scholarly journals The method of dynamic operating modes investigation in electrohydraulic drive systems with improved accuracy of positioning executive elements

2018 ◽  
Vol 226 ◽  
pp. 04024
Author(s):  
Valeriy V. Grechikhin ◽  
Galina A. Galka ◽  
Anatoliy I. Ozerskiy ◽  
Mikhail E. Shoshiashvili
Keyword(s):  
Mutual Influence ◽  
Hydraulic Drive ◽  
Joint Work ◽  
Operating Modes ◽  
Hydraulic Machines ◽  
Dynamic Operating ◽  
Electrohydraulic Drive ◽  
Drive Systems ◽  
Improved Accuracy ◽  
Executive Elements

The article describes the method of dynamic operating modes investigation in electrohydraulic drive systems with improved accuracy of positioning output element. The method is the evolution of the fundamental positions of the mechanics of continuous media with moving boundaries as applied to the research of non-stationary processes accompanying the operation of hydraulic drive systems with piston hydraulic machines. The method is based on generalized modeling (technical, physical, mathematical and computer), takes into account the peculiarities of mutual influence of electric and hydraulic machines during their joint work as part of the electrohydraulic drive, which raises the level and adequacy of actuators simulation, as well as the reliability of the assessment of their technical condition. The method extends the field of research, improves the accuracy of the calculation of the positioning of the executive elements, taking into account the different dynamic modes of the drives under study.

ENSURING QUALITATIVE-ACCURACY CHARACTERISTICS DURING RESTORING OF VEHICLE PARTS

2021 ◽  
Vol 3 (144) ◽  
pp. 116-121
Author(s):  
Nikita A. Pen’kov ◽  
◽  
Oleg A. Sidorkin ◽  
Sergey Yu. Zhachkin ◽  
Anatoliy I. Zavrazhnov ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Current Density ◽  
Hydraulic Drive ◽  
Research Purpose ◽  
Working Fluid ◽  
Agricultural Machinery ◽  
Servo Valve ◽  
Contact Points ◽  
Drive Systems

One of the most common reasons for the failure of hydraulic drive systems for agricultural machinery is the working fluid leak in the contact points of the rubbing surfaces of hydraulic blocks. The application of composite coatings based on chromium on the contacting surfaces allows you to restore the defect in the shape of the part caused by wear, as well as reduce the friction coefficient at the contact points, which positively affects the wear resistance of the part. (Research purpose) The research purpose is in developing technologies for restoring parts of agricultural machinery with predetermined operational properties. (Materials and methods) A servo valve, widely used in various hydraulic drive systems, was used as an experimental sample. Its working surface was restored with a composite coating applied by electroplating to increase the wear resistance of the servo valve. (Results and discussion) Authors conducted a series of direct measurements under the same conditions. The article presents the de-pendence of the microhardness on the parameters of the electrolysis mode and the thickness of the applied coating using the method of least squares. The nature of changes in microhardness and residual stresses was evaluated to determine the quality of the coatings. The article presents the dependences of these indicators on various control parameters (current density, temperature, tool pressure). The equations of the regression of the main qualitative and accuracy characteristics of the parts were deter-mined using the apparatus of the theory of experimental planning. (Conclusions) The article presents the method for predicting coatings of a given quality, taking into ac-count the influence of the current density and the temperature of the electrolyte during electrolysis on the nature of the precipitation obtained. The influence of the tool pressure on the depth of deformation of the formed layers was estimated. This approach allows us to evaluate the nature of the stress distribution in the formed coating and the quality of the restored parts.

Sliding Mode Analysis of a Counterbalance Valve Induced Instability in an Electrohydraulic Drive

2021 ◽  
Author(s):  
Philipp Zagar ◽  
Rudolf Scheidl
Keyword(s):  
System Dynamics ◽  
Sliding Mode ◽  
Hydraulic Drive ◽  
Mode Analysis ◽  
Order System ◽  
Full System ◽  
Reduced Order ◽  
Valve Dynamics ◽  
Electrohydraulic Drive ◽  
Saturation Effects

