Topics: Limit Documentation

Topic Reference complete roster

Every topic in the Limit stack: the production (live driving) and sim (Gazebo) sides, with location, type, owner, purpose, and status. This page is the reference roster.

Two Nav2 stacks. The Limit system runs two complete, independent Nav2 stacks, both on the bare-metal server (ROS_DOMAIN_ID=0), kept deliberately separate so simulation logic never mixes with live driving. The production stack uses standard Nav2 naming. The sim stack uses sim_* or /gazebo/* prefixes. Disjoint namespaces prevent collision. The robot runs sensor drivers only: no Nav2 nodes. Topic naming follows ROS REP 103 (Topic Names).

Topic Roster

Each row is one functional channel, showing the production (robot) topic name and the sim (Gazebo) name where one exists.

Channel	Production (robot)	Sim (Gazebo)
Odometry	`/odom`	`/sim_odom` · `/sim_odom_gt`
Map-frame pose	`/amcl_pose`	`/sim_amcl_pose`
TF	`/tf` · `/tf_static`	`/sim_tf` · `/sim_tf_static`
Commanded velocity	`/cmd_vel`	`/sim_cmd_vel` · `/sim_cmd_vel_smooth`
Joint states	`/joint_states`	`/sim_joint_states/joint_states`
Leg trajectory	`/joint_group_effort_controller/joint_trajectory`	`/sim_joint_group_effort_controller/joint_trajectory`
Foot contacts	`/foot_contacts`	`/sim_foot_contacts` · `/gazebo/contact/{lf,rf,lr,rr}`
IMU	`/zed2i_front/zed_node/imu/data` → `/imu_corrected`	`/sim_imu`
GNSS	`/fix` · `/vel`	`/sim_gps`
Camera	`/zed2i_front/zed_node/rgb/color/rect/image/compressed`	`/sim_rgb_image`
LiDAR	`/ouster/points` · `/ouster/scan`	none
Nav2	`/controller_server` · `/planner_server` · `/behavior_server` · `/bt_navigator`	none
Map	`/map` · `/goal_pose`	none

Costmaps: Global

All topics on the server: Nav2 global_costmap. Each consumed by Dash and the Nav2 stack.

Topic	Purpose
/global_costmap/costmap	Combined occupancy grid → Dash
/global_costmap/costmap_raw	Raw (unthresholded) grid → Dash
/global_costmap/costmap_updates	Combined region updates (delta grids) → Dash
/global_costmap/costmap_raw_updates	Raw region updates (delta grids) → Dash
/global_costmap/footprint	Footprint echo of `/footprint`
/global_costmap/published_footprint	Footprint echo → Dash
/global_costmap/obstacle_layer	Obstacle layer grid → Dash
/global_costmap/obstacle_layer_raw	Obstacle layer raw → Dash
/global_costmap/obstacle_layer_updates	Obstacle layer updates → Dash
/global_costmap/obstacle_layer_raw_updates	Obstacle layer raw updates → Dash
/global_costmap/static_layer	Static map layer grid → Dash
/global_costmap/static_layer_raw	Static layer raw → Dash
/global_costmap/static_layer_updates	Static layer updates → Dash
/global_costmap/static_layer_raw_updates	Static layer raw updates → Dash
/global_costmap/transition_event	`Costmap2D` component lifecycle state → Dash
/global_costmap/global_costmap/transition_event	`Costmap2D` component lifecycle state → Dash

Costmaps: Local

The local costmap's obstacle layer is the voxel layer (3D, point-cloud-based): hence the /voxel_layer* rows. All on the server.

Topic	Purpose
/local_costmap/costmap	Combined occupancy grid → Dash
/local_costmap/costmap_raw	Raw (unthresholded) grid → Dash, `behavior_server`
/local_costmap/costmap_updates	Combined region updates → Dash
/local_costmap/costmap_raw_updates	Raw region updates → Dash
/local_costmap/footprint	Footprint echo of `/footprint`
/local_costmap/published_footprint	Footprint echo → Dash
/local_costmap/obstacle_layer	Obstacle layer grid → Dash
/local_costmap/obstacle_layer_raw	Obstacle layer raw → Dash
/local_costmap/obstacle_layer_updates	Obstacle layer updates → Dash
/local_costmap/obstacle_layer_raw_updates	Obstacle layer raw updates → Dash
/local_costmap/static_layer	Static map layer grid → Dash
/local_costmap/static_layer_raw	Static layer raw → Dash
/local_costmap/static_layer_updates	Static layer updates → Dash
/local_costmap/static_layer_raw_updates	Static layer raw updates → Dash
/local_costmap/transition_event	`Costmap2D` lifecycle state → Dash
/local_costmap/local_costmap/transition_event	`Costmap2D` lifecycle state → Dash

Unscoped Costmap Layer Mirrors

Nav2 publishes costmap data both scoped and unscoped. These are unscoped mirrors of the corresponding /global_costmap/<layer> or /local_costmap/<layer> topics.

