Soft Cubes

Loading Physical Intelligence Department


Programmable matter is a material or system which can be programmed to change its physical property such as shape, stiffness, color, density, etc. The ability to change its property to the targeted, the object overcomes limitations from the static matter robotic systems. We aim to develop programmable matter which can change its shape from the simplest shape to complex 3-D shape. To achieve the large change of the shape, soft material is used in our approach. Currently, we have developed SoftCubes, which is able to change its shape from a single string to desired complex 3-D shape with the preprogrammed shape. The restoring force from the soft material gives restoration of programmed shape, and magnetic interaction minimizes shape misalignment from magnetic interaction. Potential application of this project is injectable medical implant or anchor for minimal invasive surgery or natural orifice trans-luminal endoscopic surgery (NOTES).

Project Members:

Donghoon Son

Kirstin H. Petersen

Past Members:

Sehyuk Yim

Selected Research Results and Papers

SoftCubes: Stretchable and self-assembling three-dimensional soft modular matter

This paper proposes a self-assembling soft modular matter, called SoftCubes, where soft-bodied modules are disassembled into a flexible string by an external tension and self-assemble into the preprogrammed three-dimensional (3D) shape. The developed soft modular matter has three main design features. Firstly, entire modules of the 3D shape are serially connected. Such a structure allows all the modules to be disassembled by external tension. Secondly, the outer body of the modules and the connecting parts are made of soft stretchable elastomer. Due to the soft body of the modules, after disassembling, the serially connected modules become a highly flexible and soft string, and have an extreme shape adaptation capability. Also, if the external tension is removed, the preprogrammed 3D shape is recovered by the elastic restoring force of soft-bodied modules. Finally, embedded small permanent magnets induce magnetic self-assembling forces and maintain a mechanical robustness of the 3D shape of module assembly. Due to the magnetic self-assembly, the soft modules are precisely aligned with neighboring modules in a lattice structure. The paper also presents an algorithm to generate the serial connection path of modules for creating a given 3D shape. Various physical interactions between self-assembling module prototypes are visualized in two-dimensional motion tracking experiments. Finally, the shape reconfiguration ability of soft modular matter is demonstrated. SoftCubes is a new class of programmable modular matter where shape memory ability is embedded in the structure, and shows a physical implementation of various 3D shapes with a high resolution and a high scalability.

T=0 sec ---------------------------------------> 180 sec

S. Yim and M. Sitti, “SoftCubes: Stretchable and self-assembling three-dimensional soft modular matter,” The International Journal of Robotics Research, The International Journal of Robotics Research, vol. 33 no. 8, 2014, pp. 1083-1097.

Selected Video


Strechable and self-assembling 3-dimensional soft modular matter

List of Publications



SoftCubes: Stretchable and self-assembling three-dimensional soft modular matter

S Yim, M Sitti

The International Journal of Robotics Research, vol. 33 no. 8, 2014, pp. 1083-1097.





SoftCubes: towards a soft modular matter

S Yim, M Sitti

Robotics and Automation (ICRA), 2013 IEEE International Conference on, 530-536