汽车点焊气动模糊滑模控制研究

点焊气动伺服控制系统常用于轿车白车身的焊接。在焊接过程中,保持焊点压力稳定是提高焊接质量的关键因素之一。基于焊接试验平台上,研究了气动系统的控制模型,提出模糊-滑模控制策略。针对辨识所得的气动系统,运用模糊-滑模控制策略对气动系统进行了仿真,结果表明,模糊-滑模控制策略适用于汽车点焊气动系统。     

三自由度气动并联平移机器人平台的设计

基于工业生产中广泛使用的高速并联机器人应用背景,设计了一种三自由度气动并联平移机器人平台.针对气动并联机器人平移运动的需求,设计驱动臂机构驱动机器人运动,设计辅助臂机构约束机器人的转动自由度.采用MATLAB和ADAMS对气动并联机器人进行运动学仿真.针对气动并联机器人平台系统的非线性和不确定外扰,采用线性自抗扰控制算...     

装备保障仿真实验室体系结构研究

通过仿真实验室进行装备保障研究,是提高综合装备保障能力重要途径。在装备保障仿真实验室功能需求分析的基础上,重点研究了装备保障仿真实验室的系统体系结构、运行体系结构和技术体系结构,并对其实体建模、数据交互和虚拟仿真等关键技术作了初步的探讨。     

基于AMESim的液压双缸同步动作仿真及试验研究

针对工程车辆中各机构液压双缸的同步作用,采用分流集流阀同步回路设计,运用AMESim软件中的液压仿真模块进行仿真分析,并通过试验对同步特性进行研究。仿真及试验结果表明,采用分流集流阀回路能够较好的满足同步性,同时AMESim仿真结果与试验相符合,具有较高的可信度。     

筒形件拉深成形工艺的虚拟实验研究

在毛坯材料、凸模、凹模和压边圈等条件相同的情况下,利用DYNAFORM软件及其有限元计算的方法,选取毛坯网格(BLANK)大小分别为1.0,0.5,0.25mm;上模层(PUNCH)均为1.5mm的三种组合参数,对筒形件的成形过程进行模拟试验。结果显示毛坯网格大小为0.25mm上模层为1.5mm的试验参数是最佳的,它所对应的拉深成形工艺性是最佳的。     

气缸检测的研究

传统的气缸检测,能通过定量分析来指导、控制生产的大都制造成本甚高,而成本低廉的又无法进行定量分析,漏检、误废现象严重。本文作者设计研制的检测装置,成本低,效率高,检测项目全面,检测指标量化,适用于指导、控制生产,特别是中小气缸生产企业。现已小批量投入使用,具有较强的开发潜力。本文在介绍这一新装置的同时,对有关指标参数亦进行了较详尽的计算分析。     

Eccentricity and thermoviscous effects on ultrasonic scattering from a liquid-coated fluid cylinder

Calculation of the scattered field of the eccentric scatterers is an old problem with numerous applications. This study considers the interaction of a plane compressional sound wave with a liquid-encapsulated thermoviscous fluid cylinder submerged in an unbounded viscous thermally conducting medium. The translational addition theorem for cylindrical wave functions, the appropriate wave field expansions and the pertinent boundary conditions are employed to develop a closed-form solution in the form of infinite series. The analytical results are illustrated with a numerical example in which the compound cylinder is insonified by a plane sound wave at selected angles of incidence in a wide range of dimensionless frequencies. The backscattered far-field acoustic pressure amplitude and the spatial distribution of the total acoustic pressure in the vicinity of the cylinder are evaluated and discussed for representative values of the parameters characterizing the system. The effects of incident wave frequency, angle of incidence, fluid thermoviscosity, core eccentricity and size are thoroughly examined. Limiting case involving an ideal compressible liquid-coated cylinder is considered and fair agreement with a well-known solution is established.     

交流伺服电动缸在地震模拟振动台中的应用

交流伺服电动缸凭借其优异的控制性和相对较低的成本,特别是其核心部件——交流伺服电机的控制精度高、加速性能好、有良好的矩频特性和过载能力,使得利用电动缸进行地震模拟成为可能。交流伺服电动缸振动台成本低、控制简单,在地震教学演示、构件及小型结构振动台实验中优点突出,具有广泛的应用前景。将伺服电动缸和微机控制技术相结合,实现了一条单向地震波的模拟仿真输出。结果表明,在一定的加速度范围内模拟效果良好,模拟极限加速度值和模拟效果取决于交流伺服电动缸的性能和台面载荷。     

基于三维实体造型和虚拟仿真技术的液压与气动课教学资源的制作

为了解决液压与气动课程教学中遇到的一些问题,提高教学质量,将三维实体造型技术和虚拟仿真技术应用到该课程教学中。以齿轮液压泵教学资源的制作为例,阐述三维实体造型与虚拟仿真软件的选择、三维实体模型的创建和虚拟仿真的运行过程。     

