Development of backdrivable hydraulic joint mechanism for knee joint of humanoid robots

Review of Development Stages in the Conceptual Design of an Electro-Hydrostatic Actuator for Robotics

“…Moreover, its compact size and functionality allowed maximum performance. Parallel to Kargov's work, Kaminaga et al experimented with the application of electro-hydrostatic actuator on knee-joints and a robotic hand for a humanoid robot [31,32]. The goal of this investigation was to achieve certain degree of adaptability of the mechanisms which generate robot movements, in situations when the robot interacts with humans or objects within its environment.…”

Development of friction free controller for electro-hydrostatic actuator using feedback modulator and disturbance observer

“…Given that many of the inherent nonlinearities are omitted in EHAs, the system dynamics can be well characterized by a linear model [1]. Hence, complicated controllers such as adaptive controllers [2], sliding mode controllers [3], and fuzzy controllers [4] are not necessary, while those are often implemented in hydraulic systems.…”

“…In the previously proposed controller, FMs are only activated in the low-speed domain and DOB compensation value updates are concurrently suspended. The previously proposed controller offers three advantages: (1) in the low-speed domain, the FMs eliminate frictional effects; (2) in other speed domains, DOBs operate as normal; (3) the design is simple and does not require strict parameter tuning.…”

Development of high-power and backdrivable linear electro-hydrostatic actuator

“…EHA is a displacement control type hydraulic actuator that control hydraulic motor motion with the torque supplied to the pump. We use a combination of a fixed displacement pump, a fixed displacement hydraulic motor, and a servo motor to construct an EHA [11]. In our previous study [11], [12], we developed revolute EHA with low friction.…”