Design of humanoid body trunk with “multiple spine structure” and “planar-muscle-driven” system for achievement of humanlike powerful and lithe motion

In recent years, humanlike robots have recieved a lot of attension. For making humanlike robots, a muscu-loskeletal humanoid is an effective approach. However, many musculoskeletal humanoids have not yet been equipped with really humanlike bones and muscles, especially for the body trunk, which is the core of the robot. For making a powerful and lithe humanoid body trunk with really humanlike bones and muscles, we think an enhanced “planar-muscle-driven” system and “multiple spine” structure were keys. Planar-muscle-driven systems move several wires simultaneously by using two moving-pulley bars per motor, while the prior linear-muscle-driven system moved only one wire per motor. Using the planar-muscle-driven system, we were able to simplify prior complex composition and control systems. On the other hand, we proposed a multiple spine structure, which has an S-curve alignment like the human spine. In human, the S-curve is important for upper body stability while walking and shock relaxation of heavy human head. This paper describes the “planar muscle” unit and the “multiple spine” structures, and then the body trunk containing both elements. Using the model, we performed experiments to show the efficacy of those elements.