Duel Spool Electrohydraulic Servo System

Electrohydraulic servo valve is the unit of electrical and hydraulic components. Basically it is an electrical operated valve which controls the motion of the hydraulic fluid in the circuit. This valve has the ability to control the heavy and powerful load system or control the motion of an actuator with a very small input in terms of current. Servovalves generally receive pressurized hydraulic fluid from the hydraulic pump. This pressurized fluid is used to control the actuator or load movement and the pressurized fluid is controlled by the input. The major applications of this valve are in the field of heavy industry, military, traffic signal process and aircraft etc. The electrical signal is given into the electrical unit to control the position controller or flapper to drive the pilot stage of the valve. The deflected flapper creates the differential pressure between the two ends of the spool valve which is the cause of spool movement. Hence, the motion of the actuator is initiated. In the book a mathematical model of two-stage two-spool electrohydraulic servovalve is discussed where the pressure difference between the two ends of the valve acts as the feedback element.