docs(omx): adding some examples and scripts (#3566)

* docs(omx): adding some examples and scripts

* cleaning up and reviewing the cli args

* adding __init__.py to example folder, adjusting the examples

* adding reference to pretrained act policy

* moving `.send_action` before `dataset.add_frame` for consistency

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
Signed-off-by: Maxime Ellerbach <maxime@ellerbach.net>

* adjusting docstring

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>
Signed-off-by: Maxime Ellerbach <maxime@ellerbach.net>

* adressing hardcoded dataset fps

* removed init as it worked without

---------

Signed-off-by: Maxime Ellerbach <maxime@ellerbach.net>
This commit is contained in:
Maxime Ellerbach
2026-05-11 15:36:32 +02:00
committed by GitHub
parent b607c8458e
commit 6d269b28c8
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# OMX Follower — Cube Pick And Place Example
This is an example of what is possible to do with LeRobot on a physical setup.
It is a WIP and being used internally at LeRobot and specific to our setup, but we hope it can be a useful reference for how to use LeRobot APIs and CLIs.
It includes an end-to-end example for the **OMX Follower** robot arm: pick and place a cube dataset, train a policy, and deploy it autonomously.
## Hardware
| Component | Value |
| --------- | ------------------------------------ |
| Robot | OMX Follower |
| Cameras | 2× OpenCV cameras (wrist + top-down) |
## Scripts
| Script | Purpose |
| ---------------------- | --------------------------------------------------------------- |
| `reset_environment.py` | Standalone utility: sweep workspace, grab cube, place cube |
| `record_grab.py` | Automated data collection: reset → place → record grab episodes |
## Setup
Make sure you have LeRobot installed in your env. (See [the installation guide](https://huggingface.co/docs/lerobot/installation))
Next, we will declare some environment variables for convenience. Adjust the camera indices and robot port to match your system configuration.
```bash
export ROBOT_PORT=/dev/ttyACM0
export TELEOP_PORT=/dev/ttyACM1
export HF_USERNAME=<your_hf_username>
export ROBOT_CAMERAS="{ wrist: {type: opencv, index_or_path: 0, width: 640, height: 480, fps: 30, fourcc: MJPG}, top: {type: opencv, index_or_path: 2, width: 640, height: 480, fps: 30, fourcc: MJPG} }"
```
## Step 1 — Collect Data
```bash
lerobot-record \
--robot.type=omx_follower \
--robot.port=$ROBOT_PORT \
--robot.id=omx_follower \
--robot.cameras="$ROBOT_CAMERAS" \
--teleop.type=omx_leader \
--teleop.port=$TELEOP_PORT \
--teleop.id=omx_leader \
--dataset.repo_id=$HF_USERNAME/omx_pickandplace \
--dataset.root=data/omx_pickandplace \
--dataset.num_episodes=50 \
--dataset.single_task="Pick the cube and place it in the blue square" \
--dataset.streaming_encoding=true \
--dataset.push_to_hub=true
```
### Bonus Auto-Collect script
/!\ This is specific to our setup and the task of picking and placing a cube. It is not a general-purpose data collection script. As you may notice, it doesn't require a teleop.
```bash
python -m examples.omx.record_grab \
--robot.type=omx_follower \
--robot.port=$ROBOT_PORT \
--robot.id=omx_follower \
--robot.cameras="$ROBOT_CAMERAS" \
--dataset.repo_id=$HF_USERNAME/omx_pickandplace \
--dataset.root=data/omx_pickandplace \
--dataset.num_episodes=50 \
--dataset.single_task="Pick the cube and place it in the blue square" \
--dataset.streaming_encoding=true \
--dataset.push_to_hub=true
```
Each episode:
1. The arm grabs the cube from the center of the workspace and places it at a random position.
2. The arm returns to HOME.
3. A targeted grab is recorded: HOME → approach raised → lower onto cube → grasp → lift → carry → drop → HOME.
A dataset is already available here [`maximellerbach/omx_pickandplace`](https://huggingface.co/datasets/maximellerbach/omx_pickandplace), so you can skip directly to training if you want.