Abstract This paper analyzes dynamic effects of an electro-hydraulic drive which uses a counter-balance valve for rod volume compensation. It shows that local stability analysis is not sufficient in this particular case to get general statements of the system's chattering properties. A reduced-order switched system is proposed to gain deeper insights in system dynamics with saturation effects such as the end-stop of a valve poppet and solutions are compared numerically to the full-system dynamics which incorporates pressure built-up, piston and valve dynamics as well as motor dynamics. It is shown that in cases of e.g. fast valves with small cracking pressures undesirable chattering of the full system exists which can be easily understood in terms of the reduced-order system in form of sliding mode solutions. The paper also describes under which conditions such sliding modes exist, how they behave and how they can be interpreted in terms of the full system.

scholarly journals DETERMINATION OF CHARACTERISTICS AND SMOKE EXHAUSTERS PARAMETERS IN CONDITIONS OF INDEPENDED AND JOINT WORK WITH OTHER DEVICES BASED ON MATHEMATICAL MODEL

2018 ◽  
Vol 1 (2) ◽  
pp. 10-17
Author(s):  
A Kodryk ◽  
O Titenko ◽  
V Prysiazhniuk ◽  
S Semychaievskyi
Keyword(s):  
Mathematical Model ◽  
Aerodynamic Resistance ◽  
Exhaust System ◽  
Axially Symmetric ◽  
Axial Fan ◽  
Joint Work ◽  
Mixture Flow ◽  
Operating Modes ◽  
Table Data ◽  
Independent Work

The principle of construction and examples of implementation of the developed mathematical model of the smoke exhaust system designed for operational use in case of fire for the elimination of gas pollution and lowering the temperature in the premises. Estimated target features of the installation are based on existing experience, namely: expected aerodynamic airway resistance: 80 Pa and volumetric air mixture flow rate of 3.3 m3/s. The specified characteristics and parameters necessary for the design, or modernization of existing axial fans, and their choice for three operating modes: independent work, joint work with the supply of finely divided water, joint work with the foam generating plant. Simplifications were used in the development of a mathematical model: scheme of the design of the axial fan, which does not involve the presence of a guiding apparatus; it is assumed that the flow in the operating cavity of the pump is axially symmetric; it is assumed that the thermodynamic process taking place in the pump cavity is isothermal; simplified formula of the lifting factor and drag coefficient of the grid is used on the basis of known table data. The mathematical model takes into account: the dimensions of the smoke exhaust system, the number and size of the blades, the angle of attack of the blade, the frequency of rotation, the amount of aerodynamic resistance of the airway, the density and the amount of supply of finely divided water or foam. The examples of the implementation of the developed mathematical model of the smoke exhaust system are illustrated in the form of diagrams of the location of the working points (volume flow of air mixture, m3/s, pressure, Pa; power of the engine of the smoke exhaust system, W) at operation of a smoke exhaust system in the conditions of the average airway for the three above-mentioned operating modes.

scholarly journals Improving a method for determining the maneuvering intensity of the executive element of a special-purpose system

2021 ◽  
Vol 5 (3 (113)) ◽  
pp. 75-83
Author(s):  
Spartak Hohoniants ◽  
Iurii Repilo ◽  
Oleksandr Tytarenko ◽  
Andrii Kokoiko ◽  
Oleg Golovchenko
Keyword(s):  
At Risk ◽  
Initial Data ◽  
Stochastic Modeling ◽  
Mutual Influence ◽  
Improved Method ◽  
Executive Element ◽  
Favorable Conditions ◽  
The Impact ◽  
Executive Elements ◽  
Significant Factors

The purpose of improving a method is to devise a tool for resolving contradictions in the practice of conflict events related to increasing the survivability and effectiveness of participation in a conflict event. A method for forecasting the survivability indicators of a special-purpose system based on the method of analytical-stochastic modeling of a conflict event was chosen as the basis for improvement. The improved method is intended to find a compromise between the need to increase the duration of participation in the conflict and minimize the time of being at risk of loss of ability to function. The use of the improved method, unlike the existing ones, provides an assessment of the impact of maneuver on the effectiveness of the implementation of tasks and the survivability of SPS. The method implies justifying the techniques for the executive elements to maneuver in order to create favorable conditions and effectively perform tasks in a conflict event. The method involves the procedure for the formation of initial data; determining the maneuvering intensity of executive elements; comparing the parameters for expedient (rational) and implemented maneuvering techniques; the generalization of the research results. The accepted indicators of the effectiveness and survivability of a special-purpose system in a conflict event are the mathematical expectations of the number of destructive influences and the number of preserved executive elements as a function of the intensity of maneuvering. The criteria defined for assessing the maneuvering techniques are the greatest values of the increase in efficiency and survivability with the change in the intensity of maneuvering and taking the favorable position by an executive element in a conflict event. The specified method has helped investigate the peculiarities of changing performance and survivability indicators dependent on the intensity of maneuvering and determine the criteria signs for selecting maneuvering techniques. Based on the signs of informativeness and the nature of the mutual influence of the relevant indicators, the advantage of the method is 30 % while the objectivity of taking into consideration significant factors increases by 15 %. Practice needs to predict the consequences of processes of conflicting nature on the grounds of the effectiveness and survivability of its participants

scholarly journals Theoretical background of hydraulic drive control system analysis for testing piston hydraulic cylinders

