Comparison of Virtual Electric Powered Wheelchair Driving Using a Position Sensing Joystick and an Isometric Joystick

E.Chaves, BS; R.Cooper, PhD; D. Spaeth, MS; M. Boninger MD; S. Fitzgerald PhD; S. Guo PhD.

Slide 1: title and authors


Position Sensing Joystick (PSJ)

Slide 2: Picture of a Position Sensing Joystick (PSJ)

Slide text:

  • Most used type of joystick in the electric power wheelchair market (EPW)
  • Does not always meet the needs of EPW users

Image Description

This slide shows the Position Sensing Joystick (PSJ).


Isometric Joystick (IJ)

Slide 3: Picture of Isometric Joystick (IJ)

Slide text:

  • Senses the amount and direction of the applied forces, without the stick moving

Image Description

This slide shows the isometric joystick which looks very much like a typical joystick.


Isometric Joystick with Compensation Algorithms (IJCA)

Slide 4: Isometric Joystick with Compensation Algorithms (IJCA)

Slide text:

  • Filtering the signal allows the threshold at which desired motion occurs to be lower.

Slide 5: slide with text only

Slide text:

  • No study has compared the performance of an IJCA with a PSJ on EPW users


Aim of the Study

Slide 6: slide with only text

Slide text:

Compare the performance of the PSJ and the IJCA in EPW users in a virtual world in six different tasks:
  • Vertical
  • Horizontal
  • Circle clockwise
  • Circle counter clockwise
  • Square clockwise
  • Square counter clockwise

Variables Considered

slide with text only

Slide text:

  • Root Mean Square Error (RMSE)
  • Time

Hypothesis

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Slide text:

  • Hypothesis 1: The RMSE of the IJCA for all 6 conditions will be smaller than the RMSE of the PSJ in EPW users
  • Hypothesis 2: The time of IJCA for all six conditions will be smaller than the time of PSJ in EPW users

Methods

Slide 9: slide with text

Slide text:

  • 10 experienced EPW users
  • 7 cervical spinal cord injury
  • 2 multiple sclerosis
  • 1 cerebral vascular accident

Methods

Slide 10: Picture of IJCA and PSJ

Slide text:

  • PSJ commercially available
  • IJCA designed and fabricated at HERL

Methods

Slide 11: Subject is driving Quickie P300

Slide text:

  • Quickie P300
  • EPW dynamometer

Graphic description:

The subject is driving the test wheelchair, Quickie P300 on a wheelchair dynamometer with a computer monitor positioned within the subject’s field of vision.The virtual driving tasks were presented in a “bird eye view” and the subject was asked to complete the task five times.

Results

Slide 12: slide with graph

Graphic description:

RMSE for different tasks

Results showed no significant difference between the Position Sensing Joystick (PSJ) and Isometric Joystick with Compensation Algorithms (IJCA) for any of the variable recorded.


Results

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Graphic description:

Time for the different tasks

Results showed no significant difference between the Position Sensing Joystick (PSJ) and Isometric Joystick with Compensation Algorithms (IJCA) for any of the variable recorded.


Discussion

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  • All subject have not had experience using the IJCA
  • Experimental tasks were simple
  • Subjects had good motor hand control


Future Studies

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  • Subjects with IJCA could be trained thoroughly before starting the investigation.
  • Complex tasks
  • Individuals more severely impaired

Acknowlwdgements

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Acknowledgements
  • National Institute in Disability & Rehabilitation Research
  • Rehabilitation Engineering Research Center
  • U.S. Department of Veterans Affairs
  • Rehabilitation Research & Development Services.

The End

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Updated: May 5, 2003

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Please note: This information is provided a archival information from the Rehabilitation Engineering Research Center on Wheeled Mobility from 1993 to 2002.

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