Abstract
The redundancy of human musculoskeletal system, caused by bi-articular muscles, is one of the research topics to describe such as the functional roles of the bi-articular muscles, the application for the industrial machines. In order to reveal these questions, esecially for the functional roles of bi-articular muscles in lower limb during upright standing in humans, we developed the four degree-of-freedom (DOF) inverted pendulum model. We used nine pneumatic artificial muscles (PAMs), 4/9 actuators were for the bi-articular muscles and the others as mono-articular muscles. In this paper, we demonstrated the relationships between length, load and time constant as the static characteristics of the PAMs. Last part of this paper, we described the concepts and designs of our four-DOF model..
