CORA Robot

ROS 2 Packages for the real cora robot.

ROS 2 Topics

Project Structure

cora_bringup
cora_codi
cora_description
cora_gripper_1_description
cora_moveit
cora_moveit_config
cora_msgs
cora_vision
odrive_base
odrive_ros2_control

Launch files

Some of these launch files allow specifying the gripper description package to use. See Adding a custom gripper for usage

bringup.launch.py

minimal robot launch file.

• Launch Contents:
  • codi_node
  • move.launch.py
  • vision.launch.py
• Parameters
  • use_codi
  • hardware_type
  • gripper_package

move.launch.py

launches all moveit related ros 2 nodes.

• Launch Contents:
  • move_group_node
  • moveit_py_node
  • servo_node
  • robot_state_publisher
  • ros2_control_node
  • rviz_node
  • static_tf
• Parameters
  • gripper_package
  • hardware_type

vision.launch.py

• Launch Contents:
  • camera_node
  • aruco_node

Adding a custom gripper

1. Make sure the package structure is as follows:

   gripper_description/
       meshes/
       urdf/
           cora_gripper.urdf
           cora_gripper.urdf.xacro
           cora_gripper.ros2_control.xacro

   The main cora urdf expects a gripper urdf called 'cora_gripper.urdf.xacro'. If the file name is different, xacro raises an error and the robot description will not load.

2. Wrap all contents of the xacro file in <xacro:macro/> tags with name cora_gripper_xacro, so the main urdf can instantiate it properly.

3. Add correct joint names. Finger1 for the main finger and Finger2 for the mimic.

4. Add correct fixed joints and dummy links for the moveit pipeline to use. Gripper and Camera for the links and Gripper_frame and Camera_frame for the fixed joints.

5. Add name, initial positions and hardware_type as parameters.

Examples:

• cora_gripper.urdf.xacro

    <?xml version="1.0"?>
    <robot xmlns:xacro="http://www.ros.org/wiki/xacro" name="cora_gripper">

    <xacro:macro name="cora_gripper_xacro" params="hardware_type initial_positions_file">

        <!-- Store gripper package path -->
        <xacro:property
            name="gripper_package_path"
            value="$(find cora_gripper_description)"/>

        <!-- Include gripper file using absolute path -->
        <xacro:include filename="${gripper_package_path}/urdf/cora_gripper.urdf" />
        <xacro:cora_gripper />

        <!-- Include control xacro -->
        <xacro:include filename="${gripper_package_path}/urdf/cora_gripper.ros2_control.xacro" />
        <xacro:cora_gripper_ros2_control
            name="GripperSystem"
            initial_positions_file="${initial_positions_file}"
            hardware_type="${hardware_type}"/>
    </xacro:macro>

    </robot>

• cora_gripper.ros2_control.xacro

  <?xml version="1.0"?>
  <robot xmlns:xacro="http://www.ros.org/wiki/xacro">
      <xacro:macro name="cora_gripper_ros2_control" params="name initial_positions_file hardware_type">
          <xacro:property name="initial_positions" value="${xacro.load_yaml(initial_positions_file)['initial_positions']}"/>
  
          <ros2_control name="${name}" type="system">
  
              <hardware>
              <!-- By default, set up controllers for fake system-->
              <xacro:if value="${hardware_type == 'Fake'}">
                  <plugin>mock_components/GenericSystem</plugin> <!-- Mock Components -->
              </xacro:if>
  
              <!-- Real Hardware Components -->
              <xacro:if value="${hardware_type == 'Real'}">
                  <plugin>gripper_1_ros2_control_plugin/GripperHardwareInterface</plugin>
                  <param name="can">can0</param>
              </xacro:if>
              </hardware>
  
              <joint name="Finger1">
                  <command_interface name="position"/>
                  <command_interface name="velocity"/>
                  <state_interface name="position">
                  <param name="initial_value">${initial_positions['Finger1']}</param>
                  </state_interface>
                  <state_interface name="velocity"/>
                  <param name="node_id">6</param>
              </joint>
  
          </ros2_control>
      </xacro:macro>
  </robot>
  

• cora_gripper.urdf

    <?xml version="1.0" ?>
    <robot xmlns:xacro="http://www.ros.org/wiki/xacro">
        <xacro:macro name="cora_gripper">

            <!-- Link gripper_body -->
            <link name="gripper_body">
                <inertial>
                <origin xyz="0 0 0" rpy="0 0 0"/>
                <mass value="1e-09"/>
                <inertia ixx="1e-09" ixy="0" ixz="0" iyy="1e-09" iyz="0" izz="1e-09"/>
                </inertial>
                <!-- Part gripper_body_parts -->
                <visual>
                <origin xyz="-7.4681e-15 -1.17217 -0.059" rpy="-1.5708 -1.5708 0"/>
                <geometry>
                    <mesh filename="package://cora_gripper_1_description/meshes/merged/gripper_body_visual.stl"/>
                </geometry>
                <material name="gripper_body_parts_material">
                    <color rgba="0.4 0.4 0.4 1.0"/>
                </material>
                </visual>
                <collision>
                <origin xyz="-7.4681e-15 -1.17217 -0.059" rpy="-1.5708 -1.5708 0"/>
                <geometry>
                    <mesh filename="package://cora_gripper_1_description/meshes/merged/gripper_body_collision.stl"/>
                </geometry>
                </collision>
            </link>

