README

DRIMS2 Motion Server

Overview

drims2_motion_server is a small ROS 2 package that provides a MoveIt2-backed motion server and a convenient client API for manipulation tasks. It exposes actions for moving the robot to Cartesian poses and joint configurations, services for attaching/detaching objects in the MoveIt planning scene, and a simple gripper action client example. The package also includes small TF/affine utilities for frame conversions and an optional “virtual end-effector” offset to simplify tool-centered motion.

Features

  • MotionServer node: integrates pymoveit2 to plan & execute motions.

    • Actions: move_to_pose, move_to_joint (custom drims2_msgs actions).

    • Services: attach_object, detach_object (custom drims2_msgs services).

    • Supports Cartesian vs. IK-based motions, retry logic, and broadcasting a pose_goal_frame TF for debugging.

  • MotionClient node: a lightweight client wrapper that:

    • Sends goals to the server (MoveToPose, MoveToJoint).

    • Calls attach/detach services.

    • Controls a gripper via control_msgs/GripperCommand action. Take care of the action names.

  • drims2_utils: TF ↔ affine utilities and Pose/Transform helpers.

Requirements

  • ROS 2 (tested with Humble)

  • pymoveit2 and MoveIt 2 stack

  • drims2_msgs (defines MoveToPose, MoveToJoint, AttachObject, DetachObject)

The server uses a compute_ik service provided by MoveIt.

Installation

  1. Clone the repository into your ROS 2 workspace src/.

  2. Install Python dependencies (example using pip):

pip install -r requirements.txt
# or at least:
pip install numpy scipy pymoveit2

  1. Build the workspace:

colcon build --packages-select drims2_motion_server

  1. Source the workspace:

source install/setup.bash

Configuration (ROS parameters)

The server exposes several parameters (defaults shown in the node):

  • move_group_name (string, default: manipulator)

  • joint_names (string[], default: [''])

  • base_link_name (string, default: base_link)

  • end_effector_name (string, default: tool0)

  • planner_id (string, default: BiTRRT)

  • cartesian_max_step, cartesian_fraction_threshold, cartesian_jump_threshold (floats)

  • cartesian_avoid_collisions (bool)

  • max_velocity, max_acceleration (floats)

  • use_move_group_action (bool)

  • allowed_planning_time (float)

  • tolerance_position, tolerance_orientation (floats)

  • max_motion_retries, max_ik_retries (ints)

  • ik_timeout (int)

  • virtual_end_effector (string, name of a virtual frame; default: tip)

You can set these via ros2 param set or in a launch file.

Running the server

Start your MoveIt 2-related nodes (planning, controllers, joint_state_publisher) as required by your robot. Then launch the motion server node:

ros2 run drims2_motion_server motion_server_node

If everything is configured, the server will attempt to connect to the compute_ik service and report readiness.

Quick usage examples

Move to a pose (action)

Send a MoveToPose goal using the client node or ros2 action CLI. Example with ros2 action (you need to craft a suitable goal JSON/YAML):

ros2 action send_goal /move_to_pose drims2_msgs/action/MoveToPose "{pose_target: {header: { frame_id: 'base_link'}, pose: { position: { x: 0.5, y: 0.0, z: 0.2 }, orientation: { x: 0, y: 0, z: 0, w: 1 }}}, cartesian_motion: false }"

To use Cartesian motion set cartesian_motion: true.

Move to joint configuration (action)

ros2 action send_goal /move_to_joint drims2_msgs/action/MoveToJoint "{ joint_target: [0.0, -1.0, 1.0, 0.0, 0.0, 0.0] }"

Attach / Detach object (services)

ros2 service call /attach_object drims2_msgs/srv/AttachObject "{ object_id: 'my_box', target_frame_id: 'ee_link' }"
ros2 service call /detach_object drims2_msgs/srv/DetachObject "{ object_id: 'my_box' }"

Gripper command (example)

If your system exposes a gripper control_msgs/GripperCommand action (example name: robotiq_action_controller/gripper_cmd):

ros2 action send_goal /robotiq_action_controller/gripper_cmd control_msgs/action/GripperCommand "{ command: { position: 0.04, max_effort: 5.0 } }"

API Overview

MotionServer

  • Exposes action servers for MoveToPose and MoveToJoint.

  • Exposes services attach_object and detach_object.

  • Uses pymoveit2.MoveIt2 for planning and execution.

  • Handles IK computation via the compute_ik service.

  • Broadcasts a pose_goal_frame transform for debugging when a goal pose is received.

  • Implements retry loops for both IK and motion execution.

MotionClient

Node wrapper around action servers and services to simplify usage from Python scripts. Here you can find the available API.

Contributing

Contributions and bug reports are welcome. Open issues or pull requests in the repository.