Evaluation of Lumbar Burdens for Endoskeleton-Type Assist Suit Based on Musculoskeletal Model and Its Improvement of the Utility

Abstract

In endoskeleton-type assist suits, since the compressive force is added to the spine, a lumbar disc may be badly affected. However, in general, the lumbar burdens while lifting a heavy object under wearing the endoskeleton-type assist suit have not been fully investigated. In this paper, first, lumbar burdens while lifting the heavy object under wearing the endoskeleton-type assist suit ‘Sustainable’ were investigated through dynamic analysis based on the musculoskeletal model software AnyBody Modeling System. The results of analysis showed that the lumbar burdens can be decreased under wearing the Sustainable as compared with not wearing the Sustainable. Second, in order to improve the utility of the Sustainable, suitable number of artificial muscles of the Sustainable was investigated. Under the condition that the CO2 gas cylinder is used as an air source, Sustainable with two artificial muscles and that with one artificial muscle were compared in terms of assist effect, lumbar burdens and cost performance through measurements of practical assistable times and experiments of lifting the heavy object. Then, suitable number of artificial muscles of the Sustainable was determined.