METHODOLOGY OF THE DESIGN CALCULATION OF THE ELECTRO-HYDRAULIC SERVO DRIVE OF TECHNOLOGICAL EQUIPMENT

Machine-building industries and enterprises for modernization of railway rolling stock are constantly increasing the requirements for the technical and functional characteristics of technological equipment drives. The improvement of equipment drives ensures the implementation of the optimal laws of working bodies motion, the accuracy of regulation of their movementsand the stability of speeds under variable load conditions, that has a direct impact on the quality of products and productivity.The use of automatic drives of technological equipment, in particular electrohydraulic servo drives, ensures the achievement of arbitrary kinematics of the working body and the possibility of software implementation of the optimal laws of its motion. The development of high-performance electrohydraulic servo drives and their implementation in specialized technological equipment is a rather labor-intensive process and requires the use of engineering methods of project calculation that make it possible to evaluate the main parameters, select drive elements and devices, and predict its static and dynamic characteristics.Currently, there are separate methods and procedures for designing of automatic electro-hydraulic drives for various technological equipment for mechanical processing, in particular equipment for processing materials by pressure, metal-cut-ting machine tools and systems, tool equipment, etc. The available methods are not universal, as a rule they are focused on different classes of both conventional and specialized equipment, they use different initial data, apply various calculation methods and, as a result, have incompatible calculation results.The continuous improvement of the technological equipment of modern machine-building industries and enterprises for the modernization of rolling stock of railways requires the creation of generally accepted engineering methods of project calculation of electrohydraulic servo drives of technological equipment. Based on the works of the authors by design of automatic drives of technological equipment, mathematical modeling and research of their static and dynamic characteristics, as well as correction of the quality ofregulation, a unified engineering method for the design calculation of servo electrohydraulic drives is proposed.The work is devoted to the development of an engineering methodology for the project calculation of an electrohydraulic servo drive with a throttle adjustment of technological equipment, which makes it possible to evaluate the main parameters, select drive elements and devices, and predict its static and dynamic characteristics.An engineering methodology of project calculation of an electrohydraulic servo drive with throttle control for specialized tech-nological equipment of machine-building industries and enterprises for the modernization and repair of rolling stock of railways is presented. The application of engineering methodology involves setting of the following initial data: maximum load (force); maximum tracking speed without load; maximum tracking error (or allowable tracking error at maximum speed); piston stroke; the mass of moving elements. According to the methodology the calculations are made in the following order: design of a drive scheme, selection of a working fluid and nominal working pressure; calculation of design parameters and selection of a hydraulic cylinder; choice of electrohydraulic amplifier; determination of feedbackparameters, determination of the quality factor of the drive and calculation of the transmission coefficient of electrical unit; assessment of drive static characteristics, calculation of speed and load characteristics; designing of drive linear model; durability assessment; study of drive dynamic characteristics and the quality of regulation; drive correction. An example of a project calculation of an electrohydraulic servo drive of specialized pressure processing equipment for a maximum force of 160 kN and a maximum tracking speed without load of 0,05 m/s is given. The results of calculations of the static and dynamic characteristics of the drive using the MATLAB application package are presented.An engineering method for project calculation of an electrohydraulic servo drive for specialized technological equipment is proposed. An example of a project calculation of an electrohydraulic servo drive of specialized technological equipment is given.