Determination of Transfer Functions for Electrohydraulic Servo Drive of Technological Equipment

An electrohydraulic servo drive with throttling regulation of technological equipment is considered. The following basic elements are distinguished in the drive: hydraulic cylinders, the electrohydraulic amplifier including the electromechanical transducer and the hydraulic amplifier, the feedback gauge, the electronic block. To study the dynamic characteristics of the drive a typical mathematical model of non-stationary work processes occurring in the drive is presented. The linearization of the mathematical model is carried out, the structural scheme of the drive is constructed, the transfer functions are obtained for the control signal and the loading influence. The main parameters of the drive are the time constant of the control winding, the time constants of the electrohydraulic amplifier, the time constants of the hydraulic cylinder, the coefficient of relative damping of the hydraulic cylinder, the feedback coefficient, the drive transfer coefficient by the control signal, and the drive transfer coefficient by the loading influence. The proposed linear mathematical model and transfer functions are adapted to the drives of the technological equipment. The main advantage of the presented mathematical description of the characteristics of the electrohydraulic servo drive with the throttle regulation is the ability to perform the stability evaluation, quality of control and correction of the dynamic properties of the drive using the technical certificate data of the drive elements and devices.