Advancements in Power Wheelchair Joystick Technology: Average and Excess Force Exertion on Isometric and Motion Sensing Joysticks

Brad E. Dicianno, MD^1,2,4,5 ; Donald M. Spaeth, PhD^1,3; Rory A. Cooper, PhD^1,3,4,5; Shirley G. Fitzgerald, PhD^1,2,5 ; Michael L. Boninger, MD^1,2,3,4,5; and Karl W. Brown^1,3.

¹Human Engineering Research Laboratories,
²Department of Physical Medicine and Rehabilitation,
³Department of Rehabilitation Science and Technology, and the
⁴Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania; and the
⁵VA Pittsburgh HealthCare System, Center of Excellence in Wheelchairs and Related Technology, Pittsburgh, Pennsylvania.

ABSTRACT

Novel control devices for power wheelchairs would benefit over 125,000 Americans who cannot operate a conventional motion sensing joystick (MSJ). The Isometric Joystick (IJ) theoretically requires less force but can produce unexpected speed changes and is sensitive to unintentional movements. Variable Gain Algorithm (VGA) software allows the IJ to perform similarly to an MSJ but retain the reduced force requirements of an IJ. We compared the IJ with and without VGA to the MSJ during wheelchair driving and found higher average force exerted on the IJs, likely due to lack of proprioceptive feedback and inadequate time for adaptation to the device.

KEYWORDS:

rehabilitation, joystick, motor control, isometric, force

AUTHOR CONTACT INFORMATION

Brad E. Dicianno, MD
Human Engineering Research Laboratories
VA Pittsburgh Healthcare System
7180 Highland Drive
Building 4, 2nd Floor East, 151R1-H
Pittsburgh, PA 15206
412.365.4850 x 834893 or 412-365-4893
412.365.4858 fax