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arm_navigation turtlebot considers only start&end positions

asked 2012-06-25 21:39:25 -0500

NTo gravatar image

Hello, I am using the turtlebot_arm_bringup constraint_aware_simple_arm_server.launch which uses the arm_navigation stack.

The problem
When I add a collision object that is neither at the start or end poses of the trajectory but somewhere in the middle, the arm ignores it and simply passes through it.

Attempts so far
I retrieved the planning scene before and after sending the goal to the arm, and the collision object is definitely present, and in the ¨allowed_collision_matrix¨ all entries for this object are marked as False.

When I move the object´s pose to collide with the end pose (i.e. the object pose is not identical to the end goal´s pose but the shape overlaps it) the 'move_arm' server returns ¨success: False¨ as it should. The same thing happens if the object collides with the starting pose.

What I thought the constraint_aware_simple_arm_server (or arm_kinematics_constraint_aware) is supposed to do given a goal, is calculate and execute a trajectory that will not pass through collision objects, is this wrong? Can I only get a regular (constraint-ignoring) trajectory and then check its validity?

Background details
ROS electric on ubuntu 11.10 (upgraded from 11.04)
Machine: Intel Core i5-2500 CPU @ 3.30GHz x 4. 32-bit.

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answered 2012-07-04 01:55:07 -0500

jep31 gravatar image


I'm doing the same thing with a arm robot. When I add a object between the start pose and the end pose, it's works correctly. The arm avoids the object. Add you the object during movement or before the trajectory calculation ? Me, my problem is when I add a object during the movement because the trajectory is already calculated y sent. So I check the state validity to know if there is collision but it's the same problem, I think the scene is not updated. I can't see mi object in Rviz during the movement.

How it's possible to actualize the scene ?

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Asked: 2012-06-25 21:39:25 -0500

Seen: 146 times

Last updated: Jul 04 '12