Reinhard M. Grassmann

I am a Ph.D. Candidate with the Department of Computer Science and a research assistant with the Continuum Robotics Laboratory at the University of Toronto, Canada. I work on continuum robotics and machine learning. Before all that, I completed a B.Sc. and a M.Sc. Degree in Mechatronics at the Leibniz University Hannover, Germany in 2016 and 2018, respectively. From 2018 to 2019 I worked as a research assistant at the Lehrstuhl fuer Kontinuumsrobotik at the Leibniz University Hannover.

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Research

I'm interested in continuum robotics, machine learning, and dual quaternions. Aside from that, creativity, innovation, and philosophy of science are also part of my field of interest to some extent.

During my research adventures, I have gratefully collaborated or am still collaborating with (in alphabetical order) J. Burgner-Kahrs, R. Z. Chen, P. T. Dewi, S. Haddadin, T. Hamoda, L. Johannsmeier, V. Modes, P. Le, N. Liang, S. Lilge, Q. Peyron, P. Rao, A. Senyk, and, C. Shentu.

clean-usnob Clarke Transform — A Fundamental Tool for Continuum Robotics
Reinhard M. Grassmann, Anastasiia Senyk, Jessica Burgner-Kahrs
arXiv, 2024
paper / arXiv / BibTex / Cheat Sheet / extended abstract (arXiv)

We propose the Clarke transform and Clarke coordinates enabling the development of methods on the two-dimensional manifold embedded in the n-dimensional joint space.

#Manifold #Representation #ContinuumRobot
clean-usnob On the Disentanglement of Tube Inequalities in Concentric Tube Continuum Robots
Reinhard M. Grassmann, Anastasiia Senyk, Jessica Burgner-Kahrs
IEEE ICRA, 2024
paper / IEEE Xplore / arXiv / BibTex

We derive and investigate the lower triangular transformation matrix to disentangle the tube inequalities.

#Disentanglement #Representation #ContinuumRobot
clean-usnob Open Continuum Robotics – One Actuation Module to Create them All
Reinhard M. Grassmann, Chengnan Shentu, Taqi Hamoda, Puspita Triana Dewi, Jessica Burgner-Kahrs
Frontiers in Robotics and AI, 2024
paper / arXiv / Front. Robot. AI / BibTex / OpenCR Project

To democratize continuum robots research, we propose an actuation module to build torque-controlled continuum robots and provide open-source software and hardware with our initiative called the Open Continuum Robotics Project.

#Design #TorqueControl #ContinuumRobot
clean-usnob A Dataset and Benchmark for Learning the Kinematics of Concentric Tube Continuum Robots
Reinhard M. Grassmann, Ryan Zeyuan Chen, Nan Liang, Jessica Burgner-Kahrs
IEEE/RAS IROS, 2022
paper / IEEE Xplore / BibTex / GitHub

We provide the first public dataset for a three-tube CTCR to democratize research on learning-based and physics-based modelling of the kinematics.

#Dataset #MachineLearning #ContinuumRobot
clean-usnob FAS -- A Fully Actuated Segment for Tendon-Driven Continuum Robots
Reinhard M. Grassmann, Priyanka Rao, Quentin Peyron, Jessica Burgner-Kahrs
Frontiers in Robotics and AI, 2022
paper / Front. Robot. AI / BibTex

To achieve variable tendon routing, we propose a segment design that combines two distinct characteristics of tendon-driven continuum robots, i.e. variable length and non-straight tendon routing, into a single segment by enabling rotation of its backbone.

#Design #VariableTendonRouting #ContinuumRobot
clean-usnob Learning-based Inverse Kinematics from Shape as Input for Concentric Tube Continuum Robots
Nan Liang Reinhard M. Grassmann, Sven Lilge, Jessica Burgner-Kahrs
IEEE ICRA, 2021
paper / IEEE Xplore / BibTex

We introduce methodologies to compute the inverse kinematics for concentric tube continuum robots from a desired shape as input.

#MachineLearning #ShapeRepresentation #ContinuumRobot
clean-usnob CTCR Prototype Development: An Obstacle in the Research Community?
Reinhard M. Grassmann, Sven Lilge, Phuong Le, Jessica Burgner-Kahrs
IFRR RSS Workshop on Retrospectives in Robotics, 2020
paper / OpenReview / RSS Workshop: Robotics Retrospectives / YouTube / BibTex

We discuss the impact of the current habit of developing a variety of different prototypes on the emergence of a ubiquitous robotic platform.

