An estimated 5.5 million Americans use a wheelchair, as do 65 million people worldwide. Wheelchairs are thereby commonly used assistive devices that help people with disabilities improve their mobility, so ensuring they are safe and stable for all users is essential. ANSI/RESNA WC-1:2019— RESNA American National Standard For Wheelchairs – Volume 1: Requirements And Test Methods For Wheelchairs (Including Scooters) specifies requirements for test mannequins of any mass to be used in the evaluation of wheelchairs.
The First Wheelchair
In 1595, the first clearly recorded wheelchair was invented. It was a basic chair with wheels and was designed for King Philip II of Spain, who had severe gout in his later life, making walking difficult. Consequently, he required mobility aid. This first wheelchair was elaborate in its design with plush upholstery, arm and leg rests, and four small wheels—requiring an attendant to push it.
The first self-propelled wheelchair was developed in Nuremberg, Germany by a paraplegic clockmaker Stephan Farfler in 1655. His design included three wheels and worked by turning handles attached to a geared front wheel using a system of cranks and cogwheel (similar to how a bicycle works).
Wheel Chair Safety
Throughout the centuries that followed, many advancements were made to the wheelchair to promote comfort, maneuverability, ease, and independence—and notably safety—of the user. Due to smart technology, modern wheelchairs have many safety features, such as obstacle detection systems and intelligent control systems that can automatically slow down or stop the chair or even navigate obstacles autonomously. These systems help prevent collisions with people, walls, and objects.
Besides the inclusion of smart technology, wheelchair testing is also used to better design. Wheelchair testing involves simulating crashes with a test dummy/mannequin to better understand how the human body would react during a traffic collision. By simulating the human’s response to deflections, accelerations, forces, impacts, and moments, wheel chair testing with a test dummy measures the potential for human injury in vehicle crashes.
Besides ANSI/RESNA WC-1:2019, you can learn more about other standards pertaining to test dummies for wheelchairs in this past ANSI Blog post: Test Dummies for Wheelchairs: How Standards Cut Costs and Help Simulate Human Occupants.
What Is ANSI/RESNA WC-1?
ANSI/RESNA WC-1:2019 details tests and methods of measurement applicable to all wheelchairs (manual and electric). This American National Standard is intended to enable the construction of test mannequins that will produce comparable results for stability, performance, and durability testing of manual wheelchairs and electrically powered wheelchairs, including scooters.
The standard provides formulae that specify the location of the overall center of mass of test mannequins, the masses of the segments that comprise the test mannequins, and the locations of pivots that connect the segments. The specified location for the center of mass is approximately the same as that of a human being of the corresponding mass when seated in a wheelchair, and also, for masses up to 100 kg, when in a standing position in a stand-up wheelchair. ANSI/RESNA WC-1:2019 also covers the characteristics of loading pads that support the segments.
This standard does not attempt to represent the mass distribution of a person with limb atrophy or amputation.
Constructing a Test Mannequin
ANSI/RESNA WC-1:2019 specifies that a test mannequin consists of three segments:
- The torso segment
- Thigh segment
- Lower leg segment
Typically, the torso segment and thigh segment each consists of a frame loaded with weights, which are added, removed, or repositioned to adjust the mass and location of center of mass (CoM) of the segment. The lower leg segment may have either one or two leg members.
ANSI/RESNA WC-1:2019— RESNA American National Standard For Wheelchairs – Volume 1: Requirements And Test Methods For Wheelchairs (Including Scooters) is available on the ANSI Webstore.