engleski

Control of Electrohydraulic Servosystems by Applying Various Control Devices

In modern industrial applications, electro- hydraulic systems can be of various configurations and can be controlled using different types of valves and control devices. Values that are usually controlled in these systems are position, speed or force of hydraulic actuators. This paper presents three experimental electro-hydraulic servo mechanisms made for the purpose of conducting research in the field of conventional, proportional and servo hydraulics. All three systems have the characteristics of general industrial plants and also include the necessary measuring equipment for realization of control algorithms. Various control devices were used for the implementation of the control process. The first system is a module for translational motion control of hydraulic actuator. This system consists of a main cylinder which is controlled by using a proportional directional control valve, while disturbance (i.e. reaction force) is generated by using a load cylinder with a pressure control valve. The position control of hydraulic cylinder is realized by using the CompactRIO controller programmed in LabVIEW graphical program. The second system is a module for the control of force, i.e. a hydraulic press where it is possible to regulate the pressing force. The press contains a servo-solenoid pressure-control valve for regulating the pressure in the cylinder chamber and thus the force of the hydraulic press. The force control of hydraulic press is realized by using a programmable logic controller – PLC. The third system is a module for the rotational motion control of the hydraulic actuator. In this system a hydraulic motor as a control object is used, while the disturbance is generated by using a hydraulic pump whose output pressure is adjusted with a proportional pressure valve. The velocity control of hydraulic motor is realized by using a PC with DAQ card and Matlab/Simulink/RTW program. The article is accompanied with some typical experimental results obtained during systems testing.

electrohydraulic servosystem; position; speed and force control

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