scholarly journals MATHEMATICAL MODELING OF THE HYDRAULIC DRIVE OF THE SECTIONS OF A WIDE-COLLECTING CULTIVATOR WITH SEQUENTIAL ACTIVATION OF HYDRAULIC CYLINDERS

2021 ◽  
pp. 148-158
Author(s):  
Serhiy Shargorodskiy ◽  
Volodymyr Rutkevych ◽  
Evhenyy Yaschcuk
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Cutting Tools ◽  
Hydraulic Drive ◽  
Working Fluid ◽  
Integration Step ◽  
Agricultural Engineering ◽  
Hydraulic Cylinders ◽  
Hydromechanical System ◽  
Sequential Activation

The publication discusses the issues of mathematical modeling of dynamic processes occurring in a complex hydromechanical system of the hydraulic drive of the wide-cut cultivator sections with consistent wear of the hydraulic cylinders. The analysis of known designs of wide-cutting tools and agricultural units is carried out. It is noted that one of the tendencies in the development of domestic agricultural engineering is an increase in the width of coverage of tillage machines. In this regard, hydraulic drives for decomposition and assembly of sections of these machines are widely used. The use of this type of drive is due to its compactness, speed and power. The basic schematic diagrams of hydraulic drives for decomposition of wide-cut tillage machines are considered. On the basis of the analysis, a schematic diagram of the hydraulic drive for assembling (decomposing) sections of a wide-grip cultivator with sequential actuation of hydraulic cylinders is proposed and the principle of its operation is described. A mathematical model has been developed for the hydraulic drive of the wide-grip cultivator sections in the working and transport position. The mathematical model consists of the equations of the continuity of the flows of the working fluid, which describe the processes occurring in the hydraulic drive, and the equations of moments and forces, from which it is possible to determine the force factors acting on the elements of the system. It is difficult to obtain an analytical solution to the resulting system of equations, therefore, to find solutions, numerous methods were applied, namely the Runge-Kutta-Feldberg method with an automatic change in the integration step. On the basis of the obtained dependencies, an analysis of the operation of the hydraulic drive with sequential wear of the hydraulic cylinders was carried out and recommendations were proposed on the design device and directions for improving the hydraulic drive of the tillage unit sections.

scholarly journals Mathematical model of the volumetric hydrodrive’s dynamics, sensitive to the loading variation

2018 ◽  
Vol 224 ◽  
pp. 02100 ◽  
Author(s):  
Alexandra Ivanovskaya ◽  
Vladimir Popov
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Characteristic Feature ◽  
Hydraulic Drive ◽  
Drive System ◽  
Operating Principle ◽  
Dynamic Loads ◽  
Dynamic Processes ◽  
Hydromechanical System

The paper deals with the problems of mathematical modeling of the dynamic processes proceeding in a complex hydromechanical system of the ship’s deck load-lifting devices. The characteristic feature of this class of equipment is the operation in special conditions, i.e, under the influence of external hydrometeorological factors, taking into account variations in the parameters of lifted or lowered cargo. With a view to gradual regulation of the change of torque on the working drum to reduce dynamic loads, it is offered to use a hydraulic drive that is sensitive to the variation of loading. The operating principle of the considered volumetric hydraulic drive is described. The received mathematical model allows to establish influence of the hydrodrive parameters on transients in a drive system.

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 MATHEMATICAL MODEL OF THE INTERACTION OF THE SCREW WORKING BODIES OF FOREST FIRE GROUND-THROWING MACHINES WITH THE GROUND COVER

2021 ◽  
Vol 11 (1) ◽  
pp. 163-171
Author(s):  
Petr Popikov ◽  
Anton Pozdnyakov
Keyword(s):  
Mathematical Model ◽  
Forest Fire ◽  
Forest Fires ◽  
Hydraulic Drive ◽  
Ground Cover ◽  
Forest Litter ◽  
Working Fluid ◽  
Hydraulic Motor ◽  
Working Bodies ◽  
Fire Ground

