Abstract
Joints of humanoid robots must be backdrivable in order to make them able to withstand collision and impact. The objective of this research is to propose new composition and design of lower limb of humanoid robot with electro-hydrostatic actuator (EHA), a class of backdrivable actuator. We introduce a joint that is composed of bi-articular EHA and mono-articular EHA. Bi-articular EHA has a single pump and two hydraulic motors which are connected to the pump in parallel, while mono-articular has one for each. This paper explains composition and design concept of the EHA joint. Overview and detailed design of the joint are also presented. the design specification of each EHA on the joints was determined by the joint output of human body.
