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Theoretical Analysis and Numerical Simulation of the Static and Dynamic Characteristics of Hydrostatic Guides Based on Progressive Mengen Flow controller

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Chinese Journal of Mechanical Engineering 2010年第6期23卷 709-716页

作者： GAO Dianrong ZHENG Dan ZHANG Zuochao Key laboratory of heavy machinery fluid power transmission and control of Hebei Province Yanshan University Qinhuangdao 066004 China

The oil film thickness of oil hydrostatic guide with constant pressure supply based on capillary restrictor is greatly affected by load, and this kind of hydrostatic guide is usually applied to the machine tools with moderate load. The static and dynamic characteristics of the guide have been studied by using some theoretical, numerical and experimental approaches, and some methods and measures have been proposed to improve its performances. The hydrostatic guide based on progressive mengen（PM） flow controller is especially suitable for the heavy numerical control（NC） machine tools. However, few literatures about the research on the static and dynamic characteristics of the hydrostatic guides based on PM flow controller are reported. In this paper, the formulae are derived for analyzing the static and dynamic characteristics of hydrostatic guides with rectangle pockets and PM flow controller according to the theory of hydrostatic bearing. On the basis of the analysis of hydrostatic bearing with circular pocket, some equations are derived for solving the static pressure, volume pressure and squeezing pressure which influence the dynamic characteristics of hydrostatic guides with rectangle pocket. The function and the influencing factors of three pressures are clarified. The formulae of amplitude-frequency characteristics and dynamic stiffness of the hydrostatic guide system are derived. With the help of software MATLAB, programs are coded with C＋＋ language to simulate numerically the static and dynamic characteristics of the hydrostatic guide based on PM flow controller. The simulation results indicate that the sensitive oil volume between the outlet of the PM flow controller and the guide pocket has the greatest influence on the characteristics of the guide, and it should be reduced as small as possible when the field working condition is met. Choosing the oil with a greater viscosity is also helpful in improving the dynamic performance of hydrostatic guides. The re

关键词： PM flow controller rectangle pocket static characteristics dynamic characteristics hydrostatic guides

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Oil Pocket's Bearing Capacity Analysis of Liquid Hydrostatic Worktable in Gantry Moving Milling Center

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Chinese Journal of Mechanical Engineering 2014年第5期27卷 1008-1017页

作者： ZHAO Jianhua LIANG Yingna GAO Dianrong Hebei Provincial Key laboratory of heavy machinery fluid power transmission and control Yanshan University Liren College Yanshan University

Durning the design process of hydrostatic rotary worktable,the processing and assembly tolerance,（the offset of worktable and the gap of the oil film’s thickness）is *** it will cause that the real bearing of oil pocket deviates from the initial design value,and then the performance of rotary worktable will be reduced *** to now,no effort is found toward the research of influence of the processing and assembly tolerance on the performance of the rotary *** the hydrostatic oil film is assumed as the elastomer in this paper,and then the bearing capacity of the oil pocket is studied with and without the mass offset of the worktable by taking an expression between the bearing capacity and the oil film’s thickness of the oil pocket as the deform compatibility *** influence of the processing tolerance of the oil sealing belt’s gap on the bearing capacity of the oil pocket is *** the light of the liquid hydrostatic worktable of Gantry Moving Milling Center using on the scene,the oil pocket’s pressure of the worktable is tested using Rotary Worktable Test System under the circumstance of the mass offset of the worktable and the gap tolerance of the oil sealing belt,and then the equivalent offset of worktable,the average pressure of the oil pocket and the actual thickness of the oil film are analyzed *** test results show that the bearing capacity component of the oil pocket caused by G is consistent,and the component caused by M is relative to the position of the oil *** the oil sealing belt’s gap is larger than the theoretical value,the bearing capacity of the oil pocket is smaller than the others;whereas the bearing capacity of the oil pocket is larger than the *** maximum and minimum equivalent offsets are 0.256 4 mm and 0.047 5 mm,respectively,and the average oil pocket pressure varies from 0.345 MPa to 0.460 MPa,the maximum and minimum value of the actual oil film thickness are 109.976？m（No.7 oil

关键词： Gantry Moving Milling Center bearing capacity processing and assembly tolerance mass offset

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Research on valve core’s clamping stagnation of double flapper-nozzle servo valve

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High Technology Letters 2019年第1期25卷 65-73页

作者： Zhao Jianhua Zhang Bin Chen Tao Wang Qiang Zhou Songlin Gao Dianrong Hebei Provincial Key laboratory of heavy machinery fluid power transmission and control Yanshan University