Unscoped topic	Description
/costmap	Mirror of `/global_costmap/costmap` or `/local_costmap/costmap`
/costmap_raw	Mirror of `/global_costmap/costmap_raw`
/costmap_raw_updates	Mirror of `/global_costmap/costmap_raw_updates`
/costmap_updates	Mirror of `/global_costmap/costmap_updates`
/obstacle_layer	Mirror of `/global_costmap/obstacle_layer` or `/local_costmap/obstacle_layer`
/obstacle_layer_raw	Mirror of `/global_costmap/obstacle_layer_raw`
/obstacle_layer_raw_updates	Mirror of `/global_costmap/obstacle_layer_raw_updates`
/obstacle_layer_updates	Mirror of `/global_costmap/obstacle_layer_updates`
/published_footprint	Mirror of `/global_costmap/published_footprint`
/static_layer	Mirror of `/global_costmap/static_layer`
/static_layer_raw	Mirror of `/global_costmap/static_layer_raw`
/static_layer_raw_updates	Mirror of `/global_costmap/static_layer_raw_updates`
/static_layer_updates	Mirror of `/global_costmap/static_layer_updates`
/voxel_layer	Mirror of `/local_costmap/voxel_layer` (3D point-cloud layer)
/voxel_layer_raw	Mirror of `/local_costmap/voxel_layer_raw`
/voxel_layer_raw_updates	Mirror of `/local_costmap/voxel_layer_raw_updates`
/voxel_layer_updates	Mirror of `/local_costmap/voxel_layer_updates`

ROS Internals & Lifecycle

Topic	Location & purpose
/amcl/transition_event	server: Nav2 `amcl` · AMCL lifecycle state → Dash
/behavior_server/transition_event	server: Nav2 `behavior_server` · Backup/rotate/wait actions lifecycle → Dash
/bond	robot: ros2_control · rclcpp_lifecycle bond keepalive between lifecycle nodes and `lifecycle_manager`
/bt_navigator/transition_event	server: Nav2 `bt_navigator` · Action router lifecycle → Dash
/bt_navigator_navigate_through_poses_rclcpp_node/transition_event	server · `navigate_through_poses` action server lifecycle → Dash
/bt_navigator_navigate_to_pose_rclcpp_node/transition_event	server · `navigate_to_pose` action server lifecycle → Dash
/clock	server · Sim-time clock. With `use_sim_time:=true`, all Nav2 nodes stall until this flows (25 subscribers). Gazebo `gz-sim` publishes when sim is up.
/controller_server/transition_event	server: Nav2 `controller_server` · Pure Pursuit lifecycle → Dash
/diagnostics	shared · Aggregated diagnostics. Publishers: `lifecycle_manager`, `zed_node` → Dash
/joint_group_effort_controller/joint_trajectory	robot: CHAMP `quadruped_controller` (live) · joint-effort trajectory from the gait + IK loop. Sim path: `/sim_joint_group_effort_controller/joint_trajectory`
/lifecycle_manager/managed_nodes_activated	server: `lifecycle_manager` · Which managed nodes (AMCL, map_server) are activated
/map_server/transition_event	server: Nav2 `map_server` · Map server lifecycle → Dash
/parameter_events	shared · Parameter-change events, emitted by every node
/planner_server/transition_event	server: Nav2 `planner_server` · NavFn lifecycle → Dash
/rosout	shared · System log stream: every node publishes log records
/smoother_server/transition_event	server: Nav2 `smoother_server` · Smoother lifecycle → Dash
/tf	shared · Live TF. Publishers: `amcl` (map→odom), `zed_node`, `zed2i_front_state_publisher`
/tf_static	shared · Static TF: `base_link_to_os_sensor`, `base_link_to_zed_camera`, `navsat_transform`, `os_driver`, `zed2i_front_state_publisher`
/velocity_smoother/transition_event	server: Nav2 `velocity_smoother` · Velocity smoother lifecycle → Dash

Sim Tier (on-demand: live only when sim stack is up)

No publisher in the current capture: sim stack not launched. These exist in code (gazebo_relay.yaml, limit_limit_launch.py, gazebo_topic_relay.py) and are subscribed by limit_dash_bridge (Dash Tier-1/2 fallbacks).

Topic	Purpose
/sim_amcl_pose	Map-frame sim pose = GT + constant (5,5) offset, published by `gt_pose_bridge` → Dash Tier-3 pose
/sim_cmd_vel_smooth	`cmd_vel_stamped_to_twist` → `quadruped_controller`. The single way a velocity command reaches the Gazebo legs
/sim_foot_contacts	Foot contacts (champ_msgs/ContactsStamped), bridged by `foot_contacts_bridge`
/sim_gps	Gazebo navsat fix (~zero)
/sim_imu	Gazebo IMU
/sim_joint_group_effort_controller/joint_trajectory	Joint-effort trajectory → Gazebo `joint_group_effort_controller`, published by `quadruped_controller`
/sim_joint_states/joint_states	Sim joint states (namespaced variant; robot keeps bare `/joint_states` exclusively)
/sim_odom_gt	Gazebo ground-truth odometry (world frame). Authoritative in sim; consumed by `gt_pose_bridge`
/sim_rgb_image	Gazebo camera image → Dash

/gazebo/* Relay Mirrors (on-demand)

Passive mirrors published by gazebo_topic_relay; visible only while sim stack runs; each /gazebo/* name has exactly one publisher.