## Step 2 — Train
To train a simple `ACT` policy on the collected dataset, you can use the `lerobot-train` CLI:
```bash
lerobot-train \
--dataset.repo_id=$HF_USERNAME/omx_pickandplace \
--policy.type=act \
--output_dir=outputs/train/omx_pickandplace_act \
--policy.device=cuda \
--policy.repo_id=$HF_USERNAME/omx_pickandplace_act \
--steps=20000 \
--wandb.enable=true
```
A pretrained `ACT` policy is already available here [`maximellerbach/omx_pickandplace_act`](https://huggingface.co/maximellerbach/omx_pickandplace_act).
## Step 3 — Rollout
Use the `lerobot-rollout` CLI with base strategy:
```bash
lerobot-rollout \
--strategy.type=base \
--robot.type=omx_follower \
--robot.port=$ROBOT_PORT \
--robot.id=omx_follower \
--robot.cameras="$ROBOT_CAMERAS" \
--policy.path=$HF_USERNAME/omx_pickandplace_act \
```
For continuous recording with automatic upload (sentry mode):
```bash
lerobot-rollout \
--strategy.type=sentry \
--strategy.upload_every_n_episodes=10 \
--robot.type=omx_follower \
--robot.port=$ROBOT_PORT \
--robot.id=omx_follower \
--robot.cameras="$ROBOT_CAMERAS" \
--policy.path=$HF_USERNAME/omx_pickandplace_act \
--dataset.repo_id=$HF_USERNAME/rollout_omx_pickandplace_act \
```
## Environment Reset Utility
Those are specific to this particular physical setup. Those are scripts that execute hardcoded sequences of actions on the robot to reset the environment, which is useful for data collection and evaluation. They are not general-purpose scripts.
`reset_environment.py` can be run standalone to prepare the workspace:
```bash
# Grab cube + place it at a random position on the left side
python -m examples.omx.reset_environment --port $ROBOT_PORT --mode grab_and_place
```
It also exposes `grab_cube(robot)` and `place_cube(robot)` for use in custom scripts.
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#!/usr/bin/env python3
"""
Auto-record grab episodes for the OMX robot arm.
Each episode cycle:
1. grab_and_place — grab cube from workspace center and place at a random (pan, reach) position
2. HOME — return arm to home with gripper open
3. record_grab — execute a targeted grab to the stored position while recording
observations + actions to a LeRobotDataset
Usage (run from repo root):
python -m examples.omx.record_grab \\
--robot.type=omx_follower \\
--robot.port=/dev/ttyACM0 \\
--robot.id=omx_follower \\
--robot.cameras="{ wrist: {type: opencv, index_or_path: 6, width: 640, height: 480, fps: 30, fourcc: MJPG}, top: {type: opencv, index_or_path: 4, width: 640, height: 480, fps: 30, fourcc: MJPG} }" \\
--dataset.repo_id=<hf_username>/<dataset_name> \\
--dataset.root=data/omx_grab \\
--dataset.num_episodes=50 \\
--dataset.single_task="Grab the cube" \\
--dataset.streaming_encoding=true
"""
import logging
from dataclasses import dataclass
from pprint import pformat
import numpy as np
from lerobot.cameras import CameraConfig # noqa: F401
from lerobot.cameras.opencv import OpenCVCameraConfig # noqa: F401
from lerobot.configs import parser
from lerobot.configs.dataset import DatasetRecordConfig
from lerobot.datasets import (
LeRobotDataset,
VideoEncodingManager,
aggregate_pipeline_dataset_features,
create_initial_features,
)
from lerobot.processor import make_default_processors
from lerobot.robots import RobotConfig, make_robot_from_config
from lerobot.robots.omx_follower import OmxFollower
from lerobot.utils.constants import ACTION, OBS_STR
from lerobot.utils.feature_utils import build_dataset_frame, combine_feature_dicts
from lerobot.utils.robot_utils import precise_sleep
from .reset_environment import (
APPROACH_SPEED,
GRIPPER_CLOSE_POS,
HOME_POSE,
PUSH_END_ELBOW_FLEX,
PUSH_END_SHOULDER_LIFT,
PUSH_START_ELBOW_FLEX,
PUSH_START_SHOULDER_LIFT,
array_to_pose,
grab_cube,
horizontal_wrist_flex,
move_to_pose,
place_cube,
pose_to_array,
)