Due to great changing of instantaneous temperature of hydraulic oil of double flapper-nozzle servo valve, thermal deformation between valve core and valve sleeve may result in catching phenomenon of valve core, and then the reliability of servo valve could be affected seriously. The work focuses on a particular model of double flapper-nozzle servo valve and establishes three dimension couple models of liquid-solid-thermal under extreme operating condition. The transmission route and dissipative mechanism of heat is revealed and thermal deformation behavior of valve core and valve sleeve is researched. A change law of the key fit clearance under the effect of thermal expansion and warp deformation is explored, the source of catching phenomenon of valve core is identified, and then preventive measure and improvement can be proposed. In order to verify the correctness of theoretical analysis, the moving smoothness of deformed valve core and reground valve core under the circumstance of high-temperature hydraulic oil on electrohydraulic servo valve static characteristics test table is compared and tested. The results show that as oil temperature rises, relative deformations between valve core and valve sleeve in different direction at a same cross-section are not equal, and then the key fit clearance is less than the initial value. Relative deformations in the same direction at different axial position are not equal, the deformations of middle and two ends are maximum and minimum values respectively, and then warp deformation of valve core occurs. When oil temperature is higher, the relative deformations between valve core and valve sleeve is larger, the moving smoothness of valve core gets worse, and the catching phenomenon of valve core occurs. Axial deformation of valve sleeve and valve core at different axial position is different, and the opening coefficient and stability of servo valve could be affected, especially the operation circumstance of small opening. The

关键词： double flapper-nozzle servo valve flow-solid-thermal coupling numerical simulation catching phenomenon thermal deformation mechanism smooth movement

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Theoretical and experimental research on influence of rotor taper on performance of cone-shape helical pumps

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High Technology Letters 2019年第2期25卷 174-181页

作者： Zhao Jianhua Gao Dianrong Liu Shichang Hebei Provincial Key laboratory of heavy machinery fluid power transmission and control Yanshan University

The structure of a rotor has full impact on the performance of cone-shaped helical pumps. Numerical simulation and experimental tests are applied to get pressure, velocity and flow of a cone-shaped helical pump, and explores flow condition of blood in artificial blood pump. Rotors with four different tapers of artificial pump are designed. The flow condition of blood at the entrance, near the front diffuser, near the rotor, near the rear diffuser and at the exit, the pressure difference between entrance and exit and flow of artificial blood pump with different taper rotors are simulated, and then the influence rules of rotor taper on the performance of cone-shaped helical pump are revealed. In order to verify the correctness of theoretical analysis, rotors with three different tapers are manufactured, physical model of artificial blood pump are built, and then the actual lift and flow of blood pump with different rotors are measured respectively. The results show that taper of rotor increases, the circumfluence of blood near the front and rear diffuser decreases, the blood flows more smoothly, the energy consumption is less, and then the guide role of blade is greater. The blood at the exit of blood pump flows along the axial direction steadily. As taper of rotor increases, the pressure difference between the entrance and exit and the flow of blood pump increase subsequently. The flow condition of blood and performance of blood pump with No.3 rotor are the best. The proposed research analyzes the influence of rotor taper on performance of blood pump quantitatively, and provides the theoretical reference for the design and improving of cone-shaped helical pump.

关键词： cone-shaped helical pump rotor taper circumfluence flow condition energy consumption

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Numerical Simulation and Experimental Study of Heat-fluid-solid Coupling of Double Flapper-nozzle Servo Valve

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Chinese Journal of Mechanical Engineering 2015年第5期28卷 1030-1038页

作者： ZHAO Jianhua ZHOU Songlin LU Xianghui GAO Dianrong Hebei Provincial Key laboratory of heavy machinery fluid power transmission and control Yanshan University Hebei Vocational & Technical College of Building Materials

The double flapper-nozzle servo valve is widely used to launch and guide the equipment. Due to the large instantaneous flow rate of servo valve working under specific operating conditions, the temperature of servo valve would reach 120℃ and the valve core and valve sleeve deform in a short amount of time. So the control precision of servo valve significantly decreases and the clamping stagnation phenomenon of valve core appears. In order to solve the problem of degraded control accuracy and clamping stagnation of servo valve under large temperature difference circumstance, the numerical simulation of heat-fluid-solid coupling by using finite element method is done. The simulation result shows that zero position leakage of servo valve is basically impacted by oil temperature and change of fit clearance. The clamping stagnation is caused by warpage-deformation and fit clearance reduction of the valve core and valve sleeve. The distribution roles of the temperature and thermal-deformation of shell, valve core and valve sleeve and the pressure, velocity and temperature field of flow channel are also analyzed. Zero position leakage and electromagnet＇s current when valve core moves in full-stroke are tested using Electro-hydraulic Servo-valve Characteristic Test-bed of an aerospace sciences and technology corporation. The experimental results show that the change law of experimental current at different oil temperatures is roughly identical to simulation current. The current curve of the electromagnet is smooth when oil temperature is below 80℃, but the amplitude of current significantly increases and the hairy appears when oil temperature is above 80℃. The current becomes smooth again after the warped valve core and valve sleeve are reground. It indicates that clamping stagnation is caused by warpage-deformation and fit clearance reduction of valve core and valve sleeve. This paper simulates and tests the heat-fluid-solid coupling of double flapper-nozzle servo valve, an

