When Don Hall was working on a robotic character for his Disney animation, “Big Hero 6,” he visited NASA and other robotic research centers in search of a huggable robot. Who wants to embrace a metal one? 

In 2011 he visited Carnegie Mellon University, where he beheld a soft robotic arm inside Chris Atkeson’s robotics lab that Siddharth Sanan had developed for his doctoral thesis. Made from polyurethane, the inflated, user-friendly arm was being designed to help dress, feed or comb the hair of people who are elderly or disabled. In that instant, Mr. Hall later noted, “I knew we had our huggable robot.” 

It was apparent, the movie’s co-director said, that the technology would inspire the kind of robot character never seen before.

“Everything about Baymax’s character, personality and design stemmed from that trip,” he was quoted as saying.  

Animated features typically are soft fantasy rather than hard science. But Mr. Hall combines the two. The movie’s main character, the soft, helpful robot Baymax, reflects the latest trend in developing soft, cheap and practical robots that can interact with people.

The CMU team has been collaborating with the University of Pittsburgh in operating the National Science Foundation Center for Engineering Research Center on Quality of Life Technologies, which is developing health care robots, including the soft robot arm. Pitt researchers include Jacqueline Dunbar-Jacob, dean of Pitt's School of Nursing, and Rory Cooper, director, Human Engineering Research Laboratories of Pitt and the Veterans Administration. 

People needing assistance tend to prefer a warm, soft robotic hand rather than a cold, bruising metal claw. But such robots pose structural challenges. They must be soft and lightweight but strong. Air pressure can provide strength through computer-controlled actuators, pneumatic pressure and cables.   

Meanwhile, Mr. Atkeson’s goal has been to reduce the amount of metal in his robots.

“In the glorious future,” he said, “I think we can build them out of soft materials with air pressure, soft valves and a computer filling up and deflating air compartments to make the robots walk, roll and do tasks.”

The soft robotic exterior can be elastic and contain electronic sensors. 

“If we could make robots out of cloth or plastic sheets, it potentially could make for very cheap robots,” Mr. Atkeson said. “That is one compelling reason to make inflatable robots.”

A soft robotic arm would be ideal to disarm bombs.

“If it is blown off, you can add a cheap new one, as opposed the costly, complicated metal arm,” he said. While other potential benefits could include treating people infected with Ebola, the immediate goal is routine care.

“If you can keep air in, you can keep water out,” allowing the robot to help wash, bathe or shower a person, Mr. Atkeson said. “We can build machines, but unless people like them and want to interact with them, they won’t be successful.” 

CMU now is busy creating a Center for Soft Materials and Machines led by Carmel Majdi, which will include the Soft Machines Lab and Soft Robotics and Bionics Lab. Turnabout is fair play. A goal of the new center is to develop a real Baymax.

And apparently roboticists sometimes reflect the robots they build. Mr. Atkeson said he had five soft moments while previewing the film, with tears occurring three times when his lab’s technology was depicted. Two other times simply were emotional points in the plot.

So his own movie review comes as no surprise: “The movie is a tremendous win for soft robotics.” 

First Published: November 7, 2014, 5:00 a.m.