scholarly journals EXPERIMENTAL STUDY OF THE MOVEMENT CONTROLLABILITY OF A MACHINE-AND-TRACTOR AGGREGATE OF THE MODULAR TYPE

2020 ◽  
Vol 61 (2) ◽  
pp. 9-16 ◽  
Author(s):  
Semjons Ivanovs ◽  
Volodymir Bulgakov ◽  
V. Nadykto ◽  
Ye. Ihnatiev ◽  
S. Smolinskyi ◽  
...  
Keyword(s):  
Experimental Study ◽  
Drag Coefficient ◽  
Horizontal Plane ◽  
Hydraulic Cylinder ◽  
Basic Principles ◽  
Hydraulic Cylinders ◽  
Angle Of Rotation

he paper presents an analysis of the basic principles of formation, the properties and characteristics of a new modular energy tool, consisting of the energy and the technology modules. The purpose of this study is to assess the degree of impact of the throttle in the hydraulic line, connecting the cavity of the hydraulic cylinder, upon the controllability of the modular power tool with a mounted plough during the movement of the ploughing aggregate on the headland. As a result of the conducted tests, it was proved that increasing the controllability of the movement of the aggregate on the basis of a mobile power tool is possible by throttling one of the hydraulic cylinders that limit the mutual reciprocal rotation of the modules in a horizontal plane. Installation of the throttle modular power tool on the limiting hydraulic cylinder with a drag coefficient 1.03×106∙N∙m∙s∙rad–1 allows one to reduce two times the delay in the reaction of the relative bearing of the energy module to a change in the angle of rotation of its driven wheels.

The Lower Extremity Exoskeleton Coordinated Control Method Based on Human Electromechanical Coupling

2012 ◽  
Vol 220-223 ◽  
pp. 1012-1017
Author(s):  
Qing Guo ◽  
Dan Jiang
Keyword(s):  
Lower Extremity ◽  
Electromechanical Coupling ◽  
Position Control ◽  
Control Method ◽  
Angular Displacement ◽  
Stability Margin ◽  
Hydraulic Cylinder ◽  
Load Force ◽  
Hydraulic Cylinders ◽  
Coupling Characteristics

This paper has introduced electromechanical coupling characteristics in the lower extremity exoskeleton systems, considered model ,according to legs supporting gait when people walking, established the load torque compensation model , and a mathematical model of knee position control system which is made of the servo valve, hydraulic cylinders and other hydraulic components, designed hydraulic cylinder position control loop in case of existing load force interference compensation, and used the method of combining the PID and lead correction network for frequency domain design ,ensured system to meet a certain stability margin. The simulation results show that this position control method can servo on the knee angular displacement of normal human walking, reached a certain exoskeleton boost effect, at the same time, met the needs of human-machine coordinated motion.

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

Three Dimensional Seismic Isolation System Using Hydraulic Cylinder

2002 ◽  
Author(s):  
Shinichiro Kajii ◽  
Naoki Sawa ◽  
Nobuhiro Kunitake ◽  
K. Umeki
Keyword(s):  
Seismic Isolation ◽  
Three Dimensional ◽  
Vertical Direction ◽  
Hydraulic Cylinder ◽  
Seismic Load ◽  
3D Seismic ◽  
Isolation System ◽  
Response Characteristics ◽  
Seismic Motion ◽  
Hydraulic Cylinders

A three-dimensional (3D) seismic isolation system for FBR building is under development. The proposed vertical isolation system consists form hydraulic cylinders with water-based liquid and accumulators to support large vertical static load and to realize low natural frequency in the vertical direction. For horizontal isolation, laminated rubber isolator or sliding type isolator will be combined. Because the major part of the feasibility of this isolation system depends on the sealing function and durability of the hydraulic cylinder, a series of feasibility tests of the hydraulic cylinder have been conducted to verify the reliability against seismic load and seismic motion. This paper describes the specification of the seismic isolations system, seismic response characteristics and the results of the feasibility tests of the seal. This study was performed as part of a government sponsored R&D project on 3D seismic isolation.