The paper provides an overview of research on the working processes of screw working bodies of technological machines. It is noted that at present such important issues in the theory of auger working bodies as the required number of auger turns, the required position of the auger spiral in relation to the center, etc. have not been fully resolved, since the solution of these issues can provide an increased productivity of the tool. A structural and technological scheme of a forest fire machine with multifunctional modules is proposed, which consists of auger working bodies, which can be changed modularly with a screw metal thread for a brush, depending on the area and type of soil, the rotor of the thrower, with the ability to drive the cutters-throwers and auger working bodies both from the power take-off shaft of the tractor, and using a hydraulic motor, a guide casing. A mathematical model of an auger working body with a hydraulic drive has been compiled for removing the ground cover with forest litter when extinguishing forest fires with a ground gun, so that combustible materials do not fall into the fire zone together with the soil flow from the rotor-thrower. The working process of the hydraulic drive of the auger working bodies of a forest fire ground-sweeping machine is described by a system of differential equations, including the equations of translational and rotational movements of the auger working body and the equation of the flow rate of the working fluid. The problem of optimization of kinematic and dynamic parameters of auger working bodies of forest fire ground-sweeping machine is set

scholarly journals The influence of auger wear on the parameters of the dehydration process of solid waste in the garbage truck

2021 ◽  
Vol 100 (2) ◽  
pp. 79-86
Author(s):  
O. Bereziuk ◽  
◽  
V. Savulyak ◽  
V. Kharzhevskyi ◽  
◽  
...  
Keyword(s):  
Mathematical Model ◽  
Energy Consumption ◽  
Angular Velocity ◽  
Solid Waste ◽  
Working Fluid ◽  
Integration Step ◽  
Dehydration Process ◽  
Hydraulic Motor ◽  
Variable Integration ◽  
The Cost

The article is dedicated to the study of the influence of auger wear on the parameters of the dehydration process of municipal solid waste in the garbage truck. An improved mathematical model of the drive operation of dehydration of solid waste in the garbage truck is proposed, which takes into account the wear of the auger and allowed to numerically determine the dynamics of the drive during start-up. It was also established that increasing wear of the auger, the pressure of the working fluid at the inlet of the hydraulic motor rises, and the angular velocity and speed of the auger is significantly reduced. The research of this mathematical model was carried out using the numerical Runge-Kutta-Felberg method of the 4th order with a variable integration step. By means of the method of regression analysis, the power dependencies of the change of nominal values ​​of pressures at the inlet of the hydraulic motor, angular velocity and speed of rotation of the auger from the value of its wear are determined. The last-mentioned dependence defines the detuning from the optimal speed of the auger during its wear and is used to determine the energy consumption of dehydration of solid waste, taking into account the wear of the auger. It is established that the wear of the auger by 1000 mm leads to an increase in the energy consumption of dehydration of solid waste by 11.6%, and, therefore, also leads to an increase of the cost of the process of their dehydration in the garbage truck. It was also established the expediency of further research to determine the appropriate material of the auger and the ways to increase its wear resistance.

scholarly journals Analysis of the Throttle Speed Control Efficiency in Volumetric Hydraulic Drives

2019 ◽  
pp. 13-33
Author(s):  
K. D. Efremova ◽  
V. N. Pilgunov
Keyword(s):  
Control Method ◽  
Hydraulic Drive ◽  
Hydraulic Cylinder ◽  
Movement Speed ◽  
Working Fluid ◽  
Total Efficiency ◽  
Control Methods ◽  
Output Link ◽  
Hydraulic Cylinders ◽  
Load Characteristics

