Iskanje po katalogu digitalne knjižnice

Opis: The control of pressure by means of variable displacement pumps is one of the most important tasks in the field of pump control, which is influenced by the properties of the pumps. Looking for a suitable control concept with good static behaviour, a method is tested which tunes the parameters of a controller. Instancing a variable displacement axial piston pump controlled bya 3/2 proportional valve the improvement will be achieved by fuzzy logic on the one hand and a non-linear approach - adaptation of gain of the classical controller - on the other.
Ključne besede: servo hydraulic, variable displacement pump, pressure control, conventional control structures, fuzzy control structures, nonlinear control structures
Objavljeno v DKUM: 31.05.2012; Ogledov: 1981; Prenosov: 58
Povezava na celotno besedilo

Opis: The main characteristic of an electrohydraulic pump control system is the presence of an electrical signal path. It requires at least one sensor for the controlled value (in this case pressure), delivering feedback to be compared with the electrical or numerical reference in the controller. The additonal expense penalty for the sensor and the valve is offset by the advantage of flexibility in the structure and parameters of the controller in comparison to hydraulic - mechanical concepts. Thus, the transfer response can be adapted to demands, even in the operational state. Sophisticated control structures can be implemented easily in the form of computer or microcontroller programs. The layout of electrohydraulic pressure control discussed in this study includes the presented loading unit. The variable pump is designed to act together with a proportional valve having two metering edges. It is less expensive compared to the design with a synchronizing cylinder and four metering edges. However, only inferior static and dynamic performance can be expected. Hydraulic energy is supplied to the control valve directly from the output port of the pump - with the advantage of simple assembly, as there are no additional components required - but with the drawback that there is influence on the control loop`s properties at every change in the disturbance value or reference. The aim of the study presented in this paper is a more efficient and simple concept compared to other known methods for pressure control of the above mentioned pump including the dynamics of the distribution network, and also the characteristics of the hydraulic load with special focus on improvements in steady state and dynamic behaviour.
Ključne besede: automatic control engineering, electrohydraulic systems, pressure control, self-adjusting proportional controller
Objavljeno v DKUM: 31.05.2012; Ogledov: 2291; Prenosov: 145
Povezava na celotno besedilo