scholarly journals Experimental Study of High Wind Sea Surface Drag Coefficient

2015 ◽  
Author(s):  
I.A. Repina ◽  
A.Yu. Artamonov ◽  
M.I. Varentsov ◽  
A.V. Kozyrev ◽  
◽  
...  
Keyword(s):  
Experimental Study ◽  
Drag Coefficient ◽  
Sea Surface ◽  
High Wind ◽  
Surface Drag ◽  
Wind Sea

scholarly journals Some Aspects Concerning The Impact Of The End Of Stroke On Hydraulic Cylinders

2015 ◽  
Vol 21 (3) ◽  
pp. 821-824
Author(s):  
Niculai Hauk
Keyword(s):  
Numerical Simulation ◽  
Mechanical Systems ◽  
Hydraulic Cylinder ◽  
Important Variable ◽  
Mechanical Impact ◽  
Hydraulic Cylinders ◽  
The Masses ◽  
The Impact ◽  
Simulation Systems ◽  
Classical Calculation

Abstract The increase of speeds for mechanical systems operated with hydraulic cylinder raises risks of mechanical impact of the end of the race. We are considering a number of measures to limit the impact intensity. Its size is estimated according to the masses in motion, to work pressures and to the geometry of the mechanism. Elasticity of the components is also an important variable. This paper presents a method which combines the classical calculation with numerical simulation systems.

scholarly journals Modeling Study on Stiffness Characteristics of Hydraulic Cylinder under Multi-Factors

2017 ◽  
Vol 63 (7-8) ◽  
pp. 447 ◽  
Author(s):  
Hao Feng ◽  
Qungui Du ◽  
Yuxian Huang ◽  
Yongbin Chi
Keyword(s):  
Mechanical System ◽  
Volume Expansion ◽  
Hydraulic Cylinder ◽  
Experimental Results ◽  
Axial Deformation ◽  
Response Characteristics ◽  
Stiffness Model ◽  
Hydraulic Cylinders ◽  
Stiffness Characteristics ◽  
Cylinder Barrel

For a complex mechanical system driven by hydraulic cylinders, the dynamic response characteristics of the mechanical system are significantly affected by the stiffness characteristics of hydraulic cylinders. This paper comprehensively studies the impacts of various factors on the stiffness characteristics of the hydraulic cylinders, including the oil bulk modulus, the air content in the hydraulic oil, the axial deformation of the piston rod, the volume expansion of the cylinder barrel, the volume expansion of the metal pipes and the flexible hoses, and the deformation of the hydraulic cylinder sealing. By combining the theoretical analysis and the experimental results, the level of each impacting factor was quantified, and the stiffness model of the hydraulic cylinder was established. Finally, comparative analysis of the stiffness was conducted by taking the experimental hydraulic cylinder as an example; it was verified that the calculated results of the proposed hydraulic cylinder stiffness model approximated the experimental results. Compared with stiffness models presented in current literature, the average accuracy was improved by more than 15 %.

Rigidity of telescopic boom equipment

2021 ◽  
Keyword(s):  
Horizontal Plane ◽  
Flexural Rigidity ◽  
Hydraulic Cylinder ◽  
Analytical Models ◽  
Dynamic Coefficient ◽  
Stiffness Coefficient ◽  
Uneven Wear

As a result of the study, analytical models of the rigidity of the telescopic boom equipment in the vertical and horizontal planes were developed, which take into account: the influence of uneven intersectional vertical and horizontal gaps, the flexibility of the sliding supports, the flexural rigidity of the sections, the rigidity of the telescoping hydraulic cylinder and the lifting hydraulic cylinder. The dynamic coefficient is determined, taking into account the presence of intersectional gaps, with unsteady movement in the vertical and horizontal plane. The influence of intersectional gaps on the coefficient of dynamism and rigidity of the boom equipment taking into account the uneven wear of the sliding supports is established. Keywords telescopic boom, railway crane, stiffness coefficient, dynamic coefficient

scholarly journals A Self-Contained Electro-Hydraulic Cylinder with Passive Load-Holding Capability

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 292 ◽  
Author(s):  
Damiano Padovani ◽  
Søren Ketelsen ◽  
Daniel Hagen ◽  
Lasse Schmidt
Keyword(s):  
Energy Efficiency ◽  
Cost Efficiency ◽  
Tracking Error ◽  
Hydraulic Cylinder ◽  
Position Tracking ◽  
Hydraulic Systems ◽  
Practical Applications ◽  
Hydraulic Cylinders ◽  
External Loads ◽  
Boom Crane

