Development of hydraulic cylinder diagnostic methods by modeling methods

2021 ◽  
pp. 41-45
Author(s):  
Keyword(s):  
Hydraulic Drive ◽  
Hydraulic Cylinder ◽  
Technical Condition ◽  
Diagnostic Methods ◽  
Technical Diagnostics ◽  
Remaining Service Life ◽  
Construction Machine ◽  
Piston Speed ◽  
Variable Nature ◽  
Hydraulic Cylinders

The hydraulic drive of a construction machine is a complex dynamic system that is subjected to many dynamic loads of a variable nature and operates under conditions of variable external influences caused by various factors. During operation, these loads cause failure of the hydraulic transmission elements. To prevent these malfunctions, technical diagnostics should be applied by determining their current technical condition and remaining service life. The article assesses the working condition of hydraulic cylinders using a mathematical model. Using matlab/simulink software to simulate the hydraulic cylinder and hydraulic piston speed when changing the hydraulic cylinder clearance. The simulation results are presented. Keywords: diagnostic, hydraulic cylinder, simulation, development

scholarly journals Volumetric hydraulic drive with series connection of hydraulic actuators

2020 ◽  
Vol 1 (4) ◽  
pp. 61-69
Author(s):  
V.N. Pil'gunov ◽  
◽  
K.D. Yefremova ◽  
Keyword(s):  
Single Channel ◽  
Production Systems ◽  
Experimental Studies ◽  
Hydraulic Drive ◽  
Hydraulic Cylinder ◽  
Series Connection ◽  
Power Characteristics ◽  
Serial Number ◽  
Piston Speed ◽  
Hydraulic Cylinders

The aim of the proposed work is theoretical and experimental studies of the performance of a single-channel hydraulic drive with a series connection of executive hydraulic cylinders and the de-velopment of recommendations for predicting their characteristics. The authors of the paper carried out a set of experimental studies and obtained the numerical kinematic, speed and power characteristics of a single-channel hydraulic drive with five hydraulic cylinders connected in series. It is shown that the nature of the kinematic connection is determined by the differentiation of the hydraulic cylinders. The speed of advancement of the piston of an indi-vidual hydraulic cylinder is determined by its serial number in the chain of hydraulic cylinders, while the highest speed of the piston movement is developed by the first hydraulic cylinder. The relative unevenness of the piston movement in comparison with the speed of the piston movement of the first hydraulic cylinder is determined by the differentiation of the hydraulic cylinder, while the hydraulic drive with the differentiation D = 2 has the greatest unevenness. It is shown that by the selection of the differentiation of the hydraulic cylinders, their stepwise arrangement and the displacement of the location of the bottom of the hydraulic cylinder, that it is possible to realize complex forms of the total trajectory of the points of attachment of the hydraulic cylinder rods. In the hydrostatic (power) hydraulic drive in the rod cavities of the hydraulic cylinders, depend-ing on the serial number of the hydraulic cylinder, the thrust on its rod and the differentiation set different pressure levels, and the lowest pressure will be in the piston cavity of the last hydraulic cylinder. With uniformly loaded hydraulic cylinders, the pressure in the piston cavities depends only on the number of the hydraulic cylinder and its differentiation. In a hydraulic drive with hydraulic cylinders of equal power, the last hydraulic cylinder will develop the greatest force at the lowest piston speed. In addition, the work also shows that the reproducibility of the positions of unloaded rods of hy-draulic cylinders of equal differentiation is not less than 1%. As a result of the experimental studies, a method was developed for the design of a volumetric hydraulic drive with sequential switching on of executive hydraulic cylinders, which can be used to solve the problems of hydrofication of me-chanical engineering production (bending presses, sheet stamping), in shipbuilding (ship slipways), in flexible production systems, industrial and warehouse logistics.

scholarly journals Stochastic models for ensuring parametric reliability of the construction machines

2021 ◽  
pp. 262-273
Author(s):  
Galyna Getun ◽  
Vitalii Les'ko ◽  
Iryna Bezklubenko ◽  
Olena Balina ◽  
Yurii Butsenko
Keyword(s):  
Methodological Approach ◽  
Hydraulic Drive ◽  
Hydraulic Cylinder ◽  
Technical Condition ◽  
Technical Problems ◽  
Reliability Models ◽  
Reliability Indicators ◽  
Hydraulic Machines ◽  
Parametric Reliability ◽  
Analysis Of Failures

