Quad Simulator¶

Overview¶

This directory is a meta-package that groups the Mujoco and Gazebo simulation infrastructure and all supported robot descriptions used by Quad-SDK. It contains:

gazebo_plugins/ — Gazebo system plugins for controller bridging and state estimation injection.
gazebo_scripts/ — terrain worlds, meshes, and bring-up scripts for Gazebo Harmonic.
*_description/ — URDF/meshes for each supported platform (see below).

The simulation side of Quad-SDK targets Gazebo Harmonic (via ros_gz_bridge) on ROS2 Jazzy; legacy Gazebo Classic support has been removed. A MuJoCo back-end is also available — see the top-level quad_mujoco.py launch file.

License¶

The source code is released under a MIT License. The Spirit40 model was originally created by Ghost Robotics. The Gazebo bring-up structure is based on kodlab_gazebo.

Original kodlab_gazebo author: Vasileios Vasilopoulos

Affiliation: Robomechanics Lab, Carnegie Mellon University

Maintainer: Justin Yim (jkyim@andrew.cmu.edu)

Tested under ROS2 Jazzy on Ubuntu 24.04 with Gazebo Harmonic.

Supported Robots¶

Package	Platform
`a1_description`	Unitree A1
`b2_description`	Unitree B2
`go1_description`	Unitree Go1
`go2_description`	Unitree Go2
`go2w_description`	Unitree Go2-W (wheeled)
`spirit_description`	Ghost Robotics Spirit40
`spot_description`	Boston Dynamics Spot
`vision60_description`	Ghost Robotics Vision60

Each description package ships URDF/Xacro files and collision/visual meshes. Friction and inertial parameters for foot contact are tuned in the URDF.

Subpackages¶

`gazebo_plugins`¶

C++ Gazebo plugins:

controller_plugin — bridges between the Quad-SDK control stack and Gazebo's actuator interface, applying joint torques computed by robot_driver.
estimator_plugin — publishes ground-truth state from the simulator for use as state/ground_truth or as a reference for EKF evaluation. Sets use_sim_time=true via parameter_overrides at Node construction (so node_->now() returns sim time from the first call) and skips publishing while the rclcpp clock still reports wall-clock time.
spawn_lock_plugin — pins the body link at its spawn pose for <hold_duration> seconds (default 8 s) while gz_ros2_control loads its joint controllers, then releases. Joints articulate freely throughout, so per-robot controllers can fold the legs into their commanded sit pose without the body tipping. Releases on whichever clock crosses hold_duration first (sim or wall) for resilience against per-instance sim-time stalls.

Plugins are registered via controller_plugin.xml and loaded into each simulated model by the URDF/SDF.

`gazebo_scripts`¶

Terrain models, worlds, and utility scripts. Available terrain models (under gazebo_scripts/models/):

flat                 big_flat             slope_20             slope_20_hole
step_10cm            step_15cm_local_min  step_20cm            step_25cm
step_30cm            step_10cm_local_min
gap_20cm             gap_40cm             gap_40cm_local_min   gap_80cm
rough_25cm           rough_40cm_huge      parkour_local_min

Build¶

colcon build --packages-select \
  gazebo_plugins gazebo_scripts \
  a1_description b2_description go1_description go2_description go2w_description \
  spirit_description spot_description underbrush_description vision60_description

Usage¶

Launch Gazebo with the default robot (Go2) and flat terrain:

ros2 launch quad_utils quad_gazebo.py

Launch with MuJoCo:

ros2 launch quad_utils quad_mujoco.py

Robot and terrain selection are set via launch arguments — see quad_utils/launch/quad_gazebo.py for the full argument list.

Bugs & Feature Requests¶

Please report bugs and request features using the Issue Tracker.