Franka — seven-DOF bare arms

FrankaCfg, catalog ID Franka, selects a bare seven-joint arm. Both variants expose only arm; the default TCP is the flange and no end effector is attached implicitly.

Franka — bare arm (default FR3 model)

The image is a native OfflineRT render of the configured FR3 asset in its initial joint pose, ending at the mounting flange. No physics steps or tool attachments are used. The render record preserves source URDF hashes, named joints, camera and renderer settings. The original Panda variant is selected separately through arm_model below.

Variant	Source arm	Solver	Flange
fr3 (default)	Historical FR3 asset, Franka/Panda/Panda.urdf	FEP	fr3_link8
panda	Pinned original Panda, FrankaPandaArm/Panda/PandaExactV1.urdf	Pink	ee_link

Construction and preview

from embodichain_robots import FrankaCfg

arm = FrankaCfg.from_dict({})  # FR3 by default
panda_arm = FrankaCfg.from_dict({"arm_model": "panda"})
assert set(arm.control_parts) == {"arm"}
assert len(arm.init_qpos) == 7

Add the selected configuration to SimulationManager with sim.add_robot(cfg=arm). The catalog and preview CLI use the same configuration:

embodichain preview-robot --robot Franka --variant fr3 --renderer rt
embodichain preview-robot --robot Franka --variant panda --renderer rt

Franka and the historical FrankaPanda entry

Selection	Constructed robot	Tool ownership
Franka / FrankaCfg, arm_model: fr3	Seven-joint FR3 arm	Embodiment or standard RobotCfg overrides
Franka / FrankaCfg, arm_model: panda	Seven-joint original Panda arm	Embodiment or standard RobotCfg overrides
FrankaPanda / FrankaPandaCfg	Historical FR3 arm, with legacy robot_type: panda	Explicit assembly is also required
franka_panda embodiment	FR3 arm plus native Panda Hand	Component declares hand joints, drives, mount and TCP

The legacy FrankaPanda name continues to select the historical FR3 asset family. The original Panda is selected by FrankaCfg with arm_model: panda. See FrankaPanda and its native-hand setup for the compatibility constructor and a visual comparison with the explicit hand assembly.

Mounting end effectors

Use the same standard RobotCfg overrides as UR arms: append a hand URDF component, declare its control group, drives and initial joints, and set the flange-to-TCP matrix in solver_cfg.arm.tcp. The component’s transform is the flange-to-hand mounting transform. The TCP matrix includes that mounting transform and the tool-local TCP offset once.

The reusable embodiment components provide concrete qualified assemblies:

• franka_panda.yaml and franka_panda_rgb_224.yaml mount the authored FR3 hand as a separate component, preserving its finger joints and contact TCP.

• franka_panda_robotiq85.yaml mounts the shared Robotiq_V2 2F-85 at the explicitly declared 18 mm adapter, with a 150 mm tool-local offset. It owns the six linkage joint declarations, signed limits, tool drives, nominal inertial overlays and solver iteration calibration.

The FR3 hand component Franka/Panda/Fr3HandV1.urdf is derived from the pinned PandaWithHand.urdf hand subtree. The original file is retained. Link and joint names, collision geometry and authored inertials are preserved; a sidecar records the source and derived hashes. The arm and hand URDFs share their original asset directory so relative mesh paths remain valid.

The Robotiq assembly retains its qualified asset, component order and assembly name. The separate Robotiq2F85 archive is a different model identity and is not substituted. Opening conversion remains available from embodichain_robots.robotiq.two_finger.robotiq85_joint_positions.

Migration

gripper, gripper_mount_z_m, gripper_mount_yaw_rad and tcp_offset_m are removed from FrankaCfg; supplying them fails with assembly guidance. Use the ordinary component and solver fields described above. Tool identity is owned by the explicitly selected tool asset rather than a second arm selector.

FrankaPandaCfg and catalog ID FrankaPanda remain legacy selectors for the historical FR3 arm (robot_type: panda). They now also produce a bare arm. Callers needing fingers must use an explicit embodiment or mount their tool. Bare dual-arm composition contains fourteen arm joints; finger groups are added only by a tool-equipped deployment. Official native-hand and PGI consumers assemble their tools explicitly.

Model-specific Panda inertial overlays remain arm-owned. Tool and contact calibrations are embodiment-owned. Identified inertials, nominal tool values and the explicit 5 g pad assumption establish simulation settings, not hardware dynamics qualification. See the model README and asset provenance for sources.