© 2017 HCII Institute, Carnegie Mellon University

Pneumatic Shape Changing Composite

2014

PneUI is an enabling technology to build shape-changing interfaces through pneumatically actuated soft composite materials. The composite materials integrate the capabilities of both input sensing and active shape output. This is enabled by the composites’ multilayer structures with different mechanical or electrical properties. The shape-changing states are computationally con- trollable through pneumatics and a predefined structure.

  • Lining Yao, Ryuma Niiyama, Jifei Ou, Sean Follmer, Hiroshi Ishii

  • Tangible Media Group, MIT Media Lab

  • Paper - UIST 2013, ACM
  • Best Paper Award
  • Best Demo Nominee

(Up) The dynamic control of the curvature is determined by two factors: air pressure and crease pattern. First, air pressure can control the degree of curvature. Second, the design of paper crease patterns will affect the deformation. We vary three factors of crease patterns in our experiments: density, location and angle. Low-density creases enable sharper bends and, by vary- ing the location of crease, we can control the bending location on the surface. Laying out the crease lines diagonally generates helical shapes instead of curling on a single plane.

We introduced two primitive structures in PneUI with regard to the type of transformation, namely, bending: elongation for bending and compression for bending.
In terms of elongation for bending, the composite material includes three layers: a silicon layer with embedded airbags connected by air channels, a paper layer with crease patterns, and a thin silicon layer at the bottom, which bonds and protects the paper layer. While soft actuators have been introduced before, our work focuses on introducing a paper composite with various crease patterns to control the bending behavior. When inflated, the inner airbags function as actuators to generate elongation and force the surface to bend towards the opposite direction.
In terms of compression for bending, the composite material includes two layers: a plain paper layer and plastic airbags with low elasticity. Airbags are fabricated using plastic welding and glued to the paper layer. While inflated, the airbags behave like biceps (the muscle to pull the arms up) and self-compresses to cause the surface to bend.
We also explored tunable surface textures. We perceived the change in texture as a local and micro level shape changing behavior occurring on the surface. Each column of air bubbles can be inflated separately. We can vary the density, frequency and sequence of texture by pumping and vacuuming air in separate columns at different times. The combination of the three factors is capable of communicating different types of information, such as directional signals and speed.

Our pneumatically actuated soft composite material is designed to enable both isotropic and anisotropic deformation in response to air pressure. Without considering the electronic sensing components, the composite material is fabricated with two structural layers. One structural layer utilizes an elastomeric polymer (or elastomer) as the main material to enable isotropic shape deformation. To go beyond isotropic deformation, an additional structural layer us required, which includes a range of materials with different elasticity to create constrained anisotropic deformation in response to air pressure. In the original PneUI paper, more add-on layers were integrated, including a sensing layer and a multifunctional layer (e.g., a stiffness-changing layer or a color-changing layer).

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