Launching Gripper Click Tool

The gripper click tool in this package is implemented as rviz display. It will be integrated to the package pr2_gripper_click in the future and will be started as part of the pr2_interactive_manipulation package and please refer to that package's document on how to start the entire interactive manipulation pipeline then.

For now, please follow the steps as in below:

On the robot

Start the following launch file:

roslaunch pr2_interactive_manipulation pr2_interactive_manipulation_robot.launch

On the desktop

Run the grasp evaluation service node:

rosrun graspable_features grasp_evaluation_server

Start the following launch file:

roslaunch graspable_features pr2_interactive_manipulation_with_GripperClick_Voxelgrid_desktop.launch

Note that this launch file will bring up rviz. The PR2 Interactive Manipulation tools are implemented as rviz plugins. In particular, you will see the Interactive manipulation dialog pop up:

The launch file above will also instantiate all the other rviz displays that you need, although some of them will be disabled on launch.

Using Gripper Click Tool

The display will not display anything unless called by the interactive manipulation pipeline. An image from the narrow angle robot camera will be shown if called. Points which doesn't have associated depth information will be marked in light red, and those are not usable for grasp selection.

Grasping

You just need to select a location, which is supposed to be roughly the location on the object to be grasped, and drag an arrow, denoting the projection of the gripper's approaching direction on the image plane

• left click on a non-red point on the image to select the gripper location
• drag to choose the approaching direction (projected to the image plane)

If you want to approach the object perpendicular to the image plane,

• left click on a non-red point on the image to select the gripper location
• double click to finish the selection

Possible 6-d gripper poses based on the user's input will be sampled and evaluated. Some gripper pose suggestions will be made based on the evaluation results and the gripper will be shown on the interface.

• middle click to switch to the next available pose suggestion

Placing

Since it's not integrated with pr2_gripper_click yet, there's no placing functionality in this tool. Simply open the gripper, object will fall out of the robot hand.

ROS API

API Stability

• ROS API is UNREVIEWED and UNSTABKE

Services Offered

/grasp_evaluation_server_node/evaluate_grasp (graspable_features/EvaluateGrasp)

• This service takes in a point cloud and a list of grasp poses, which will be evaluated on this point cloud. A list of scores will be returned. The score of a grasp represents the possibility that this grasp is likely to succeed. It has a range of [0, 1].

Technical Details

Please refer to Emma Zhang's intern presentation for technical details. You can read the slide either from this link or the incoming intern blog post on http://www.willowgarage.com/blog