Gazebo and ros2_control

Gazebo Harmonic is the physics simulator (gz-sim 8): rigid bodies, contacts, cameras, custom system plugins. It is the physical ground truth for the baseline.

ros2_control is the standard control stack: a controller manager loads controllers (joint trajectory, gripper position, joint-state broadcaster) that read/write hardware interfaces.

gz_ros2_control is the bridge plugin: simulated joints look like a real robot to ros2_control. Controllers do not care whether the “motor” is metal or a physics engine.

Why it matters here

MoveIt does not talk to Gazebo directly:

MoveIt trajectory
  → FollowJointTrajectory controllers
  → gz_ros2_control
  → Gazebo joints

Grasping uses a custom Gazebo attachment system (detachable joint) plus a ROS adapter, because beverage restock needs carry semantics beyond open/close fingers. The baseline uses wrist RGB-D confirmation for operational object poses and wrist surveys for lane evidence. The ground-truth adapter publishes separate evaluator topics by default; it is an explicit opt-in operational source.

Arm and rail controllers are velocity (+ feed-forward); the gripper is position (simulation lag on the gripper is expected). The simulation clock arrives on /clock: use it for acquisition stamps, TF lookups, observation freshness and controller timing. Operation and whole-task budgets deliberately use a steady clock, so a paused or slow simulation can still exceed a deadline. Record both clocks when investigating a timeout.

This project

Piece	Path
World SDF	restocker_gazebo/worlds/restocking.sdf
Attachment plugin	restocker_gazebo/src/attachment_system.cpp
Ground-truth adapter	…/src/ground_truth_adapter.cpp
Attachment ROS node	…/src/attachment_adapter_node.cpp
Hardware tags	restocker_description/urdf/ros2_control.xacro
Controllers	restocker_control/config/controllers.yaml

ros2_control                         Gazebo Harmonic
────────────                         ───────────────
controller_manager
  ├─ arm_controller ──┐
  ├─ rail_controller ─┼─► gz_ros2_control ─► joints / physics / cameras
  ├─ gripper_controller┘
  └─ joint_state_broadcaster

attachment_system plugin ─► attachment ROS adapter

References

• Official docs: Gazebo Harmonic get started
• Official docs: ROS 2 interoperability (Harmonic)
• Official docs: ros2_control (Jazzy)
• Official docs: gz_ros2_control (Jazzy)
• Reference implementation: ros-controls/gz_ros2_control
• This project: Simulation and control · packages restocker_gazebo/, restocker_control/