Flexible Shoulder in Quadruped Animals and Robots Guiding Science of Soft Robotics

Cursorial quadrupeds have different connections to the trunk for forelimbs and hindlimbs: a flexible connection through the muscles to the forelimb, and a secure connection through the hip joint to the hindlimb. Although anatomical and biological studies have described the structure and behavior of cur-sorial quadrupeds by focusing on flexible shoulders, the functionality of the flexible shoulder remains un-clear. In this study, we first survey the anatomical and biological studies. Second, we introduce our robotics studies, which focus on flexible connections for proxi-mal limb joints. Further, we discuss future directions for extracting a design principle based on complex animal body structures, and we suggest the potential for interdisciplinary research between anatomy and soft robotics.