The Variable Compliance Joystick: To Flex or Not to Flex

Karl W. Brown, BSAE, Donald M. Spaeth, PhD, RET, Rory A. Cooper, PhD
Human Engineering Research Laboratories, Pittsburgh VA Healthcare System, Pittsburgh PA


While effective for most consumers, some individuals find it difficult to control an electric powered wheelchair with a conventional position sensing joystick (PSJ). Researchers have had success with isometric joysticks and the personalization of an interface for each consumer. This paper presents a joystick interface that can span the spectrum of compliance settings from PSJ to isometric. It is being used as a platform for examining interface types and customized programming for EPW driving tasks. The joystick incorporates a variety of control enhancers (e.g., handles, templates) and can be augmented with advanced programming (e.g. an adaptive notch filter to mitigate tremor and gain adaptation to mitigate fatigue in multiple sclerosis). It has been validated statically and dynamically against conventional PSJs.


joysticks, personalization, user interface, wheelchair control


This study was funded by the Department of Veteran’s Affairs Grant Number B3287R. The author would like to thank Dr. Shirley Fitzgerald, Megan Yarnall, and Erik Wolf for their assistance with this study.

Author Contact Information

Karl Brown
Human Engineering Research Laboratories
VA Pittsburgh Healthcare System
7180 Highland Drive
Building 4, 2nd Floor East, 151R1-H
Pittsburgh, PA 15206


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