ROS 2 interface¶

Namespace /kachaka, as on the real robot.

Topic	Type	Rate
`manual_control/cmd_vel`	`geometry_msgs/Twist` (subscribed), ≤ 0.3 m/s
`goal_pose`	`geometry_msgs/PoseStamped` (subscribed): MOVE_TO_POSE
`odometry/odometry`	`nav_msgs/Odometry`	20 Hz
`wheel_odometry/wheel_odometry`	`nav_msgs/Odometry`	20 Hz
`lidar/scan`	`sensor_msgs/LaserScan`	10 Hz
`imu/imu`	`sensor_msgs/Imu`	100 Hz
`front_camera/image_raw`, `back_camera/image_raw`	`sensor_msgs/Image` (rgb8, 640×480) + `camera_info`	10 Hz
`tof_camera/image_raw`	`sensor_msgs/Image` (16UC1, mm) + `camera_info`	10 Hz
`object_detection/result`	`kachaka_interfaces/ObjectDetectionListStamped`, see Object detection (`object_detection_relay`)	10 Hz
`joint_states`, `robot_description`
`robot_info/battery_state`	`sensor_msgs/BatteryState` (level, charging or discharging, voltage, current; see Battery)	1 Hz
`robot_info/version`	stub
`sim/ground_truth`	`nav_msgs/Odometry` (simulator only)	20 Hz
`sim/charger_pose`	`geometry_msgs/PoseStamped` (simulator only, latched)
`sim/charger_detection`	`geometry_msgs/PoseStamped`, charger relative to the robot within 1.5 m (simulator only)	20 Hz
`sim/layout`	`std_msgs/String`, JSON with the shelves and extra locations (simulator only, latched)
`sim/shelf_poses`	`geometry_msgs/PoseArray`, shelves in the map frame (simulator only)	2 Hz
`sim/shelf_detection`	`geometry_msgs/PoseArray`, shelves relative to the robot (simulator only)	20 Hz
`sim/shelf_docked`	`std_msgs/String`, id of the towed shelf or empty (simulator only, latched)
`sim/shelf_dock`	`std_srvs/SetBool` service: raise or lower the pin (simulator only)
`sim/autonomous/cmd_vel`	`geometry_msgs/Twist` (subscribed), autonomous motion from `nav_bridge` and `command_server`, ≤ 0.8 m/s (simulator only, see Speed limits)
`sim/speech`	`std_msgs/String`, text of SPEAK and `tts_on_success` (simulator only)
`sim/front_stop/state`	`std_msgs/String`, JSON `{"enabled", "muted", "blocked"}` of the front obstacle stop (simulator only, latched, on change)
`sim/front_stop/set_enabled`, `sim/front_stop/mute`	`std_srvs/SetBool` services: switch the front obstacle stop (the app setting), or mute it while a command runs (`command_server`) (simulator only)
`sim/cliff`	`std_msgs/String`, JSON `{"enabled", "paused", "over"}` of the step sensors (simulator only, latched, on change)
`sim/collision`	`std_msgs/String`, JSON `{"stamp", "count", "with", "pose"}` for each collision of the body (simulator only)
`sim/errors`	`std_msgs/String`, JSON list of the error codes `GetError` lists (simulator only, latched, on change)
`sim/power_button`	`std_srvs/Trigger` service: resume from a pause after a step or a collision (simulator only)
`sim/object_detection`	`std_msgs/String`, JSON detections of each front camera image (simulator only)	10 Hz
`sim/torch`	`std_msgs/String`, JSON `{"front", "back"}`: torch levels 0-255 (simulator only, latched)
`sim/reset`	`std_srvs/SetBool` service: back to the start state, `data: true` also clears the SLAM map (simulator only, see Resetting the simulator)
`sim/reset/event`	`std_msgs/String`, JSON `{"id", "clear_map"}` after each reset (simulator only)
`sim/movers`	`std_msgs/String`, JSON `{"stamp", "frame_id", "movers": [...], "closest"}`: the moving people and boxes' ground truth (simulator only, 20 Hz, see Moving people and boxes)
`sim/doors`	`std_msgs/String`, JSON `{"doors": [...]}`: each door's state (simulator only, latched, on change and every 0.1 s while a panel moves, see Doors)
`sim/doors/<id>/set_open`	`std_srvs/SetBool` service: open (`true`) or close a door (simulator only)
`sim/command/start`, `sim/command/cancel`	`std_msgs/String`, JSON: commands from the kachaka-api server to `command_server` (simulator only)
`sim/command/state`	`std_msgs/String`, JSON: running command and last result (simulator only, latched)

kachaka_sim_bringup's command_server provides what the real robot does itself: the kachaka_command/execute action, goal_pose, layout/locations/list and layout/shelves/list, and the auto_homing/set_enabled service. Do not run it with a real Kachaka (command_server:=false).

/clock and /tf are published at the top level; use use_sim_time:=true on the ROS 2 side. See docs/design.md for the details and the decisions behind them.

Using the ROS 2 package with a real Kachaka¶

ros2_ws/src/kachaka_sim_bringup only depends on the /kachaka topics, so it should also work with a real robot (use_sim_time:=false, command_server:=false). This has not been tested. nav_bridge then sends Nav2's commands to manual_control/cmd_vel, which the real bridge caps at 0.3 m/s: lower MPPI's vx_max and the velocity smoother's max_velocity in nav2_params.yaml (0.8 m/s for the simulator) to match.