Topic	Mirrors
/gazebo/base_to_footprint_pose	`/sim_base_to_footprint_pose`
/gazebo/body_pose	`/sim_body_pose`
/gazebo/camera/image	`/sim_rgb_image`
/gazebo/cmd_vel	`/cmd_vel` (TwistStamped view)
/gazebo/contact/lf	`/sim_lf_foot_contacts`
/gazebo/contact/lr	`/sim_lr_foot_contacts`
/gazebo/contact/rf	`/sim_rf_foot_contacts`
/gazebo/contact/rr	`/sim_rr_foot_contacts`
/gazebo/fix	`/sim_gps`
/gazebo/foot	`/sim_foot` (foot contact/pose)
/gazebo/foot_contacts	`/sim_foot_contacts`
/gazebo/imu_corrected	`/sim_imu`
/gazebo/odom	`/sim_odom` (fused sim odometry)
/gazebo/odom_ground_truth	`/sim_odom_gt`
/gazebo/odom_raw	`/sim_odom_raw`

Command & Control

Topic	Type	Owner	Purpose
/cmd_vel	geometry_msgs/Twist (CHAMP) / TwistStamped (Nav2)	Dash (drive) / velocity_smoother (autonomous)	Robot velocity command: single bus. All motion arrives here: Nav2 FollowPath (via smoother, 20 Hz, accel-limited), behavior_server Spin/BackUp, operator teleop.
/cmd_vel_raw	geometry_msgs/TwistStamped	Nav2 controller_server	Pre-smoother velocity from controller_server
/safety/e_stop	std_srvs/srv/Trigger	Dash / operator	Mandatory. Request → immediate all-axis stop
/safety/reset	std_srvs/srv/Trigger	Dash / operator	Mandatory. Clear stop/fault state, re-enter closed loop
/locomotion/status	std_msgs/String (JSON)	CHAMP (robot)	Health summary: per-motor {node_id, ok, last_heartbeat_age_ms, iq_a, fault_code}, watchdog state, e-stop state. 1 Hz + on-change. For Dash/monitoring.
/locomotion/can	std_msgs/String (hex frames)	CHAMP (robot)	Verbose CAN trace for bring-up; default OFF
/limit/handshake	std_msgs/String (latched)	limit_handshake	Dash↔robot handshake status (latched): handshake channel
/limit/handshake_request	std_msgs/String	limit_dash_bridge	Handshake request channel: Dash / launch tooling request, the robot (`limit_handshake`) responds on `/limit/handshake`

Sensors

Topic	Type	Rate	Status
/ouster/points	sensor_msgs/PointCloud2	~3–6 Hz (driver reader cap)	LIVE Obstacle + AMCL source
/ouster/scan	sensor_msgs/LaserScan	~3–6 Hz	LIVE Ouster 2D scan (pointcloud_to_laserscan)
/scan_corrected	sensor_msgs/LaserScan	~3–6 Hz	Timestamp-corrected scan → AMCL (stamp_shift)
/imu_corrected	sensor_msgs/Imu	~80–99 Hz	LIVE Timestamp-corrected IMU → EKF imu0 (stamp_shift)
/zed2i_front/zed_node/odom	nav_msgs/Odometry	~20–28 Hz	LIVE ZED 2i VIO odometry: EKF odom0 is `/zed_odom_corrected` (stamp-shifted)
/zed2i_front/zed_node/imu/data	sensor_msgs/Imu	~99 Hz	LIVE IMU source of record
/zed2i_front/zed_node/pose	geometry_msgs/PoseWithCovarianceStamped	~10.8 Hz	display only frame_id="map", read by the dash for display, not fused into EKF/AMCL
/zed2i_front/zed_node/point_cloud/cloud_registered	sensor_msgs/PointCloud2	~4.9 Hz (448×256)	LIVE Not in any costmap
/zed2i_front/zed_node/rgb/color/rect/image/compressed	sensor_msgs/CompressedImage	~2.3 Hz	LIVE → dash viewer
/fix	sensor_msgs/NavSatFix	~1 Hz	standby active with sky view; standby indoors
/odometry/gps	nav_msgs/Odometry	none	standby navsat_transform output: flows when a GNSS fix is available
/joint_states	sensor_msgs/JointState	≥ 50 Hz	LIVE 12-joint state. Robot-exclusive
/foot_contacts	champ_msgs/ContactsStamped	≥ 50 Hz	LIVE contacts = bool[4] in order lf, rf, lr, rr