Cosserat's Rod Model for Statics of Tendon-Driven Continuum Robots

Overview

• C++ Library: High-performance, header-only implementation of Cosserat rod equations for TDCRs, including physics-based modeling and a shooting method for solving boundary value problems (BVP).
• Python Bindings: Lightweight pybind11 interface for using the C++ library in Python with native performance.
• PyTorch Implementation: Differentiable physics-based model built in PyTorch, featuring RK4-based shooting and Newton-Raphson optimization for BVPs. Includes NumPy wrappers for use with SciPy’s BVP solver.

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Build & Install

First clone the repository

C++ Library Only

Required for C++ Library:

• CMake ≥ 3.30
• C++17 compatible compiler (e.g., g++, clang++)
• Blaze Library – Header-only linear algebra
• LAPACK – Linear Algebra Package
• openBLAS – Basic Linear Algebra Subprograms

cd repo-name
mkdir build && cd build
cmake .. -DBUILD_PYBIND=OFF
make -j

C++ Library + Python Bindings

cd repo-name
mkdir build && cd build
cmake .. -DBUILD_PYBIND=ON
make -j
sudo make install

This builds tdcr_physics.so, which can be imported into Python.

Install PyTorch Version

python3 -m venv venv
source venv/bin/activate
pip install -e .

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Folder Structure

TDCR_Cosserat_Rod_Model/
├── CMakeLists.txt         # Build configuration
├── lib_tdcr/              # C++ core library
├── pybindings/            # pybind11 bindings
├── python/                # PyTorch implementation
├── examples/              # Example use cases
├── setup.py               # Python package setup script
└── README.md

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References

• Rucker, D. Caleb, and Robert J. Webster III. "Statics and dynamics of continuum robots with general tendon routing and external loading." IEEE Transactions on Robotics 27.6 (2011): 1033-1044.
• Till, John, Vincent Aloi, and Caleb Rucker. "Real-time dynamics of soft and continuum robots based on Cosserat rod models." The International Journal of Robotics Research 38.6 (2019): 723-746.
• Adapted in part from Filipe Pedrosa’s original codebase.