric::RRTConnect'. Additional configuration parameters will be set when the planner is constructed.
[ WARN] [1562088292.080857118, 130.982000000]: RRTConnect: Skipping invalid start state (invalid state)
[ERROR] [1562088292.080920947, 130.982000000]: RRTConnect: Motion planning start tree could not be  initialized!
[ INFO] [1562088292.080951436, 130.982000000]: No solution found after 0.000269 seconds
[ WARN] [1562088292.089499438, 130.991000000]: Goal sampling thread never did any work.
[ INFO] [1562088292.089602649, 130.991000000]: Unable to solve the planning problem

It appears from the output that there is a collision between the two links specified and for this reason the start state is invalid. However, in the SRDF, I have the following line:

<disable_collisions link1="housing_back" link2="housing_inner" reason="Adjacent" />

My understanding is that this line would prevent such a collision from generating an invalid state. Am I misinterpreting the log output or have I disabled collisions between these links incorrectly?

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answered 2020-01-09 13:05:47 -0500

agoins gravatar image

The move_group node loads the SRDF from the /robot_description_semantic or ~/robot_description_semantic rosparams. If you have run the MoveIt! setup assistant, you should have a my_robot_moveit_config package. In the package there is a planning_context.launch file which uploads the URDF and SRDF to the parameter server. Make sure that you are launching this file first. If that still doesn't fix the problem, try a remapping inside the move_group node: <remap from="~/robot_description_semantic" to="/robot_description_semantic" /> as it may be looking in the node's namespace, rather than in the global namespace.

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I'm having the same issue and tried your suggestions but the error is still there. Any other suggestions?

truhoang_ubtrobot gravatar image truhoang_ubtrobot  ( 2020-01-27 15:30:53 -0500 )edit

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Asked: 2019-07-02 12:43:32 -0500

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Last updated: Jan 09 '20