2019 ◽  
Vol 19 (3) ◽  
pp. 242-249 ◽  
Author(s):  
A. T. Rybak ◽  
I. K. Tsybriy ◽  
S. V. Nosachev ◽  
A. R. Zenin
Keyword(s):  
Mathematical Modeling ◽  
Hydraulic System ◽  
Energy Recovery ◽  
Test Bench ◽  
Hydraulic Drive ◽  
Mechanical Transmission ◽  
Hydraulic Motor ◽  
Hydraulic Machines ◽  
Life Tests ◽  
Hydraulic Cylinders

Introduction. The durability and performance of hydraulic machines is determined through life tests. At that, various braking devices (mechanical, electric, hydraulic, etc.) are used for strength loading of the hydraulic motor, as a result of which a significant amount of energy is lost. This can be avoided if the method of rotational motion with energy recovery is used during life tests. This approach is applicable for hydraulic pumps, motors, and hydraulic cylinders.Materials and Methods. A test bench is presented, the design of which provides recreation of the conditions most appropriate for the field operation of hydraulic cylinders. In this case, energy recovery is possible. To solve the research problems, methods of mathematical modeling were used, the basic functional parameters of the proposed design were calculated. The determination of the pressure increment at various points in the hydraulic system is based on the theory of volumetric rigidity. When modeling the motion of the moving elements of the bench hydraulic system, the laws of rotor motion are used.Research Results. In the structure of the test bench, the cylinders in question are located in the pressure main between the hydraulic pump and the hydraulic motor. This enables to significantly reduce the bench itself and to save a significant amount of energy due to its recovery. A basic hydraulic diagram of the test bench for piston hydraulic cylinders is presented, in which the operation of the moving elements of the system is shown. A mathematical modeling of the hydraulic system of the bench is performed. A kinematic diagram of the mechanism for transmitting motion between test cylinders is shown.Discussion and Conclusions. The system of equations presented in the paper shows how the increment of pressure at the selected nodal points of the energy recovery system is determined (in particular, how the increment depends on time, reduced coefficient of volumetric rigidity, operating fluid consumption, and piston areas). The velocities of the hydraulic pistons are determined according to the kinematic scheme of the mechanical transmission of the bench. Thus it can be argued that, thanks to the solution presented in the paper, the life test results of hydraulic cylinders will adequately reflect their operation under rated duties.

scholarly journals Optimal feedforward control of hydraulic drive systems with long pipelines

PAMM ◽  
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Christopher Pietschnig ◽  
Lukas Marko ◽  
Wolfgang Kemmetmüller ◽  
Andreas Kugi
Keyword(s):  
Feedforward Control ◽  
Hydraulic Drive ◽  
Drive Systems

scholarly journals Concept and modelling of the electrohydraulic valve with DC and stepper motors

2019 ◽  
Vol 252 ◽  
pp. 06003 ◽  
Author(s):  
Dominik Rybarczyk
Keyword(s):  
Hydraulic Drive ◽  
Dc Motor ◽  
Stepper Motor ◽  
Proportional Valve ◽  
Positioning Accuracy ◽  
Accuracy Requirement ◽  
Stepper Motors ◽  
New Type ◽  
Drive Systems ◽  
Electrohydraulic Valve

The article describes concept and modelling of a new type of electrohydraulic valve controlled by the combination of a stepper motor and a DC motor. The aim of this invention is to use in the proportional valve two motors with the different properties. Both motors are responsible for the movement of a valve spool. The stepper motor and the DC motor are connected to a shaft by using a bellows coupling. Transfer from rotary to linear motion is performed by use of a bolt-nut system. According to the invention, presented here valve can be used in hydraulic drive systems with high positioning accuracy requirement. The author was granted a patent no. P.421994 on the invention described in this paper.

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