            <!-- Frame Gripper (dummy link + fixed joint) -->
            <link name="Gripper">
                <origin xyz="0 0 0" rpy="0 -0 0"/>
                <inertial>
                <origin xyz="0 0 0" rpy="0 0 0"/>
                <mass value="1e-9"/>
                <inertia ixx="0" ixy="0" ixz="0" iyy="0" iyz="0" izz="0"/>
                </inertial>
            </link>
            <joint name="Gripper_frame" type="fixed">
                <origin xyz="-1.75447e-17 0 -0.112" rpy="-3.14159 1.57702e-16 -1.11972e-30"/>
                <parent link="gripper_body"/>
                <child link="Gripper"/>
                <axis xyz="0 0 0"/>
            </joint>

            <!-- Frame Camera (dummy link + fixed joint) -->
            <link name="Camera">
                <origin xyz="0 0 0" rpy="0 -0 0"/>
                <inertial>
                <origin xyz="0 0 0" rpy="0 0 0"/>
                <mass value="1e-9"/>
                <inertia ixx="0" ixy="0" ixz="0" iyy="0" iyz="0" izz="0"/>
                </inertial>
            </link>
            <joint name="Camera_frame" type="fixed">
                <origin xyz="0.016614 0.0515 -0.0460957" rpy="-3.14159 3.23996e-14 3.14159"/>
                <parent link="gripper_body"/>
                <child link="Camera"/>
                <axis xyz="0 0 0"/>
            </joint>

            <!-- Link gripper_fingers -->
            <link name="gripper_fingers">
                <inertial>
                <origin xyz="0 0 0" rpy="0 0 0"/>
                <mass value="1e-09"/>
                <inertia ixx="1e-09" ixy="0" ixz="0" iyy="1e-09" iyz="0" izz="1e-09"/>
                </inertial>
                <!-- Part gripper_fingers_parts -->
                <visual>
                <origin xyz="1.17667 0.0095 0.07" rpy="-1.5708 -1.2413e-09 1.5708"/>
                <geometry>
                    <mesh filename="package://cora_gripper_1_description/meshes/merged/gripper_fingers_visual.stl"/>
                </geometry>
                <material name="gripper_fingers_parts_material">
                    <color rgba="0.4 0.4 0.4 1.0"/>
                </material>
                </visual>
                <collision>
                <origin xyz="1.17667 0.0095 0.07" rpy="-1.5708 -1.2413e-09 1.5708"/>
                <geometry>
                    <mesh filename="package://cora_gripper_1_description/meshes/merged/gripper_fingers_collision.stl"/>
                </geometry>
                </collision>
            </link>

            <!-- Joint from gripper_body to gripper_fingers -->
            <joint name="Finger1" type="prismatic">
                <origin xyz="0.07 0.0045 -0.0685" rpy="1.5708 -2.55351e-15 -1.5708"/>
                <parent link="gripper_body"/>
                <child link="gripper_fingers"/>
                <axis xyz="0 0 1"/>
                <limit effort="10" velocity="10" lower="0.0" upper="0.0385"/>
            </joint>

            <!-- Link gripper_fingers_2 -->
            <link name="gripper_fingers_2">
                <inertial>
                <origin xyz="0 0 0" rpy="0 0 0"/>
                <mass value="1e-09"/>
                <inertia ixx="1e-09" ixy="0" ixz="0" iyy="1e-09" iyz="0" izz="1e-09"/>
                </inertial>
                <!-- Part gripper_fingers_2_parts -->
                <visual>
                <origin xyz="-1.16767 0.0095 0.07" rpy="1.5708 1.2413e-09 1.5708"/>
                <geometry>
                    <mesh filename="package://cora_gripper_1_description/meshes/merged/gripper_fingers_2_visual.stl"/>
                </geometry>
                <material name="gripper_fingers_2_parts_material">
                    <color rgba="0.4 0.4 0.4 1.0"/>
                </material>
                </visual>
                <collision>
                <origin xyz="-1.16767 0.0095 0.07" rpy="1.5708 1.2413e-09 1.5708"/>
                <geometry>
                    <mesh filename="package://cora_gripper_1_description/meshes/merged/gripper_fingers_2_collision.stl"/>
                </geometry>
                </collision>
            </link>

            <!-- Joint from gripper_body to gripper_fingers_2 -->
            <joint name="Finger2" type="prismatic">
                <origin xyz="-0.07 -0.0045 -0.0685" rpy="1.5708 5.4956e-15 1.5708"/>
                <parent link="gripper_body"/>
                <child link="gripper_fingers_2"/>
                <axis xyz="0 0 1"/>
                <limit effort="10" velocity="10" lower="0.0" upper="0.0385"/>
                <mimic joint="Finger1" multiplier="1.0"/>
            </joint>

            <!-- Joint from endeffector to gripper_body -->
            <joint name="GripperFix" type="fixed">
                <origin xyz="4.44089e-16 3.45864e-19 -0.024" rpy="-6.10623e-15 4.51028e-15 1.5708"/>
                <parent link="endeffector"/>
                <child link="gripper_body"/>
                <axis xyz="0 0 1"/>
                <limit effort="10" velocity="10"/>
            </joint>

        </xacro:macro>
    </robot>