HYDRAULIC ACTIVE GUIDE ROLLER SYSTEM FOR HIGH-SPEED ELEVATOR BASED ON FUZZY CONTROLLER

Increase of elevator speed brings about amplified vibrations of high-speed elevator. In order to reduce the horizontal vibrations of high-speed elevator, a new type of hydraulic active guide roller system based on fuzzy logic controller is developed. First the working principle of the hydraulic guide system is introduced, then the dynamic model of the horizontal vibrations for elevator cage with active guide roller system and the mathematical model of the hydraulic system are given. A fuzzy logic controller for the hydraulic system is designed to control the hydraulic actuator. To improve the control performance, preview compensation for the controller is provided. Finally, simulation and experiments are executed to verify the hydraulic active guide roller system and the control strategy. Both the simulation and experimental results indicate that the hydraulic active guide roller system can reduce the horizontal vibrations of the elevator effectively and has better effects than the passive one, and the fuzzy logic controller with preview compensation can give superior control performance.

Analysis and Optimization of Inside-Cushion Structure in High-Speed Hydraulic Cylinders

An inside-cushion structure with sidestep and taper-shaped plungers is studied to address the problems of high impact and vibration in high-speed hydraulic cylinders.First,the three stages of cushion processes are discussed according to the varying flow area as the piston moves.Then,to establish a precise mathematical model,the states of the flow field are estimated in terms of the Reynolds number.Accordingly,the simulation model parameterized against measured data is developed and verified by experiment.Last,the average velocity,peak cushion pressure,and terminal velocity are defined to evaluate cushion performance.According to these optimized objectives,the non-linear programming by quadratic Lagrange(NLPQL)algorithm is applied to optimize the structure parameters.The optimization results indicate that the peak cushion pressure is reduced by 28%and terminal velocity is reduced by 21%without reduction of average velocity.

RELIABILITY ANALYSIS OF THE PRIMARY CYLINDER OF THE 10MN HYDRAULIC PRESS

According to the demand of high reliability of the primary cylinder of the hydraulic press, the reliability model of the primary cylinder is built after its reliability analysis. The stress of the primary cylinder is analyzed by finite element software—MARC, and the structure reliability of the cylinder based on stress strength model is predicted, which would provide the reference to the design.

HYBRID CONTROL OF HYDRAULIC PRESS MACHINE BASED ON ROBUST CONTROL

A robust control algorithm is proposed to focus on the non-linearity and variables of the hydraulic press machine with the proportional vatve. The proposed robust controller does not need to design stable compensator in advance, which is simple in design and has large scope of uncertainty applications. The feedback gains of the proposed robust controller are small, so it is easily implemented in engineering applications. The theoretical and experimental research on the position and speed control of the hydraulic press machine is carried out. The control requirements of the hydraulic press machine during the working process are met in the position and speed at the same time. Experimental results show that the proposed controller has better robustness subject to load variables and adaptability of parameter variations of the hydraulic press machine with the proportional valve.

Fuzzy iterative learning control of electro-hydraulic servo system for SRM direct-drive volume control hydraulic press

A new kind of volume control hydraulic press that combines the advantages of both hydraulic and SRM(switched reluctance motor) driving technology is developed.Considering that the serious dead zone and time-variant nonlinearity exist in the volume control electro-hydraulic servo system,the ILC(iterative learning control) method is applied to tracking the displacement curve of the hydraulic press slider.In order to improve the convergence speed and precision of ILC,a fuzzy ILC algorithm that utilizes the fuzzy strategy to adaptively adjust the iterative learning gains is put forward.The simulation and experimental researches are carried out to investigate the convergence speed and precision of the fuzzy ILC for hydraulic press slider position tracking.The results show that the fuzzy ILC can raise the iterative learning speed enormously,and realize the tracking control of slider displacement curve with rapid response speed and high control precision.In experiment,the maximum tracking error 0.02 V is achieved through 12 iterations only.

Stress and Deformation Analysis of Cylinder-Crown Integrated Hydraulic Press with Large Capacity

Cylinder-crown integrated hydraulic press( CCIHP) is a new press structure. The hemispherical hydraulic cylinder also functions as a main portion of crown,which has lower weight and higher section modulus compared with the conventional hydraulic cylinder and press crown. In order to design cylinder-crown integrated hydraulic press with large capacity, the theoretical design of hemispherical hydraulic cylinder was first proposed,and the structural parameters of 150 MN CCIHP were listed. Then the simulation was carried out to analyze the stress and deformation of CCIHP,and weight comparison was conducted between CCIHP and conventional press. It is shown that the weight reduction for hydraulic cylinder and press crown is about 20% compared with that for conventional press,and the stress and deformation are both within the range of constraints including strength and stiffness conditions. It is possible to manufacture cylinder-crown integrated hydraulic press with large capacity.

