Development of Micro Hydraulic Actuator for force assistive wearable robot

This paper presents Micro Hydraulic Actuator (MHA). MHA has high power density and it is small enough to be installed inside of a small robot, such as humanoid robots. MHA consists of a cylindrical cam mechanism, pistons having ball joints, and combination of a valve plate and a cylinder block. The cylindrical cam has a Modified Sine (MS) curve and dwells at the trapping region of the cylinder ports on the cylinder block. The valve plate has slot ports in a circumferential direction on the inside and it induces high-precision contact with the cylinder block. In this study, MHA is designed and produced focusing on the mechanisms mentioned above and the applicability of the humanoid robots through the performance test is verified.