# ── Grab-episode motion parameters ────────────────────────────────────────────
# Shoulder-lift offset for the raised approach phase (subtracted from the target sl, arm is higher).
GRAB_RAISE_SL_OFFSET = 20.0
GRAB_LOWER_SPEED = 20.0
RECORD_SPEED = 30.0
# Pose the arm travels to after closing the gripper (cube held).
GRAB_CARRY_POSE = {
"shoulder_pan.pos": -23.0,
"shoulder_lift.pos": 5.0,
"elbow_flex.pos": 18.0,
"wrist_flex.pos": -14.0,
"wrist_roll.pos": 0.0,
"gripper.pos": GRIPPER_CLOSE_POS,
}
# Per-joint jitter limits (degrees) applied to transit waypoints for human-like variation.
# Cube-approach and carry poses are never jittered to preserve precision.
_JITTER_LIMITS: dict[str, float] = {
"shoulder_pan.pos": 5.0,
"shoulder_lift.pos": 4.0,
"elbow_flex.pos": 4.0,
"wrist_flex.pos": 3.0,
"wrist_roll.pos": 2.0,
"gripper.pos": 0.0,
}
def _jitter_pose(pose: dict, rng: np.random.Generator) -> dict:
"""Return a copy of pose with independent per-joint random perturbations."""
return {
k: v + rng.uniform(-_JITTER_LIMITS.get(k, 0.0), _JITTER_LIMITS.get(k, 0.0)) for k, v in pose.items()
}
def _random_stuck_pose(rng: np.random.Generator) -> dict:
"""Return a physically plausible stuck pose (failed grasp), gripper closed.
ef bounds are piecewise-linear in sl so the arm stays in a reachable,
table-safe envelope across the full sl range:
sl=-50 → ef ∈ [ 0, 50] (arm raised, can be bent forward)
sl= 0 → ef ∈ [-25, 25] (mid reach)
sl= 30 → ef ∈ [-20, 0] (arm extended, little room to flex)
wrist_flex is randomly offset from the horizontal value.
"""
pan = float(rng.uniform(-5.0, 35.0))
sl = float(rng.uniform(-50.0, 30.0))
if sl <= 0.0:
alpha = (sl + 50.0) / 50.0 # 0 at sl=-50, 1 at sl=0
ef_lo = alpha * -25.0 # 0 → -25
ef_hi = 50.0 + alpha * -25.0 # 50 → 25
else:
alpha = sl / 30.0 # 0 at sl=0, 1 at sl=30
ef_lo = -25.0 + alpha * 5.0 # -25 → -20
ef_hi = 25.0 + alpha * -25.0 # 25 → 0
ef = float(rng.uniform(ef_lo, ef_hi))
wf = horizontal_wrist_flex(sl, ef) + float(rng.uniform(-15.0, 15.0))
return {
"shoulder_pan.pos": pan,
"shoulder_lift.pos": sl,
"elbow_flex.pos": ef,
"wrist_flex.pos": wf,
"wrist_roll.pos": float(rng.uniform(-15.0, 15.0)),
"gripper.pos": GRIPPER_CLOSE_POS,
}
logger = logging.getLogger(__name__)
@dataclass
class OmxRecordGrabConfig:
robot: RobotConfig
dataset: DatasetRecordConfig
# Resume recording on an existing dataset.
resume: bool = False
# Fraction of episodes that start from a random stuck pose (gripper closed) to
# generate recovery data. 0.0 = disabled, 1.0 = all episodes are recovery starts.
recovery_prob: float = 0.5
def record_episode_spline(
robot: OmxFollower,
waypoints: list[dict],
speeds: list[float],
dataset: LeRobotDataset,
task: str,
) -> None:
"""Execute a Catmull-Rom-style spline through waypoints, recording each frame.
Segment durations are parameterized from the maximum absolute joint delta
between consecutive waypoints divided by the requested segment speed,
producing non-uniform timing in joint space. Interior tangents are derived
from the adjacent per-segment velocities, with clamped (zero-velocity)
endpoints so the arm starts and stops smoothly. Each segment is cubic
Hermite, giving C1 continuity at every waypoint.
