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New Method to Improve Dynamic Stiffness of Electro-hydraulic Servo Systems

Chinese Journal of Mechanical Engineering 2013年第5期26卷 997-1005页

作者： BAI Yanhong quan long Key Laboratory of Advanced Transducers and Intelligent Control System of Ministry of Education Taiyuan University of Technology School of Electronics Information Engineering Taiyuan University of Science and Technology

Most current researches working on improving stiffness focus on the application of control *** controller in closed-loop hydraulic control system takes effect only after the controlled position is deviated,so the control action is *** dynamic performance against force disturbance and dynamic load stiffness can’t be improved evidently by advanced control *** this paper,the elementary principle of maintaining piston position unchanged under sudden external force load change by charging additional oil is *** this basis,the conception of raising dynamic stiffness of electro hydraulic position servo system by flow feedforward compensation is put *** a scheme using double servo valves to realize flow feedforward compensation is presented,in which another fast response servo valve is added to the regular electro hydraulic servo system and specially utilized to compensate the compressed oil volume caused by load impact in *** two valves are arranged in parallel to control the cylinder ***,the model of flow compensation is derived,by which the product of the amplitude and width of the valve’s pulse command signal can be *** determination rules of the amplitude and width of pulse signal are concluded by analysis and *** the proposed scheme,simulations and experiments at different positions with different force changes are *** simulation and experimental results show that the system dynamic performance against load force impact is largely improved with decreased maximal dynamic position deviation and shortened settling *** is,system dynamic load stiffness is evidently *** paper proposes a new method which can effectively improve the dynamic stiffness of electro-hydraulic servo systems.

关键词： electro-hydraulic servo system flow feedforward compensation dynamic load stiffness double-valve actuation

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Mathematical Model of Hydrodynamic Torque Converter and Analytic Description of Streamline

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Chinese Journal of Mechanical Engineering 2009年第1期22卷 70-77页

作者： LIU Shiping quan long Institute of Mechatronics Engineering Taiyuan University of Technology Taiyuan 030024 China

The mathematical model of a 3-element centripetal-turbine hydrodynamic torque converter and analytic description of fluid flow inside the hydrodynamic torque converter are investigated. A new torus coordinate system is proposed so as to quantitatively describe fluid movement inside the hydrodynamic torque converter. The particle movement inside the hydrodynamic torque converter is decomposed into meridional component movement and torus component movement, and a universal meridional streamline equation is derived. According to the relationship between the converter wheel velocity polygon and its blade angle, a torus streamline differential equation is established. The universal meridional streamline equation is approximated with square polynomials. The approximation error curve is given and the percentage error is not greater than 0.86%. Considered as a function of polar angle, the blade angle cotangent of each converter wheel varies linearly with polar angle. By using integral calculus, torus streamline equations are obtained. As a result, the problem of difficult flow description of the hydrodynamic torque converter is solved and a new analytic research system is established.

关键词： hydrodynamic torque converter toms coordinate system analytic description meridional streamline equation toms streamline equation

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Cavitation of a Submerged Jet at the Spherical Valve Plate/Cylinder Block Interface for Axial Piston Pump

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Chinese Journal of Mechanical Engineering 2020年第5期33卷 197-211页

作者： Bin Zhao Weiwei Guo long quan College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan 030024China Transducers and Intelligent Control System of Ministry of Education and Shanxi Province Taiyuan University of TechnologyTaiyuan 030024China The State Key Laboratory of Fluid Power&Mechatronic Systems Zhejiang UniversityHangzhou 310027China

