From a press release by the Biodesign Institute at Arizona State University about their efforts to develop a robotic arm to help stroke survivors recover the ability to perform essential tasks:
Dubbed “RUPERT,” for Robotic Upper Extremity Repetitive Therapy, the ASU team is partnering with Tempe-based Kinetic Muscles, Inc., to produce the arm. The project is funded by the National Institutes of Health.
There are two key benefit phases for stroke victims in the project development timetable, according to Dr. He. Currently, the device is able to mimic a fluid, natural extension of the arm using pneumatic muscles and can be programmed for repetitive exercises specific to the user that improve arm and hand flexibility and strength.
The team is now working to engineer greater intelligence into the device so that it responds directly to a user’s intent. “We want RUPERT to be able to sense when the user is attempting to reach for something, and to automatically assist their volitional movement.” said Dr. He. “Not only is the goal to make the motion more intuitive, but we want the robot to assist at those points in the movement where the individual needs it,” said He. As the individual’s motor function improved, RUPERT would adapt to allow the user faster recovery by requiring the muscles to work independently where possible.
The first RUPERT prototype was fitted and tested on able-bodied individuals and stroke survivors at Banner Good Samaritan Regional Medical Center in Phoenix. Eight able-bodied individuals tried on RUPERT I to see how well it could be adjusted to fit each in each case. The testers ranged from 5-foot females to over-6-foot males. In addition, two stroke survivors completed a three-week course of therapy using the device. RUPERT II, a second generation prototype, is under development using results of the fitting evaluations and therapy testing at the medical center.
RUPERT I and II are powered by four pneumatic muscles to assist movement at the shoulder, elbow and wrist. The design was based on a kinematics model of the arm, which showed where to locate the pneumatic muscles and how much force was needed for normal reaching and feeding movements. The mechanical arm is adjustable to accommodate different arm lengths and body sizes.