dora-openarm-kinematics 0.2.0

dora-rs nodes for forward and inverse kinematics on OpenArm

dora-openarm-kinematics

Dora nodes for forward and inverse kinematics on the OpenArm bimanual robot, backed by MuJoCo and mink. FK/IK logic lives in the openarm_control package, imported as control.

Install

uv sync

Dora Nodes

dora-openarm-fk — Forward Kinematics

Converts per-arm joint angles to end-effector poses via mj_forward.

Inputs	position_right, position_left [{"qpos": float32[8]}] — joints 1–7 + gripper (flat float32[8] also accepted)
Outputs	pose_right, pose_left [{"pose": float32[8]}] — [px, py, pz, qw, qx, qy, qz, gripper_value]

--mode           right | left | bimanual  (default: bimanual)
--frame-right    MuJoCo site/body/geom name for right EE  (default: right_ee_control_point)
--frame-left     MuJoCo site/body/geom name for left EE   (default: left_ee_control_point)
--frame-type-*   body | site | geom  (default: site)
--keyframe       initial keyframe name  (default: home)
--xml            MJCF scene file

---

dora-openarm-ik — Differential IK

Solves joint angles from EE pose targets using mink's QP-based differential IK. Both arms share one mink.Configuration and are solved in a single QP per step. DOFs not driven by IK outputs are frozen (finger joints, lifter).

Inputs	target_right, target_left [{"pose": float32[7]}] — EE pose targets; position [{"qpos": float32[16]}] — optional joint-state sync (flat arrays also accepted); trigger_right / trigger_left float32[1] — gripper pass-through
Outputs	position_right, position_left [{"qpos": float32[8]}]

--mode           right | left | bimanual  (default: bimanual)
--max-iters      IK iterations per event  (default: 5)
--dt             integration timestep per iteration  (default: 0.5)
--damping        global Tikhonov regularization  (default: 1e-3)
--lm-damping     per-task LM damping  (default: 1e-4)
--posture-cost   posture task weight, 0 = disabled  (default: 0.0)
--pos-cost       position task cost  (default: 1.0)
--ori-cost       orientation task cost  (default: 1.0)
--solver         QP backend  (default: daqp)
--frame-right    site/body name for right EE  (default: right_ee_control_point)
--frame-left     site/body name for left EE   (default: left_ee_control_point)
--keyframe       initial keyframe  (default: home)
--xml            MJCF scene file

Quick Start

FK — visualise leader arm poses

Reads joint angles from a physical leader arm and publishes end-effector poses. Requires a connected leader device.

uv run dora build example/dataflow-dummy-fk.yaml --uv
uv run dora run example/dataflow-dummy-fk.yaml --uv

---

FK → IK roundtrip

Pipes FK output directly back into IK to verify the solver round-trips correctly. No physical hardware needed beyond the leader.

uv run dora build example/dataflow-dummy-ik.yaml --uv
uv run dora run example/dataflow-dummy-ik.yaml --uv

Dataflow: leader → fk (joints → poses) → ik (poses → joints) → viewer

Tune the ik solver parameters in:

args: "--mode bimanual --max-iters 5 --dt 0.1 --damping 0.25 --posture-cost 0.01 --lm-damping 0.01"

License

Licensed under the Apache License 2.0. See LICENSE for details.

Copyright 2026 Enactic, Inc.

Code of Conduct

All participation in the OpenArm project is governed by our Code of Conduct.