Custom Part Manufacturing Guide
Calculating Kinematics of a CTR
Graph Paper In-Plane Bending Experiment
Out-of-Plane Rotation Experiment
Concentric tube robots (CTRs) are a type of continuum robot that are designed for minimally invasive surgery [1], [2]. CTRs consist of multiple curved tubes nested inside of each other; this results in a surgical instrument with a small diameter and high degree of dexterity [3]. The mechanical design, kinematics, and control for concentric tube robots are all still active areas of research.
Here we offer an open-source actuation system for concentric tube robots suited for kinematic experiments and course projects. This system consists of a sturdy base and multiple “carts” that can translate along that base. Each cart actuates a single tube by both translating and rotating it.
This page contains all the materials and assembly guides you’ll need to build your own concentric tube robot actuation system. You will need to purchase materials listed in the Structural Components, Electronics and Motors, and Hardware sections, unless you already have similar items on hand. You will need to either laser cut or 3D print items listed in the Custom Part Files section. See the Custom Part Manufacturing Guide for tips on laser cutting and 3D printing. The Tube Materials section contains items that you must both purchase and 3D print.
To assemble your actuation system, view the Full System Assembly page. This will also link you to the Cart Assembly page, which describes how to assemble one of the carts.
The Tube Fabrication page describes the procedure for heat-setting your own pre-curved tubes.
To actuate the system, we use a Big TreeTech Octopus V1.1 board and six stepper motors. There are instructions to configure the board for our use, install custom firmware, and conduct a simple test to make sure the system is actuating correctly.
The Calculating Kinematics for a CTR page will guide you through the calculations for a simple kinematics model for a CTR. This includes links to papers and videos that go into more depth about these topics. This page is meant to introduce you to basic
[1] Fabrication of Concentric Tube Robots: A Survey,” IEEE Trans. Robot., vol. 39, no. 4, pp. 2510–2528, Aug. 2023, doi: 10.1109/TRO.2023.3255512.
[2] J. Burgner-Kahrs, D. C. Rucker, and H. Choset, “Continuum Robots for Medical Applications: A Survey,” IEEE Trans. Robot., vol. 31, no. 6, pp. 1261–1280, Dec. 2015, doi: 10.1109/TRO.2015.2489500.
[3] R. J. Webster, J. M. Romano, and N. J. Cowan, “Kinematics and calibration of active cannulas,” in 2008 IEEE International Conference on Robotics and Automation, Pasadena, CA, USA: IEEE, May 2008, pp. 3888–3895. doi: 10.1109/ROBOT.2008.4543808.