制砖机液压系统中脱模增速缸设计

为了满足制砖机液压系统中脱模缸既要有大的瞬间推力又要有较大的工进速度和回程速度的要求,设计了一种子母型液压增速缸。文章给出了结构设计和主要参数确定的全过程,并对其进行了压杆稳定校核。经生产实践表明,该脱模增速缸运行平稳、可靠,提高了脱模质量和生产效率,达到了设计要求。     

信息化装备仿真实验室建设初探

在需求分析的基础上，通过系统论证，提出了信息化装备仿真实验室的基本目标、主要功能，为军队武器装备发展和整体建设规划搭建技术演示平台，形成实际战斗力的“孵化器”。     

液压与气动技术课程教学改革的研究

从课程设置、教材与教学内容、教学方法和手段、师资水平、课程考核方式等方面对液压与气压传动课程的教学进行研究与改革,取得了一定的效果。     

Performance investigation of 2D lattice Boltzmann simulation of forces on a circular cylinder

The lattice Boltzmann method (LBM) is employed to simulate the uniform flow past a circular cylinder. The performance of the two-dimensional LBM model on the prediction of force coefficients and vortex shedding frequency is investigated. The local grid refinement technique and second-order boundary condition for curved walls are applied in the calculations. It is found that the calculated vortex shedding frequency, drag coefficient and lift coefficient are consistent with experimental results at Reynolds nu...     

CFD技术在无环量圆柱绕流多媒体教学中的应用研究

CFD技术是当前高等院校多媒体教学的热门手段和方法,特别是在如流体力学这样概念抽象,理论性强,与实际流动现象结合紧密的课程中显得尤为突出。文章应用Gambit,Fluent和Tecplot等相关软件,对无环量圆柱绕流的流动机理进行数值模拟与分析。目的在于验证无环量圆柱绕流数学、物理理论的正确性,观察流动现象,分析产生各种现象的原因。通过研究表明,以直观演示和定量分析相结合的方法,能够非常好地解决许多教学中的难点和重点问题,使学生对抽象的教学内容产生深刻的印象,增强了学习兴趣。     

“油藏数值模拟”课程教学探讨

＂油藏数值模拟＂是一门综合性很强的课程。本文从＂油藏数值模拟＂课程的结构设置特点和该课程在现场应用的实际特点分析入手,提出了有助于改变该课程目前现状的教学方法和思路。     

发动机气缸垫失效的原因分析及其预防

发动机气缸垫失效易使发动机工作性能下降,并导致维修困难或造成机件报废.其失效原因主要是发动机过热和发动机装配质量不过关,而防止发动机气缸垫失效最主要的是要确保气缸垫密封良好,另外,注意尽量避免重复使用气缸垫.     

Thermoelastic stresses in a uniformly heated functionally graded isotropic hollow cylinder

The axisymmetric themoelastic problem of a uniformly heated, functionally graded isotropic hollow cylinder is considered. An analytical form of solution is proposed. For the case when the Young's modulus and thermal expansion coefficient have a power-law dependence on the radial coordinate, explicit exact solution is obtained. For the degenerated case, i.e. when the cylinder is homogeneous and isotropic, no stresses will occur provided it is subjected to a uniform temperature. Numerical results are finally given and some important inclusions are obtained. Project (No.10002016) supported by the National Natural Science Foundation of China (NSFC).     

Dynamic response of RPC-filled steel tubular columns with high load carrying capacity under axial impact loading

Experimental investigation into impact-resistant behavior of reactive powder concrete (RPC)-filled steel tubular columns was conducted,and dynamic response of the columns under axial impact loading was studied by means of numerical simulation method.Increase coefficient of load carrying capacity and ratio of load carrying capacity between steel tube and RPC core of col-umns were obtained.     

Analysis of a functionally graded piezothermoelastic hollow cylinder

INTRODUCTION Piezoelectric symmetric structures always play an important role in the use of piezoelectric materials (Olesiak and Pyryev, 1995; Ding et al., 2003; Wu et al., 2003). To improve the durability of this kind of piezoelectric structures, functionally gradient piezo- electric materials (FGPM) have been developed and used to produce these devices such as sensors and actuators (Hauke et al., 2000; Zhu et al., 1995). For the case when a rectangular plate made of function- ally gr…     

Dynamic responses of a multilayer piezoelectric hollow cylinder under electric potential excitation

INTRODUCTION Recently, more and more investigations have been conducted on multilayer piezoelectric media. Kharouf and Heyliger (1994) and Heyliger and Ra- mirez (2000) dealt with the free vibration problems of laminated piezoelectric cylinders and discs, respec- tively. Chen (2000) considered the free vibration of (multilayer) nonhomogeneous piezoceramic hollow spheres by employing a separation formulation for displacements. Chen (2001) developed a state-space method for free vibration …