prl_ur5_robot_configuration

This repo holds the current configuration of the bimanual UR5 robot.

Setups

For different experiments, the robot can be equipped with different grippers and sensors. To simplify the modification of the description, changeable parameters are placed in separate setup files in the config/ directory. Each setup file contains a list of used devices and calibration parameters. The calibration parameters contain the positions of the arms, grippers, sensors, and kinematic parameters of UR5 arms.

Custom gripper URDF

In the *_setup.yaml file, the type of gripper used for each arm is specified. Standard types are: 'onrobot-rg2', 'onrobot-rg6', 'onrobot-rg6-v2', ... (that are industrial gripper available at PRL). To attach custom tools at the end of one arm, custom URDFs need to be created to update the robot model. Those custom tools/URDF might not be long-lasting enough to integrate them in prl_ur5_robot repo. Thus, is what the custom_gripper/ directory of this repo is made for.

Usage

For example, to create a custom tool/gripper named my_gripper, prl_ur5_description expects to see :

• A file prl_ur5_robot_configuration/urdf/my_gripper.urdf.xacro containing:

<?xml version="1.0"?>
<robot xmlns:xacro="http://wiki.ros.org/xacro">
  <xacro:macro name="my_gripper" params="parent *origin prefix">
      ...
  </xacro:macro>
</robot>

with the first link being the child of ${parent} with a transform of *origin and all the link and joint having the prefix ${prefix} in front of their names.

• A file prl_ur5_robot_configuration/urdf/my_gripper.srdf.xacro containing:

<?xml version="1.0" encoding="UTF-8"?>
<robot xmlns:xacro="http://wiki.ros.org/xacro">
    <xacro:macro name="cylinder_tool_group_define" params="prefix">
        ...$1...
    </xacro:macro>

    <xacro:macro name="cylinder_tool_autocol" params="prefix">
        ...$2...
    </xacro:macro>

    <xacro:macro name="cylinder_tool_col_with" params="prefix link">
        ...$3...
    </xacro:macro>
</robot>

with $1 being <link> and <joint> tags defining the gripper, $2 being <disable_collision> tags to disable all the necessary autocollisions inside the gripper, and $3 being <disable_collision> tags to disable the collisions between all the gripper links and an arbitrary ${link} link.

Then in *_setup.yaml set:

...
  gripper: "custom:my_gripper"
...

Note: It is strongly recommended to create a link named ${prefix}_grasp_frame in the gripper URDF (corresponding to the tip/grasp point of the gripper/tool) to keep consistency with the other grippers.