"""
pts = [pose_to_array(w) for w in waypoints]
n = len(pts)
# Steps and duration per segment
n_steps_list = []
timestamps = []
for i in range(n - 1):
max_dist = float(np.max(np.abs(pts[i + 1] - pts[i])))
ns = max(1, int(max_dist / speeds[i] * dataset.fps)) if max_dist >= 0.5 else 0
n_steps_list.append(ns)
timestamps.append(ns / dataset.fps)
# Velocity tangents (deg/sec) — clamped at endpoints, Catmull-Rom for interior
vels = [np.zeros_like(pts[0])]
for i in range(1, n - 1):
v_prev = (pts[i] - pts[i - 1]) / timestamps[i - 1] if timestamps[i - 1] > 0 else np.zeros_like(pts[0])
v_next = (pts[i + 1] - pts[i]) / timestamps[i] if timestamps[i] > 0 else np.zeros_like(pts[0])
vels.append(0.5 * (v_prev + v_next))
vels.append(np.zeros_like(pts[0]))
dt = 1.0 / dataset.fps
for seg in range(n - 1):
ns = n_steps_list[seg]
if ns == 0:
continue
p0, p1 = pts[seg], pts[seg + 1]
# Scale velocity (deg/sec) to t-space tangent (deg/t-unit, where t: 0→1 over ns steps)
m0 = vels[seg] * timestamps[seg]
m1 = vels[seg + 1] * timestamps[seg]
for step in range(1, ns + 1):
t = step / ns
h00 = 2 * t**3 - 3 * t**2 + 1
h10 = t**3 - 2 * t**2 + t
h01 = -2 * t**3 + 3 * t**2
h11 = t**3 - t**2
commanded = h00 * p0 + h10 * m0 + h01 * p1 + h11 * m1
action = array_to_pose(commanded)
robot.send_action(action)
obs = robot.get_observation()
obs_frame = build_dataset_frame(dataset.features, obs, prefix=OBS_STR)
action_frame = build_dataset_frame(dataset.features, action, prefix=ACTION)
dataset.add_frame({**obs_frame, **action_frame, "task": task})
precise_sleep(dt)
def record_grab_episode(
robot: OmxFollower,
dataset: LeRobotDataset,
pan: float,
t: float,
task: str,
recovery_start: bool = False,
) -> None:
"""Execute a targeted grab to the stored (pan, t) position, recording every frame.
Normal sequence (initial HOME move is NOT recorded):
HOME → raised approach above cube → lower → close gripper
→ raise [jittered] → retract [jittered] → GRAB_CARRY_POSE → drop → HOME
Recovery sequence (recovery_start=True): arm is moved to a random stuck pose
(gripper closed) without recording, then recording begins from there:
stuck_pose → raised approach above cube → [normal grab sequence from there]
All segments are joined by a Catmull-Rom spline (C1-continuous velocities).
"""
sl = PUSH_START_SHOULDER_LIFT + t * (PUSH_END_SHOULDER_LIFT - PUSH_START_SHOULDER_LIFT)
ef = PUSH_START_ELBOW_FLEX + t * (PUSH_END_ELBOW_FLEX - PUSH_START_ELBOW_FLEX)
sl_raised = sl - GRAB_RAISE_SL_OFFSET
wf_horizontal = horizontal_wrist_flex(sl, ef)
rng = np.random.default_rng()
if recovery_start:
stuck_pose = _random_stuck_pose(rng)
logger.info(f"Recovery start: {stuck_pose}")
move_to_pose(robot, stuck_pose, APPROACH_SPEED)
first_waypoints = [stuck_pose]
first_speeds = []
else:
jittery_start = _jitter_pose(HOME_POSE, rng)
move_to_pose(robot, jittery_start, APPROACH_SPEED)
first_waypoints = [jittery_start]
first_speeds = []
waypoints = first_waypoints + [
{ # raised approach: arm above cube
"shoulder_pan.pos": pan,
"shoulder_lift.pos": sl_raised,
"elbow_flex.pos": ef,
"wrist_flex.pos": horizontal_wrist_flex(sl_raised, ef),
"wrist_roll.pos": 0.0,
"gripper.pos": 60.0,
},
{ # lower onto cube — no jitter: precision needed
"shoulder_pan.pos": pan,
"shoulder_lift.pos": sl,
"elbow_flex.pos": ef,
"wrist_flex.pos": wf_horizontal,
"wrist_roll.pos": 0.0,
"gripper.pos": 60.0,
},
{ # close gripper — no jitter: precision needed
"shoulder_pan.pos": pan,
"shoulder_lift.pos": sl,
"elbow_flex.pos": ef,
"wrist_flex.pos": wf_horizontal,
"wrist_roll.pos": 0.0,
"gripper.pos": GRIPPER_CLOSE_POS,
},
_jitter_pose(