#SystemThinking #ContinuumRobot
clean-usnob Quaternion-Based Smooth Trajectory Generator for Via Poses in SE(3) Considering Kinematic Limits in Cartesian Space
Reinhard M. Grassmann, Jessica Burgner-Kahrs
IEEE RA-L, 2019
paper / IEEE Xplore / BibTex

We address the problem of generating a singularity-free trajectory for multiple via poses in SE(3), while complying with the requirement of C4 continuity.

#TrajectoryGeneration #Quaternion #LightWeightRobot
clean-usnob On the Merits of Joint Space and Orientation Representations in Learning the Forward Kinematics in SE(3)
Reinhard M. Grassmann, Jessica Burgner-Kahrs
IFRR RSS, 2019
paper / RSS XV / BibTex / Poster

We investigate the influence of different joint space and orientation representations on the approximation of the forward kinematics.

#MachineLearning #Quaternion #ContinuumRobot
clean-usnob Smooth Point-to-Point Trajectory Planning in SE(3) with Self-Collision and Joint Constraints Avoidance
Reinhard M. Grassmann, Lars Johannsmeier, Sami Haddadin
IEEE/RSJ IROS, 2018

paper / IEEE Xplore / BibTex

We introduce a point-to-point trajectory planner for serial robotic structures that combines the ability to avoid self-collisions and to respect motion constraints, while complying with the requirement of being C4 continuous.

#TrajectoryGeneration #Quaternion #LightWeightRobot
clean-usnob Learning the Forward and Inverse Kinematics of a 6-DOF Concentric Tube Continuum Robot in SE(3)
Reinhard M. Grassmann, Vincent Modes, Jessica Burgner-Kahrs
IEEE/RSJ IROS, 2018
paper / IEEE Xplore / BibTex

We introduce a joint description to learn the forward and inverse kinematics for concentric tube continuum robots from real robot measurements.

#MachineLearning #Quaternion #ContinuumRobot
Theses

Theses that I wrote during my mechatronics studies at Leibniz University Hannover.

clean-usnob

"Artificial Neural Networks for Learning Forward and Inverse Kinematics of Tubular Continuum Robots"

Master’s thesis supervised by Prof. Dr.-Ing. Jessica Burgner-Kahrs

clean-usnob

"Generating Smooth Trajectories for Obstacle Avoidance via Quaternions in Cartesian Space"

Bachelor’s thesis supervised by Prof. Dr.-Ing. Sami Haddadin

clean-usnob

"Data Fusion Using an Extended Kalman Filter for an Optically Navigated Light Weight Robot"

Project thesis supervised by Prof. Dr.-Ing. Tobias Ortmaier

Research Projects

Research projects with my involvement.

clean-usnob

"Open Continuum Robotics Project" (link to OpenCR Project, link to project description)

Principle investigator is Prof. Dr.-Ing. Jessica Burgner-Kahrs

Relevant papers:
- Open Continuum Robotics – One Actuation Module to Create them All
- CTCR Prototype Development: An Obstacle in the Research Community?

clean-usnob

"Learning the Kinematics of Tubular Continuum Robots" (link to project description)

Principle investigator is Prof. Dr.-Ing. Jessica Burgner-Kahrs

Relevant papers:
- A Dataset and Benchmark for Learning the Kinematics of Concentric Tube Continuum Robots
- Learning-based Inverse Kinematics from Shape as Input for Concentric Tube Continuum Robots
- On the Merits of Joint Space and Orientation Representations in Learning the Forward Kinematics in SE(3)
- Learning the Forward and Inverse Kinematics of a 6-DOF Concentric Tube Continuum Robot in SE(3)

clean-usnob

"Algorithms for Continuum Robots" (link to project description)

Principle investigator is Prof. Dr.-Ing. Jessica Burgner-Kahrs

Relevant papers:
- Clarke Transform — A Fundamental Tool for Continuum Robotics
- On the Disentanglement of Tube Inequalities in Concentric Tube Continuum Robots
- Quaternion-Based Smooth Trajectory Generator for Via Poses in SE(3) Considering Kinematic Limits in Cartesian Space

Acknowledgment

I made it in the acknowledgment section of the following papers :)

- A Non-Linear Model Predictive Task-Space Controller Satisfying Shape Constraints for Tendon-Driven Continuum Robots (arXiv, 2024)
- A Lightweight Modular Segment Design for Tendon-Driven Continuum Robots with Pre-Programmable Stiffness (RoboSoft 2024)
- Shape Representation and Modeling of Tendon-Driven Continuum Robots Using Euler Arc Splines (IEEE RA-L, 2022)
- Experiments in Autonomous Driving Through Imitation Learning (arXiv, 2020)

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