New robot grows like vine to reach tight spaces
New robot grows like vine to reach tight spaces
By Benny Evangelista July 31, 2017 Updated: July 31, 2017 3:48pm
Elliot Hawkes found an unusual inspiration for a new type of robot — in the creeping vine of an office ivy plant.
Robots typically move stiffly and, well, robotically. But over time, Hawkes noticed the vine growing slowly but smoothly across an office bookshelf, bending itself around the corner so it could reach sunlight from a window.
So Hawkes and a team of Stanford University researchers built a prototype soft robot that can stretch like a vine into tight crevices and around obstacles like nails, glue and ice.
“We found it was virtually impossible to stop the robot from extending,” said Hawkes, a visiting UC Santa Barbara assistant professor.
The vine robot has reached only a proof-of-concept stage, far from becoming a finished commercial product. But the researchers are already working on versions for two potential applications: looking for disaster victims in collapsed buildings and probing blood vessels of medical patients.
Hawkes, Stanford graduate students Laura Blumenschein and Joey Greer, and mechanical engineering Professor Allison Okamura detailed their robot in a paper published last month in Science Robotics. Stanford has also posted a YouTube video showing the robot in action.
Worldwide purchases of robotics, including related hardware, software, services and drones, will reach about $97.2 billion this year, an almost 18 percent increase from last year, according to research firm IDC. There’s increasing interest in soft robotics, which uses light, pliable materials. For example, a team of Harvard University scientists last year built an eight-armed pneumatic robot called octobot.
The vine robot, which has no formal name, is like a tightly rolled-up sock turned inside out to form a tube, according to Hawkes, the paper’s lead author who had been working on pneumatically controlled artificial muscles at Stanford’s Collaborative Haptics and Robotics in Medicine lab. It’s also similar to the popular Water Wigglies slippery tube toy, which keeps rolling into itself, he said.
For the prototype, researchers used an inexpensive electronics plastic wrap bought on Amazon, said Greer, who is finishing his doctorate in mechanical engineering.
Air pumped into one end pushes the plastic material inside out from the other end, unfurling into new outside walls. At the same time, more plastic wrap is continuously drawn through the tube. Greer said they were able to extend the robot as much as 250 times its original length.
From left: UC Santa Barbara assistant professor and mechanical engineer Elliot Hawkes and Stanford graduate students Joey Greer and Laura Blumenschein demonstrate how the vine-like robot grows and navigates. Hawkes found inspiration for the robot in ivy that grew from its pot. Photo: Santiago Mejia, The Chronicle Photo: Santiago Mejia, The Chronicle
Greer, who had been working on steerable medical needles, programmed the robot’s steering mechanism, using a small video camera that remains on the moving end to “sense the environment like the human eye does.” The camera and software Greer developed helps the robot navigate corners, through small holes and around obstacles.
Like the ivy plant, the robot’s base with controllers and power supply remains in the same place. Meanwhile, the robot’s tip extends into tight spaces with little friction. The system allows for a smoother roll out than, for example, a medical needle’s tip that continually creates friction points when inserted into a blood vessel, Hawkes said.
To their surprise, the researchers also discovered the pneumatic pressure created a way to lift heavy objects such as a 165-pound crate, once the vine bot wormed its way underneath.
The material inside the vine can also pull other objects, which could mean rescuers could deliver medicines or devices to survivors trapped in a collapsed building.
The team envisions using the vine bot to explore pipes, or create free-standing structures like a ladder if a foam designed to harden is pumped through the center. The robot also pulled cables through walls and a dropped ceiling, which could help electricians.
Since the paper’s publication, several people from around the world interested in adapting the robot to their fields have contacted the team; these include a professional sports-cave explorer, doctors specializing in kidney stones, an amusement park operator and a space robotics firm, Hawkes said.
Greer said he could envision a vine bot becoming ready for search and rescue operations in a few years since the materials needed are relatively cheap and would be easy to produce. Vine bots for medical purposes, however, would need years, maybe decades, of testing to meet federal standards.