Development and evaluation of a gyroscope-based wheel rotation monitor for manual wheelchair users

Abstract

Objective

To develop and evaluate a wireless gyroscope-based wheel rotation monitor (G-WRM) that can estimate speeds and distances traveled by wheelchair users during regular wheelchair propulsion as well as wheelchair sports such as handcycling, and provide users with real-time feedback through a smartphone application.

Methods

The speeds and the distances estimated by the G-WRM were compared with the criterion measures by calculating absolute difference, mean difference, and percentage errors during a series of laboratory-based tests. Intraclass correlations (ICC) and the Bland–Altman plots were also used to assess the agreements between the G-WRM and the criterion measures. In addition, battery life and wireless data transmission tests under a number of usage conditions were performed.

Results

The percentage errors for the angular velocities, speeds, and distances obtained from three prototype G-WRMs were less than 3% for all the test trials. The high ICC values (ICC (3,1) > 0.94) and the Bland–Altman plots indicate excellent agreement between the estimated speeds and distances by the G-WRMs and the criterion measures. The battery life tests showed that the device could last for 35 hours in wireless mode and 139 hours in secure digital card mode. The wireless data transmission tests indicated less than 0.3% of data loss.

Conclusion

The results indicate that the G-WRM is an appropriate tool for tracking a spectrum of wheelchair-related activities from regular wheelchair propulsion to wheelchair sports such as handcycling. The real-time feedback provided by the G-WRM can help wheelchair users self-monitor their everyday activities.

Keywords:

• Wheelchairs
• Handcycle
• Wheelchair Propulsion
• Activity Monitor
• Wireless
• Sensors
• Smartphones
• Spinal cord injuries
• Paraplegia
• Wheelchair sports

Acknowledgements

The work is supported by the Department of Defense (W81XWH-10-1-0816). SVH's work on this article was funded through the Switzer Research Fellowship (H133F110032) awarded by the National Institute on Disability and Rehabilitation Research, Department of Education. The work is also supported by the Human Engineering Research Laboratories, VA Pittsburgh Healthcare System. The contents do not represent the views of the Department of Veterans Affairs or the United States Government. The authors thank their colleagues at the Human Engineering Research Laboratories, especially Kunal Mankodiya, Monsak Socharoentum, Matthew Hannan, and Christopher Okonkwo for their input and effort during development and data collection.