The solution of technical problems to ensure the working capacity is largely determined by the effectiveness of theoretical and applied developments in an area of estimation and prediction of their reliability indicators. An effective approach to the analysis of failures and the development of operability and parametric reliability models provides an opportunity to obtain more adequate models of reliability of hydraulic drives of machines, as they more fully take into account the specifics of the structure and functioning of the hydro drive elements of construction machines, their relationships and features of the formation of parameters failures. And this will allow to get more real and accurate results of estimation of reliability indicators of hydraulic drives of both construction and other hydraulic machines. They do not exhaust all possible variants of models that can take place when analyzing the reliability of hydraulic drives of machines, but at the same time they to a certain extent extend and refine the set of known reliability models. Specific in terms of formation of parametrical failures are such consistently connected in terms of the layout of hydraulic elements, as working sections of hydraulic distributors and hydraulic cylinders, which are part of the subsystems of GPs and form the so-called functional areas (FA). Reaching the FA limit is a compatible result of the combined random process of evolution of the volumetric efficiency JCUA  these elements, and the technical condition of the FA is estimated to be generalized by the JCUA, which equals the product of the JCUA of consecutively connected elements: . In this case, the probability of maintaining the capacity of the FA will be: . The processing of diagnostic information and the study of the reliability of GPs in real conditions of their operation showed that the distribution of JCUD hydraulic elements with a sufficient degree of consistency can be described under several theoretical laws. It is considered when the JCUA sections of the hydraulic distributor and hydraulic cylinder are distributed by gamma distribution and exponential distribution. The use of the general methodological approach to the analysis of failures and the construction of models of operability and parametric reliability provides an opportunity to obtain more adequate models of reliability of hydraulic drives of machines, as they more fully take into account the specifics of the structure and functioning of the hydraulic drive elements, They don't exhaust all possible models that can take place when analyzing the reliability of hydraulic drives, but at the same time they are to some extent expanding and refining the range of already known models of reliability.

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.

MULTIPARAMETRIC DIAGNOSTICS OF GAS TURBINE ENGINES

2021 ◽  
Vol 156 (A2) ◽  
Author(s):  
J Sinay ◽  
A Tompos ◽  
M Puskar ◽  
V Petkova
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Technical Condition ◽  
Diagnostic Methods ◽  
Turbine Engines ◽  
Technical Diagnostics ◽  
Suitable Model ◽  
Gas Turbine Engines ◽  
Advantages And Disadvantages ◽  
The Matrix

This article addresses the issue of diagnostics and maintenance of Gas Turbine Engines which are located in high Speed Ferries, Cruisers, Frigates, Corvettes, etc. Assurance of reliable operation can be performed only by using correct diagnostic methods and procedures of monitoring the condition of the devices and by selecting the correct strategy of maintenance. The issue of monitoring the technical condition of Gas Turbine Engines is treated through multiparametric methods of technical diagnostics incorporated into predictive maintenance, which is a part of proactive maintenance. There are methods of vibrodiagnostics, thermography, tribology, borescopy and emissions measurement. Each of these methods has lots of advantages and disadvantages; therefore it is very important to ensure their correct combination for trouble-free operation of those important facilities. Their suitability at work is discussed in the matrix of diagnostic methods application and the PF chart. The output of the work is a proposal of a suitable model of maintenance control which uses multiparametric diagnostic methods for small and big Gas Turbine Engines and optimizes maintenance costs.

scholarly journals Assessment of Technical Condition of C Series Power Hydraulic Cylinders of Mounted Hydraulic Systems of Tractors

2019 ◽  
Vol 29 (3) ◽  
pp. 396-413 ◽  
Author(s):  
Sergey A. Velichko ◽  
Pavel V. Chumakov ◽  
Alexander V. Kolomeychenko
Keyword(s):  
Regression Model ◽  
Hydraulic Cylinder ◽  
Technical Condition ◽  
Total Efficiency ◽  
Technical Documentation ◽  
Steep Ascent ◽  
Limit Condition ◽  
Limit Values ◽  
Technical Requirements ◽  
Hydraulic Cylinders