{ # raise with cube
"shoulder_pan.pos": pan,
"shoulder_lift.pos": sl_raised,
"elbow_flex.pos": ef,
"wrist_flex.pos": horizontal_wrist_flex(sl_raised, ef),
"wrist_roll.pos": 0.0,
"gripper.pos": GRIPPER_CLOSE_POS,
},
rng,
),
_jitter_pose(
{ # retract: fold arm toward HOME before sweeping to carry zone
"shoulder_pan.pos": pan * 0.25,
"shoulder_lift.pos": HOME_POSE["shoulder_lift.pos"] + 5.0,
"elbow_flex.pos": HOME_POSE["elbow_flex.pos"] - 5.0,
"wrist_flex.pos": 0.0,
"wrist_roll.pos": 0.0,
"gripper.pos": GRIPPER_CLOSE_POS,
},
rng,
),
GRAB_CARRY_POSE, # no jitter: target drop zone
{**GRAB_CARRY_POSE, "gripper.pos": 60.0}, # drop cube
HOME_POSE,
]
speeds = first_speeds + [
RECORD_SPEED, # (HOME →) raised approach
GRAB_LOWER_SPEED, # raised approach → lower
GRAB_LOWER_SPEED, # lower → close gripper
RECORD_SPEED, # close gripper → raise
RECORD_SPEED, # raise → retract
RECORD_SPEED, # retract → carry pose
RECORD_SPEED, # carry pose → drop
RECORD_SPEED, # drop → HOME
]
record_episode_spline(robot, waypoints, speeds, dataset, task)
# Dwell at HOME for ~0.5 s before next episode
home_action = build_dataset_frame(dataset.features, HOME_POSE, prefix=ACTION)
dt = 1.0 / dataset.fps
for _ in range(int(dataset.fps * 0.5)):
robot.send_action(HOME_POSE)
obs = robot.get_observation()
obs_frame = build_dataset_frame(dataset.features, obs, prefix=OBS_STR)
dataset.add_frame({**obs_frame, **home_action, "task": task})
precise_sleep(dt)
@parser.wrap()
def record_grab(cfg: OmxRecordGrabConfig) -> LeRobotDataset:
logging.basicConfig(level=logging.INFO, format="%(levelname)s: %(message)s")
logger.info(pformat(cfg))
robot = make_robot_from_config(cfg.robot)
use_videos = cfg.dataset.video
teleop_action_processor, _, robot_obs_processor = make_default_processors()
dataset_features = combine_feature_dicts(
aggregate_pipeline_dataset_features(
pipeline=teleop_action_processor,
initial_features=create_initial_features(action=robot.action_features),
use_videos=use_videos,
),
aggregate_pipeline_dataset_features(
pipeline=robot_obs_processor,
initial_features=create_initial_features(observation=robot.observation_features),
use_videos=use_videos,
),
)
num_cameras = len(robot.cameras) if hasattr(robot, "cameras") else 0
dataset = None
try:
if cfg.resume:
dataset = LeRobotDataset.resume(
cfg.dataset.repo_id,
root=cfg.dataset.root,
streaming_encoding=cfg.dataset.streaming_encoding,
batch_encoding_size=cfg.dataset.video_encoding_batch_size,
vcodec=cfg.dataset.vcodec,
encoder_threads=cfg.dataset.encoder_threads,
image_writer_processes=cfg.dataset.num_image_writer_processes if num_cameras > 0 else 0,
image_writer_threads=cfg.dataset.num_image_writer_threads_per_camera * num_cameras
if num_cameras > 0
else 0,
)
else:
cfg.dataset.stamp_repo_id()
dataset = LeRobotDataset.create(
cfg.dataset.repo_id,
cfg.dataset.fps,
root=cfg.dataset.root,
robot_type=robot.name,
features=dataset_features,
use_videos=use_videos,
streaming_encoding=cfg.dataset.streaming_encoding,
batch_encoding_size=cfg.dataset.video_encoding_batch_size,
vcodec=cfg.dataset.vcodec,
encoder_threads=cfg.dataset.encoder_threads,
image_writer_processes=cfg.dataset.num_image_writer_processes if num_cameras > 0 else 0,
image_writer_threads=cfg.dataset.num_image_writer_threads_per_camera * num_cameras
if num_cameras > 0
else 0,
)
robot.connect(calibrate=True)
rng = np.random.default_rng()
with VideoEncodingManager(dataset):
for episode_idx in range(cfg.dataset.num_episodes):
logger.info(f"=== Episode {episode_idx + 1}/{cfg.dataset.num_episodes} ===")
logger.info("Step 1: grabbing and placing cube...")