The spherical valve plate/cylinder block pair has the advantages of strong overturning resistance and large bearing ***,the configurations of the unloading and pre-boosting triangular grooves on the spherical valve plate are different from those in the planar valve plate,resulting in special cavitation phenomenon on the spherical port plate *** order to study cavitation characteristics of spherical port plate pair,a dynamic CFD model of the piston pump including turbulence model,cavitation model and fluid compressibility is established.A detailed UDF compilation scheme is provided for modelling of the micron-sized spherical oil film mesh,which makes up for the lack of research on the meshing of the spherical oil *** this paper,using CFD simulation tools,from the perspectives of pressure field,velocity field and gas volume fraction change,a detailed analysis of the transient evolution of the submerged cavitation jet in a axial piston pump with spherical valve plate is carried *** study indicates the movement direction of the cavitation cloud cluster through the cloud image and the velocity vector direction of the observation *** sharp decrease of velocity and gas volume fraction indicates the collapse phenomenon of bubbles on the part wall *** discoveries verify the special erosion effect in case of the spherical valve plate/cylinder block *** submerged cavitation jet generated by the unloading triangular grooves distributed on the spherical valve plate not only cause denudation of the inner wall surface of the valve plate,but also cause strong impact and denudation on the lower surface of the cylinder ***,the direction of the unloading triangular groove was modified to extend the distance between it and the wall surface which can effectively alleviate the erosion effect.

关键词： Cavitation submerged jet Spherical valve plate/cylinder block pair Axial piston pump

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Detecting the Position of the Moving-iron Solenoid by Non-displacement Sensor Based on Parameter Identification of Flux Linkage Characteristics

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Chinese Journal of Mechanical Engineering 2013年第6期26卷 1204-1211页

作者： WANG Xuping quan long XIONG Guangyu Key Laboratory of Advanced Transducers and Intelligent Control System of Ministry of Education Taiyuan University of Technology

Currently, most researches use signals, such as the coil current or voltage of solenoid, to identify parameters; typically, parameter identification method based on variation rate of coil current is applied for position estimation. The problem exists in these researches that the detected signals are prone to interference and difficult to obtain. This paper proposes a new method for detecting the core position by using flux characteristic quantity, which adds a new group of secondary winding to the coil of the ordinary switching electromagnet. On the basis of electromagnetic coupling theory analysis and simulation research of the magnetic field regarding the primary and secondary winding coils, and in accordance with the fact that under PWM control mode varying core position and operating current of windings produce different characteristic of flux increment of the secondary winding. The flux increment of the electromagnet winding can be obtained by conducting time domain integration for the induced voltage signal of the extracted secondary winding, and the core position from the two-dimensional fitting curve of the operating winding current and flux-linkage characteristic quantity of solenoid are calculated. The detecting and testing system of solenoid core position is developed based on the theoretical research. The testing results show that the flux characteristic quantity of switching electromagnet magnetic circuit is able to effectively show the core position and thus to accomplish the non-displacement transducer detection of the said core position of the switching electromagnet. This paper proposes a new method for detecting the core position by using flux characteristic quantity, which provides a new theory and method for switch solenoid to control the proportional valve.

关键词： switch solenoid flux characteristic quantity position detection non-displacement sensor

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Excavator Energy-saving Efficiency Based on Diesel Engine Cylinder Deactivation Technology

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Chinese Journal of Mechanical Engineering 2012年第5期25卷 897-904页

作者： YANG Jing quan long YANG Yang Key Laboratory of Advanced Transducers and Intelligent Control System of Ministry of Education Taiyuan University of Technology Taiyuan 030024 China The State Key Lab of Fluid Power Transmission and Control Zhejiang University Hangzhou 31002 7 China

The hydraulic excavator energy-saving research mainly embodies the following three measures： to improve the performance of diesel engine and hydraulic component, to improve the hydraulic system, and to improve the power matching of diesel-hydraulic system-actuator. Although the above measures have certain energy-saving effect, but because the hydraulic excavator load changes frequently and fluctuates dramatically, so the diesel engine often works in high-speed and light load condition, and the fuel consumption is higher. Therefore, in order to improve the economy of diesel engine in light load, and reduce the fuel consumption of hydraulic excavator, energy management concept is proposed based on diesel engine cylinder deactivation technology. By comparing the universal characteristic under diesel normal and deactivated cylinder condition, the mechanism that fuel consumption can be reduced significantly by adopting cylinder deactivation technology under part of loads condition can be clarified. The simulation models for hydraulic system and diesel engine are established by using AMESim software, and fuel combustion consumption by using cylinder-deactivation-technology is studied through digital simulation approach. In this way, the zone of cylinder deactivation is specified. The testing system for the excavator with this technology is set up based on simulated results, and the results show that the diesel engine can still work at high efficiency with part of loads after adopting this technology; fuel consumption is dropped down to 11% and 13% under economic and heavy-load mode respectively under the condition of driving requirements. The research provides references to the energy-saving study of the hydraulic excavators.

