Services, Actions, and Runtime Parameters

Service names below are relative to the server namespace, usually /mujoco_server.

Simulation Control

set_pause (mujoco_ros_msgs/SetPause): Pauses or resumes the simulation.
reset (std_srvs/Empty): Resets the current simulation state.
reload (mujoco_ros_msgs/Reload): Reloads the current model or loads a replacement model string/path from the request.
shutdown (std_srvs/Empty): Requests server shutdown.
set_rt_factor (mujoco_ros_msgs/SetFloat): Changes the desired real-time factor.
load_initial_joint_states (std_srvs/Empty): Re-applies configured initial joint positions and velocities.
get_loading_request_state (mujoco_ros_msgs/GetStateUint): Reports the current loading request state.
get_sim_info (mujoco_ros_msgs/GetSimInfo): Returns model path, validity, load count, loading state, pause state, pending step count, measured real-time factor, and desired real-time factor.

State and Property Services

get_body_state / set_body_state: Read or update a body by body name or by a geom belonging to that body. The setter can selectively apply pose, twist, mass, and qpos reset behavior.
get_geom_properties / set_geom_properties: Read or update geom type, body mass, friction, and size fields.
get_eq_constraint_parameters / set_eq_constraint_parameters: Read or update equality constraint parameters by name, including active state, solver parameters, anchor/relative pose fields, torquescale, and polynomial coefficients.
get_gravity / set_gravity: Read or update the simulation gravity vector.
get_plugin_stats (mujoco_ros_msgs/GetPluginStats): Returns plugin load/reset timing and exponential moving averages for control, passive, render, and last-stage callbacks.

Step Action

step (mujoco_ros_msgs/StepAction): Steps a paused simulation for num_steps MuJoCo steps. Feedback reports steps_left. The action succeeds when all requested steps complete and is preempted if the simulation is unpaused, reset, shut down, or the action is canceled.

Admin Hash

Protected requests include an admin_hash field. When eval_mode is disabled, the server accepts the operations normally. When eval_mode is enabled, mutating or sensitive operations require the request hash to match the hash configured at launch.

Runtime Parameters

ROS 1 exposes mujoco_ros/SimParams through dynamic reconfigure. ROS 2 exposes the same runtime tuning surface as standard node parameters on /mujoco_server. The parameter names are intentionally flat and match the ROS 1 dynamic reconfigure names.

The most important user-facing groups are:

Pause/resume through running.
Runtime admin_hash updates.
Physics options: integrator, friction cone, Jacobian type, and solver.
Algorithmic options: timestep, solver iterations/tolerances, CCD, and SDF iteration settings.
Physical options: gravity, wind, magnetic field, density, viscosity, and impedance ratio.
MuJoCo enable/disable flags such as gravity, contact, actuation, warmstart, and related solver/runtime flags.

unpause is a startup parameter. Use running for runtime pause/resume through dynamic reconfigure in ROS 1 or ros2 param set in ROS 2.

Example ROS 2 runtime updates:

ros2 param set /mujoco_server running false
ros2 param set /mujoco_server timestep 0.002
ros2 param set /mujoco_server gravity "0 0 -3.71"

Use services for scripted state changes and runtime parameters for interactive physics tuning.

Plugin Services

/sensors/register_noise_models: Provided by mujoco_ros_sensors. Registers per-sensor noise models.
/set_mocap_state: Provided by mujoco_ros_mocap_plugin. Applies a mujoco_ros_msgs/MocapState to named mocap bodies.