grab_cube(robot)
pan, t = place_cube(robot)
logger.info(f"Cube placed at pan={pan:.1f}, reach={t:.2f}")
recovery_start = cfg.recovery_prob > 0 and float(rng.random()) < cfg.recovery_prob
logger.info(f"Step 2: recording {'recovery ' if recovery_start else ''}grab episode...")
record_grab_episode(
robot,
dataset,
pan,
t,
cfg.dataset.single_task,
recovery_start=recovery_start,
)
dataset.save_episode()
logger.info(f"Episode {episode_idx + 1} saved.")
finally:
if dataset:
dataset.finalize()
if robot.is_connected:
robot.disconnect()
if cfg.dataset.push_to_hub and dataset and dataset.num_episodes > 0:
dataset.push_to_hub(tags=cfg.dataset.tags, private=cfg.dataset.private)
return dataset
if __name__ == "__main__":
record_grab()
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#!/usr/bin/env python3
"""
Auto-reset and cube-grab utility for the OMX robot arm.
Provides:
- grab_cube(robot): sweep workspace, center cube, close gripper
- place_cube(robot): carry cube to a random position, release
Standalone usage (run from repo root):
python -m examples.omx.reset_environment --port /dev/ttyACM1 --mode grab
python -m examples.omx.reset_environment --port /dev/ttyACM1 --mode grab_and_place
Joint range: -100 to 100 for arm joints; gripper: 50 = closed, 80 = open.
To read current joint values for calibration, add after robot.connect():
obs = robot.get_observation()
print({k: round(obs[k], 1) for k in JOINT_NAMES})
robot.disconnect(); raise SystemExit
Parallel-to-ground IK: wrist_flex = WRIST_HORIZONTAL_OFFSET - shoulder_lift - elbow_flex.
Linear interpolation preserves this constraint between any two poses that satisfy it.
"""
import argparse
import logging
import numpy as np
from lerobot.robots.omx_follower import OmxFollower, OmxFollowerConfig
from lerobot.robots.robot import Robot
from lerobot.utils.robot_utils import precise_sleep
logger = logging.getLogger(__name__)
# ── Poses ─────────────────────────────────────────────────────────────────────
HOME_POSE = {
"shoulder_pan.pos": 0.0,
"shoulder_lift.pos": -50.0,
"elbow_flex.pos": 50.0,
"wrist_flex.pos": 0.0,
"wrist_roll.pos": 0.0,
"gripper.pos": 60.0,
}
SWEEP_WAYPOINTS = [
{
"shoulder_pan.pos": -60.0,
"shoulder_lift.pos": 50.0,
"elbow_flex.pos": -60.0,
"wrist_flex.pos": -20.0,
"wrist_roll.pos": 0.0,
"gripper.pos": 60.0,
},
{
"shoulder_pan.pos": -30.0,
"shoulder_lift.pos": 50.0,
"elbow_flex.pos": -60.0,
"wrist_flex.pos": -5.0,
"wrist_roll.pos": 0.0,
"gripper.pos": 60.0,
},
{
"shoulder_pan.pos": 20.0,
"shoulder_lift.pos": 50.0,
"elbow_flex.pos": -55.0,
"wrist_flex.pos": -5.0,
"wrist_roll.pos": 0.0,
"gripper.pos": 60.0,
},
]
# ── Motion parameters ─────────────────────────────────────────────────────────
CONTROL_HZ = 30
APPROACH_SPEED = 50.0
SWEEP_SPEED = 40.0
# ── Grab-sequence parameters ──────────────────────────────────────────────────
GRAB_PAN = 0.0
SWEEP_LEFT_PAN = -60.0
SWEEP_RIGHT_PAN = 60.0
SWEEP_END_OFFSET = 5.0 # stop before center so the cube isn't pushed past GRAB_PAN
SWEEP_END_PAN_RANGE = (15.0, 20.0)
SWEEP_LOW_SHOULDER_LIFT = 50.0
SWEEP_LOW_ELBOW_FLEX_START = -60.0
SWEEP_LOW_ELBOW_FLEX_END = -55.0
SWEEP_HIGH_WRIST_FLEX = -20.0 # wrist tilted up during high approach to clear obstacles
