Study on the Usability Evaluation of Prosthetic Leg Products Based on Ergonomics

The prosthetic leg (PL) is a typical human-machine system in which the dynamic interaction between the human body and PL (machine) determines a high requirement of ergonomics design for PL and consequently needs to consider an indicator of usability indicating the performance of gait biomechanics. How to evaluate the indexes of usability for PL products is critical to the design technology of PL based on ergonomics. The gait symmetry of PL products, which is a core usability index, was experimentally analyzed by using a specially designed testing device in this paper. The test results show that the swing speed symmetry for intelligent prosthetic leg (IPL) is high up to 96.5%, which indicates a high performance for gait tracking. Then, a comprehensive evaluation was made for the usability of PL products with the analysis method of Grey Correlation Degree. Three types of PL product, including ordinary PL, IPL and Gait-following IPL (GL-IPL), were used in the evaluation. The evaluation results show that the GL-IPL product is the best in usability while both of IPL and GF-IPL products based on ergonomics are obviously better than the ordinary PL. The method of usability evaluation studied here is expected to help directing the design of prosthetic leg products.