Robots go from soft to rigid (... jokes follow)

Researchers are figuring out ways to bring the benefits of soft robotics to rigid structures with novel dual phase engineering

Researchers from Harvard's Wyss Institute are building robots that incorporate novel structures capable of transforming from soft to rigid.

The materials could solve an important problem: How do you combine the flexibility and durability of soft robots with the precision of traditional rigid engineering?

Earlier this week I wrote about the impact soft grippers are likely to have on the adaptability of industrial robots. Once the three million-plus industrial robots that will soon be online can grab and manipulate a wide variety of items, a task made easier via soft, pliable grippers, adoption and penetration are likely to soar.

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The Harvard researchers have been working with a structure built from several layers of pliable material surrounded by a plastic sleeve. A vacuum source attached to the air-tight sleeve can effectively change the properties of the material.

"When the vacuum is off," explains Wyss spokesperson Leah Burrows, "the structure behaves exactly as you would expect, bending, twisting and flopping without holding shape. But when a vacuum is applied, it becomes stiff and can hold arbitrary shapes, and it can be molded into additional forms."

In engineering speak, this process is called "laminar jamming," according to Burrows. Pressure against the interior elements results in friction, making them temporarily rigid.

"The frictional forces generated by the pressure act like glue," says Yashraj Narang, a researcher in Harvard's John A. Paulson School of Engineering and Applied Sciences (SEAS), and first author on two papers about the dual phase materials. "We can control the stiffness, damping, kinematics, and dynamics of the structure by changing the number of layers, tuning the pressure applied to it, and adjusting the spacing between multiple stacks of layers."

Possible short-term applications include shock absorbers that can be tuned for different situations, surgical instruments that can be inserted into a body cavity while in flexible form, and portable pliable speakers.