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The colman_description package contains the Xacro robot model and ros2_control controller configuration files for the Colman arm. It is the single source of truth for the robot’s kinematic structure, inertial properties, and hardware interface parameters used by robot_state_publisher, the controller manager, and MoveIt 2.

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Robot model

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colman.urdf.xacro

The top-level Xacro file that assembles the complete robot by composing upstream description packages. It accepts two parameters that control which links and hardware interfaces are included:
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gripper_type
string
default:"custom"
Selects the end-effector model and the corresponding ros2_control hardware interface.
ValueGripper description sourceController config
customgripper_descriptiongripper_controllers.yaml
robotiqrobotiq_descriptionrobotiq_controllers.yaml
vacuumgripper_description (vacuum tip)gripper_controllers.yaml
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use_camera
bool
default:"true"
When true, the OAK-D Pro depth camera model from oakd_description is attached to the wrist link. Set to false for configurations without the camera.
The Xacro also threads through all ur_robot_driver connection parameters (robot_ip, ur_type, tf_prefix, use_mock_hardware, headless_mode, script ports, etc.) to the upstream ur_description macro so a single file covers both real hardware and mock/simulation modes.
In simulation the bringup uses colman_gazebo/urdf/colman_gazebo.xacro instead of this file, which adds Gazebo-specific plugins. The two files share the same Xacro parameters so launch arguments are identical.

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Controller configuration

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gripper_controllers.yaml

Used when gripper_type is custom or vacuum. Configures controller_manager at 1000 Hz and defines four controllers:
ControllerType
joint_state_broadcasterjoint_state_broadcaster/JointStateBroadcaster
joint_trajectory_controllerjoint_trajectory_controller/JointTrajectoryController
forward_velocity_controllervelocity_controllers/JointGroupVelocityController
forward_position_controllerposition_controllers/JointGroupPositionController
gripper_controllerposition_controllers/GripperActionController
The joint_trajectory_controller controls all six UR joints via position command interfaces, publishing joint state at 100 Hz. The gripper_controller drives the servotodrivegear joint. 
# excerpt: gripper_controller parameters
gripper_controller:
  ros__parameters:
    default: true
    joint: servotodrivegear
    action_monitor_rate: 20.0
    allow_stalling: false
    stall_velocity_threshold: 0.001
    stall_timeout: 1.0

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robotiq_controllers.yaml

Used when gripper_type is robotiq. Identical arm controller definitions as above, but replaces gripper_controller with:
ControllerType
robotiq_gripper_controllerposition_controllers/GripperActionController
The Robotiq controller drives robotiq_85_left_knuckle_joint with a goal tolerance of 0.01 rad, max velocity 1.0 rad/s, and a 2 s stall timeout. 
# excerpt: robotiq_gripper_controller parameters
robotiq_gripper_controller:
  ros__parameters:
    default: true
    joint: robotiq_85_left_knuckle_joint
    stall_timeout: 2.0
    goal_tolerance: 0.01
    max_velocity: 1.0

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Runtime usage

colman_description does not expose any executables of its own. It is consumed by other packages:

colman_bringup

bringup.launch.py and rsp.launch.py invoke xacro on colman.urdf.xacro and pass the result to robot_state_publisher. The controller YAML files are loaded by ros2_control_node.

colman_moveit_config

colman_moveit.urdf.xacro inside colman_moveit_config wraps this description (without the ur_robot_driver hardware interfaces) to produce a model suitable for move_group.

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External dependencies

The package composes its URDF from these upstream description packages:
  • ur_description — UR3e kinematic chain and meshes
  • robotiq_description — Robotiq 2F-85 gripper model
  • oakd_description — OAK-D Pro camera link and visuals
  • gripper_description — custom parallel gripper and vacuum tip models

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