System Architecture

Two modes: simulation (Isaac Sim on workstation) and real robot (Unitree G1 with Jetson Orin). Both share the same Isaac ROS container on the workstation for GPU perception and visualization.

Simulation Mode

Data Flow (Sim)

Isaac Sim renders scene + simulates physics for G1 robot
Bundled ROS 2 bridge publishes camera, IMU, joint state topics via DDS
Isaac ROS container receives topics over UDP DDS (FastDDS SHM disabled)
GPU perception runs on RTX 3090: SLAM, AprilTag, nvblox
H.264 NVENC republisher encodes camera feeds for remote viewing
foxglove-bridge exposes all topics over WebSocket on port 8765
Foxglove Studio connects from browser (Mac via Tailscale)

Isaac Lab Training

Isaac Lab runs headless in the isaaclab conda env
Trains RL policies for G1 locomotion, manipulation
No Isaac ROS container needed during training (pure sim loop)
Trained policies deploy to real G1 via unitree_ros2

Real Robot Mode

Data Flow (Real)

G1’s Orin publishes camera, IMU, joint state topics via CycloneDDS
Workstation’s Isaac ROS container receives topics over DDS (Ethernet)
GPU perception runs on RTX 3090 (offloaded from Orin for heavy tasks)
Results published back to G1 over DDS (SLAM pose, detections, maps)
foxglove-bridge + H.264 republisher provide remote visualization
Foxglove Studio connects from browser

G1 Network Topology

Device	IP	Role
Development PC (workstation)	192.168.123.99	Isaac ROS container, visualization
G1 internal RockChip	192.168.123.161	Low-level motor control
G1 internal Orin	192.168.123.164	High-level control, sensors, ROS 2

G1 ROS 2 Topics

Topic	Type	Direction
`/lowstate`	`unitree_hg::LowState`	G1 -> workstation
`/lowcmd`	`unitree_hg::LowCmd`	workstation -> G1
`/api/sport/request`	High-level motion	workstation -> G1
Camera topics	`sensor_msgs/Image`	G1 -> workstation
IMU topics	`sensor_msgs/Imu`	G1 -> workstation

DDS Configuration

G1 uses CycloneDDS (not FastDDS). Set in the Isaac ROS container:

export RMW_IMPLEMENTATION=rmw_cyclonedds_cpp
export CYCLONEDDS_URI='<CycloneDDS><Domain><General><Interfaces>
  <NetworkInterface name="eth0" priority="default" multicast="default"/>
</Interfaces></General></Domain></CycloneDDS>'

ros2_jazzy base image ships with rmw_cyclonedds_cpp pre-installed.

Orin vs Workstation GPU Perception

The G1’s Orin can run Isaac ROS perception locally, but the RTX 3090 is far more powerful.

Workload	Location	Examples
Heavy perception	Workstation (RTX 3090)	SLAM, nvblox, large model inference
Latency-critical	Orin (final deployment)	Obstacle detection, emergency stop

During development, run everything on workstation.

Isaac ROS Container — What’s Inside

Base: Full NVIDIA Image

nvcr.io/nvidia/isaac/ros:noble-ros2_jazzy_<hash>-amd64

Includes ROS 2 Jazzy (50+ packages), TensorRT, PyTorch, nav2, rviz2, foxglove-bridge, slam_toolbox, OpenCV, CUDA dev tools, VPI, CV-CUDA, and Triton.

Custom Dockerfile Additions

Package	Purpose
`ros-jazzy-isaac-ros-apriltag`	GPU AprilTag detection
`ros-jazzy-isaac-ros-visual-slam`	cuVSLAM
`ros-jazzy-isaac-ros-nvblox`	GPU 3D reconstruction
`ros-jazzy-foxglove-compressed-video-transport`	H.264 NVENC for Foxglove
`ros-jazzy-ffmpeg-encoder-decoder`	ffmpeg NVENC support
`ffmpeg`	CLI tool
FastDDS no-SHM XML	Fix SHM transport for sim mode
Entrypoint: `50-foxglove-bridge.sh`	Auto-start foxglove-bridge
Entrypoint: `60-h264-republisher.sh`	Auto-start H.264 NVENC republisher

What’s NOT Needed in the Container

Unitree SDK — runs on the G1’s Orin, not the workstation
Unitree ROS 2 packages — G1 publishes standard ROS 2 topics, container just subscribes
System ROS 2 on host — conflicts with Isaac Sim’s bundled Python 3.11 rclpy
Separate Unitree Docker container — G1 is a standard ROS 2 robot from the container’s perspective

Unitree Software Stack (Reference)

Runs on the G1, not the workstation.

Package	Location	Purpose
`unitree_sdk2`	G1 Orin	C++ SDK for motor control
`unitree_sdk2_python`	G1 Orin	Python bindings via pybind11
`unitree_ros2`	G1 Orin	ROS 2 bridge (publishes topics)
CycloneDDS 0.10.2+	G1 Orin	DDS middleware

Simulation Equivalents

Real	Simulated
`unitree_ros2` on Orin	Isaac Sim’s bundled ROS 2 bridge
Physical sensors	Simulated cameras/IMU in Isaac Sim
`unitree_sdk2` motor control	Isaac Sim physics engine
G1 USD model	`unitree_sim_isaaclab` or Isaac Lab `g1.usd`