A method to calculate and counterbalance the inertia force of slider-crank mechanisms in high-speed presses

A new method to calculate and counterbalance the inertia force of slider-crank mechanisms in high-speed mechanical presses was put forward. By analyzing the kinematic characteristics of a center-located slider-crank mechanism whose crank rotates at a constant angular velocity,the kinematic parameters of the slide,connecting rod and crank were formulated approximately. On the basis of the results above,three inertia forces and the input moment in the mechanism during its idle running were investigated and formulated by dynamic analysis. A verification experiment was performed on a slider-crank mechanism at a high-speed press machine. The forces derived from the established formulas were compared respectively with those obtained by the ADAMS software and the classical method of connecting rod mass substitution. It was experimentally found that the proposed formulas have an improved performance over related earlier techniques. By use of these results,a 1 000 kN 1 250 rpm four-point high-speed press machine was designed and manufactured. The slide of this press is driven by four sets of slider-crank mechanisms with symmetrical layout and opposite rotation directions to counterbalance the horizontal inertia forces. Four eccentric counterbalance blocks were designed to counterbalance the vertical force after their mass and equivalent eccentric radius were formulated. The high-speed press machine designed by the proposed counterbalance method has worked with satisfactory performance and good dynamic balance for more than four years in practical production.

Design of a 70 MPa Two-Way Proportional Cartridge Valve for Large-Size Hydraulic Forging Press

For an ultra-high-pressure hydraulic transmission system of a large-size hydraulic forging press(LHFP),a 70 MPa two-way proportional cartridge valve has been developed to improve the power weight ratio of the hydraulic forging press.In this study,a nominal diameter 25 mm(DN25)cartridge valve is taken as the research object.A longer concentric cylindrical annular gap is set to effectively prevent the ultra-high-pressure oil from flowing to the pilot stage and a seated valve structure is set to form the linear sealing zone in the closing state of the main valve port.Electric-displacement feedback is adopted to realize precise control of the main valve port flow and the features of this valve are investigated.In order to verify the strength and static and dynamic characteristics,the finite element model and a simulation model of the valve proposed above are built.There is a little deformation which does not affect the main valve spool movement,and the main valve port flow meets the design demands.Then,the prototype of DN2570 TPCV is manufactured and a ultra-high-pressure experimental platform is developed.The experimental results show that the DN2570 TPCV designed in this study has the advantage of fast response,high control precision,and low leakage,which can meet the requirements of LHFPs.

Coordination control for crankshaft forging hydraulic press

Taking a new type of full-fiber crankshaft forging hydraulic press as the research object,an upsetting-bending stroke coordination control is studied to improve crankshaft forming accuracy.A master-slave proportion integration differentiation(PID)coordination control strategy based on velocity feed-forward is proposed to improve the coordination control accuracy.The structure and working process of the full-fiber crankshaft forging hydraulic press are introduced,and a mathematical model of the upsetting and bending control system are established.The coordination control strategy is verified experimentally.The experimental results show that the maximum tracking error of the coordination control strategy is reduced by 66%compared with the traditional PID controller,and the coordination motion accuracy is improved effectively.

Forming-Precision-Driven Structure Design of Hydraulic Press: Methodology and Case Study

The structure stiffness of presses has great effects on the forming precision of workpieces, especially in near-net or net shape forming. Conventionally the stiffness specification of presses is empirically determined, resulting in poor designs with insufficient or over sufficient stiffness of press structures. In this paper, an approach for the structure design of hydraulic presses is proposed, which is forming-precision-driven and can make presses costeffective by lightweight optimization. The approach consists of five steps:(1)the determination of the press stiffness specification in terms of the forming precision requirement of workpieces;(2)the conceptual design of the press structures according to the stiffness and workspace specifications, and the structure configuration of the press;(3)the prototype design of the press structures by equivalently converting the conceptual design to prototypes;(4)the selection of key structure parameters by sensitivity analysis of the prototype design; and(5)the optimization of the prototype design. The approach is demonstrated and validated through a case study of the structure design of a 100 MN hydraulic press.

Position Control Optimization of Aerodynamic Brake Device for High-speed Trains

The aerodynamic braking is a clean and non-adhesion braking, and can be used to provide extra braking force during high-speed emergency braking. The research of aerodynamic braking has attracted more and more attentions in recent years. However, most researchers in this field focus on aerodynamic effects and seldom on issues of position control of the aerodynamic braking board. The purpose of this paper is to explore position control optimization of the braking board in an aerodynamic braking prototype. The mathematical models of the hydraulic drive unit in the aerodynamic braking system are analyzed in detail, and the simulation models are established. Three control functions--constant, linear, and quadratic--are explored. Two kinds of criteria, including the position steady-state error and the acceleration of the piston rod, are used to evaluate system performance. Simulation results show that the position steady state-error is reduced from around 12-2 mm by applying a linear instead of a constant function, while the acceleration is reduced from 25,71-3.70 m/s2 with a quadratic control function. Use of the quadratic control function is shown to improve system performance. Experimental results obtained by measuring the position response of the piston rod on a test-bench also suggest a reduced position error and smooth movement of the piston rod. This implies that the acceleration is smaller when using the quadratic function, thus verifying the effectiveness of control schemes to improve to system performance. This paper proposes an effective and easily implemented control scheme that improves the position response of hydraulic cylinders during position control.

