Robot Body Surrogates Help People With Profound Motor Impairments

An augmented reality interface system could help people with profound motor impairments operate a humanoid robot to feed themselves and perform routine personal care tasks. Such tasks might include feeding and performing routine personal care tasks such as scratching an itch and applying skin lotion.

The web-based interface displays a “robot’s eye view” of surroundings to help users interact with the world through the machine.

The system could help make sophisticated robots more useful to people who don’t have experience operating complex robotic systems. Study participants interacted with the robot interface using standard assistive computer access technologies — such as eye trackers and head trackers — that they already used to control their personal computers.

Robotic Body Surrogates

The paper details two studies showing how such “robotic body surrogates” — which can perform tasks similar to those of humans — could improve the quality of life for users. The work could provide a foundation for developing faster and more capable assistive robots.

“Our results suggest that people with profound motor deficits can improve their quality of life using robotic body surrogates. We have taken the first step toward making it possible for someone to purchase an appropriate type of robot, have it in their home, and derive real benefit from it,”

says first author Phillip Grice, a recent doctoral graduate of the Georgia Institute of Technology.

Mobile Manipulation Goals

Grice and Charlie Kemp, professor in the biomedical engineering department at Georgia Tech and Emory University, used a PR2 mobile manipulator for the two studies. The wheeled robot has 20 degrees of freedom, with two arms and a “head,” giving it the ability to manipulate objects such as water bottles, washcloths, hairbrushes, and even an electric shaver.

“Our goal is to give people with limited use of their own bodies access to robotic bodies so they can interact with the world in new ways,”

Kemp says.

In the first study, Grice and Kemp made the PR2 available across the internet to a group of 15 participants with severe motor impairments. The participants learned to control the robot remotely, using their own assistive equipment to operate a mouse cursor to perform a personal care task.

The interface used to operate the robotic body surrogate
The interface used to operate the robotic body surrogate.
(A) ‘Looking’ mode. (B) ‘Spine’ mode. (C) ‘Driving’ mode. (D) ‘Hand position’ mode. (E) ‘Hand rotation’ mode. (F) ‘3D Peek’ depth display.
Credit: Grice, Kemp CC-BY

Eighty percent of the participants could manipulate the robot to pick up a water bottle and bring it to the mouth of a mannequin.

“Compared to able-bodied persons, the capabilities of the robot are limited. But the participants were able to perform tasks effectively and showed improvement on a clinical evaluation that measured their ability to manipulate objects compared to what they would have been able to do without the robot,”

Grice says.

Empowering And Liberating

In the second study, the researchers gave the PR2 and interface system to Henry Evans, a California man who has been helping Georgia Tech researchers study and improve assistive robotic systems since 2011.

Henry Evans
Here, Henry Evans, a California man who helped researchers with improvements to a web-based interface, uses the robot to shave.
Credit: Henry Clever, Phillip Grice/Georgia Tech

Evans, who has very limited control of his body, tested the robot in his home for seven days and not only completed tasks, but also devised novel uses combining the operation of both robot arms at the same time — using one arm to control a washcloth and the other to use a brush.

“The system was very liberating to me, in that it enabled me to independently manipulate my environment for the first time since my stroke,” Evans says. “With respect to other people, I was thrilled to see Phil get overwhelmingly positive results when he objectively tested the system with 15 other people.”

The way Evans developed new uses for the robot, combining motion of the two arms in ways they had not expected pleased the researchers.

“When we gave Henry free access to the robot for a week, he found new opportunities for using it that we had not anticipated. This is important because a lot of the assistive technology available today is designed for very specific purposes. What Henry has shown is that this system is powerful in providing assistance and empowering users. The opportunities for this are potentially very broad,”

Grice says.

Intuitive Interface

The interface allowed Evans to care for himself in bed over an extended period of time.

“The most helpful aspect of the interface system was that I could operate the robot completely independently, with only small head movements using an extremely intuitive graphical user interface,”

he says.

The web-based interface shows users what the world looks like from cameras located in the robot’s head. Clickable controls overlaid on the view allow the users to move the robot around in a home or other environment and control the robot’s hands and arms.

The view through the PR2’s cameras
The view through the PR2’s cameras showing the environment around the robot. Clicking the yellow disc allows users the control the arm.
Credit: Phillip Grice, Georgia Tech

When users move the robot’s head, for instance, the screen displays the mouse cursor as a pair of eyeballs to show where the robot will look when the user clicks. Clicking on a disc surrounding the robotic hands allows users to select a motion. While driving the robot around a room, lines following the cursor on the interface indicate the direction it will travel.

Building the interface around the actions of a simple single-button mouse allows people with a range of disabilities to use the interface without lengthy training sessions.

“Having an interface that individuals with a wide range of physical impairments can operate means we can provide access to a broad range of people, a form of universal design. Because of its capability, this is a very complex system, so the challenge we had to overcome was to make it accessible to individuals who have very limited control of their own bodies,”

Grice notes.

Improvements Still Needed

While the results of the study demonstrated what the researchers had set out to do, Kemp agrees they can still make improvements. The existing system is slow, and user mistakes can create significant setbacks. Still, he says,

“People could use this technology today and really benefit from it.”

The developers will need to make significant reductions in cost and size to make the PR2 commercially viable, Evans says.

The end-effector orientation control augmented reality interface with virtual preview (yellow) and goal (green) gripper displays.
The end-effector orientation control augmented reality interface with virtual preview (yellow) and goal (green) gripper displays.
Credit: Grice, Kemp CC-BY

The studies point the way to a new type of assistive technology, Kemp adds.

“Together, these results suggest that robotic body surrogates could provide improved independence and self-care self-efficacy for individuals with profound motor deficits,”

the paper’s authors conclude.

Grice PM, Kemp CC
In-home and remote use of robotic body surrogates by people with profound motor deficits
PLoS ONE 14(3): e0212904. https://doi.org/10.1371/journal.pone.0212904

Top Image: Phillip Grice, Georgia Tech


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