Rational Linkages

This Python-based package provides a collection of methods for the synthesis, analysis, design, and rapid prototyping of the single-loop rational linkages, allowing one to create 3D-printable collision-free mechanisms synthesised for a given task (set of poses).

The package was originally developed as a part of the research project at the Unit of Geometry and Surveying, University of Innsbruck, Austria.

Documentation, tutorials, issues

Rational Linkages Documentation is hosted on Read the Docs, and provides a comprehensive overview of the package with examples and tutorials.

Since the self-hosted repository (Gitlab, University of Innsbruck) does not allow external users to create issues, please, use the package mirror hosted on GitHub for submitting issues and feature requests. Additionally, you can "watch/star" the issue tracker package to get notified about the updates (new releases will be also announced there).

You can test live-example of Jupyter notebook using Binder, by clicking on the following badge:

In case of other questions or contributions, please, email the author at: daniel.huczala@snu.ac.kr

STL files of some mechanisms may be found as models on Printables.com.

The results may look like this Bennett manipulator made by our collaborators from the Department of Robotics, VSB -- Technical University of Ostrava. See full video on Youtube.

Intallation instuctions

Recommended Python version is 3.13, when it provides the smoothest plotting (but 3.10 or higher are supported). Python 3.13 is also the version used for development. Some dependencies not yet support Python 3.14, therefore it is not recommended to use for full functionality of the package.

Install from PyPI

Using pip:

pip install rational-linkages

or with optional dependencies:

pip install "rational-linkages[opt,cad]"

for installing also optional dependencies (ipython - inline plotting, scipy - optimization problems solving, matplotlib - alternative engine for 3D plotting) and cad dependencies (exudyn - multibody simulations, ngsolve - work with meshes in exudyn, build123d - generating STEP files of linkages, trimesh + manifold3d - generating STL files).

On Linux systems, to run GUI interactive plotting, some additional libraries might be required for plotting with PyQt6. For example, on Ubuntu, it can be installed as follows:

sudo apt install libgl1-mesa-glx libxkbcommon-x11-0 libegl1 libdbus-1-3

or on Ubuntu 24.04 and higher:

sudo apt install libgl1 libxkbcommon-x11-0 libegl1 libdbus-1-3

On 64-bit platform, gmpy2 package for optimized symbolic computations can be useful.

Install from source

1. Clone the repository (use preferably your client, or clone with the button on top of this page or using the following line)

   git clone https://git.uibk.ac.at/geometrie-vermessung/rational-linkages.git

2. Navigate to the repository folder

   cd rational-linkages

3. Install the editable version of the package using pip:

   pip install -e ".[opt,cad]"

   or

   pip install -e ".[opt,cad,dev,doc]" including the development and documentation dependencies.

To locally develop, you need to install the Rust toolchain and build the Rust code yourself. On top of that, on Windows, you need to install a C++ build toolchain. In Visual Studio Installer, select:

• MSVC v143 - VS 2022 C++ x64/x86 build tools (latest)
• Windows 11 SDK
• C++ CMake tools for Windows

Alternatively, on Linux, you need to install:

• build-essential

Then, if adding Rust-based functions, navigate to the rational_linkages/rust folder and run:

cargo build --release

Citing the package

For additional information, see our preprint paper, and in the case of usage, please, cite it:

Huczala, D., Siegele, J., Thimm, D.A., Pfurner, M., Schröcker, HP. (2024). Rational Linkages: From Poses to 3D-Printed Prototypes. In: Lenarčič, J., Husty, M. (eds) Advances in Robot Kinematics 2024. ARK 2024. Springer Proceedings in Advanced Robotics, vol 31. Springer, Cham. DOI: 10.1007/978-3-031-64057-5_27.

@inproceedings{huczala2024linkages,
    title={Rational Linkages: From Poses to 3D-printed Prototypes},
    author={Daniel Huczala and Johannes Siegele and Daren A. Thimm and Martin Pfurner and Hans-Peter Schröcker},
    year={2024},
    booktitle={Advances in Robot Kinematics 2024. ARK 2024},
    publisher={Springer International Publishing},
    url={https://doi.org/10.1007/978-3-031-64057-5_27},
    doi={10.1007/978-3-031-64057-5_27},
}

Preprint of the paper

On arXiv:2403.00558: https://arxiv.org/abs/2403.00558.

Acknowledgements

Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Research Executive Agency (REA). Neither the European Union nor the granting authority can be held responsible for them.