Morphing "Y": A One-DOF Six-bar Developable Mechanism

Summary

This is a one-DOF (degree of freedom) six-bar rigid-body mechanism. Traditional engineering kinematics states that the mechanism will have the same motion regardless of the shapes of the rigid links. This makes for interesting motion as the links all move with respect to each other.

Because the links for this mechanism are shaped such that, in one of the mechanism's positions, the links conform to the BYU "Y" logo shape, this is a developable mechanism.

What is a Developable Mechanism?

A developable mechanism is a mechanism that, at some point in its motion, conforms to a developable surface. In other words, it is a device that can move and that is shaped to match a curved surface (or combination of curved surfaces) in a certain position. In this case, the developable surface that the mechanism conforms to is a generalized cylinder whose planar image is that of the BYU "Y" logo.

Visit https://www.compliantmechanisms.byu.edu/about-developable-mechanisms to learn more about developable mechanisms.

Printing Instructions

We recommend that you print one test link to make sure that the sizes are correct before you print the rest of the links.

This Thing can be 3D printed using any rigid filament. We print with PLA and find that works well. Support material is not necessary, but may help ensure the countersink holes come out the right depth. This Thing should not be scaled, as it will mess up the hole sizes.

Assembly

Assemble the pieces using LEGO connector pieces (the black or grey round cylindrical ones).

Use the pictures or your intuition to figure out the order of the links.
Link Y1 connects to links Y2, Y4, and Y6.
Link Y2 connects to links Y1 and Y3.
Link Y3 connects to links Y2, Y4, and Y5.
Link Y5 connects to links Y3 and Y6.
Link Y6 connects to links Y5 and Y1.

Learn More

This design was developed by the Compliant Mechanisms Research Group (CMR) from Brigham Young University (BYU). Follow us at @byucmr on Instagram, @CompliantMechanismsResearchGroup on Facebook, or visit the BYU Compliant Mechanisms Research (CMR) website to learn more about compliant mechanisms.

See https://rdcu.be/dnHx0 for an article in Nature Communications about how and why we share these maker resources.

Technical Information 

For in-depth technical information, see the following publications:

Nelson, T., Zimmerman, T., Magleby, S., Lang, R., and Howell, L., “Developable Mechanisms on Developable Surfaces,” Science Robotics, Vol. 4, Issue 2, DOI: 10.1126/scirobotics.aau5171, 2019. 

Greenwood, J.R., Magleby, S.P., and Howell, L.L., “Developable Mechanisms on Regular Cylindrical Surfaces,” Mechanism and Machine Theory, Vol. 142, https://doi.org/10.1016/j.mechmachtheory.2019.103584, 2019. 

Hyatt, L.P., Magleby, S.P., Howell, L.L., “Developable Mechanisms on Right Conical Surfaces,” Mechanism and Machine Theory, Vol. 149, paper no. 103813, https://doi.org/10.1016/j.mechmachtheory.2020.103813, 2020.

Sheffield, J.L., Sargent, B., and Howell, L.L., “Embedded Linear-Motion Developable Mechanisms on Cylindrical Developable Surfaces,” Journal of Mechanisms & Robotics, Vol. 16, 015001-1 to 015001-11, https://doi.org/10.1115/1.4062133, 2024. 

Hyatt, L, Greenwood, J., Butler, J., Magleby, S.P., Howell, L.L., “Methods for Mapping Mechanisms to Developable Surfaces,” International Journal of Mechanisms and Robotic Systems, special issue associated with the 2020 USCToMM Symposium on Mechanical Systems and Robotic, https://doi.org/10.1504/IJMRS.2021.115154, Vol. 5, Nos. 1-2, pp. 39-60, 2021

Seymour, K., Bilancia, P., Magleby, S., Howell, L., “Hinges and Curved Lamina Emergent Torsional Joints in Cylindrical Developable Mechanisms,” Journal of Mechanisms and Robotics, https://doi.org/10.1115/1.4049439, Vol. 13, 031002-1 to 031002-8, 2021. 

Butler, J., Greenwood, J., Howell, L.L., Magleby, S.P., “Limits of Extramobile and Intramobile Motion of Cylindrical Developable Mechanisms,” Journal of Mechanisms and Robotics, https://doi.org/10.1115/1.4048833, Vol 13, 011024-1 to 011024-8, 2021.

Visit the BYU Compliant Mechanisms Research (CMR) website to learn more about compliant mechanisms, or check out these books: Compliant Mechanisms, Handbook of Compliant Mechanisms.

Intellectual Property

The downloadable 3D print files provided here may be used, modified, and enjoyed for noncommercial use. To license developable mechanism technology for commercial applications, contact:

BYU Technology Transfer Office

3760 Harold B. Lee Library

Brigham Young University

Provo, UT 84602

Phone: (801) 422-6266 

https://techtransfer.byu.edu/contact