Self-contained electro-hydraulic cylinders have the potential to replace both conventional hydraulic systems and the electro-mechanical counterparts enhancing energy efficiency, plug-and-play installation, and reduced maintenance. Current commercial solutions of this technology are limited and typically tailor-made, whereas the research emphasis is primarily on cost efficiency and power applications below five [kW]. Therefore, there is the need of developing more flexible systems adaptable to multiple applications. This research paper offers a contribution in this regard. It presents an electro-hydraulic self-contained single-rod cylinder with passive load-holding capability, sealed tank, capable of recovering energy, and scalable up to about eighty [kW]. The system implementation on a single-boom crane confirms its feasibility: The position tracking error remains well within ±2 [mm], oscillations are limited, and the overall energy efficiency is about 60 [%] during actuation. Concerning the passive load-holding devices, it is shown that both vented and non-vented pilot-operated check valves achieve the desired functioning and can hold the actuator position without consuming energy. Additional observations about the size and the arrangement of the load-holding valves are also provided. In conclusion, this paper demonstrates that the proposed self-contained cylinder can be successfully extended to several practical applications, especially to those characterized by overrunning external loads and the need of securing the actuator position.

Internal leakage identification of hydraulic cylinder based on intrinsic mode functions with random forest

2019 ◽  
Vol 233 (15) ◽  
pp. 5532-5544 ◽  
Author(s):  
Lin Li ◽  
Yixiang Huang ◽  
Jianfeng Tao ◽  
Chengliang Liu
Keyword(s):  
Random Forest ◽  
Hydraulic Cylinder ◽  
Support Vector ◽  
Hydraulic Systems ◽  
Intrinsic Mode Functions ◽  
Random Forest Algorithm ◽  
Mode Decomposition ◽  
Empirical Mode Decomposition Method ◽  
Hydraulic Cylinders ◽  
Experimental Pressure

Monitoring for internal leakage of hydraulic cylinders is vital to maintain the efficiency and safety of hydraulic systems. An intelligent classifier is proposed to automatically evaluate internal leakage levels based on the newly extracted features and random forest algorithm. The inlet and outlet pressures as well as the pressure differences of two chambers are chosen as the monitoring parameters for leakage identification. The empirical mode decomposition method is used to decompose the raw pressure signals into a series of intrinsic mode functions to obtain the essence in experimental signals. Then, the features extracted from intrinsic mode functions in terms of statistical analysis are formed the input vector to train the leakage detector. The classifier based on random forest is established to categorize internal leakage into proper levels. The accuracy of the internal leakage evaluator is verified by the experimental pressure signals. Moreover, an internal leakage evaluator is established based on the support vector machine algorithm, in which the wavelet transform is applied for feature extraction. The accuracy and efficiency of different classifiers are compared based on leakage experiments. The results show that the classifier trained by the intrinsic mode function features in terms of random forest algorithm may more effectively and accurately identify internal leakage levels of hydraulic cylinders. The leakage evaluator provides probability for online monitoring of the internal leakage of hydraulic cylinders based on the inherent sensors.

Diagnosis Method for Valve-Controlled Hydraulic Cylinder Leakage Based on Subspace Identification

2018 ◽  
Author(s):  
Junxia Guo ◽  
Jianfeng Tao ◽  
Lin Li ◽  
Chengliang Liu
Keyword(s):  
State Space Model ◽  
Hydraulic Cylinder ◽  
High Accuracy ◽  
Subspace Identification ◽  
State Variables ◽  
System Matrix ◽  
Space Model ◽  
Hydraulic Cylinders ◽  
Diagnosis Method ◽  
Identification Theory

This paper proposes a fault diagnosis method based on subspace identification for the leakage fault detection of valve-controlled hydraulic cylinders. Firstly, the state-space model for the system is established, in which the external force on the piston of the hydraulic cylinder is selected as input signal, and the pressure of the two chambers, displacement and velocity of piston rod are chosen as state variables. Then, the estimation value of specific elements of the system matrix can be obtained in terms of the subspace identification theory. On this basis, the existence, type and level of the leakage fault are determined. Finally, the numerical simulation is conducted through MATLAB-Simulink to verify the proposed method. The results demonstrate that the proposed method is effective and has high accuracy.

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