lerobot/examples/9_use_aloha.md

This tutorial explains how to use Aloha and Aloha 2 stationary with LeRobot.

Setup

Follow the documentation from Trossen Robotics for setting up the hardware and plugging the 4 arms and 4 cameras to your computer.

Install LeRobot

On your computer:

1. Install Miniconda:

mkdir -p ~/miniconda3
wget https://repo.anaconda.com/miniconda/Miniconda3-latest-Linux-x86_64.sh -O ~/miniconda3/miniconda.sh
bash ~/miniconda3/miniconda.sh -b -u -p ~/miniconda3
rm ~/miniconda3/miniconda.sh
~/miniconda3/bin/conda init bash

2. Restart shell or source ~/.bashrc

3. Create and activate a fresh conda environment for lerobot

conda create -y -n lerobot python=3.10 && conda activate lerobot

4. Clone LeRobot:

git clone https://github.com/huggingface/lerobot.git ~/lerobot

5. Install LeRobot with dependencies for the Aloha motors (dynamixel) and cameras (intelrealsense):

cd ~/lerobot && pip install -e ".[dynamixel, intelrealsense]"

For Linux only (not Mac), install extra dependencies for recording datasets:

conda install -y -c conda-forge ffmpeg
pip uninstall -y opencv-python
conda install -y -c conda-forge "opencv>=4.10.0"

Teleoperate

*/!\ FOR SAFETY, READ THIS /!* Teleoperation consists in manually operating the leader arms to move the follower arms. Importantly:

1. Make sure your leader arms are in the same position as the follower arms, so that the follower arms don't move too fast to match the leader arms,
2. Our code assumes that your robot has been assembled following Trossen Robotics instructions. This allows us to skip calibration, as we use the pre-defined calibration files in .cache/calibration/aloha_default. If you replace a motor, make sure you follow the exact instructions from Trossen Robotics.

By running the following code, you can start your first SAFE teleoperation:

python lerobot/scripts/control_robot.py teleoperate \
    --robot-path lerobot/configs/robot/aloha.yaml \
    --robot-overrides max_relative_target=5

By adding --robot-overrides max_relative_target=5, we override the default value for max_relative_target defined in lerobot/configs/robot/aloha.yaml. It is expected to be 5 to limit the magnitude of the movement for more safety, but the teleoperation won't be smooth. When you feel confident, you can disable this limit by adding --robot-overrides max_relative_target=null to the command line:

python lerobot/scripts/control_robot.py teleoperate \
    --robot-path lerobot/configs/robot/aloha.yaml \
    --robot-overrides max_relative_target=null

Record a dataset

Once you're familiar with teleoperation, you can record your first dataset with Aloha.

If you want to use the Hugging Face hub features for uploading your dataset and you haven't previously done it, make sure you've logged in using a write-access token, which can be generated from the Hugging Face settings:

huggingface-cli login --token ${HUGGINGFACE_TOKEN} --add-to-git-credential

Store your Hugging Face repository name in a variable to run these commands:

HF_USER=$(huggingface-cli whoami | head -n 1)
echo $HF_USER

Record 2 episodes and upload your dataset to the hub:

python lerobot/scripts/control_robot.py record \
    --robot-path lerobot/configs/robot/aloha.yaml \
    --robot-overrides max_relative_target=null \
    --fps 30 \
    --repo-id ${HF_USER}/aloha_test \
    --tags aloha tutorial \
    --warmup-time-s 5 \
    --episode-time-s 40 \
    --reset-time-s 10 \
    --num-episodes 2 \
    --push-to-hub 1

Visualize a dataset

If you uploaded your dataset to the hub with --push-to-hub 1, you can visualize your dataset online by copy pasting your repo id given by:

echo ${HF_USER}/aloha_test

If you didn't upload with --push-to-hub 0, you can also visualize it locally with:

python lerobot/scripts/visualize_dataset_html.py \
  --repo-id ${HF_USER}/aloha_test

Replay an episode

*/!\ FOR SAFETY, READ THIS /!* Replay consists in automatically replaying the sequence of actions (i.e. goal positions for your motors) recorded in a given dataset episode. Make sure the current initial position of your robot is similar to the one in your episode, so that your follower arms don't move too fast to go to the first goal positions. For safety, you might want to add --robot-overrides max_relative_target=5 to your command line as explained above.

Now try to replay the first episode on your robot:

python lerobot/scripts/control_robot.py replay \
    --robot-path lerobot/configs/robot/aloha.yaml \
    --robot-overrides max_relative_target=null \
    --fps 30 \
    --repo-id ${HF_USER}/aloha_test \
    --episode 0

Train a policy

To train a policy to control your robot, use the python lerobot/scripts/train.py script. A few arguments are required. Here is an example command:

python lerobot/scripts/train.py \
  dataset_repo_id=${HF_USER}/aloha_test \
  policy=act_aloha_real \
  env=aloha_real \
  hydra.run.dir=outputs/train/act_aloha_test \
  hydra.job.name=act_aloha_test \
  device=cuda \
  wandb.enable=true

Let's explain it:

1. We provided the dataset as argument with dataset_repo_id=${HF_USER}/aloha_test.
2. We provided the policy with policy=act_aloha_real. This loads configurations from lerobot/configs/policy/act_aloha_real.yaml. Importantly, this policy uses 4 cameras as input cam_right_wrist, cam_left_wrist, cam_high, and cam_low.
3. We provided an environment as argument with env=aloha_real. This loads configurations from lerobot/configs/env/aloha_real.yaml. Note: this yaml defines 18 dimensions for the state_dim and action_dim, corresponding to 18 motors, not 14 motors as used in previous Aloha work. This is because, we include the shoulder_shadow and elbow_shadow motors for simplicity.
4. We provided device=cuda since we are training on a Nvidia GPU.
5. We provided wandb.enable=true to use Weights and Biases for visualizing training plots. This is optional but if you use it, make sure you are logged in by running wandb login.

Training should take several hours. You will find checkpoints in outputs/train/act_aloha_test/checkpoints.

Evaluate your policy

You can use the record function from lerobot/scripts/control_robot.py but with a policy checkpoint as input. For instance, run this command to record 10 evaluation episodes:

python lerobot/scripts/control_robot.py record \
  --robot-path lerobot/configs/robot/aloha.yaml \
  --robot-overrides max_relative_target=null \
  --fps 30 \
  --repo-id ${HF_USER}/eval_act_aloha_test \
  --tags aloha tutorial eval \
  --warmup-time-s 5 \
  --episode-time-s 40 \
  --reset-time-s 10 \
  --num-episodes 10 \
  --num-image-writer-processes 1 \
  -p outputs/train/act_aloha_test/checkpoints/last/pretrained_model

As you can see, it's almost the same command as previously used to record your training dataset. Two things changed:

1. There is an additional -p argument which indicates the path to your policy checkpoint with (e.g. -p outputs/train/eval_aloha_test/checkpoints/last/pretrained_model). You can also use the model repository if you uploaded a model checkpoint to the hub (e.g. -p ${HF_USER}/act_aloha_test).
2. The name of dataset begins by eval to reflect that you are running inference (e.g. --repo-id ${HF_USER}/eval_act_aloha_test).
3. We use --num-image-writer-processes 1 instead of the default value (0). On our computer, using a dedicated process to write images from the 4 cameras on disk allows to reach constent 30 fps during inference. Feel free to explore different values for --num-image-writer-processes.

More

Follow this previous tutorial for a more in-depth explaination.

If you have any question or need help, please reach out on Discord in the channel #aloha-arm.