3D printed objects from the new tool. Source: Disney Research

Scientists at Disney Research have created a new computation design tool that takes a conventional rigidly articulated device and automatically substitutes parts that do the same function but are flexible and elastic.

"Compliant mechanisms enjoy widespread use in industry—ranging from miniature actuators in microelectromechanical systems to the binder clips, backpack latches and shampoo lids common in everyday life," says Bernhard Thomaszewski, a former Disney scientist who is now an assistant professor at the University of Montreal. "Even broader use in machines is attractive because of their precision and because they can be readily manufactured."

However, designing for flexibility is more difficult than for rigidity because it demands a better understanding of how materials behave as their shape changes, researchers say.

The tool replaced conventional joints and linkages with compliant versions with the exception of hinge joints that rotate more than 360 degrees. The tool then optimizes performance of the device and modifies the design as necessary to achieve stability, eliminating instances where joint components might collide during use and reduce strains that might break it, researchers say.

The tool also makes sure the device does what it is intended to do, such as achieving a desired gait with a leg assembly, and favors robustness in design, although this sometimes comes at the expense of performance accuracy.

"With its ability to create complex geometry using a variety of strong and flexible materials, 3D printing is an ideal way to manufacture these compliant mechanisms," says Stelian Coros, assistant professor at Carnegie Mellon University.

The researchers demonstrated the method by 3D printing several mechanisms including a steering mechanism for a toy car, a compliant hand and a multi-jointed leg mechanism known as Jansen’s Linkage.