PUSH_START_SHOULDER_LIFT = 0.0
PUSH_START_ELBOW_FLEX = 45.0
PUSH_END_SHOULDER_LIFT = 50.0
PUSH_END_ELBOW_FLEX = -50.0
# Subtracted from shoulder_lift during the push sweep to clear the platform surface.
# Does not affect the grab-target interpolation in record_grab.py.
PUSH_RAISE_OFFSET = 5.0
WRIST_HORIZONTAL_OFFSET = 0.0 # tune if gripper tilts during push: + tilts nose up, - down
GRIPPER_CLOSE_POS = 50.0
PLACE_LEFT_PAN_RANGE = (5.0, 30.0) # random pan range for cube placement on the left side
PLACE_REACH_RANGE = (0.1, 0.7) # 0 = arm retracted (PUSH_START), 1 = fully extended (PUSH_END)
JOINT_NAMES = [
"shoulder_pan.pos",
"shoulder_lift.pos",
"elbow_flex.pos",
"wrist_flex.pos",
"wrist_roll.pos",
"gripper.pos",
]
# ── Helpers ───────────────────────────────────────────────────────────────────
def pose_to_array(pose: dict) -> np.ndarray:
return np.array([pose[k] for k in JOINT_NAMES])
def array_to_pose(arr: np.ndarray) -> dict:
return {k: float(arr[i]) for i, k in enumerate(JOINT_NAMES)}
def horizontal_wrist_flex(shoulder_lift: float, elbow_flex: float) -> float:
return WRIST_HORIZONTAL_OFFSET - shoulder_lift - elbow_flex
def _low_sweep_pose(pan: float, elbow_flex: float, wrist_flex: float | None = None) -> dict:
sl = SWEEP_LOW_SHOULDER_LIFT
return {
"shoulder_pan.pos": pan,
"shoulder_lift.pos": sl,
"elbow_flex.pos": elbow_flex,
"wrist_flex.pos": horizontal_wrist_flex(sl, elbow_flex) if wrist_flex is None else wrist_flex,
"wrist_roll.pos": 0.0,
"gripper.pos": 60.0,
}
def _high_sweep_pose(pan: float) -> dict:
return {**HOME_POSE, "shoulder_pan.pos": pan, "wrist_flex.pos": SWEEP_HIGH_WRIST_FLEX}
def _push_pose(shoulder_lift: float, elbow_flex: float, pan: float = GRAB_PAN, gripper: float = 70.0) -> dict:
return {
"shoulder_pan.pos": pan,
"shoulder_lift.pos": shoulder_lift,
"elbow_flex.pos": elbow_flex,
"wrist_flex.pos": horizontal_wrist_flex(shoulder_lift, elbow_flex),
"wrist_roll.pos": 0.0,
"gripper.pos": gripper,
}
def move_to_pose(robot: Robot, target: dict, speed: float) -> None:
"""Interpolate from current position to target at the given speed (units/s)."""
obs = robot.get_observation()
current = np.array([obs[k] for k in JOINT_NAMES])
goal = pose_to_array(target)
max_distance = float(np.max(np.abs(goal - current)))
if max_distance < 0.5:
return
n_steps = max(1, int(max_distance / speed * CONTROL_HZ))
dt = 1.0 / CONTROL_HZ
for step in range(1, n_steps + 1):
t = step / n_steps
robot.send_action(array_to_pose(current + t * (goal - current)))
precise_sleep(dt)
# ── Sequences ─────────────────────────────────────────────────────────────────
def grab_cube(robot: Robot) -> None:
"""Left sweep → right sweep → extend arm parallel to ground → close gripper."""
