Hydraulics is a promising technology for robots. However, traditional hydraulic infrastructures are often large and power-inefficient, with power sources that hinder mobility. In contrast, electro-hydrostatic actuators relatively efficient, but their cost weight can be excessive in systems higher number of degrees freedom. this paper, we propose new alternating pressure control system freedom b...

this paper proposes an efficient tracking method for velocity control of an electro-hydraulic servo system (ehss) in the presence of flow nonlinearities and internal friction. the tracking method controller is a kind of feedback error learning structure. in the proposed method, the feedback error learning (fel) algorithm is used to control the velocity. there is no need to compute the system ja...

This paper deals with the challenging aspect concerning the state estimation in hydraulic actuators characterized by not negligible nonlinearities. Particularly,. One of the most common hard nonlinearities in hydraulic actuator is the deadzone. More specifically, dead-zone occurs in hydraulic control valves when its spool occludes the orifice with an overlap, so that for a range of spool positi...

This paper presents the design of a magnetic resonance imaging (MRI) compatible pneumatic actuator regulated by piezoelectric valve for image guided robotic intervention. After comparing pneumatic, hydraulic and piezoelectric MRI compatible actuation technologies, we present a piezoelectric valve regulated pneumatic actuation system consisted of PC, custom servo board driver, piezoelectric valv...

Two electro-mechanical actuators are examined for a semi­ active Helmholtz resonator acoustic device. The device is used to reflect narrowband noise back to the source in an acoustic duct. The controller and actuator are used to tune the system on-line allowing optimum performance over a range of operating conditions. Actuator. dynamics play an important role in the controller design and the op...