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Robotic Arms to Aid People with Disabilities

Devices Designed to Grasp, Manipulate Objects

Computer Science doctoral candidate Katherine Tsui demonstrates DORA, the low-cost Door-Opening Robot Arm developed by Erin Rapacki at the UMass Lowell Robotics Lab.

01/06/2010
By Edwin L. Aguirre

Opening and closing doors, picking up the phone or drinking a cup of coffee. These are simple, mundane activities that people do every day and often take for granted. But for individuals with physical disabilities or cognitive impairments, these can be daunting tasks.

Two prototype systems being developed at UMass Lowell’s Robotics Lab may be able to lend a helping hand.

The first system, a low-cost compact unit called DORA (Door Opening Robot Arm), is mounted on a motorized wheelchair and has a special gripper that an operator can use specifically to unlatch a variety of doorknobs and handles. It is the brainchild of Erin Rapacki, who graduated this year with a master’s degree in mechanical engineering and now works at Anybots, a robotics company based in Mountain View, Calif.

“The gripper is what I consider the new and innovative part of DORA,” says Rapacki. “It uses only a single motor to turn a knob or handle clockwise or counterclockwise.”

Her project was funded through a National Science Foundation (NSF) CAREER grant awarded to Computer Science Prof. Holly Yanco, the Lab’s director.

“I was the primary concept and mechanical designer,” says Rapacki. “An undergraduate electrical engineering student named Bill Harmon did all of the electronics. Prof. Yanco and Prof. Chris Niezrecki of the Mechanical Engineering Department were my thesis advisers. Campus machinist Keith Flynn gave me a lot of design and machining advice. Lastly, I consulted everyone in the Robotics Lab for opinions and advice.”

According to her, in rigorous tests conducted on 14 different doors on the campus, the gripper was able to open 12 of them (in 100 out of 140 trials, or a 71 percent success rate). Rapacki presented her findings at the IEEE International Conference on Technologies for Practical Robot Applications in Woburn in November.

You can watch video clips of DORA in action in UMass Lowell’s YouTube page.

The second system, named Halo, was designed by computer science doctoral candidate Katherine Tsui. It uses a commercially made Manus ARM from Exact Dynamics in the Netherlands to help people pick up objects on the floor or shelf.

“The current menu-driven control system for the Manus ARM is difficult to learn and remember, especially for people with cognitive impairments,” says Tsui. “Our goal is to simplify the control using a vision-based interface, which offers a greater level of autonomy and requires less user input.”

Halo uses tiny stereo cameras mounted over the arm and on the gripper to display the desired object on a flat-screen monitor. The operator simply touches the screen (or uses a joystick) to select the object, and the arm then uses its gripper to autonomously retrieve the object and bring it to the operator.

The project is funded through a three-year, nearly $168,000 NSF grant awarded to Yanco. The algorithm for controlling the gripper and for recognizing various objects was developed in collaboration with Dr. Aman Behal of the University of Central Florida and his team.

Volunteers from the Crotched Mountain School and Brain Injury Center in Greenfield, N.H., participated in the trials. Tsui also demonstrated Halo at the first annual Robotics Innovations Competition and Conference at Worcester Polytechnic Institute in November.

Visit UMass Lowell’s YouTube page to see a demonstration of Halo’s capability.

Yanco says these robot assistive technologies have the potential to improve the quality of life for many people.

“Our target population is comprised of people with limited movement in their upper extremities who use power wheelchairs,” she says. “We have been working with people who have cerebral palsy and traumatic brain injury at the Crotched Mountain Rehabilitation Center. The goal is to help these people to function more independently in a variety of environments, whether a grocery store, a living room, a library or an office.”

For more information, visit the Robotics Lab website.


DORA, which is mounted on a motorized wheelchair, has a special gripper that can unlatch a variety of doorknobs and handles using only one motor.
Tsui demonstrates Halo, a prototype robotic arm that she has designed at the Robotics Lab to help people with physical disabilities reach for objects on a table or shelf.