The new way forward: Soft robotics

In a converted pipe organ factory in San Francisco's Mission District, Saul Griffith works on products that are smarter, cheaper and, above all, squiggly. Inside the cavernous building and a nearby garage occupied by Griffith's research company Otherlab, small teams gather around laser cutters and machining tools. Some work on arrays of solar panels that follow the sun, guided by what look like ribbed soda bottles and powered by pneumatic pressure. Others fiddle with inflatable exoskeletons intended to help soldiers run far with heavy loads or to help paraplegics walk.

These are the kinds of futuristic products promised for years by conventional engineering that are now being made real by a handful of low-budget inventors with an unusual vision: they want to replace traditional brawn and metal with unconventional materials to create cheaper and more effective soft machines.

RoboThespian, made by a British company, is multilingual and designed for human interaction in public. PoseiDrone's soft arms can help it to navigate rocky, uneven surfaces. The robot can also propel itself by expelling water from its flexible body. "Every problem in mechanical engineering has been addressed with more weight, more power and more stiffness," said Griffith, co-founder and chief executive of Otherlab. "But nature - the real world - is squiggly."

Griffith is at the forefront of a movement known as soft robotics, which aims to revolutionise the way we think about building things. Researchers at Harvard University have released a tool kit to make loudspeakers and prosthetic hands using soft materials. Last summer's hit movie Big Hero 6 featured a squishy-bodied robot inspired by work at Carnegie Mellon University. Biologically inspired designs are also shared freely on the Internet by various user groups.

The work contrasts with more mainstream robotics. Amazon's drones and factory pickers, or the welding robots at Tesla, are decidedly hard and use traditional mechanical engineering approaches. Many of those machines have heavy arms and need objects placed in the same position every time, so they can move fast to the correct location. Traditional bionic exoskeletons proposed for the military and paraplegics are also heavy. More weight in the robot or exoskeleton means it will take more energy for the parts to move. That translates into either short battery life or an external power source.

Since squiggly things have less precise motions than hard things do, they need lots of sensors and semiconductors to correct their movements. Those once expensive parts have become cheaper thanks to the explosion of cellphones, which use many of the same components. Lifting things without crushing them, a problem with metal robots, is also easier with intelligent soft robots.

"There was an assumption that pneumatic things were sloppy and slow," said Gill A. Pratt, a programme manager at the Defense Advanced Research Projects Agency. Now, he said, "you can do precision with modern sensors and controls." Even the military initially had issues with the comical look of some pneumatics. An inflatable quarantine room "looks silly at first, because you say, 'Oh, it's a bouncy castle,'" Pratt said. "But it's incredibly effective, and a lot safer."

Griffith's first big project in the San Francisco Bay Area was Makani Power, a Google-backed effort to generate power by flying giant kites - and taking advantage of their soft shapes to withstand storms. He lost the company in the 2008 financial crisis, though Google is still pursuing the idea. To keep costs down, Griffith tries to do things as cheaply as possible. The prototype for the solar panel manipulator was created with a soda bottle and a hot plate, instead of a proposed $150,000 machine.

© 2015 The New York Times