scholarly journals Compensator Designed for Electro-Hydraulic Servo System in Laminar State

Mechanika ◽  
2021 ◽  
Vol 27 (2) ◽  
pp. 107-114
Author(s):  
Le Zeng ◽  
Jun Yang ◽  
Jianping Tan
Keyword(s):  
Hydraulic System ◽  
Flow Characteristics ◽  
Flow Equation ◽  
The Novel ◽  
Flow State ◽  
Control Performance ◽  
Feed Forward Control ◽  
Orifice Flow ◽  
Hydraulic Servo ◽  
Laminar State

The study researched the orifice flow equation when the flow state of the orifice is laminar. Based on the novel flow equation and the expected linear flow equation, a compensator is designed to compensate the non-linearity and make the flow characteristics linear. The characteris-tics experiment result shows that the flow after compensa-tion control is close to the expected flow, in which the pres-sure difference was increased from 0.5MPa to 4MPa, and the error is less than 20%. When the compensator is used as feed forward control in the EHSS and compound with proportional (P) control, the sinusoidal response error with frequency of 0.5Hz and amplitude of 5mm is within 0.4mm under large external load. While the error of the uncompensated system is up to 0.8mm. The compensator can be used into the electro-hydraulic system with larger load disturbance and improve the control performance compounded with the simplest proportional (P) controller.

Performance Improvement of Electro-Hydraulic Servo Valve Using a Feed-Forward Control and an Input Shaping Filter

2019 ◽  
Author(s):  
Illyeong Lee ◽  
Istanto Iwan ◽  
Saeryung Choi ◽  
Junyoung Huh
Keyword(s):  
Control System ◽  
Displacement Sensor ◽  
Input Shaping ◽  
Hydraulic Control ◽  
Control Performance ◽  
Hydraulic Systems ◽  
Servo Valve ◽  
Shaping Filter ◽  
Feed Forward Control ◽  
Hydraulic Servo

Abstract The control performance of hydraulic systems is basically influenced by the performance of electro-hydraulic servo valve used in a hydraulic control system. In this study, the authors propose a control design to improve the control performance of servo valves with a non-contact eddy current type displacement sensor. Mathematical model for the valve is obtained through an experimental identification process. A PI-D controller together with a feedforward (FF) controller is applied to the valve. To further improve the response of the servo valve, an input shaping filter (ISF) is incorporated into the valve control system. Finally, the effectiveness of the proposed control system is verified experimentally.

Research on the Impact Pressure of the Hydraulic Rolling-Cut Shear

2010 ◽  
Vol 145 ◽  
pp. 410-413 ◽  
Author(s):  
Jing Wang ◽  
He Yong Han ◽  
Qing Xue Huang ◽  
Jun Wang
Keyword(s):  
Hydraulic System ◽  
Impact Pressure ◽  
Direct Impact ◽  
Actual Situation ◽  
Work Situation ◽  
Servo Valve ◽  
Indirect Impact ◽  
Hydraulic Servo ◽  
Hydraulic Servo System ◽  
The Impact

The reasons for impact pressure are obtained by the research the hydraulic system of Hydraulic Rolling-Cut Shear. The impact pressure of hydraulic system is divided into direct impact and indirect impact. Based on analyzing the actual situation the measures should be taken to reduce the impact pressure when design hydraulic system. The suitable length of pipeline can improve the performance of the hydraulic system because the length is important for the impact pressure. The accumulator can absorb impact pressure and improve the work situation of servo valve. Therefore, the suitable accumulators should be set in the hydraulic system. The study provides theory basis for the pipe design of large hydraulic servo system.

Application of Load Sensing Technology in New Type of Steel Arch Installing Machine

2013 ◽  
Vol 655-657 ◽  
pp. 1456-1459
Author(s):  
Li Ping Xu ◽  
Chen Fei Zhan ◽  
De Zhi Ren
Keyword(s):  
Energy Efficient ◽  
Hydraulic System ◽  
Control Performance ◽  
Multiple Fault ◽  
Type Steel ◽  
Load Sensing ◽  
Sensing Technology ◽  
New Type ◽  
Actuator Control

Because ordinary hydraulic system exists multiple fault, power waste and hard controlling in actuators due to the complexity of actuators and variability of load. A new hydraulic system based on the load sensing technology is designed for the new type steel arch installing machine. The results of the simulation for forearm loop based on AMESim show that the designed hydraulic system is energy-efficient and load sensing function is effectively achieved, the actuator control performance is well.

scholarly journals Flow characteristics of fractal fracture with different fractal dimension and different fracture width

2021 ◽  
Vol 25 (6 Part B) ◽  
pp. 4477-4484
Author(s):  
Jun-Jun Liu ◽  
Jing Xie ◽  
Yi-Ting Liu ◽  
Gui-Kang Liu ◽  
Rui-Feng Tang ◽  
...  
Keyword(s):  
Fractal Dimension ◽  
Rock Mass ◽  
Flow Characteristics ◽  
Fracture Network ◽  
Basic Element ◽  
Single Fracture ◽  
Flow State ◽  
Complex Flow ◽  
Fracture Width ◽  
Fracture Models

Single fracture is the most basic element in complex fracture network of rock mass. Therefore, the study of flow characteristics of single fracture is an important way to reasonably predict the complex flow state in engineering rock mass. In order to study the flow characteristics of fractal single fracture, fracture models with dif?ferent fractal dimension and different fracture width are established in this paper. The results show that: the blocking effect of rough structure on fluid is obviously enhanced under high pressure. In addition, it is weakened and reaches a steady-state with the increase of fracture fractal dimension. The larger the fracture width is, the more obvious the phenomenon is. The hydraulic gradient index tends to 0.5 with the increase of fracture width when fractal dimension is greater than 1.3. It also could tend to 0.5 with the increase of fractal dimension when fracture width is greater than 1 mm.

scholarly journals Study on the Dynamic Characteristics of a Hydraulic Continuous Variable Compression Ratio System

2019 ◽  
Vol 9 (21) ◽  
pp. 4484 ◽  
Author(s):  
Chen ◽  
Wang ◽  
Liu ◽  
Yang
Keyword(s):  
Dynamic Characteristics ◽  
Compression Ratio ◽  
Hydraulic System ◽  
Flow Characteristics ◽  
Engine Performance ◽  
Fast Response ◽  
Continuous Variable ◽  
Variable Compression Ratio ◽  
Bottom Dead Center ◽  
Variable Compression

Variable compression ratio (VCR) technology has long been recognized as a method for improving the engine performance, efficiency, and fuel economy of automobiles, with reduced emissions. In this paper, a novel hydraulic continuous VCR system based on the principle of an adjustable hydraulic volume is introduced. The continuous variable compression ratio of the VCR system is realized by the hydraulic system controlling the rotation of the eccentric pin to change the positions of the top dead center (TDC) and the bottom dead center (BDC). The construction of the mathematical model and simulation model of the VCR system is also presented in this paper. The piston motion characteristics, flow characteristics, and pressure characteristics of the hydraulic system of the VCR system at different engine speeds and adjustment quantities are studied by simulation in this paper. The simulation results show that the VCR system has a fast response and good dynamic characteristics, and can achieve continuous adjustment of the compression ratio.

Enhancement of heat transfer in a square channel by roughened surfaces in rib-elements and turbulent flow manipulation

2017 ◽  
Vol 27 (7) ◽  
pp. 1571-1595 ◽  
Author(s):  
Jian Liu ◽  
Gongnan Xie ◽  
Bengt Ake Sunden ◽  
Lei Wang ◽  
Martin Andersson
Keyword(s):  
Heat Transfer ◽  
Turbulent Flow ◽  
Research Work ◽  
Flow Characteristics ◽  
High Heat ◽  
The Novel ◽  
Content Type ◽  
Flat Surfaces ◽  
Square Channel ◽  
High Heat Transfer

Purpose The purpose of this paper is to augment heat transfer rates of traditional rib-elements with minimal pressure drop penalties. Design/methodology/approach The novel geometries in the present research are conventional cylindrical ribs with rounded transitions to the adjacent flat surfaces and with modifications at their bases. All turbulent fluid flow and heat transfer results are presented using computation fluid dynamics with a validated v2f turbulence closure model. Turbulent flow characteristics and heat transfer performances in square channels with improved ribbed structures are numerically analyzed in this research work. Findings Based on the results, it is found that rounded transition cylindrical ribs have a large advantage over the conventional ribs in both enhancing heat transfer and reducing pressure loss penalty. In addition, cylindrical ribs increase the flow impingement at the upstream of the ribs, which will effectively increase the high heat transfer areas. The design of rounded transition cylindrical ribs and grooves will be an effective way to improve heat transfer enhancement and overall thermal performance of internal channels within blade cooling. Originality/value The novel geometries in this research are conventional cylindrical ribs with rounded transitions to the adjacent flat surfaces and with modifications at their bases. The combination of cylindrical ribs and grooves to manipulate the turbulent flow.

Research of Velocity Stability of Separate Meter in and Separate Meter out Control System for Over-Running Load

2015 ◽  
Vol 727-728 ◽  
pp. 752-756
Author(s):  
Zhong Yi Cao ◽  
Xin Ming Liu ◽  
Wan Rong Wu
Keyword(s):  
Control System ◽  
Simulation Model ◽  
Hydraulic System ◽  
The Novel ◽  
Velocity Control ◽  
Factors Affecting ◽  
Simulation And Experiment ◽  
The Stability

There are some defects in the traditional over-running load hydraulic system, such as velocity control is poor and prone to velocity jitter, etc. In order to improve these weaknesses, the components and work principle of the separate meter in and separate meter out (SMISMO) were introduced and the actuator’s feature were analyzed , the simulation model of hydraulic studied system was built, the factors affecting the stability of the system are discussed in this paper. Simulation and experiment showed that the novel control system possessed higher velocity control precise and good stable characteristics.

Load-Force-Adaptive Outlet Throttling: An Easily Commissionable Independent Metering Control Strategy

2016 ◽  
Author(s):  
Jan Lübbert ◽  
André Sitte ◽  
Benjamin Beck ◽  
Jürgen Weber
Keyword(s):  
Hydraulic System ◽  
Control Algorithm ◽  
Systematic Approach ◽  
Load Force ◽  
Chamber Pressure ◽  
The Novel ◽  
Test Rig ◽  
Mechanical Pressure ◽  
And Control ◽  
Inlet Chamber

This paper deals with a novel independent metering valve system which is intended to be used in medium sized mobile machines. The system uses a mechanical pressure compensator to enable a very simple SISO control algorithm which does not need any feedback parameters to be adjusted. The algorithm is capable of handling resistive and pulling loads at a certain desired velocity and inlet chamber pressure level. The paper gives a brief summary of the systematic approach to deriving the valves structure and compares different control approaches for the complete hydraulic system comprising several actuators. Special emphasis is given to the preferred solution, which is verified on a laboratory test rig consisting of reasonably priced mobile machine components. Furthermore a linear model of system and control structure is constructed to give detailed information regarding the dynamic characteristics of the controlled drive. The energetic benefits of the novel system architecture in comparison to a standard coupled metering flow sharing system are investigated by means of a levelling movement performed on the test rig and a simulated synthetic high power digging cycle.

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