关键词： double flapper-nozzle servo valve heat-fluid-solid coupling numerical simulation warpage-deformation clamping stagnation zero position leakage

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Impact of Typical Steady-state Conditions and Transient Conditions on Flow Ripple and Its Test Accuracy for Axial Piston Pump

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Chinese Journal of Mechanical Engineering 2015年第5期28卷 1012-1022页

作者： XU Bing HU Min ZHANG Junhui State Key laboratory of fluid power transmission and control Zhejiang University

The current research about the flow ripple of axial piston pump mainly focuses on the effect of the structure of parts on the flow ripple. Therein, the structure of parts are usually designed and optimized at rated working conditions. However, the pump usually has to work in large-scale and time-variant working conditions. Therefore, the flow ripple characteristics of pump and analysis for its test accuracy with respect to variant steady-state conditions and transient conditions in a wide range of operating parameters are focused in this paper. First, a simulation model has been constructed, which takes the kinematics of oil film within friction pairs into account for higher accuracy. Afterwards, a test bed which adopts Secondary Source Method is built to verify the model. The simulation and tests results show that the angular position of the piston, corresponding to the position where the peak flow ripple is produced, varies with the different pressure. The pulsating amplitude and pulsation rate of flow ripple increase with the rise of pressure and the variation rate of pressure. For the pump working at a constant speed, the flow pulsation rate decreases dramatically with the increasing speed when the speed is less than 27.78% of the maximum speed, subsequently presents a small decrease tendency with the speed further increasing. With the rise of the variation rate of speed, the pulsating amplitude and pulsation rate of flow ripple increase. As the swash plate angle augments, the pulsating amplitude of flow ripple increases, nevertheless the flow pulsation rate decreases. In contrast with the effect of the variation of pressure, the test accuracy of flow ripple is more sensitive to the variation of speed. It makes the test accuracy above 96.20% available for the pulsating amplitude of pressure deviating within a range of ~6% from the mean pressure. However, with a variation of speed deviating within a range of ±2% from the mean speed, the attainable test accuracy o

关键词： axial piston pump flow ripple test accuracy steady-state condition transient condition wide operating ranges

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Product Modular Design Incorporating Preventive Maintenance Issues

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Chinese Journal of Mechanical Engineering 2016年第2期29卷 406-420页

作者： GAO Yicong FENG Yixiong TAN Jianrong State Key laboratory of fluid power transmission and control Zhejiang University

Traditional modular design methods lead to product maintenance problems, because the module form of a system is created according to either the function requirements or the manufacturing considerations. For solving these problems, a new modular design method is proposed with the considerations of not only the traditional function related attributes, but also the maintenance related ones. First, modularity parameters and modularity scenarios for product modularity are defined. Then the reliability and economic assessment models of product modularity strategies are formulated with the introduction of the effective working age of modules. A mathematical model used to evaluate the difference among the modules of the product so that the optimal module of the product can be established. After that, a multi-objective optimization problem based on metrics for preventive maintenance interval different degrees and preventive maintenance economics is formulated for modular optimization. Multi-objective GA is utilized to rapidly approximate the Pareto set of optimal modularity strategy trade-offs between preventive maintenance cost and preventive maintenance interval difference degree. Finally, a coordinate CNC boring machine is adopted to depict the process of product modularity. In addition, two factorial design experiments based on the modularity parameters are constructed and analyzed. These experiments investigate the impacts of these parameters on the optimal modularity strategies and the structure of module. The research proposes a new modular design method, which may help to improve the maintainability of product in modular design.

关键词： modular design modularity strategy preventive maintenance optimization design

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Design and analysis of an underwater inductive coupling power transfer system for autonomous underwater vehicle docking applications

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Journal of Zhejiang University-Science C(Computers and Electronics) 2014年第1期15卷 51-62页

作者： Jian-guang SHI De-jun LI Can-jun YANG State Key laboratory of fluid power transmission and control

We develop a new kind of underwater inductive coupling power transfer(ICPT)system to evaluate wireless power transfer in autonomous underwater vehicle(AUV)docking *** that determine the performance of the system are systematically analyzed through mathematical methods.A circuit simulation model and a finite element analysis(FEA)simulation model are developed to study the power losses of the system,including copper loss in coils,semiconductor loss in circuits,and eddy current loss in transmission *** characteristics of the power losses can provide guidelines to improve the efficiency of ICPT *** results and simulation results are validated by relevant experiments of the prototype *** output power of the prototype system is up to 45 W and the efficiency is up to *** preliminary results indicate that the efficiency will increase as the transmission power is raised by increasing the input *** the output power reaches 500 W,the efficiency is expected to exceed *** efficiency can be further improved by choosing proper semiconductors and *** analysis methods prove effective in predicting the performance of similar ICPT systems and should be useful in designing new systems.