move_to_pose(robot, HOME_POSE, APPROACH_SPEED)
for pan, end_pan in [
(SWEEP_LEFT_PAN, GRAB_PAN - SWEEP_END_OFFSET),
(SWEEP_RIGHT_PAN, GRAB_PAN + SWEEP_END_OFFSET),
]:
logger.info(f"Sweeping {'left' if pan < 0 else 'right'} → center...")
move_to_pose(robot, _high_sweep_pose(pan), APPROACH_SPEED)
move_to_pose(
robot, _low_sweep_pose(pan, SWEEP_LOW_ELBOW_FLEX_START, wrist_flex=-20.0), APPROACH_SPEED
)
move_to_pose(robot, _low_sweep_pose(end_pan, SWEEP_LOW_ELBOW_FLEX_END, wrist_flex=0.0), SWEEP_SPEED)
move_to_pose(robot, HOME_POSE, APPROACH_SPEED)
logger.info("Extending to push cube into gripper...")
move_to_pose(
robot,
_push_pose(PUSH_START_SHOULDER_LIFT - PUSH_RAISE_OFFSET, PUSH_START_ELBOW_FLEX),
APPROACH_SPEED,
)
move_to_pose(
robot,
_push_pose(PUSH_END_SHOULDER_LIFT - PUSH_RAISE_OFFSET, PUSH_END_ELBOW_FLEX),
SWEEP_SPEED,
)
logger.info("Closing gripper...")
move_to_pose(
robot,
_push_pose(PUSH_END_SHOULDER_LIFT, PUSH_END_ELBOW_FLEX, gripper=GRIPPER_CLOSE_POS),
APPROACH_SPEED,
)
logger.info("Grab complete.")
def place_cube(robot: Robot) -> tuple[float, float]:
"""Carry the cube (gripper closed) to a random position on the left side, then release.
Returns:
(pan, t): pan angle and reach scalar [0, 1] of the placement position.
"""
pan = float(np.random.uniform(*PLACE_LEFT_PAN_RANGE))
t = float(np.random.uniform(*PLACE_REACH_RANGE))
sl = PUSH_START_SHOULDER_LIFT + t * (PUSH_END_SHOULDER_LIFT - PUSH_START_SHOULDER_LIFT)
ef = PUSH_START_ELBOW_FLEX + t * (PUSH_END_ELBOW_FLEX - PUSH_START_ELBOW_FLEX)
logger.info(f"Placing cube at pan={pan:.1f}, reach={t:.2f}...")
move_to_pose(robot, {**HOME_POSE, "gripper.pos": GRIPPER_CLOSE_POS}, APPROACH_SPEED)
move_to_pose(
robot, {**HOME_POSE, "shoulder_pan.pos": pan, "gripper.pos": GRIPPER_CLOSE_POS}, APPROACH_SPEED
)
move_to_pose(robot, _push_pose(sl, ef, pan=pan, gripper=GRIPPER_CLOSE_POS), APPROACH_SPEED)
move_to_pose(robot, _push_pose(sl, ef, pan=pan, gripper=80.0), APPROACH_SPEED)
move_to_pose(robot, HOME_POSE, APPROACH_SPEED)
logger.info("Place complete.")
return pan, t
# ── Entry point ───────────────────────────────────────────────────────────────
def main():
parser = argparse.ArgumentParser(description="OMX arm reset / grab script")
parser.add_argument("--port", default="/dev/ttyACM1")
parser.add_argument("--robot_id", default="omx_follower")
parser.add_argument("--mode", choices=["grab", "grab_and_place"], default="grab_and_place")
args = parser.parse_args()
logging.basicConfig(level=logging.INFO, format="%(levelname)s: %(message)s")
robot = OmxFollower(OmxFollowerConfig(port=args.port, id=args.robot_id))
robot.connect(calibrate=True)
try:
if args.mode == "grab":
grab_cube(robot)
elif args.mode == "grab_and_place":
grab_cube(robot)
place_cube(robot)
finally:
robot.disconnect()
if __name__ == "__main__":
main()