Volumetric Grasping Network

VGN is a 3D convolutional neural network for real-time 6 DOF grasp pose detection. The network accepts a Truncated Signed Distance Function (TSDF) representation of the scene and outputs a volume of the same spatial resolution, where each cell contains the predicted quality, orientation, and width of a grasp executed at the center of the voxel. The network is trained on a synthetic grasping dataset generated with physics simulation.

This repository contains the implementation of the following publication:

• M. Breyer, J. J. Chung, L. Ott, R. Siegwart, and J. Nieto. Volumetric Grasping Network: Real-time 6 DOF Grasp Detection in Clutter. Conference on Robot Learning (CoRL 2020), 2020. [pdf][video]

If you use this work in your research, please cite accordingly.

The next sections provide instructions for getting started with VGN.

• Installation
• Dataset Generation
• Network Training
• Simulated Grasping
• Robot Grasping

Installation

The following instructions were tested with python3.8 on Ubuntu 20.04. A ROS installation is only required for visualizations and interfacing hardware. Simulations and network training should work just fine without. The Robot Grasping section describes the setup for robotic experiments in more details.

OpenMPI is optionally used to distribute the data generation over multiple cores/machines.

sudo apt install libopenmpi-dev

Clone the repository into the src folder of a catkin workspace.

git clone https://github.com/ethz-asl/vgn

Create and activate a new virtual environment.

cd /path/to/vgn
python3 -m venv --system-site-packages .venv
source .venv/bin/activate

Install the Python dependencies within the activated virtual environment.

pip install -r requirements.txt

Build and source the catkin workspace,

catkin build vgn
source /path/to/catkin_ws/devel/setup.zsh

or alternatively install the project locally in "editable" mode using pip.

pip install -e .

Finally, download the data folder here, then unzip and place it in the repo's root.

Data Generation

Generate raw synthetic grasping trials using the pybullet physics simulator.

python scripts/generate_data.py data/raw/foo --scene pile --object-set blocks [--num-grasps=...] [--sim-gui]

• python scripts/generate_data.py -h prints a list with all the options.
• mpirun -np <num-workers> python ... will run multiple simulations in parallel.

The script will create the following file structure within data/raw/foo:

• grasps.csv contains the configuration, label, and associated scene for each grasp,
• scenes/<scene_id>.npz contains the synthetic sensor data of each scene.

Clean the generated grasp configurations using the data.ipynb notebook.

Finally, generate the voxel grids/grasp targets required to train VGN.

python scripts/construct_dataset.py data/raw/foo data/datasets/foo

• Samples of the dataset can be visualized with the vis_sample.py script and vgn.rviz configuration. The script includes the option to apply a random affine transform to the input/target pair to check the data augmentation procedure.

Network Training

python scripts/train_vgn.py --dataset data/datasets/foo [--augment]

Training and validation metrics are logged to TensorBoard and can be accessed with

tensorboard --logdir data/runs

Simulated Grasping

Run simulated clutter removal experiments.

python scripts/sim_grasp.py --model data/models/vgn_conv.pth [--sim-gui] [--rviz]

• python scripts/sim_grasp.py -h prints a complete list of optional arguments.
• To detect grasps using GPD, you first need to install and launch the gpd_ros node (roslaunch vgn gpd.launch).

Use the clutter_removal.ipynb notebook to compute metrics and visualize failure cases of an experiment.

Robot Grasping

This package contains an example of open-loop grasp execution with a Franka Emika Panda and a wrist-mounted Intel Realsense D435. Since the robot drivers are not officially supported on ROS noetic yet, we used the following workaround:

• Launch the roscore and hardware drivers on a NUC with libfranka installed.
• Run MoveIt and the VGN scripts on a second computer with a ROS noetic installation connected to the same roscore following these instructions. This requires the latest version of panda_moveit_config.

First, on the NUC, start a roscore and launch the robot and sensor drivers:

roscore &
roslaunch vgn panda_grasp.launch

Then, on the 20.04 computer, run

roslaunch panda_moveit_config move_group.launch
python scripts/panda_grasp.py --model data/models/vgn_conv.pth

Citing

@inproceedings{breyer2020volumetric,
 title={Volumetric Grasping Network: Real-time 6 DOF Grasp Detection in Clutter},
 author={Breyer, Michel and Chung, Jen Jen and Ott, Lionel and Roland, Siegwart and Juan, Nieto},
 booktitle={Conference on Robot Learning},
 year={2020},
}