To control a movement speed of the output link of an executive hydraulic engine (hydraulic cylinder or hydraulic motor), volumetric hydraulic drives traditionally use volumetric and throttle control methods. Under volumetric control, a supply unit employs a pressure-regulated positive displacement pump, as a result of which it is impossible or difficult to separate and independently control the movement speed of the output links of the hydraulic cylinders. In case of throttle control, there is a significant dependence of the speed of the output link on the load it overcomes, a low efficiency of the hydraulic drive and hereto related active heating of the working fluid, as well as large energy losses. However, in embodiment, due to lack of an expensive variable pump, this method of control is much cheaper and can be used in a multi-channel hydraulic drive with a centralized supply unit.Depending on the throttling device localization in the hydraulic drive circuit, there are series (primary or secondary control) and parallel (working fluid bypass adjustment) throttle connection schemes. The secondary control scheme, which generates a pressure in the outlet of the executive hydraulic engine, is preferable due to the fact that it provides an increased pressure in both cavities of the executive hydraulic engine and, accordingly, a lack of combined air bubbles in the working fluid. Heat released in the throttle is discharged directly into the tank, and the pressure in the outlet reduces the danger level of the emergency situation consequences in the event of an unauthorized change in the sign of the load to be overcome. The quality of control is, mainly, assessed by the type of load characteristics, i.e. dependences of the output link speed and its developed power on the load to be overcome, as well as by the control efficiency (the total efficiency value of the regulating and executive subsystems of the hydraulic drive). The dependence of the dynamics and kinematics of the hydraulic drive on the control methods are of particular interest.The proposed paper, based on the developed mathematical models and their testing for specific sizes of hydraulic cylinders presents the numerical values of the load characteristics and dependences of the total efficiency on the load value to be overcome. Shows that the speed load characteristic steepness of an executive hydraulic cylinder and the sign of its derivative are determined by the throttle control method. The greatest power developed by the output link of the hydraulic engine is shifted to the loads that are 50 ... 70% of their maximum value.As a result of theoretical studies using numerical calculation methods, a technique has been developed for selecting a throttle control method with an assessment of its quality and efficiency. The results of the conducted studies expand the capabilities to forecast the dynamics and kinematics of the output link of the hydraulic drive at the stage of its engineering design.

scholarly journals Development of mathematical model prime cost milling operations optimization.

2014 ◽  
Vol 2014 (2) ◽  
pp. 86-91
Author(s):  
Андрей Аверченков ◽  
Andrey Averchenkov ◽  
Евгений Кукло ◽  
Evgeniy Kuklo
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Cutting Tools ◽  
Prime Cost ◽  
Automatic Selection ◽  
Milling Operations ◽  
Software Modules ◽  
Operations Optimization ◽  
Selection Of

The automatic selection of cutting tools for efficient milling was issued. Mathematical modeling procedures and developing software modules for the automated selection of cutting tools were described.

IMPROVEMENT OF THE HYDRAULIC DRIVE MECHANISM OF THE LIFT-ING BOOM MANIPULATOR AUTOLEASE

2016 ◽  
Vol 3 (1) ◽  
pp. 106-109
Author(s):  
Черных ◽  
Aleksandr Chernykh ◽  
Попиков ◽  
Petr Popikov ◽  
Родионов ◽  
...  
Keyword(s):  
Hydraulic Drive ◽  
Hydraulic Cylinder ◽  
Working Fluid ◽  
Drive Mechanism ◽  
Hydraulic Cylinders

The questions of optimization of the positions of the hydraulic cylinder with consideration of flexibility of the hydraulic drive. Optimization of the positions of the connection points of the hydraulic cylinders of the lifting mechanism for moving and stationary elements of forest manipulator allows to reduce the pressure peaks of the working fluid and the energy for lifting.

scholarly journals RESULTS OF EXPERIMENTAL RESEARCHES OF WORKING PROCESSES OF BLOCKLESS LOGGING CAPTURE WITH ENERGY-SAVING HYDRAULIC DRIVE

2020 ◽  
Vol 8 (1) ◽  
pp. 123-128
Author(s):  
P. Popikov ◽  
Denis Kanishchev ◽  
A. Sutolkin
Keyword(s):  
Energy Saving ◽  
Hydraulic System ◽  
Hydraulic Drive ◽  
Metal Structure ◽  
Working Fluid ◽  
Operating Modes ◽  
Recovery System ◽  
Hydraulic Cylinders ◽  
Hydraulic Accumulator ◽  
Experimental Researches

During the movement of the tractor in the unit with the lockless grabs on the roughness of the terrain on the cuttings there are fluctuations that cause jumps of the working fluid in the hydraulic system. This leads to loss of fluid through the gaps and seals of the moving elements of the pump and hydraulic cylinders. For laboratory studies of these phenomena, a laboratory installation was made with the introduction of a pneumatic-hydraulic accumulator of the A5579-0 series into the hydraulic circuit. Laboratory tests were carried out, which showed that the pneumohydraulic battery allows, due to the energy accumulated during operation, to reduce the pressure spikes of the working fluid in the hydraulic system. This reduces the dynamic load on the metal structure of the grip, the hydraulic pump drive and the tractor transmission, as well as increases the volumetric efficiency. After processing waveforms of operating modes to capture with energy saving hydraulic drive using the program STATISTICA was established replications of individual load magnitudes and histograms of pressure without the use of a hydropneumatic accumulator and to its use. It was found that the energy recovery system reduces the pressure spikes of the working fluid during transients by 1.4-1.7 times and allows you to store power within 1.7 ... 2.1 kW.

