Abstract

The derivation of a robot’s equation of motion is typically focused on placing multiple coordinate frames to express their kinematic and dynamic relationships. The Denavit-Hartenberg convention is commonly used to place the coordinate frames. While this approach is highly popular, it has several limitations. To overcome these limitations, we introduce our open source software, Exp[licit], which is based on the Differential Geometric method of Exponential Maps and can be used by researchers and engineers with basic knowledge of geometry and robotics.

Paper

A pre-print of our paper “Exp[licit]-A Robot modeling Software based on Exponential Maps” can be found here. If you are using the software, it would be great if you could cite the paper:

	@misc{lachner2023explicit,
        title={Exp[licit]-A Robot modeling Software based on Exponential Maps}, 
        author={Johannes Lachner and Moses C. Nah and Stefano Stramigioli and Neville Hogan},
        year={2023},
        eprint={2309.06648},
        archivePrefix={arXiv},
        primaryClass={cs.RO}
        }

Software and Installation

With Exp[licit]-MATLAB, you can model various robots, e.g., 2-DOF planar robots (unlimited DOF!), a Franka robot, and the KUKA LBR iiwa. Our member functions also accept symbolic arguments, which is helpful for control methods that require an analytical formulation of the robot’s equations of motion (e.g., adaptive control methods).

We also provide our Exp[licit]-C++, the software written in C++. For instance, this interface be used to control the KUKA LBR iiwa via the FRI-Interface. In future, Exp[licit] will offer a Python option that can be used for real-time control of robots. Stay tuned!

You can install our software from our Github repository. The software is licenced by MIT and it’s intended for academic and/or non-profit internal research purposes.

For more information, check out our website.

Acknowledgements

This software was developed together with my colleague Moses Chong-ook Nah.

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