MoveIt2 Motion Planning#

Overview#

MoveIt2 is the primary motion planning integration for the WMX ROS2 application. It provides collision-aware trajectory planning, and the follow_joint_trajectory_server node executes the planned trajectories on real hardware via the WMX cubic spline engine.

Architecture#

MoveIt2 integration — end-to-end data flow

Prerequisites#

MoveIt2 must be installed as part of the workspace dependencies:

sudo apt install ros-${ROS_DISTRO}-moveit*

See Getting Started for the complete dependency list.

Configuration#

The follow_joint_trajectory_server node must be configured with the correct action name that MoveIt2 expects. This is set in the config YAML:

follow_joint_trajectory_server:
  ros__parameters:
    joint_number: 6
    joint_trajectory_action: /movensys_manipulator_arm_controller/follow_joint_trajectory

The action name must match the controller configuration in the MoveIt2 setup for your robot.

The manipulator_state node must publish to /joint_states so MoveIt2 can read the current robot state:

manipulator_state:
  ros__parameters:
    encoder_joint_topic: /joint_states

Usage#

  1. Launch the WMX ROS2 manipulator nodes (see Getting Started):

    sudo --preserve-env=PATH \
     --preserve-env=AMENT_PREFIX_PATH \
     --preserve-env=COLCON_PREFIX_PATH \
     --preserve-env=PYTHONPATH \
     --preserve-env=LD_LIBRARY_PATH \
     --preserve-env=ROS_DISTRO \
     --preserve-env=ROS_VERSION \
     --preserve-env=ROS_PYTHON_VERSION \
     --preserve-env=ROS_DOMAIN_ID \
     --preserve-env=RMW_IMPLEMENTATION \
     bash -c "source /opt/ros/\${ROS_DISTRO}/setup.bash && \
              source ~/wmx_ros2_ws/install/setup.bash && \
              ros2 launch wmx_ros2_package \
                wmx_ros2_cr3a_manipulator.launch.py \
                use_sim_time:=false"

  2. Launch MoveIt2 with your robot’s MoveIt configuration package.

  3. Plan and execute trajectories through the MoveIt2 interface (RViz plugin or programmatic API).

Trajectory Execution Details#

When MoveIt2 sends a trajectory, the follow_joint_trajectory_server processes it as described in the ROS2 Actions page:

  • Maximum 1000 waypoints per trajectory

  • Cubic spline interpolation via AdvancedMotion::StartCSplinePos()

  • The server blocks until motion completes

  • Returns error_code = 0 on success