四缸驱动起模机非线性PID同步控制研究

针对翻转起模机中四缸同步驱动起模过程存在的同步性能较差的问题,设计了四缸伺服同步驱动系统,建立了起模过程的非线性动力学模型。根据起模过程中的跟踪性能和同步性能指标要求,结合输出变量的二阶泰勒矢量展开、最优控制原理和非线性扰动观测器设计理论,提出了一种类似经典PID控制器结构的非线性PID同步控制策略。仿真和实际应用结果表明,该控制策略比常规PID同步控制策略具有更好的跟踪性能和同步驱动性能。

重型翻转式起模机的开发应用

重型翻转式起模机应用于大件铸造造型生产线模型翻转起模单元中,适合的最大砂箱外形尺寸4 200 mm×2 400 mm×800 mm。本文介绍了重型翻转式起模机的开发与应用。

翻转起模机电气控制系统设计及应用

翻转起模机是树脂砂造型过程中所用的关键设备之一。针对目前翻转起模机存在的起模精度和效率都偏低的问题,结合起模机的工作原理和工艺特点,应用电液比例同步控制技术,设计了该机的液压系统和电气控制系统,并采用西门子S7-300 PLC系统和Borland C++Builder软件,设计了翻转起模机的控制软件,最后进行了该机实际运行情况的分析。实际应用结果表明,该系统达到较好的起模精度,双缸动态同步起模精度≤2 mm,稳态同步驱动精度≤0.1 mm,运行平稳,可以满足起模的工艺要求。

进口翻转起模机电控系统的国产化设计

通过对进口ＳＸ－０３Ｔ型翻转起模机工作过程的系统分析，得出了其动作节拍表。在此基础上，提出对电气控制部分进行国产化设计的思想；并详细地介绍了硬件及软件的设计。

基于Flexsim的翻转起模机仿真实现方法研究

对某铸造生产线中的重要设备——翻转起模机仿真建模的实现方法,及在生产线仿真软件Flexsim中铸造设备动作方式的直接实现方法等问题进行了研究。通过分析翻转起模机的动作流程,借助Flexsim软件的动画编辑器功能及模型库中实体的固有属性,编写程序,二次开发了翻转起模机的实体模型,达到了预期仿真效果。仿真效果逼真,为保证整个生产线仿真项目的准确度起到了关键作用,同时可为其他仿真工作者提供参考。

翻箱起模机电控系统的国产化设计

通过对西德ＥＣＯ公司生产的ＳＸ－０３Ｔ型翻箱起模机的系统分析，得出了该机的动作节拍表，在此基础上，提出了对其电控部分国产化设计的思想，并详细地介绍了硬件与软件的设计。

树脂砂造型设备液压系统油温过高问题分析与处理

介绍了液压系统油温过高的原因及危害,对某企业树脂砂造型生产线翻转机液压系统油温过高问题进行了深入分析,找出了导致油温过高的原因,采取了针对性的解决措施,方案实施后,效果显著,系统油温过高问题得到彻底解决。

ROBOTIC DYNAMIC MODEL ON LOAD SWING OF SLEWING CRANE

This paper sets up a robotic manipulator model on slewing crane. The model can synthetically describe the dynamic behavior of the load of slewing crane in rotating, elevating and hoisting motions. The dynamic equations of the system are recursively derived by a Newton Euler method. The dynamic behavior of the load of slewing crane in rotating motion is simulated on a computer. The method of robotic dynamics to derive the dynamic equations of the swing of load is accurate and convenient and it has good regularity. The result of the study provides a base in theory on design of crane and an accurate mathematical model for controlling the swing of load.

Pep-Set树脂砂脱箱造型生产线的研发与应用

Pep-Set树脂砂脱箱造型自动生产线经过近几年的研发,技术逐渐成熟。整个生产线由旧砂处理系统、混砂造型系统及铸工输送环三大部分组成。采用Pep-Set树脂砂工艺,利用翻转起模机进行震动脱模,实现脱箱造型。整个造型生产线采用PLC人机界面控制,自动化程度高,可操作性强。

Pendulation reduction on ship-mounted container crane via T-S fuzzy model

Ship-mounted container cranes are challenging industrial applications of nonlinear pendulum-like systems with oscillating disturbance which can cause them unstable.Since wave-induced ship motion causes the hoisted container to swing during the transfer operation,the swing motion may be dangerously large and the operation must be stopped.In order to reduce payload pendulation of ship-mounted crane,nonlinear dynamics of ship-mounted crane is derived and a control method using T-S fuzzy model is proposed.Simulation results are given to illustrate the validity of the proposed design method and pendulation of ship-mounted crane is reduced significantly.