Introduction. The existing methods of assessing the technical condition of power hydraulic cylinders do not allow one to conclude about the need to restore worn surfaces of parts. The data on limit values of wear of parts (wear and tear value at which a decision is made to repair) in technical requirements to overhaul and other technical documentation of hydraulic cylinders are not currently available. The aim of the study is to determine limit values of wear of working surfaces of hydraulic cylinder parts of C series. Materials and Methods.To assess the technical condition of hydraulic cylinders used, the authors developed a device on the basis of the stand KI-28097M-GOSNITI, equipped with an independent hydraulic station and load hydraulic cylinder, at which bench tests were carried out in the operation of С series hydraulic cylinders to determine overall efficiency values. Results. Results of bench and micrometer tests of the former hydraulic cylinders of the С series (С75/30, С90/30, С100/40) are presented. The regression model of the relationship between total efficiency of C series hydraulic cylinders (С75/30, С90/30, С100/40) and wear of working surfaces of parts was obtained. According to this regression model obtained using the method of steep ascent, limit values of wear of the working surfaces of C series hydraulic cylinder parts (С75/30, С90/30, С100/40) were determined. Discussion and Conclusion.19,5 % of hydraulic cylinders of С series (С75/30, С90/30, С100/40) were operated in an out-of-limit condition. In case of technical service companies carrying out the input control of to-be-repaired hydraulic cylinders, limit values of wear for hydraulic cylinder surfaces, determined by the method of steep ascent, allow for making proper decisions on the need of their restoration.

scholarly journals Analysis of Diagnostic Methods and Energy of Production Systems Drives

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 843
Author(s):  
Ivan Kuric ◽  
Ivana Klačková ◽  
Yury Rafailovich Nikitin ◽  
Ivan Zajačko ◽  
Miroslav Císar ◽  
...  
Keyword(s):  
Fuzzy Inference ◽  
Diagnostic System ◽  
Sensory Systems ◽  
Technical Condition ◽  
Repair Time ◽  
Diagnostic Methods ◽  
Technical Diagnostics ◽  
Inference System ◽  
Diagnostic Parameters ◽  
Industrial Enterprises

This article deals with solving the urgent scientific problem of the diagnostics of drives of technological robotized workplaces with support of sensors. The dependence of diagnostic parameters on the technical state of drives of automated technological systems, which is of great economic importance for industrial enterprises, is being investigated. Diagnostic models have been developed based on sensory systems to diagnose drive models of technological robotized workplaces. The use of these models may also include monitoring systems in which it is possible to build a system for identifying detected changes. These systems identify many contradictory changes and thereby reduce the false alarm frequency of monitoring sensory systems. Numerous methods for solving technical diagnostics problems are often based on methods based on mathematical models describing work processes, as well as on spectral analysis of measured parameters, such as vibrations, noise, and electric current. A fuzzy inference system for assessing the technical condition, a system for estimating the residual resource of drives, and asystem for calculating diagnostic intervals based on fuzzy knowledge have been developed. Based on the historical trend of the diagnostic parameters, the intelligent diagnostic system determines the current technical condition of the actuator and predicts future technical condition changes, determines the remaining service life and the time intervals for diagnostics. The analysis of the time spent on planned preventive maintenance of technological equipment makes it possible to conclude that, after the modernization of equipment in 2018, the repair time was reduced from 350 h to 260 h per year (26%). Since 2019, there is a tendency to increase repair time by 30 h each year.

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 Electro-Hydraulic Drive of the Variable Ratio Lifting Device under Active Load

2021 ◽  
pp. 599-610
Author(s):  
Andrzej Kosucki ◽  
Łukasz Stawiński ◽  
Adrian Morawiec ◽  
Jarosław Goszczak
Keyword(s):  
Asynchronous Motor ◽  
Experimental Studies ◽  
Hydraulic Drive ◽  
Hydraulic Cylinder ◽  
Open Loop ◽  
Control Mode ◽  
Gear Pump ◽  
Hydraulic Systems ◽  
Energy Recuperation ◽  
Hydraulic Cylinders

