Advanced signal processing expands artificial limb capabilities
Digital signal controllers provide the key to a new generation of prosthetics
From: Portable Design - May 2006 - page 32
By: Chris Clearman, Texas Instruments

In May 2001, Jesse Sullivan, a veteran power lineman in Dayton, TN,
accidentally touched a power line, causing 7,200 V of electricity to surge
through his body. He had forgotten to wear his rubber gloves. A surgeon later
amputated both of his arms and shoulder joints. In the past, this amputation
would have meant that Sullivan would have been able to obtain only very
limited usage from an artificial limb because upper-limb prostheses were
limited to only three axes of motion-elbow, wrist, and hand-which are
typically controlled by flexing the triceps and biceps, the most common
control inputs for transhumeral (above the elbow) amputees. 

Shoulder disarticulation amputees can sometimes use chest and back muscles or
switches to control a prosthesis; however, because of Sullivans
skin-grafting procedures after the power accident, these muscles were not
available for use with his prosthesis. Without any of these muscles
available, Sullivan may have commissioned an expensive custom design to
accommodate some other method of controlling the arm. He would have had to
relearn how to make even the simplest motions. Although his artificial limb
would have been able to move at the elbow, wrist, and hand, it would have
hung limply at his side because he could not move it at the shoulder.  

Today, however, a new generation of prostheses uses an advanced
signal-processing-based motor control strategy to dramatically improve these
capabilities. The Boston Digital Arm from Liberating Technologies provides
amputees with unique upper-limb prostheses that are dramatically more
flexible and capable, in large part due to the control-optimized performance
and integration offered by advanced digital signal controllers 

  Control systems key to artificial limb performance

  Inputs and outputs key to digital signal controller selection

  Custom solution for every user

Read the entire article at:
http://pd.pennnet.com/Articles/Article_Display.cfm?ARTICLE_ID=254414&p=21&cat=Appli

Links:
LTI Boston Arm Systems
http://www.liberatingtech.com/products/LTI_Boston_Arm_Systems.asp

Liberating Technologies' Boston Digital Arm Offers Increased Interface
  Options and More Life-Like Control Than Conventional Upper Limb Prostheses 
http://i-newswire.com/pr26529.html