关键词： Inductive coupling power transfer(ICPT) Autonomous underwater vehicle(AUV) docking Coupling coefficient Resonant capacitance power transfer efficiency power loss Eddy current

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Metamorphic Manipulating Mechanism Design for MCCB Using Index Reduced Iteration

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Chinese Journal of Mechanical Engineering 2013年第2期26卷 232-241页

作者： XU Jinghua ZHANG Shuyou ZHAO Zhen LIN Xiaoxia State Key laboratory of fluid power transmission and control Zhejiang University

The present research on moulded case circuit breaker（MCCB） focuses on the enhancement of current-limiting interrupting performance during short circuit, overload, under voltage and phase failure, involving electrics, magnetic, mechanics, thermal, material, friction, arc extinguishing, impact vibration, skin effect, etc. The rigid-flexible coupling of the parts and components of the metamorphic manipulating mechanism in multi-fields leads to the non-rigid, high frequency, high damping, singularity of the Euler-Lagrange equations which represents the multi-body dynamics. The small step iteration which is used for obtaining the instantaneous and short time critical interrupting performance of metamorphic mechanism appears inaccuracy. It is difficult to realize top-down design by existing CAD systems. Therefore, a metamorphic manipulating mechanism design method for MCCB using index reduced iteration（IRI） is put forward. The metamorphic manipulating mechanism of MCCB is decomposed into three mechanisms： main switch connector mechanism, electromagnet-drawbar-jump buckle mechanism, and bimetallic strip-drawbar mechanism, which is respectively described by electro-dynamic force, electromagnet force, and bimetallic strip force. The dummy part（virtual rigid） without moment of inertia and mass is employed as intermediate to join the flexible body and rigid body. The model of rigid-flexible coupling metamorphic mechanism multi-body dynamics is built. The differential algebraic equations（DAEs） of the multibody dynamics model are converted to pure ordinary differential equations（ODEs） by coordinate partition. Order reduced integration with multi-step and variable step-size is preceded based on IRI. The non-linear algebraic equations are solved in each integration step by Newton-Rapson iteration. There is no ill-condition and singularity of Jacobian matrix when step size reduces to zero. The independent prototype design system using ACIS R13, HOOPS V11.0 and Visual C＋＋.NET 2003 h

关键词： index reduced iteration (IRI) moulded case circuit breaker (MCCB) metamorphic manipulating mechanism Euler-Lagrange equations rigid-flexible coupling multi-body dynamics current interrupting simulation

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Position, Singularity and Workspace Analysis of 3-PSR-O Spatial Parallel Manipulator

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Chinese Journal of Mechanical Engineering 2015年第3期28卷 437-450页

作者： SHAO Jiejie CHEN Wenyu FU Xin State Key laboratory of fluid power transmission and control Zhejiang University

Although the parallel mechanisms have the advantages of high accuracy, velocity, stiffness, and payload capacity, the shortcomings of the space utilization and workspace limit the applications in the confined space. A novel 3 degrees of freedom spatial parallel manipulator 3-PSR-O（prismatic-spherical-revolute） is proposed, which possesses a compact architecture and extended workspace while maintaining the inherent advantages of the parallel mechanisms. The direct-inverse position, singularity and workspace are investigated. The mapping method is adopted in the position analysis, and the closed form solution is derived in the form of a six order equation. The singularity analysis of the mechanism is also carried out based on the geometrical constraints, including six singularity boundaries. A feature boundary, which is independent of the prismatic joints＇ stroke limit, is obtained by integrating the six singularity boundaries. According to the formation of the reachable workspace, a concept of basic workspace is also introduced and presented in the analytical way. By demarcating the basic workspace along the central height with the feature boundary, the reachable workspace can be derived and analyzed more efficiently. Finally, a comparative study on the space utilization between the 3-PSP parallel mechanism and the new mechanism is also presented. The area of feature boundary of the new mechanism is about 140% of the 3-PSP parallel mechanism, while its installation radius is only 1/2 of the 3-PSP parallel mechanism. The proposed parallel mechanism shows great space utilization, and is ideally suited for applications in confined space occasions such as immersion lithography, nano-imprint etc.

关键词： spatial-planar parallel mechanism direct-inverse position analysis reachable workspace basic workspace feature boundary

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