Hydraulic systems fed by fixed displacement pumps driven by frequency-controlled electric motors can replace conventional throttling systems due to their ability to control the speed of hydraulic cylinders regardless of the value and direction of the load. These systems can improve the energy efficiency of the drive or even provide the possibility of energy recuperation during lowering. This paper presents experimental studies of the new drive system with volumetric control of the speed of the lifted/lowered payload using the example of a scissor lift. The system uses a reversible gear pump driven by an asynchronous motor fed by a frequency inverter operating in field-oriented control mode. Comparative studies of the mapping of the assumed speed of the hydraulic cylinder and platform are presented, as well as studies of the influence of the load change on the speed and positioning of the mechanism driven by the open-loop controlled system.

Multiparametric Diagnostics of Gas Turbine Engines

2014 ◽  
Vol 156 (A2) ◽  
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Technical Condition ◽  
Diagnostic Methods ◽  
Turbine Engines ◽  
Technical Diagnostics ◽  
Suitable Model ◽  
Gas Turbine Engines ◽  
Advantages And Disadvantages ◽  
The Matrix

This article addresses the issue of diagnostics and maintenance of Gas Turbine Engines which are located in high Speed Ferries, Cruisers, Frigates, Corvettes, etc. Assurance of reliable operation can be performed only by using correct diagnostic methods and procedures of monitoring the condition of the devices and by selecting the correct strategy of maintenance. The issue of monitoring the technical condition of Gas Turbine Engines is treated through multiparametric methods of technical diagnostics incorporated into predictive maintenance, which is a part of proactive maintenance. There are methods of vibrodiagnostics, thermography, tribology, borescopy and emissions measurement. Each of these methods has lots of advantages and disadvantages; therefore it is very important to ensure their correct combination for trouble-free operation of those important facilities. Their suitability at work is discussed in the matrix of diagnostic methods application and the PF chart. The output of the work is a proposal of a suitable model of maintenance control which uses multiparametric diagnostic methods for small and big Gas Turbine Engines and optimizes maintenance costs.

Impact Assessment of Dynamic Characteristics on the Hydraulic Driven Machinery Operation

2018 ◽  
pp. 1-12
Author(s):  
A. D. Terenteva
Keyword(s):  
Dynamic Error ◽  
Total Error ◽  
Soil Layer ◽  
Hydraulic Drive ◽  
Hydraulic Cylinder ◽  
Working Mechanism ◽  
Automated Control ◽  
Vertical Coordinate ◽  
Construction Machinery ◽  
The Difference

In civil engineering in Russia, trenching for utilities is currently under digging. To perform such works, it is necessary to use high-precision construction machinery, because inaccurate performance of works can lead to the break down of existing utilities, thereby affecting the residents of nearby houses and demanding the additional works for renewal.The most universal labour saver to perform construction works is hydraulic driven single-bucket excavators, which provide up to 38% of works. Therefore, to improve technical characteristics that affect the accuracy of the work performed is an important task.High requirements for the performance of works are defined by existing construction regulations: an allowable soil layer to remain is at most 0.05 m. To fulfil such requirements, an exact assessment of the working mechanism position and a trench profile is necessary.Examination of a manually operated digging process shows that an operator provides operations untimely, however an automated control system can solve this problem. Dynamic phenomena in the working mechanism have the greatest impact on the accuracy of the works performed.To assess the bucket digging edge position accuracy, a mathematical model of the working mechanism has been created. Based on the cycle scheme of the working process, the excessive displacements of the hydraulic cylinder rods under the load are taken into account. By the end of the cycle, the difference between the specified and obtained positions along the vertical coordinate has been 0.0892 m.A dynamic error of the hydraulic drive system of the working mechanism is considered as a sum of the error due to excessive displacements of the hydraulic cylinder rods and the error due to delay of the hydraulic drive, with the latter being calculated for the average time of delay taking into account the data available in the literature. The total error of the bucket digging edge position of the working mechanism is 0.1176 m, which is 2 times more than the value of 0.05 mConformity of all the links with specification requirements does not guarantee compliance with the required displacement accuracy of the bucket digging edge, and, thus, the soil layer to remain in the base of the trench can exceed the regulated value of 0.05 m.

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