A significant number of individuals with disabilities are denied powered mobility because they lack the visual, motor, or cognitive skills required to operate a powered wheelchair safely. The Drive-Safe System (DSS) is an add-on, distributed, shared control navigation assistance system for powered wheelchairs, intended to provide safe and independent mobility to these individuals. The DSS is a human-machine system in which the user and machine share navigation control. The user is responsible for high-level control of the system, such as choosing the destination, path planning, and some navigation actions, while the DSS overrides unsafe maneuvers through autonomous collision avoidance, automatic wall following, and door crossing.
This dissertation reports the design and development of the DSS, followed by results from rigorous engineering and clinical evaluations. The engineering tested technical aspects of the DSS such as sensor coverage, maximum safe speed, maximum detection distance, and power consumption. Clinical evaluations included testing the DSS with Orientation & Mobility (O&M) specialists, ambulatory and non-ambulatory visually impaired individuals, and able-bodied controls. We compared the performance of the DSS with conventional navigation aids such as canes that are commonly used in conjunction with wheelchairs based on measures such as time for task completion and number of collisions. Additionally, we collected data with the NASA-TLX to gain insight into users subjective experience with the DSS.
Results indicate that the DSS was able to provide a uniform and reliable sensor coverage field around the wheelchair and could successfully detect obstacles as small as 3 inches in height to overhanging obstacles at a height of 55 inches. The DSS significantly reduced the number of collisions compared to using a cane. Users rated the DSS favorably despite the fact they took longer to navigate the same obstacle course than they would using a cane. Visually impaired participants reported experiencing less physical demand, and had to exert less effort in order to achieve better performance when using the DSS, compared to using a cane. These findings suggest that the DSS can be a viable solution for powered mobility in populations with visual impairment.
| Identifer | oai:union.ndltd.org:PITT/oai:PITTETD:etd-07172009-103647 |
| Date | 11 July 2011 |
| Creators | Sharma, Vinod Kumar |
| Contributors | Richard C. Simpson, PhD, Edmund F. LoPresti, PhD, Dan Ding, Rory A. Cooper, PhD, Mark Schmeler, PhD |
| Publisher | University of Pittsburgh |
| Source Sets | University of Pittsburgh |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.library.pitt.edu/ETD/available/etd-07172009-103647/ |
| Rights | restricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University of Pittsburgh or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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