Power and Control System Testing of Five Different Types of Power Wheelchairs

Algood D, Cooper RA, Rentschler AJ, Vitek JM, Wolf EJ, Ammer WA
Department of Rehab Science and Technology
University of Pittsburgh

Slide 1
Power and Control System Testing of Five Different Types of Power Wheelchairs

Algood D, Cooper RA, Rentschler AJ, Vitek JM, Wolf EJ, Ammer WA

Department of Rehab Science and Technology

University of Pittsburgh

Slide 2
Background

• ANSI/RESNA Standards used by the FDA
  

Currently, no comparative study exists on the market

Importance of the safety of a power wheelchair’s electrical system

12% of wheelchair related injuries result of electrical system failing 1

Part 14 – Electrical and Control Systems of Power Wheelchairs

1. Kirby RL, Ackroyd SA. “Wheelchair safety – adverse reports to the United States Food and Drug Administration.” Am J Phys Med Rehabil. 1995;74:308-312

Slide 3
Research Question

Are there any differences in performance when the power and control systems of five different types of electric wheelchairs are tested according to Section 14 of the ANSI/RESNA Standards?

Slide 4
Chairs Used in this Study

Graphic Description: photographs of the five types of chairs used for testing during the study. These are going clockwise from right to left, the Invacare Action Storm, the Permobil Chairman, the Pride Jazzy, the Quickie P200, and the E & J Lancer 2000. The Invacare, the E & J, and the Quickie are all rear wheel drive power wheelchairs. The Jazzy is a midwheel drive power wheelchair and the Permobil is a front wheel drive power wheelchair.

Slide 5
Testing Equipment

Graphic Description: three photographs of testing equipment going clockwise from right to left: a photo of a circuit breaker, a force gauge, a DC Ammeter, and a digital multimeter, a photo of switches for short circuit, open circuit, and microprocessor tests, a photo of standard jointed and unjointed test fingers. The standard unjointed and jointed test fingers a made out of aluminum and are designed to simulate the human finger for safety testing purposes.

Slide 6
Tests and Results

Graphic Description: a table showing the results of 10 tests, sections 6.1 through 6.10. 0% of the chairs passed the battery and circuit connection diagram test, section 6.1. 20% of the chairs passed the color and marking of battery wires test, section 6.2. 100% of the chairs passed the electical isolation of wheelchair test, section 6.3. 80% of the chairs passed the safety when replacing fuses test, section 6.4. 100% of the chairs passed the interchangeability of connectors test, section 6.5. 100% of the chairs passed the attaching and positioning of wires test, section 6.6. 100% of the chairs passed the protection from non-insulated parts test, section 6.7. 100% of the chairs passed the short circuit protection at the battery test, section 6.8. 87% of the chairs passed the safety when changing batteries test, section 6.9. 80% of the chairs passed the reversed polarity at batteries test, section 6.10.

Slide 7
Tests and Results (cont.)

Graphic Description: a table showing the results of 10 tests, sections 6.11 through 6.17, 7.3, 8.3, and 10.3. 100% of the chairs passed the contoller over-voltage protection test, section 6.11. 100% of the chairs passed the controller command signal processing failure test, section 6.12. 87% of the chairs passed the controller output device failure test, section 6.13. 100% of the chairs passed the stalled condition protection test, section 6.14. 100% of the chairs passed the ability to stop when the power is lost test, section 6.15. 100% of the chairs passed the controller microprocessor watchdog test test, section 6.16. 100% of the chairs passed the saftey with discharged batteries test, section 6.17. 73% of the chairs passed the non-power mobility test, section 7.3. 100% of the chairs passed the safety guard test from pinch points test, section 8.3. 100% of the chairs passed the forces needed to operate control devices test, section 10.3.

Slide 8
Test Photos

Graphic Description: This slide contains three photos from testing. These are (going clockwise from right to left): a photo of a person in the Invacare Action Storm driving up and down a hill with the battery very low, a photo of a person in the Quickie P200 driving down a hill with a switch set up to simulate the power failing, and the final photo is of a damaged pin on the controller circuit.

Slide 9
Results: Overall Chair Performance

Graphic Description: A table showing the overall passing percentages of the 5 chairs. The Pride Jazzy passed 95% of all tests, the E&J Lancer 2000 90%, the Invacare Action Storm 85%, the quickie P200 85%, the Permibile Chairman 78%.

Slide 10
Discussion

Important tests:

6.3: Electrical isolation of wheelchair

• All passed
  

6.9: Safety when charging batteries

• Two out of three Quickies failed
  

6.10: Reversed polarity at battery

• Invacare failed
  

6.15: Ability to stop when power is lost

• All passed
  

Slide 11
Discussion (cont.)

Issue of chairs failing safely

• Ex: Invacare, Permobil, E&J, Jazzy, chairs had damage to controllers due to Sec. 6.12, but still passed the test as set up by standards
  

Sec 6.10 not performed on two Invacares due to prior controller damage and schematic

Still a need for improvement in design of power wheelchairs

Slide 12
Acknowledgements

• This project was supported in part by:
  
  • The Paralyzed Veterans of America (PVA)
  • The National Institute on Disability & Rehabilitation Research (NIDRR)
  • The Rehabilitation Engineering Research Center (RERC)
    
• HERL Support Staff
  
  

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Updated: March 12, 2002