fr3-stack

Low-latency, ROS-free control stack for the Franka Research 3. C++ daemon on the NUC (libfranka, 1 kHz); Python client over ZMQ + Cap'n Proto.

Build the docs locally:

pip install mkdocs-material
mkdocs serve

📚 Docs · Quickstart

Install

# NUC Side
./fr3-stack build
./fr3-stack up

# Workstation
pip install -e .

Hello world

import time
from fr3_stack import Robot

pos, quat = [0.5, 0.0, 0.4], [0, 0, 0, 1]

with Robot("nuc.local") as robot:
    # 1. large distance movement
    robot.send_move_to(pos, quat, run_time=2.0)
    time.sleep(2.0)
    
    # 2. cartesian control for policy
    robot.send_cartesian_impedance(
        target_pos       = pos,
        target_quat_xyzw = quat,
    )

    # 3. hybrid force-position
    robot.send_hybrid_force_position(
        target_pos       = pos,
        target_quat_xyzw = quat,
        target_force     = [0, 0, -5, 0, 0, 0],
        S                = [1, 1, 0, 1, 1, 1],   # Z = force, rest = position
    )

Use RobotAgent for policy loops (reset - observe - step), or Robot for admittance / hybrid / joint impedance.

Controllers

Controller	What it does
idle	hand-guidable: gravity comp + inertia-aware per-joint damping + optional Coulomb-friction comp
cartesian_impedance	spring/damper at the EE in base frame ($J^{\top}$-projected)
hybrid	per-axis force PID on n_af axes + position elsewhere

Plus MoveTo for min-jerk setup moves.

Status

Pre-alpha. APIs will change. Single FR3 only.

License

MIT