Parts catalog and slots

Every part is a macro in bluerobotics_parts/urdf/parts.xacro; type names are the directory names in bluerobotics_parts/models/. The chassis are parts too: an assembly is a chassis plus whatever its slots carry.

Catalog

type	Part	Product page	In simulation
blueboat_chassis	BlueBoat hulls, crossbeams and both thruster bodies	BlueBoat	assembly root; displacement declared at the assembly
bluerov2_chassis	BlueROV2 standard hull (frame, tanks, foam)	BlueROV2	assembly root; declares every slot including thruster bodies and propellers
bluerov2_heavy_chassis	BlueROV2 Heavy kit hull	Heavy kit	as the standard chassis with eight thruster and body slots
m200_weedless_prop_cw, m200_weedless_prop_ccw	weedless propellers	link	default BlueBoat motor occupants, driven by the Thruster plugin
t200_prop_cw, t200_prop_ccw	standard T200 propellers	link	default ROV propellers; alternative BlueBoat motor occupants
t200_thruster	T200 thruster body	link	default occupant of the ROV thruster body slots; the BlueBoat chassis already carries its bodies
blueboat_flag	flag	components	geometry
blueboat_antenna_mast	antenna and accessory mast	link	geometry
basestation_antenna	BaseStation directional antenna kit	link	geometry
blueboat_payload_bracket	payload bracket	link	geometry
blueboat_ping_singlebeam_mount	Ping2 integration kit bracket	link	geometry; declares the ping slot
ping_singlebeam	Ping2 echosounder	link	single beam range sensor at its beam frame
ping360	Ping360 scanning sonar	link	planar scanning sensor
dvl_a50	Water Linked DVL A50	link	native DVL sensor; its backend loads only when fitted
explorehd_camera	exploreHD underwater camera	link	camera sensor
marinesitu_c3	MarineSitu C3 stereo camera	link	rgbd sensor; macro pending delivery
newton_gripper	Newton gripper	link	one DOF claw with a position controller; macro pending delivery
sediment_sampler	Newton sediment sampler attachment	link	one DOF claw with a position controller
payload_skid	BlueROV2 payload skid	link	geometry
roof_rack	ROV roof rack	link	geometry
omniscan_450_sidescan	Cerulean Omniscan 450 side scan sonar	link	geometry only
surveyor_multibeam	Cerulean Surveyor 240-16 multibeam	link	geometry only

Parts whose final mesh has not landed yet use placeholder geometry; a type marked pending delivery cannot be fitted until its macro lands.

Slots

Each slot is a TF frame named <instance>_<slot>; the occupant is named after the slot by default.

BlueBoat chassis

Part	Slot	Accepts	Default	Joint
blueboat_chassis	motor_port	m200_weedless_prop_ccw, t200_prop_ccw	m200_weedless_prop_ccw	continuous
	motor_stbd	m200_weedless_prop_cw, t200_prop_cw	m200_weedless_prop_cw	continuous
	flag	blueboat_flag	blueboat_flag	fixed
	mast	blueboat_antenna_mast	none	fixed
	payload	blueboat_payload_bracket	none	fixed
	ping_mount	blueboat_ping_singlebeam_mount	blueboat_ping_singlebeam_mount	fixed
blueboat_ping_singlebeam_mount	ping	ping_singlebeam	ping_singlebeam	fixed

BlueROV2 chassis

Part	Slot	Accepts	Default	Joint
bluerov2_chassis	thruster_1 … thruster_6	t200_prop_ccw or t200_prop_cw per position	the matching propeller	continuous
	thruster_body_1 … thruster_body_6	t200_thruster	t200_thruster	fixed
	camera	explorehd_camera, marinesitu_c3	explorehd_camera	fixed
	sonar	ping360	none	fixed
	dvl	dvl_a50	none	fixed
	gripper	newton_gripper, sediment_sampler	none	fixed
	payload	payload_skid	none	fixed
	rack	roof_rack	none	fixed

bluerov2_heavy_chassis extends the pattern to thruster_1 … thruster_8 and thruster_body_1 … thruster_body_8 and keeps the same accessory slots.

Configuration keys

The vehicle config (<vehicle>_description/config/<vehicle>.yaml, or any file passed as config_file:=) is one YAML document, identical in shape for both vehicles:

Key	Required	Meaning
topic_namespace	no (the vehicle name)	prefix of every part topic: /<name>/<name>/...
base	yes	the root part: {type, name (default base_link), collision (default true)}
parts	no ([])	slot entries and free placements, see below
slots	no	ad hoc slots: {of (instance, default base_link), name, xyz, rpy (default "0 0 0"), accepts (list, optional), default (type or none), joint}
hull_displacement	BlueBoat	the box pontoons the Gazebo composition places on the hull_displacement link: {length, width, height, x, y, z, segments}
buoyancy	BlueROV2	{net_buoyancy (kg), cob_offset, cob_frame (com/base_link), fluid_density, footprint}, realized as a dedicated displacement link solved from the assembled mass; see Buoyancy
extra_bridge_topics	no	list appended verbatim to the generated ros_gz bridge config (native syntax)

A slot entry in parts (has slot):

Key	Meaning
slot	slot name on the carrying instance
of	instance carrying the slot (default: the base). Not on: YAML reads a bare on as true
type	a type the slot accepts, or none to leave it empty
name	instance name (default: the slot name); must be unique across the vehicle
xyz, rpy	offset from the slot pose (default zero)
joint	joint type for the occupant (default: the slot’s, else continuous for a propeller, else fixed)
axis	joint axis override (default: the part’s own spin axis)
collision	false to fit the part without its contact geometry
topic, gz_topic, ros_topic, bridge	parts with topics (propellers, sensors): topic base for both sides / one side, under the namespace unless it starts with a slash; native bridge keys merged into the entry

A free placement (no slot):

Key	Meaning
type, name	required
xyz, rpy	pose relative to parent (xyz required)
parent	link to attach to (default: the base)
joint, axis, collision, topic keys	as above

Resolution rules, including how defaults fill, are in Slots and assembly. Errors name the problem and fail the build or launch; a key outside these tables is reported as a typo. Avoid the other YAML 1.1 boolean words (yes, no, off, y, n) as bare values too, or quote them.

Frames

Published as TF by robot_state_publisher from the generated URDF. The frames follow the fitted parts, with the same naming patterns on both vehicles:

Pattern	Kind	Meaning
base_link	root link	the chassis part: origin at the mesh centroid, x forward, y left, z up (REP 103); floats with its origin at the waterline
<instance>	link	one frame per fitted part, named after its slot or its name (motor_port, thruster_1, ping, camera); spinning parts sit on their continuous joint <instance>_joint
<parent>_<slot>	massless link	one per slot a part declares, whether filled or not (base_link_motor_port, base_link_camera, ping_mount_ping)
<instance>_<frame>	massless link	frames the part itself declares (ping_beam, the transducer face); sensor messages carry them as frame_id, resolved by TF

The displacement volume is not in the URDF or TF: each Gazebo package adds it to the composed model as a dedicated link (hull_displacement on the boat, buoyancy_displacement on the ROV). In Gazebo every fixed joint is lumped into base_link; the names survive as SDF frames, which is how sensors are placed. See Gazebo composition.

Slot poses, accepted types and defaults live in each part’s <part>_info macro (bluerobotics_parts/urdf/<part>.urdf.xacro); this page mirrors them.