An electrohydraulic actuator (EHA) system is a combination of hydraulic systems and electrical which can produce rapid response, high power-to-weight ratio, large stiffness. Nevertheless, the EHA has nonlinear behaviors modeling uncertainties such as frictions, internal external leakages, parametric uncertainties, lead to significant challenges in controller design for trajectory tracking. Ther...

Machine-building industries and enterprises for modernization of railway rolling stock are constantly increasing the requirements technical functional characteristics technological equipment drives. The improvement drives ensures implementation optimal laws working bodies motion, accuracy regulation their movementsand stability speeds under variable load conditions, that has a direct impact on ...

Wehere report on a novel approach to deliver a fully covered self-expanding metal stent (SEMS) into the bile duct during double-balloon enteroscopy (DBE)-assisted endoscopic retrograde cholangiopancreatography (ERCP) using the overtube as an “accessory” or working channel. An 87-year-old woman with a history of a Billroth II reconstruction many years previously and complex choledocholithiasis h...

Hydraulic actuator has been widely used in industrial applications due to its fast response and capability of moving heavy load. The nonlinear properties of hydraulic cylinder had challenged researchers to design a suitable controller for position control, motion control and tracking control. Based on these problems, we had done a real-time digital tracking control studies on electrohydraulic c...

The control synchronization of multiple electrohydraulic actuators (MEHAs) is initially discussed to ensure the consensus every actuator (EHA) with three-order isomorphic dynamics. First, EHA model linearized using Lie derivative method obtain state-space MEHAs. Then, disturbance observer used estimate and compensate for unknown external load caused by driving force a motion plant. Via Lyapunov...

A nonlinear dynamic model for an unconventional, commercially available electrohydraulic flow control servovalve is presented. The valve is a two-stage valve and differs from the conventional servovalve in that it does not require a feedback wire and ball, and the boost stage uses two spools, instead of a single spool, to meter flow into and out of the valve separately. Consequently, the valve ...

Hydraulic systems, as power source and transmission, offer many advantages over electromechanical or purely mechanical counterparts in terms of power density, flexibility and portability. Many hydraulic systems require touching and contacting the physical environments; and many of these systems are directly controlled by human. If hydraulic systems are passive, they would be safer to interact w...