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Making autonomous vehicles safe for all: UMTRI developing an automated wheelchair tiedown and occupant restraint system (AWTORS)

February 28, 2020


Building on 30-years of expertise, UMTRI researcher Kathleen Klinich Jinweng Hu, Miriam Manary, Kyle Boyle, and Nicole Orton Richie have received a $500,000 grant from the National Highway Traffic Safety Administration to develop an automated wheelchair tiedown and occupant restraint system (AWTORS) that can be used independently in automated vehicles by people who travel while seated in their wheelchairs.

The automated wheelchair tiedown system will be based on the Universal Docking Interface Geometry (UDIG) specified in voluntary wheelchair safety standards WC18 and WC19. “This is similar in concept to the standardization of trailer hitches that allows any semi-tractor to attach and tow any trailer. UDIG has been proposed as a solution to allow any wheelchair user to dock in any vehicle if the hardware on each meets dimensional specifications,” said Dr. Klinich. 

This system also will incorporate advanced seatbelt features to improve belt fit for a variety of occupant sizes and optimize protection in a crash. In addition, different airbag designs will be explored to provide supplemental restraint for occupants whose seat height and width may vary.

“The primary element of the automated occupant restraint system will be a 3-point safety belt that can be placed on the occupant using a hand control to rotate the shoulder or lap anchor point into position,” said Klinich. 

The AWTORS prototypes will be developed using a combination of computational modeling, volunteer evaluation, and dynamic testing. To provide data for model validation, a surrogate wheelchair fixture equipped with UDIG securement hardware will be dynamically tested in front and side impact conditions using the sled equipped with docking hardware.

Computational modeling will be used to optimize belt anchorage geometry to accommodate a range of wheelchair and occupant sizes, as well as airbags to provide protection in front and side loading conditions. A minivan shell equipped with wheelchair ramps will be adapted to include variations of the automatic belt system and the docking hardware; wheelchair users will be recruited to assess the usability of the docking station and belt system and the range of belt fit.

After additional modeling to incorporate findings from the volunteer tests, the revised AWTORS design, including airbags, may be tested dynamically in front and side impact using the midsize male “anthropomorphic test device” (ATD) also known as crash test dummy, and the surrogate wheelchair fixture. Additional testing may be performed using production wheelchairs equipped with UDIG-compliant attachment hardware and small female and mid-sized male ATDs.