Apr 29, 2007
First DARPA Limb Prototype
From the DARPA press release
An international team led by the Johns Hopkins University Applied Physics Laboratory (APL) in Laurel, Md., has developed a prototype of the first fully integrated prosthetic arm that can be controlled naturally, provide sensory feedback and allows for eight degrees of freedom--a level of control far beyond the current state of the art for prosthetic limbs. Proto 1, developed for the Defense Advanced Research Projects Agency (DARPA) Revolutionizing Prosthetics Program, is a complete limb system that also includes a virtual environment used for patient training, clinical configuration, and to record limb movements and control signals during clinical investigations.
The DARPA prosthetics program is an ambitious effort to provide the most advanced medical and rehabilitative technologies for military personnel injured in the line of duty. Over the last year, the APL-led Revolutionizing Prosthetics 2009 (RP 2009) team has worked to develop a prosthetic arm that will restore significant function and sensory perception of the natural limb. Proto 1 and its virtual environment system were delivered to DARPA ahead of schedule, and Proto 1 was fitted for clinical evaluations conducted by team partners at the Rehabilitation Institute of Chicago (RIC) in January and February.
"This progress represents the first major step in a very challenging program that spans four years and involves more than 30 partners, including government agencies, universities, and private firms from the United States, Europe, and Canada," says APL's Stuart Harshbarger, who leads the program. "The development of this first prototype within the first year of this program is a remarkable accomplishment by a highly talented and motivated team and serves as validation that we will be able to implement DARPA's vision to provide, by 2009, a mechanical arm that closely mimics the properties and sensory perception of a biological limb."
APL, which was responsible for much of the design and fabrication of Proto 1, and other team members are already hard at work on a second prototype, expected to be unveiled in late summer. It will have more than 25 degrees of freedom and the strength and speed of movement approaching the capabilities of the human limb, combined with more than 80 individual sensory elements for feedback of touch, temperature, and limb position.
"There is still significant work to be done to determine how best to control this number of degrees of freedom, and ultimately how to incorporate sensory feedback based on these sensory inputs within the human nervous system," Harshbarger says. "The APL team is already driving a virtual model of Proto 2 with data recorded during the clinical evaluation of Proto 1, and the team is working to identify a robust set of grasps that can be controlled by a second patient later this year."Another exciting development is the functional demonstration of Injectable MyoElectric Sensor (IMES) devices--very small injectable or surgically implantable devices used to measure muscle activity at the source verses surface electrodes on the skin that were used during testing of the first prototype.