SYNTHESIS OF ELECTRIC HYDRAULIC FOLLOWING DRIVE PARAMETERS BASED ON THE PRESCRIBED ACCURACY OF POSITIONING OF THE WORKING BODY, FAST SPEED AND CHARACTER OF THE TRANSITION PROCESS

A methodology for the dynamic synthesis of an electro-hydraulic servo drive is described to ensure a given performance, a given transient shape and accuracy of the positioning of the working body. The structural scheme of the electro-hydraulic tracking drive was constructed, on the basis of which its mathematical model was compiled based on the equations of the dynamic balance of the system. Based on the obtained transfer functions of individual elements, a structural diagram of the system was constructed. During dynamic analysis and synthesis by the method of logarithmic amplitude-phase-frequency characteristics, the transfer function of an open drive is considered, given in the form of the product of transfer functions of three typical links - integrating, aperiodic and oscillatory. The primary and secondary errors are determined and expressions for the system Q factor are obtained. Based on the given requirements for positioning accuracy, the forbidden region in the low-frequency part of the logarithmic amplitude-frequency characteristics is determined. The forbidden region in the mid-frequency part of the logarithmic amplitude-frequency characteristics is also determined based on the given dynamic characteristics of the drive. Real and desired logarithmic amplitude-frequency and phase-frequency characteristics are constructed. Since the existing drive structure could not fully satisfy the requirements, it was decided to introduce a corrective link into the structural diagram, formulated the requirements for the structure of the corrective link and its transfer function. The parameter that is to be adjusted in the system is determined - the gain of the electronic amplifier. This made it possible to obtain a drive that fully meets the set requirements.
Keywords: electrohydraulic servo drive, logarithmic characteristics, quality factor, corrective link