allow gripper collision on the PR-2

Question

I want to allow the PR-2 gripper to collide with objects on a table. I am designing linear pushing motions. I am using motion_planning_msgs/CollisionOperation message in the MoveArmGoal message, but it does not seem to work.

Here are the message definitions. I use their example of object1 = "gripper" and object2 = COLLISION_SET_ALL. Any suggestion will be very helpful!

# A definition of a collision operation
# E.g. ("gripper",COLLISION_SET_ALL,ENABLE) will enable collisions 
# between the gripper and all objects in the collision space

string object1
string object2
string COLLISION_SET_ALL="all"
string COLLISION_SET_OBJECTS="objects"
string COLLISION_SET_ATTACHED_OBJECTS="attached"

# The penetration distance to which collisions are allowed. This is 0.0 by default.
float64 penetration_distance

# Flag that determines whether collisions will be enabled or disabled for the pair of objects specified above
int32 operation
int32 DISABLE=0
int32 ENABLE=1

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Originally posted by guzza on ROS Answers with karma: 11 on 2011-03-31

Post score: 0

Answer 1

Hi guzza,

If i remember well, for the pick action, the motion to the pre-grasp is planified with collision detection. But the last trajectory segment, from pre-grasp to grasp position, is made without collision detection.

I would suggest you to adopt the same approach: go to a pre-push position with a collision aware method and then switch to a non-collision-aware movement.

For how to do this last operation you can take a look at this tutorial.

Hope this helps,

Guido

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Originally posted by Guido with karma: 514 on 2011-03-31

This answer was ACCEPTED on the original site

Post score: 1