Pneumatic Gaussian cells

In Nature, plants leaves or petals may develop into very complex shapes through differential growth. Such change of a surface into a well-defined 3D shape requires both distorting distance along the plane and bending curvature simultaneously. However, current mechanisms are usually limited to either bending or metric distortion with soft systems. Programming complete morphing in stiff structures are relevant for engineering applications remains a challenge.

 

Here, we present and rationalize a novel and versatile gaussian morphing approach inspired by pneumatic actuation in monocotyledon plant leaves (bulliform cells). Our method relies on two pieces of airtight fabric separated by a network of thin walls that define pneumatic Gaussian cells. Both in-plane contraction and angular deflection of the panels can be programmed simultaneously through the cross section of the walls and the width of the cell. In addition, the stiffness of the structure is proportional to the applied pressure, which paves the way for the development of large-scale objects. These surfaces with controlled stiffness and fast actuation are manufactured using consumer-grade materials and constitutes an important milestone towards large-scale shape-morphing robotics applications.