title: A prototype power assist wheelchair that provides for obstacle detection and avoidance for those with visual impairments.
abstract: BACKGROUND
  Almost 10% of all individuals who are legally blind also have a mobility impairment. The majority of these individuals are dependent on others for mobility. The Smart Power Assistance Module (SPAM) for manual wheelchairs is being developed to provide independent mobility for this population.
  
  
  METHODS
  A prototype of the SPAM has been developed using Yamaha JWII power assist hubs, sonar and infrared rangefinders, and a microprocessor. The prototype limits the user to moving straight forward, straight backward, or turning in place, and increases the resistance of the wheels based on the proximity of obstacles. The result is haptic feedback to the user regarding the environment surrounding the wheelchair.
  
  
  RESULTS
  The prototype has been evaluated with four blindfolded able-bodied users and one individual who is blind but not mobility impaired. For all individuals, the prototype reduced the number of collisions on a simple navigation task.
  
  
  CONCLUSIONS
  The prototype demonstrates the feasibility of providing navigation assistance to manual wheelchair users, but several shortcomings of the system were identified to be addressed in a second generation prototype.
authors.affiliation: Department of Rehabilitation Science and Technology, University of Pittsburgh, Pittsburgh, PA, USA. ris20@pitt.edu
authors.forename: Richard
authors.initials: R
authors.lastname: Simpson
authors.forename: Edmund
authors.initials: E
authors.lastname: LoPresti
authors.forename: Steve
authors.initials: S
authors.lastname: Hayashi
authors.forename: Songfeng
authors.initials: S
authors.lastname: Guo
authors.forename: Dan
authors.initials: D
authors.lastname: Ding
authors.forename: William
authors.initials: W
authors.lastname: Ammer
authors.forename: Vinod
authors.initials: V
authors.lastname: Sharma
authors.forename: Rory
authors.initials: R
authors.lastname: Cooper