CWA 17664:2021

Lower-limb wearable devices - Performance test method for walking on uneven terrain

Scope

This CEN Workshop Agreement defines a methodology to obtain performance indicators of lower-limb wearable devices during locomotion on uneven terrain, which enables a quantitative comparison of these performance indicators between systems.
This document includes:
- a morphological description of a test bed composed of different combinations of inclined uneven, stepped, soft and unstructured terrain,
- a set of required and recommended performance indicators,
- the experimental procedure needed to collect the performance indicators, and
- the structure of a unified test report.
This document is intended to be used by developers, manufacturers, researchers, and end-users of any type of lower-limb orthoses, exoskeleton or prostheses, independently from the structural properties (hard or soft), actuation typology (powered or unpowered), body coverage (trunk, spine, hip, knee, ankle, full leg), and application domain (industrial, healthcare, consumer).
Part of this document may be applied to other types of bipedal systems, e.g. humanoids, either autonomous or teleoperated. In these cases, this CWA represents a basis that may be extended by including other aspects specifically related to these bipedal systems (e.g. autonomy decision, perception, or cognitive abilities).
This document does not apply to non-bipedal over ground systems, e.g. wheeled robots, quadrupeds, and hexapods. It is out of the scope of this document to provide a scientific or clinical meaning to the proposed performance indicators. The interpretation of the results obtained from the application of this CWA is left to the user of the document.
The defined methodology is not suitable for comparing the performance of lower-limb orthopaedic devices in activities of daily living, although elements of the test bed appear to be similar to everyday obstacles.
As different users of orthopaedic devices show different conditions, the comparison of quantified performance indicators is only valid for the same subject. Performing activities of daily living similar to the described test is for example accompanied by sudden deflecting events like dual tasks, decreasing concentration and tiring. In contrast, the test bed provides repeatable constraints.
The comparisons obtainable by this test method refer to the performance of the entire bipedal system; in the orthopaedic field, that includes the individual embedding of the remaining body structure and several other components assembled in the orthopaedic device. This methodology does not support conclusions about the performance of single elements in the observed system.