ocs2_ros2_control

Minimal ROS 2 control package that embeds the OCS2 mobile manipulator MPC stack in a ros2_control workflow. It provides:

• A fake hardware plugin (RidgebackUr5Hardware) that simulates Ridgeback + UR5 mobile manipulator (differential-drive mobile robot + 6-axis arm).

• An Ocs2Ros2Controller which bridges the hardware state to the OCS2 MRT/MPC interface and streams back the optimal commands.

The package is intentionally self‑contained (urdf/xacro, task and rviz config), but it depends on the upstream OCS2 ROS 2 repositories for the solver libraries and marker/MPC nodes.

Prerequisites

1. Install ROS 2 Humble (or a newer distro with the same APIs).
2. Clone and build wei-hsuan-cheng/ocs2_ros2 up to ocs2_mobile_manipulator_ros pkg:

   cd ~/ros2_ws
   colcon build --packages-up-to ocs2_mobile_manipulator_ros --symlink-install

   • Make sure the ocs2_ros2 workspace is sourced before building this package.

Build and Run Demo

# Build and install
cd ~/ros2_ws
colcon build --symlink-install --packages-select ocs2_ros2_control && . install/setup.bash
# Run ridgeback_ur5 demo with an interactive marker (default)
ros2 launch ocs2_ros2_control ridgeback_ur5_bringup.launch.py commandType:=marker
# Or: constant twist target for the mobile base + end-effector
ros2 launch ocs2_ros2_control ridgeback_ur5_bringup.launch.py commandType:=twist
# Or: figure-eight end-effector trajectory target
ros2 launch ocs2_ros2_control ridgeback_ur5_bringup.launch.py commandType:=trajectory

If you built ocs2_ros2 in another workspace, source it before running the commands above (so their messages and plugins are discoverable).

The demo launch file starts:

• ros2_control_node with the fake Ridgeback + UR5 hardware and the Ocs2Ros2Controller.
• The joint_state_broadcaster that publsihes joint_states from hardware.
• A target/command node selected via commandType (marker, twist, or trajectory).
• OCS2 MPC and marker nodes from ocs2_mobile_manipulator_ros.
• RViz (unless rviz:=false) with the copied visualization config.

Useful arguments:

Argument	Default	Description
rviz	true	Enable/disable RViz + interactive marker.
taskFile	local	Path to the OCS2 task.info file.
libFolder	local	Folder containing the auto-generated OCS2 libs.
urdfFile	local	URDF used by visualization nodes.
commandType	marker	Target interface to start: marker, twist, or trajectory.
markerPublishRate	100.0	Interactive marker publish rate (Hz, commandType=marker).

Folder layout

auto_generated/   -> pre-built OCS2 libraries (CppAD) for Ridgeback + UR5
config/           -> ros2_control YAML + task files
description/      -> xacro/urdf assets (ros2_control settings included)
include/          -> Header files
rviz/             -> RViz configuration copied from OCS2 examples
src/
  control/        -> ros2_control controllers (OCS2 bridge)
  hardware/       -> Ridgeback + UR5 fake_hardware (SystemInterface)
  visualization/  -> Marker, trajectory, and pose visualizations in RViz2

Notes

• The fake hardware integrates velocities directly; it is intended for controller bring-up and visualization only.
• auto_generated/ridgeback_ur5 is copied from the OCS2 examples for convenience. Regenerate those libraries if you modify the task model.
• The OCS2 MPC core process is provided by ocs2_mobile_manipulator_ros, make sure that package is present (from the upstream repo mentioned above).

Contact

• Author: Wei-Hsuan Cheng (johnathancheng0125@gmail.com)
• Homepage: wei-hsuan-cheng
• GitHub: wei-hsuan-cheng