Development of High-Speed On-Of Valves and Their Applications

With the widespread application of the computer and microelectronic technology in the industry,digitization becomes the inevitable developing trend of the hydraulic technology.Digitization of the hydraulic components is critical in the digital hydraulic technology.High-speed on-of valves(HSVs)which convert a train of input pulses into the fast and accurate switching between the on and of states belong to widely used basic digital hydraulic elements.In some ways,the characteristics of the HSVs determine the performance of the digital hydraulic systems.This paper discusses the development of HSVs and their applications.First,the HSVs with innovative structures which is classifed into direct drive valves and pilot operated valves are discussed,with the emphasis on their performance.Then,an overview of HSVs with intelligent materials is presented with considering of the switching frequency and fow capacity.Finally,the applications of the HSVs are reviewed,including digital hydraulic components with the integration of the HSVs and digital hydraulic systems controlled by the HSVs.

基于ANSYS的80MN等温锻造液压机有限元分析

80MN等温锻造液压机是根据用户专有的工艺需求而设计的专用液压机,属于重型锻造装备。根据技术协议,要求设计出三维模型,然后采用三维软件SolidWorks对80MN等温锻造液压机进行建模,并利用有限元分析软件ANSYS分析优化液压机的机身结构,合理优化了结构布局和材料的利用率,为公称力在60MN~100MN范围间的等温锻造液压机的快速设计提供了参考和借鉴。

环锻液压机横梁强度设计与分析

利用ANSYS有限元分析软件对环锻液压机的横梁受力情况进行分析,并与传统的公式计算结果进行对比。通过对比,总结数据差异,为后续同类型设备的快速设计提供设计依据。

5000t环锻液压机机械结构设计

绿色能源发展越来越快。随着风电、水电等行业的快速发展,锻造法兰的需求量越来越大,竞争也越来越激烈,造成企业老旧设备需要不断优化成本,如将已有压机进行升级改造,将原有的自由锻设备改造为专用法兰制胚的锻造压机。另一方面,随着锻件质量越来越大,原有风电塔筒的主机厂为了节约成本,将采购大型环锻液压机。从而给主机厂带来机遇和挑战,要求主机厂从用户的利益出发设计出满足用户工艺的锻造设备,达到性价比最优的目的。本文通过对环锻液压机的结构介绍,提供设计思路和依据,便于后续的快速设计。

重型锻造液压机理论设计与实际变形对比研究分析

重型锻造液压机的精度是保证制件精度的一个重要指标,而设备机架的刚度指标是横梁设备整个精度保持性的一个标准。本文利用ANSYS有限元分析软件对重型锻造液压机的框架变形情况进行了分析,并与现场实际测量的变形值进行了对比研究。通过对比,得出数据差值,为后续同类型设备的刚度设计提供相应的设计依据。

非焊接管道系统在液压机中的应用

液压机的液压管路具有工作压力高、对油液清洁度敏感、管路规格多、系统复杂等特点。传统的液压管路连接采用焊接方式,焊接后管路需X射线探伤检验、酸洗、磷化,最后使用液压油冲洗来保证焊接后管路质量和内部清洁度。施工流程多,工艺较复杂。本文通过对非焊接管道系统原理及结构的分析,对液压机的非焊接管道系统应用进行了论述。实践证明:非焊接管道系统技术工艺简单,污染和泄漏容易控制,在液压机上的应用推广具有明显优势,具有广泛的应用前景。

不锈钢球形把手液压成型技术研究

基于四柱单动液压成型技术,其结构简单,设计一套液压传动系统。通过元器件和行程开关的配合来控制液压缸进给和退料速度。通过模具内水压的变化,进行液压成型来生产不锈钢球形把手。批量生产后,可得到合格的产品。

L48型液压轮胎定型硫化机的研发

介绍L48型液压轮胎定型硫化机的研发背景、工艺参数和主要结构等。L48型液压轮胎定型硫化机主要由机座部件、下硫化室及调模装置、中心机构、上硫化室、装卸胎机械手、活络模调节装置和液压后充气装置组成,结构布局合理,控制系统采用最先进的可编程逻辑控制器,具有生产效率、自动化程度、轮胎定型精度高,更换轮胎规格容易、维护使用方便及性价比高等优点。

基于液压内胎硫化机的硫化飞边原因分析及控制措施

基于液压内胎硫化机的结构特点,分析造成内胎硫化飞边问题的原因,并提出相应的控制措施。通过采取准确计算硫化机合模力、检验新模具质量、控制模具预热变形、加强模具清洗和存放管理工作、将硫化机的空心热板更换为加厚的实心热板及将导向机构由工字型滚轮/铁板导轨更换为直线滑轨/滑块等措施,大幅降低了内胎硫化飞边出现的频率,为内胎硫化飞边问题提供设备检修流程的理论依据。