  Musculoskeletal humanoids have been developed by imitating humans and
expected to perform natural and dynamic motions as well as humans. To achieve
desired motions stably in current musculoskeletal humanoids is not easy because
they cannot maintain the sufficient moment arm of muscles in various postures.
In this research, we discuss planar structures that spread across joint
structures such as ligament and planar muscles and the application of planar
interskeletal structures to humanoid robots. Next, we develop MusashiOLegs, a
musculoskeletal legs which has planar interskeletal structures and conducts
several experiments to verify the importance of planar interskeletal
structures.
