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Usability evaluation of a Self-levelling robotic wheelchair for tip prevention in outdoor environments

Sivakanthan, Sivashankar (2019) Usability evaluation of a Self-levelling robotic wheelchair for tip prevention in outdoor environments. Master's Thesis, University of Pittsburgh. (Unpublished)

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Tips and falls are the most prominent causes of wheelchair accidents in the US when driving on uneven terrains and non-accessible environments. The Mobility Enhancement Robotic Wheelchair (MEBot) was designed to tackle these environmental challenges and address the mobility limitations of conventional electric-powered wheelchairs (EPW).
MEBot offers a self-leveling application to maintain a stable seat in uneven terrains with the use of position sensors at each wheel and an attitude sensor to move each wheel accordingly. The self-leveling application can be enabled/disabled via a switch.
The goal of the study was to perform a usability evaluation of MEBot’s self-leveling application in terms of the wheelchair’s performance and the participant’s perception. Ten participants were asked to drive their own EPW and MEBot through a driving course that simulated outdoor environmental obstacles for five times in each device.
The wheelchair’s performance hypotheses included MEBot’s ability to be safe by maintaining a lower change in seat angle change than participants’ EPWs and MEBot’s self-leveling time would be within or lower than an average person’s walking speed. Additionally, it was hypothesized that participants would score better on the NASA-TLX and QUEST assessment tools for MEBot than their own EPW.
Results showed that MEBot has lower angle change when going up and down a 10° slope; MEBot (5.6° ± 1.6°, 6.6° ± 0.5°) than their own wheelchair (14.6° ± 2.6°, 12.1° ± 2.6°) absolute deviation going up and down the slope, respectively. This contrasts with the participants’ EPWs when ascending and descending both slopes as MEBot required a longer time (7.8 ± 3.0 seconds) with a greater angle change when driving over an obstacle. The participant’s perception towards each EPW favored MEBot with respect to the NASA TLX and QUEST than their own wheelchair based upon the interpretation of the written feedback.
The results demonstrated that the self-leveling application can work effectively but it is hindered by mechanical limitations. Future work will involve a redesign with electro-hydraulic actuators to mitigate this mechanical limitation and similar usability evaluation to evaluate MEBot improvements.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Sivakanthan, Sivashankarsis65@pitt.edusis650000-0001-6121-5142
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairCooper, RARCOOPER@pitt.eduRCOOPER
Dicianno, Brad Edicianno@pitt.eduDICIANNO0000-0003-0738-0192
Candiotti, Jorgejlc118@pitt.edujlc118
Date: 16 September 2019
Date Type: Publication
Defense Date: 17 June 2019
Approval Date: 16 September 2019
Submission Date: 4 June 2019
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 40
Institution: University of Pittsburgh
Schools and Programs: School of Health and Rehabilitation Sciences > Rehabilitation Science and Technology
Degree: MS - Master of Science
Thesis Type: Master's Thesis
Refereed: Yes
Uncontrolled Keywords: Robotic wheelchairs; self-leveling; tips and falls; electric powered wheelchairs
Date Deposited: 16 Sep 2019 19:09
Last Modified: 16 Sep 2019 19:09


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