关键词： diesel engine cylinder deactivation hydraulic excavator energy-saving

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A robust three-stage approach to large-scale urban scene recognition

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Science China(Information Sciences) 2017年第10期60卷 239-251页

作者： Jinglu WANG Yonghua LU Jingbo LIU long quan Department of Computer Science and Engineering The Hong Kong University of Science and Technology School of Resource and Environmental Sciences Wuhan University

To obtain the ultimate high-level description of urban scenes, we propose a three-stage approach to recognizing the 3D reconstructed scene with efficient representations. First, we develop a joint semantic labeling method to obtain a semantic labeling of the triangular mesh-based representation by exploiting both image features and geometric features. The labeling is formulated over a conditional random field(CRF) that incorporates local spacial smoothness and multi-view consistency. Then, based on the labeled reconstructed meshes, we refine the man-made object segmentation in the recomposed global orthographic map with a graph partition algorithm, and propagate the coherent segmentation to the entire 3D meshes. Finally, we propose to generate a compact, abstracted geometric representation for each man-made object which is more visually appealing than the original cluttered models. This abstraction algorithm also leverages CRF formation to partition building footprints into minimal sets of structural linear features which are then used to construct profiles for large-scale scenes. The proposed recognition approach is able to robustly handle reconstructions with poor geometry and connectivity, thanks to the higher order CRF formulations which impose the ubiquitous regularity priors in urban scenes. Each stage performs an individual and uncoupling task. The intensive experiments have demonstrated the superior performance of our approach in robustness, accuracy and applicability.

关键词： 3D reconstruction urban scene recongition semantic segmentation CRF

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IMPROVE THE KINETIC PERFORMANCE OF THE PUMP CONTROLLED CLAMPING UNIT IN PLASTIC INJECTION MOLDING MACHINE WITH ADAPTIVE CONTROL STRATEGY

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Chinese Journal of Mechanical Engineering 2006年第1期19卷 9-13页

作者： quan long LIU Shiping Institute of Mechatronics Engineering Taiyuan University of Technology Taiyuan 030024 China Department of Mechanical Engineering North China Institute of Water Conservation and Hydroelectric Power Zhengzhou 450008 China

The kinetic characteristics of the clamping unit of plastic injection molding machine that is controlled by close loop with newly developed double speed variable pump unit are investigated. Considering the wide variation of the cylinder equivalent mass caused by the transmission ratio of clamping unit and the severe instantaneous impact force acted on the cylinder during the mold closing and opening process, an adaptive control principle of parameter and structure is proposed to improve its kinetic performance. The adaptive correlation between the acceleration feedback gain and the variable mass is derived. The pressure differential feedback is introduced to improve the dynamic performance in the case of small inertia and heavy impact load. The adaptation of sum pressure to load is used to reduce the energy loss of the system. The research results are verified by the simulation and experiment, The investigation method and the conclusions are also suitable for the differential cylinder system controlled by the traditional servo pump unit.

