Planned outcomes

After completing this guide, you will have a UR5e mock-hardware stack built on the TalTech ROS Desktop Jazzy image on the ROS computer and Unity 6000.3.23f1 on the Unity computer. ROS 2 stays inside the container: the host only needs Docker. You will build the application layer yourself, so there are no mystery layers to debug later.

UR mock hardware + joint_trajectory_controller
  → /joint_states (sensor_msgs/JointState)
  → ROS TCP Endpoint :10002
  → ROSConnection in Unity
  → RobotJointStatesListener
      validates and maps by exact joint name
  → RobotJointStateMirror
      forwards each newly accepted immutable snapshot
  → UrdfRobotMotionController
      revalidates robot metadata and actuates ArticulationBody joints

Layer	Owns	Does not own
UR driver / `ros2_control`	Robot state and trajectory execution	Unity rendering
ROS TCP Endpoint	ROS ↔ TCP message bridge	Robot semantics
`ROSConnection`	Socket lifecycle and ROS serialization	Joint mapping
`RobotJointStatesListener`	Validation, name mapping, telemetry, accepted snapshots	Actuation
`RobotJointStateMirror`	Snapshot handoff and failure isolation	Transport or kinematics
`UrdfRobotMotionController`	Metadata-bound articulation targets	ROS subscription

Prerequisites

ROS computer — Docker Engine with the Compose plugin. Do not install ROS 2 on the host; the TalTech ROS Desktop Jazzy image provides Ubuntu 24.04, ROS 2 Jazzy, build tools, and the desktop environment.
Unity computer — Unity Hub and Unity 6000.3.23f1. It may be the same machine.
One normal host account that can run docker compose without entering the container as root.

Pick one unused ROS_DOMAIN_ID for this stack. The examples use 72.

Steps

1. Build the ROS application image

Create a small project on the ROS computer:

mkdir -p ~/ur5e-ros2-unity
cd ~/ur5e-ros2-unity

mkdir -p ~/.config/ur5e-unity
umask 077
openssl rand -base64 24 > ~/.config/ur5e-unity/selkies-password
chmod 600 ~/.config/ur5e-unity/selkies-password

Create Dockerfile:

FROM taltechivarlab/ros-desktop:jazzy@sha256:119849d6fd85af83ced74b80a2988c864546fa72446d92f0a39c33fa3f25a27a

ARG ROS_TCP_ENDPOINT_REV=54c1a64b6d5ef6ffa0a0431570bb74329b79b15b

USER root
RUN apt-get update && \
    apt-get install -y --no-install-recommends \
      git \
      ros-jazzy-ros2controlcli \
      ros-jazzy-ur && \
    rm -rf /var/lib/apt/lists/*

RUN mkdir -p /opt/ros2_unity_ws/src/ros_tcp_endpoint && \
    git -C /opt/ros2_unity_ws/src/ros_tcp_endpoint init && \
    git -C /opt/ros2_unity_ws/src/ros_tcp_endpoint remote add origin \
      <https://github.com/Unity-Technologies/ROS-TCP-Endpoint.git> && \
    git -C /opt/ros2_unity_ws/src/ros_tcp_endpoint fetch --depth=1 origin \
      "${ROS_TCP_ENDPOINT_REV}" && \
    git -C /opt/ros2_unity_ws/src/ros_tcp_endpoint checkout --detach FETCH_HEAD && \
    test "$(git -C /opt/ros2_unity_ws/src/ros_tcp_endpoint rev-parse HEAD)" = \
      "${ROS_TCP_ENDPOINT_REV}" && \
    bash -lc 'source /opt/ros/jazzy/setup.bash && cd /opt/ros2_unity_ws && colcon build --merge-install --packages-select ros_tcp_endpoint'

This keeps TalTech's tested Jazzy environment as the base, then adds the Universal Robots ROS 2 Driver and the exact validated ROS TCP Endpoint revision as a reproducible application layer.

<aside> 💡

The base-image digest is pinned deliberately. Update it only after validating a newer jazzy image; do not silently turn the tutorial into a moving target.

</aside>

2. Launch the container

Create compose.yaml: