A Symmetric Multichamber Hydraulic Cylinder with Variable Piston Area: An Approach to Compact and Efficient Electrohydrostatic Actuation

2020 ◽  
pp. 1-35
Author(s):  
Harrison Bartlett
Keyword(s):  
Design Methodology ◽  
Hydraulic Cylinder ◽  
Power Losses ◽  
Symmetry Constraint ◽  
Standard Methods ◽  
Motor Torque ◽  
Actuation System ◽  
Constant Area ◽  
Hydraulic Cylinders ◽  
Simulation Results

Abstract This paper presents an approach for designing symmetric (effective cylinder area during extension is the same as that during retraction) multichamber cylinders with discretely variable piston area. The design methodology is presented in a generalizable manner and is demonstrated on an example five chamber cylinder design. A method for finding symmetric multichamber cylinder configurations from a given cylinder topology is presented, and subsequently, a method for discretely varying the effective piston area is developed, subject to a cylinder symmetry constraint. Furthermore, an algorithm is presented to optimally switch the effective cylinder area of an electrohydrostatic actuation system either to minimize the magnitude of motor torque or to minimize resistive power losses in the system. Additionally, a method for optimizing standard (constant area) hydraulic cylinders to minimize motor torque magnitude or resistive power losses is presented. These methods are then demonstrated on an example electrohydrostatic actuation system via simulation. Results indicate that this multichamber cylinder approach with discretely variable piston area may allow for the design of compact and efficient actuators relative to standard methods.

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

scholarly journals Confidence Intervals for the Mixture Transition Distribution (MTD) Model and Other Markovian Models

Symmetry ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 351
Author(s):  
André Berchtold
Keyword(s):  
Markov Chains ◽  
Markov Model ◽  
Em Algorithm ◽  
Hidden Markov Model ◽  
Confidence Intervals ◽  
Hidden Markov ◽  
Simple Calculation ◽  
Standard Methods ◽  
Transition Distribution ◽  
Simulation Results

The Mixture Transition Distribution (MTD) model used for the approximation of high-order Markov chains does not allow a simple calculation of confidence intervals, and computationnally intensive methods based on bootstrap are generally used. We show here how standard methods can be extended to the MTD model as well as other models such as the Hidden Markov Model. Starting from existing methods used for multinomial distributions, we describe how the quantities required for their application can be obtained directly from the data or from one run of the E-step of an EM algorithm. Simulation results indicate that when the MTD model is estimated reliably, the resulting confidence intervals are comparable to those obtained from more demanding methods.

scholarly journals Strategies of traversing obstacles and the simulation for a forestry chassis

2018 ◽  
Vol 15 (3) ◽  
pp. 172988141877390 ◽  
Author(s):  
Yue Zhu ◽  
Jiangming Kan ◽  
Wenbin Li ◽  
Feng Kang
Keyword(s):  
Multibody Dynamics ◽  
Inclination Angle ◽  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Hydraulic Cylinder ◽  
Single Side ◽  
Simulation Results ◽  
Maximum Inclination ◽  
Three Degrees Of Freedom ◽  
Small Inclination

As to the complicated terrain in forest, forestry chassis with an articulated body with three degrees of freedom and installed luffing wheel-legs (FC-3DOF&LW) is a novel chassis that can surmount obstacles. In addition, the rear frame of FC-3DOF&LW is regarded as the platform to carry equipment. Small inclination angle for rear frame contributes to stability and ride comfort. This article describes the strategy of traversing obstacles and simulation for FC-3DOF&LW that drives in forest terrain. First, key structures of FC-3DOF&LW are briefly introduced, which include articulated structure with three degrees of freedom and luffing wheel-leg. Based on the sketch of luffing wheel-leg, the movement range of luffing wheel-leg is obtained by hydraulic cylinder operation. Second, the strategy of crossing obstacles that are simplified three models of terrain is presented, and the simulation for surmounting obstacles is constructed in multibody dynamics software. The simulation results demonstrate that the inclination angle of rear frame is 18° when slope is 30°. A maximum 12° decrease of inclination angle for rear frame can be acquired when luffing wheel-legs are applied. For traversing obstacles with both sides, the maximum inclination angle of rear frame is about 1.2° and is only 3° for traversing obstacles with single side.

Design and optimization of heating, cooling and lightening systems for a residential villa at Saman city, Iran

2019 ◽  
Vol 17 (1) ◽  
pp. 41-52 ◽  
Author(s):  
Javad Riahi Zaniani ◽  
Shahab Taghipour Ghahfarokhi ◽  
Mehdi Jahangiri ◽  
Akbar Alidadi Shamsabadi
Keyword(s):  
Energy Consumption ◽  
Light Intensity ◽  
Design Methodology ◽  
Climatic Conditions ◽  
Content Type ◽  
Design And Optimization ◽  
Simulation Results ◽  
Annual Reduction ◽  
Reduction Of Energy Consumption ◽  
Heating Loads

Purpose This paper, using energy softwares, designed of Iran and optimized a residential villa in Saman city located in Chaharmahal and Bakhtiari Province. Design/methodology/approach Having used the ideas of Climate Consultant software, the basic designing was conducted by Design Builder Software, and the cooling and heating loads and lighting tools and equipment were calculated. Then, the amount of consuming of heating, cooling and lighting load of the building was optimized through insulation of walls and ceiling, using green roof, double glazing UPVC windows, light intensity sensor and variable refrigerant flow (VRF) system. Findings Simulation results for the stated scenarios showed an annual reduction in energy consumption of 21.1, 7.9, 26.41, 27.3 and 72.3 per cent, respectively. Also, by combining all the five scenarios, an optimal state was achieved which, from the results, brought about an annual reduction of 86.9 per cent in the energy consumption. Originality/value The authors hope that the results of the current paper could be helpful for designers and engineers in reduction of energy consumption for designing a building in similar climatic conditions.

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.

Design and vibration analysis of a self-adaptive piston in a novel nanoimprint system

2017 ◽  
Vol 69 (4) ◽  
pp. 591-597
Author(s):  
Chaoran Liu ◽  
Yufeng Su ◽  
Jinzhao Yue ◽  
Junjie Wang ◽  
Weiwei Xia ◽  
...  
Keyword(s):  
Nanoimprint Lithography ◽  
Vibration Analysis ◽  
Design Methodology ◽  
The Self ◽  
Ball Screw ◽  
Piston Rings ◽  
Content Type ◽  
Simulation Results ◽  
The One ◽  
Self Adaptive

Purpose A self-adaptive piston is designed for the compressional gas cushion press nanoimprint lithography system. It avoids the lube pollution and high wear of traditional piston. Design/methodology/approach The self-adaptive piston device consists of symmetrical piston bodies, piston rings and other parts. The two piston bodies are linked by a ball-screw. The locking nut adjusts the distance between two piston bodies to avoid the piston rings from being stuck. The piston rings are placed between two piston bodies. Findings The simulation results based on COMSOL indicate that cylinder vibration caused by self-adaptive piston is 15.9 times smaller than the one caused by a traditional piston. Originality/value The self-adaptive piston is superior to the traditional piston in decreasing cylinder vibration.

An improved circuit for modulator based on nanostructured memristor

Circuit World ◽  
2016 ◽  
Vol 42 (4) ◽  
pp. 178-182 ◽  
Author(s):  
Shao-Fu Wang ◽  
D.Z. Xu
Keyword(s):  
Amplitude Modulation ◽  
Design Methodology ◽  
Content Type ◽  
Amplitude Modulator ◽  
Simulation Results

Purpose This paper aims to propose the modeling of nanostructured memristor, and the circuit of amplitude modulator was designed and analyzed with memristor. The simulation results show that the nanostructured memristor can be utilized to implement the desired amplitude modulated signal. Design/methodology/approach The modeling of nanostructured memristor is proposed in this paper, and the circuit of amplitude modulator was designed and analyzed with memristor, amplifiers and BPF device. For measuring the modulated signal, the emulator circuit of memristor is designed. The simulation results show that the nanostructured memristor can be utilized to implement the desired amplitude modulated signal. Findings The innovations of this work are as follows: the AM modulator circuit using memristor has been proposed, analyzed and simulated. The emulator of memristor is given. Originality/value The innovations of this work are as follows: the AM modulator circuit using memristor has been proposed, analyzed and simulated. The emulator of memristor is given, and the results of this work demonstrate that the nonlinearity of the memristor can be used to generate the desired amplitude modulation free of harmonic sidebands, because of distortion of the modulating signal.

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 %.

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