国外抛砂造型概述

抛砂造型迄今已有近六十年的历史了。在这半个多世纪里,国外抛砂机的发展开始怎样,后来怎样,现在怎样,从中找出规律性的东西,以利于促进我国抛砂造型及其与其它造型方法综合应用的发展。

Modeling a magneto-rheological soft starter for use with belt conveyors

The theory of magnetic circuit design, the constitutive equations of a magneto-theological fluid, and the load properties of belt conveyors were used to design a magneto-rheological soft starter test-bed. The magnetic field distribution in the working gap was analyzed and the current-speed relationship was investigated. A mathematical model for the time response was deduced. The results show that a linear relationship between current and magnetic field is seen when the magnetic materials are not saturated and the magnetic field is uniform in the working section. The rotation speed of the driven shaft changes linearly with increasing time. The response is rapid and can be as short as milliseconds. This meets the starting requirements of belt conveyors.

Mathematical Model for Takeoff Simulation of a Wing in Proximity to the Ground

Aircraft flying close to the ground benefit from enhanced efficiency owing to decreased induced drag and increased lift. In this study, a mathematical model is developed to simulate the takeoff of a wing near the ground using an Iterative Boundary Element Method （IBEM） and the finite difference scheme. Two stand-alone sub-codes and a mother code, which enables communication between the sub-codes, are developed to solve for the self-excitation of the Wing-In-Ground （WIG） effect. The aerodynamic force exerted on the wing is calculated by the first sub-code using the IBEM, and the vertical displacement of the wing is calculated by the second sub-code using the finite difference scheme. The mother code commands the two sub-codes and can solve for the aerodynamics of the wing and operating height within seconds. The developed code system is used to solve for the force, velocity, and displacement of an NACA6409 wing at a 4° Angle of Attack （AoA） which has various numerical and experimental studies in the literature. The effects of thickness and AoA are then investigated and conclusions were drawn with respect to generated results. The proposed model provides a practical method for understanding the flight dynamics and it is specifically beneficial at the pre-design stages of a WIG effect craft.

Drivability improvements for a single-motor parallel hybrid electric vehicle using robust controls

For a single-motor parallel hybrid electric vehicle, during mode transitions （especially the transition from electric drive mode to engine/parallel drive mode, which requires the clutch engagement）, the drivability of the vehicle will be signifi- cantly affected by a clutch torque induced disturbance, driveline oscillations and jerks which can occur without adequate controls. To improve vehicle drivability during mode transitions for a single-motor parallel hybrid electric vehicle, two controllers are proposed. The first controller is the engine-side controller for engine cranking/starting and speed synchronization. The second controller is the motor-side controller for achieving a smooth mode transition with reduced driveline oscillations and jerks under the clutch torque induced disturbance and system uncertainties. The controllers are all composed of a feed-forward control and a robust feedback control. The robust controllers are designed by using the mu synthesis method. In the design process, control- oriented system models that take account of various parameter uncertainties and un-modeled dynamics are used. The results of the simulation demonstrate the effectiveness of the proposed control algorithms.

Prediction of stall inception in multi-stage compressors based on an eigenvalue approach

A stability model for multi-stage compressor is developed on the basis of the eigenvalue approach.This model assumes that the unsteady flow field can be decomposed into pressure,vortex and entropy waves.Besides,a linear cascade of blades is modeled by three-dimensional semi-actuator disk theory and the characteristics of steady flow field are also considered in the present model.The connection between the analytical solution for stator,rotor and gap can be established by applying mode matching approach,the relevant stability equation can be expressed in the form of matrix,while the compressor system stability can be judged by the imaginary part of the matrix eigenvalue.The capacity of the stall inception model to predict the stall inception point of multi-stage compressor is assessed against the experimental data of National Aeronautics and Space Administration(NASA) two stage fan.The theoretical results show that this model can predict the stall onset points of a two-stage fan at different operating speeds with a reasonable accuracy.