关键词： Adaptive control Pump controlled system Clamping unit Plastic injection molding machine

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Interference-induced suppression of particle emission from a Bose-Einstein condensate in lattice with time-periodic modulations

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Chinese Physics B 2024年第10期33卷 153-158页

作者： long-quan Lai Zhao Li School of Science Nanjing University of Posts and TelecommunicationsNanjing 210023China School of Electronic Engineering Chengdu Technological UniversityChengdu 611730China

Emission of matter-wave jets from a parametrically driven condensate has attracted significant experimental and theoretical attention due to the appealing visual effects and potential metrological *** this work,we investigate the collective particle emission from a Bose-Einstein condensate confined in a one-dimensional lattice with periodically modulated interparticle *** give the regimes for discrete modes,and find that the emission can be distinctly *** configuration induces a broad band,but few particles are ejected due to the interference of the matter *** further qualitatively model the emission process and demonstrate the short-time *** engineering provides a way to manipulate the propagation of particles and the corresponding dynamics of condensates in lattices,and may find application in the dynamical excitation control of other nonequilibrium problems with time-periodic driving.

关键词： Bose-Einstein condensate matter-wave jet periodic modulation

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Variational Solution of Coral Reef Stability Due to Horizontal Wave Loading

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Journal of Ocean University of China 2022年第3期21卷 647-655页

作者： ZHANG Qiyi long quan LI Xiaowu Department of Ocean Engineering College of EngineeringOcean University of ChinaQingdao266100China Key Laboratory of Ocean Engineering of Shandong Province Ocean University of ChinaQingdao266100China

This paper proposes a theoretical method that can be used in calculating the stability of coral reefs or artificial *** this work,we employ the variational limiting equilibrium procedure to theoretically determine the slope stability of coral reefs covered with hard reef shells as a result of horizontal wave loads.A reasonable functional is proposed and its extremum is calculated based on the conservation of ***,we deduce the stability factor Ns of coral reefs under combined vertical self-gravity and horizontal wave loads,which is consistent with the published *** compare some classic examples of homogeneous slopes without hard shells in order to analyze the accuracy of results generated by this variational *** variational results are accurate and reliable according to the results of a series of detailed calculations and ***,some other influence parameters on the reef stability,including the top-layer tensile strength of coral reef,the amplitude of wave loading,and the tensile crack,are calculated and discussed in *** analysis results reveal that the existence of a hard reef shell could enhance the stability of reef slope and that there is a nonlinear relationship between the stability factor Ns,the shear strength,and the thickness Ds of the covered coral reef ***,the emergence of top-layer tensile cracks on the coral reefs reduces their stability,and the action of horizontal wave loads greatly decreases the stability of coral ***,the hard shell strength and its thickness Ds,surface tensile crack,and wave loading require more careful attention in the field of practical engineering.

关键词： coral reef stability tensile crack variational solution horizontal wave loading

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Research on Energy Efficiency Characteristics of Mining Shovel Hoisting and Slewing System Driven by Hydraulic-Electric Hybrid System

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Chinese Journal of Mechanical Engineering 2023年第6期36卷 197-211页

作者： Xiangyu Wang Lei Ge Yunhua Li long quan College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan 030024China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

Mining shovel is a crucial piece of equipment for high-efficiency production in open-pit mining and stands as one of the largest energy consumption sources in ***,substantial energy waste occurs during the descent of the hoisting system or the deceleration of the slewing *** reduce the energy loss,an innovative hydrau-lic-electric hybrid drive system is proposed,in which a hydraulic pump/motor connected with an accumulator is added to assist the electric motor to drive the hoisting system or slewing platform,recycling kinetic and potential *** utilization of the kinetic and potential energy reduces the energy loss and installed power of the min-ing ***,the reliability of the mining shovel pure electric drive system also can be *** this paper,the hydraulic-electric hybrid driving principle is introduced,a small-scale testbed is set up to verify the feasibil-ity of the system,and a co-simulation model of the proposed system is established to clarify the system operation and energy *** test and simulation results show that,by adopting the proposed system,compared with the traditional purely electric driving system,the peak power and energy consumption of the hoisting electric motor are reduced by 36.7%and 29.7%,***,the slewing electric motor experiences a significant decrease in peak power by 86.9%and a reduction in energy consumption by 59.4%.The proposed system expands the application area of the hydraulic electric hybrid drive system and provides a reference for its application in over-sized and super heavy equipment.

关键词： Mining shovel Hoisting and slewing system Hydraulic-electric hybrid drive Energy saving

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