Skip to content

Integration Notes

Goal: Run VLASH (MIT HAN Lab) with the Piper arm (WeGo Robotics lerobot_piper) on Jetson AGX Orin inside a single Pixi environment.

Four code changes were required. None touch VLASH's core logic or the robot driver — they are all compatibility shims.

Why lerobot_piper

Three Piper-related forks exist; only one works with VLASH:

Fork Status
lerobot_piper_community (brucecai) No Piper robot code despite the name
lerobot-agilex (official Agilex) Uses ROS2 inference scripts — incompatible with VLASH's robot interface
lerobot_piper (WeGo Robotics) ✅ Has PiperFollower robot class + PiperMotorsBus with CAN driver

1. lerobot_piper/pyproject.toml

Three line changes:

Field Before After Why
version 0.3.3 0.4.1 VLASH pins lerobot==0.4.1. Without the bump, pixi resolves to official lerobot 0.4.1 from PyPI (no Piper support), silently overwriting lerobot_piper.
rerun-sdk >=0.21.0,<0.23.0 >=0.23.0 Versions 0.21–0.22 have no manylinux_2_28_aarch64 wheels — the package is simply absent for Jetson Orin's architecture.
transformers >=4.50.3,<4.52.0 >=4.50.3 VLASH's git-pinned transformers is ≥4.52.0. The upper bound caused a hard dependency conflict. Removing it lets both coexist.

2. lerobot_piper/src/lerobot/utils/constants.py (new file)

from lerobot.constants import *  # noqa: F401, F403

VLASH imports OBS_IMAGES, ACTION, OBS_STATE from lerobot.utils.constants. In lerobot_piper these constants live at lerobot.constants, not lerobot.utils.constants. This one-liner shim bridges the import path without modifying either upstream package.

3. lerobot_piper/src/lerobot/utils/visualization_utils.py

Two changes:

Added at the bottom of the file: 

init_rerun = _init_rerun
VLASH imports init_rerun (public name) but lerobot_piper only defines _init_rerun (private name). This alias bridges the gap without renaming the private function.

Renamed all 4 occurrences of rr.Scalar( → rr.Scalars(
rerun ≥ 0.23 renamed rr.Scalar to rr.Scalars. Without this fix, running with display_data: true crashes immediately with AttributeError: module 'rerun' has no attribute 'Scalar'.

4. vlash/vlash/configs/run_config.py

Two changes:

Added import: 

from lerobot.robots.piper_follower import PiperFollowerConfig  # noqa: F401
draccus (lerobot's config parser) populates its robot type registry from imports. Without this, type: piper_follower in any YAML raises KeyError: 'piper_follower' — the type is simply not registered.

Wrapped reachy2 import in try/except: 

try:
    from lerobot.robots.reachy2 import Reachy2RobotConfig  # noqa: F401
except ModuleNotFoundError:
    pass
lerobot_piper does not ship the reachy2 module. The bare import in VLASH crashed on startup even when reachy2 is never used, because the import runs at module load time before any config is parsed.

5. pixi.toml (new file)

A single Pixi environment that resolves all conflicts between lerobot_piper and VLASH:

  • Pins Jetson-specific PyTorch wheels from pypi.jetson-ai-lab.io/jp6/cu126
  • Installs lerobot_piper as editable as the lerobot package (satisfying VLASH's lerobot==0.4.1 pin)
  • Installs vlash as editable
  • [activation] runs scripts/activate.sh which preloads the correct libstdc++.so.6 to fix pyarrow GLIBCXX mismatch on aarch64
  • Sets platforms = ["linux-aarch64"]

Key dependency pins:

[pypi-options]
extra-index-urls = ["https://pypi.jetson-ai-lab.io/jp6/cu126/+simple/"]
index-strategy = "unsafe-best-match"

[pypi-dependencies]
torch = "==2.11.0"
torchvision = "==0.26.0"
torchcodec = "==0.10.0"
triton = "==3.6.0"
lerobot = { path = "lerobot_piper", editable = true, extras = ["feetech", "smolvla", "intelrealsense"] }
vlash = { path = "vlash", editable = true }
piper-sdk = ">=0.4.1"
wego-piper = ">=0.0.2"
peft = "==0.18.0"
bitsandbytes = ">=0.48.2"