Development of a Joint Structure for a Musculoskeletal Robot

When dealing with musculoskeletal robots with pneumatic actuators, the use of bearings would limit the amount of degrees-of-freedom offered by these actuators. This way, the development of a new joint structure is needed to explore the movement freedom.

In this group, we create a polymer joint, as shown in Figure 1 (patent pending). By using an open type joint such as this, impact resistance and ease to generate natural motions is achieved while offering low friction. As a result, our humanoid robots from the Pneumat-BR series, such as Pneumat-BRP (Pneumatic Biped Runner Prototype, Fig.2-left), Pneumat-BR (Pneumatic Biped Runner, Fig.2-middle) and Pneumat-BR2 (Pneumatic Biped Runner 2, Fig.2-right) were able to achieve natural walking and running gaits．

Fig. 1 Human inspired open joint

Fig. 2 Pneumat-BR series

By using such joints it is possible to create humanoid robots whose structure mimics human structure, helping us to understand our own body and analyzing our own motion and muscle functions.