Modeling workflows of energy-saving hydraulic drive of technological equipment of timber-hauling machine

2015 ◽  
Vol 5 (1) ◽  
pp. 223-234
Author(s):  
Посметьев ◽  
Viktor Posmetev ◽  
Канищев ◽  
Denis Kanishchev ◽  
Попиков ◽  
...  
Keyword(s):  
Energy Saving ◽  
Fluid Pressure ◽  
Hydraulic Drive ◽  
Vertical Axis ◽  
Working Fluid ◽  
Forward Movement ◽  
Restoring Force ◽  
Hydraulic Manipulators ◽  
Wide Range ◽  
Hydraulic Cylinders

Workflow mechanisms of forestry cranes tower rotation are accompanied by large dynamic loads that cause sudden changes in fluid pressure in balancing and braking modes. When the rotary column stops at different positions damping of pressure of the working fluid vibration occurs due to its overflow from one chamber to another through an orifice, wherein the hydraulic energy is transformed into heat one, resulting in overheating and energy loss of fluid. Efficient are energy-saving hydropneumatic drives of column of the manipulator which are able to recover energy during transient conditions and to return some of the energy back into the system. For hydraulic manipulators with four paired hydraulic cylinders of rotation mechanism of the column one pair of cylinders is proposed to be replaced by pneumatic cylinders connected to a rotary column through the gear and toothed rack that allows you to transfer it into recovery mode of energy. A mathematical model of the boom rotation of the manipulator is developed; equations for a hydro pneumatic system recovery are made. In the model three mechanical processes are considered: the rotational movement of the column about the vertical axis of the manipulator, the forward movement of the plunger along the axis of the damper, and sway of the load relative to the attachment point on the manipulator arm. To solve the system of differential equations, computer program for the simulation of hydraulic manipulator equipped with a hydraulic damper is composed. The dependence of the restoring force of the displacement of the toothed rack is get. In the vicinity of the equilibrium position, this dependence is nearly linear over a wide range of rack movement: from about 50 to 180 mm. With significant turns of the column volume of one of the chambers of the air cylinder approaches zero value, whereby the restoring force of the module increases significantly, which helps braking of the column in the final step of rotation and influences the process of energy accumulation.

Application of the method of mathematical modeling for forecasting channel deformations at the underwater crossing of the main pipeline

2020 ◽  
Vol 10 (6) ◽  
pp. 599-609
Author(s):  
Valery А. Gruzdev ◽  
◽  
Georgy V. Mosolov ◽  
Ekaterina A. Sabayda ◽  
◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Roughness Coefficient ◽  
Computational Domain ◽  
Channel Deformations ◽  
Geological Surveys ◽  
Kuban River ◽  
The Stability ◽  
Protective Structures

In order to determine the possibility of using the method of mathematical modeling for making long-term forecasts of channel deformations of trunk line underwater crossing (TLUC) through water obstacles, a methodology for performing and analyzing the results of mathematical modeling of channel deformations in the TLUC zone across the Kuban River is considered. Within the framework of the work, the following tasks were solved: 1) the format and composition of the initial data necessary for mathematical modeling were determined; 2) the procedure for assigning the boundaries of the computational domain of the model was considered, the computational domain was broken down into the computational grid, the zoning of the computational domain was performed by the value of the roughness coefficient; 3) the analysis of the results of modeling the water flow was carried out without taking the bottom deformations into account, as well as modeling the bottom deformations, the specifics of the verification and calibration calculations were determined to build a reliable mathematical model; 4) considered the possibility of using the method of mathematical modeling to check the stability of the bottom in the area of TLUC in the presence of man-made dumping or protective structure. It has been established that modeling the flow hydraulics and structure of currents, making short-term forecasts of local high-altitude reshaping of the bottom, determining the tendencies of erosion and accumulation of sediments upstream and downstream of protective structures are applicable for predicting channel deformations in the zone of the TLUC. In all these cases, it is mandatory to have materials from engineering-hydro-meteorological and engineering-geological surveys in an amount sufficient to compile a reliable mathematical model.

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