RESNA Annual Conference - 2012

Improving accuracy of slope detection on a reminding and monitoring system of power seat function usage.

Yu-Kuang Wu, MS PT1,2, Hsin-Yi Liu, MS PT1,2, Rory A. Cooper, PhD1,2

1Human Engineering Research Laboratories, Department of Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, PA, USA

2Department of Rehabilitation Sciences and Technology, School of Health and Rehabilitation Sciences, University of Pittsburgh


Driving safety has always been a high priority when educating wheelchair users. One safety issue is driving on a ramp. Our Virtual Coach program has the ability to remind and instruct users to execute the correct powered wheelchair driving maneuver by adjusting their seat angle via an inclinometer when the wheelchair is on a ramp. However, the data from the inclinometer is easily affected by the acceleration of the powered wheelchair. In this study, we used the data from wheel encoders to calculate the acceleration and deceleration of the powered wheelchair and to correct the incline angle. Two tests were conducted for this study. The first test evaluated the corrected incline angle on different terrains. The other test was used to determine the percentage of the occurrence of false alerts caused by acceleration and deceleration of the powered wheelchair. The results show that this correction can eliminate the effect of acceleration and deceleration, and further decrease the occurrence of false alerts from 40% to 8.3%. Using an inclinometer with correction could be a simple and effective way to detect terrain changes and remind users to drive safely.


wheelchair; acceleration; inclinometer.

The contents of this paper do not represent the views of the Department of Veterans Affairs or the United States Government.