An automated, pre-programmed, multiplexed hydraulic valve actuator is described. The valve is membrane-based and normally open. In contrast to the membrane-based pneumatic valve, the hydraulic valve uses hydraulic liquid to exert the control pressure. The line pressure is controlled with a roller moving over a prefabricated topology. Multiple rollers, each traversing its own track, are assemble...

In practical electro-pneumatic or hydraulic servo mechanism, there is usually an unavoidable operating delay time in the solenoid valves. This may sometimes cause closed-loop instability if the time delay is not treated carefully in the control system designs. Furthermore, pneumatic actuators can offer high performance at low cost, but are often suffered from external disturbances depending on ...

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...

A problem with pneumatic positioning systems is the low energetic efficiency. This paper presents a structure of a compressed air saving for pneumatic positioning systems with capacity to move high loads. This structure use the loading to save compressed air and thus to increase the energetic efficiency of these systems. This configuration adds a fast switching on/off valve in a feedback betwee...

Inherent nonlinearities like, deadband, stiction and hysteresis in control valves degenerate plant performance. Valve stiction standouts as a more widely recognized reason for poor execution in control loops. Measurement of valve stiction is essential to maintain scheduling. For industrial scenarios, loss of execution due to nonlinearity in control valves is an imperative issue that should be t...

This paper presents a detailed model of a novel electropneumatic valve actuator for both engine intake and exhaust valves. The valve actuator’s main function is to provide variable valve timing and variable lift capabilities in an internal combustion engine. The pneumatic actuation is used to open the valve and the hydraulic latch mechanism is used to hold the valve open and to reduce valve sea...

In this contribution, three nonlinear control strategies are presented for a two-degree-offreedom parallel robot that is actuated by two pairs of pneumatic muscle actuators as depicted in Fig. 1. Pneumatic muscles are innovative tensile actuators consisting of a fibrereinforced vulcanised rubber hose with appropriate connectors at both ends. The working principle is based on a rhombical fibre s...

This study considers the practical issue of severe noise observed in a multi-stage sleeve control valve within an engineering project. Employing computational fluid dynamics (CFD) methodology, we initially performed numerical simulations to analyze steady-state flow field valve. Subsequently, identified underlying factors contributing To assess aerodynamic valve, applied FW-H acoustic analogy t...