If such hands can be mounted on long stumps - as there seems to be no requirement for a motor that may take up hand or wrist space - and if they can be gradually cable controlled (rather than through electrodes), these may offer very promising options. The thing is that myoelectric control may not only look slow, it also can be very uncomfortable to wear and only allow very limited function because of that. Despite that, a lot of funding, sales activity, general opinion making or media presence seems to be taken up by high-tech gadgets such as the DEKA arm, Otto Bock's Michelangelo hand or TouchBionics' iLimb whose demos can be matched with cable controlled arm demos and you will immediately understand - also from simple analysis of requirements - that a caring and responsible setup will improve an amputee's ability to work, act, and be well rather than addressing the needs of a prosthetic gadget builder -- two subjects that may, but do not necessarily have to, overlap.
The Robotics and Mechanisms Laboratory (RoMeLa) of the College of Engineering at Virginia Tech has developed a unique robotic hand that can firmly hold objects as heavy as a can of food or as delicate as a raw egg, while dexterous enough to gesture for sign language.
Named RAPHaEL (Robotic Air Powered Hand with Elastic Ligaments), the fully articulated robotic hand is powered by a compressor air tank at 60 psi and a novel accordion type tube actuator. Microcontroller commands operate the movement to coordinate the motion of the fingers.
This air-powered design is what makes the hand unique, as it does not require the use of any motors or other actuators, the grasping force and compliance can be easily adjusted by simply changing the air pressure, said Dennis Hong, RoMeLa (http://www.me.vt.edu/romela/) director and the faculty adviser on the project. RoMeLa is part of Virginia Tech's department of mechanical engineering (http://www.me.vt.edu) (ME).
The grip derives from the extent of pressure of the air. A low pressure is used for a lighter grip, while a higher pressure allows for a sturdier grip. The compliance of compressed air also aids in the grasping as the fingers can naturally follow the contour of the grasped object.
There would be great market potential for this hand, such as for robotic prosthetics, due to the previously described benefits, as well as low cost, safety and simplicity, Hong said. The concept has won RoMeLa first place in the recent 2008-2009 Compressed Air and Gas Institute (http://www.cagi.org) (CAGI)'s Innovation Award Contest, with team members sharing $2,500 and the College of Engineering receiving a separate $8,000 monetary award.
The $10,500 prize was announced in April by the Cleveland, Ohio-based CAGI, an industry organization. The design competition was an invitation-only program, with projects overviews including written reports and video being sent to the judging panel. Teams from Virginia Tech, the Milwaukee School of Engineering and Buffalo State College each submitted entries on their air-powered designs for judging. Six teams in all participated, according to Hong.
RoMeLa already has captured several prizes for its work, including the grand prize at the 2008 International Capstone Design Fair (http://www.vtnews.vt.edu/story.php?relyear=2008&itemno=808) for a trio of pole-climbing serpentine robots designed to take the place of construction workers tasked with dangerous jobs such as inspecting high-rises or underwater bridge piers.
It is the second year in a row that RoMeLa has won first place in the CAGI competition. A judge on the panel said of the robotic hand, It is a cutting edge concept, and the engineering was no less than brilliant.