大型火焰切割机数控系统的研制

本文介绍了我们研制开发的一种专用于大型火焰切割机的数控系统。文中讨论了整个系统的组成、工作原理和主要特点,列出了主要技术指标。该系统目前已形成批量生产,并正在推广应用。结果表明,该系统的各项性能指标均已达到国外同类产品水平。     

Active structural-acoustic control of laminated composite plates using vertically/obliquely reinforced 1–3 piezoelectric composite patch

This article deals with the active structural-acoustic control of thin laminated composite plates using vertically reinforced 1–3 piezoelectric fiber-reinforced composite (PFRC) material for constraining layer of active constrained layer damping (ACLD) treatment. A finite element model is developed for the laminated composite plates integrated with ACLD patches and coupled with acoustic cavity to describe the coupled structural-acoustic behavior of the plates enclosing the cavity. Both in-plane and out of plane actuation of the constraining layer of the ACLD treatment have been utilized for deriving the finite element model. The analysis revealed that the vertical actuation dominates over the in-plane actuation. The performance of PFRC layers of the patches has been investigated for active control of sound radiated from thin symmetric and antisymmetric cross-ply and antisymmetric angle-ply laminated composite plates into the acoustic cavity.     

动态数字视频实时记录

:介绍一种基于计算机的数字视频实时记录系统。它可将每秒 2 5帧 ,格式为 51 2× 51 2× 8bit的图象实时地记录在 SCSI硬盘上 ,并且无信息损失 ,为事后的分析判断提供了良好的基础。     

Risk-based investment trade-off related to building facility management

Due to his or her profession, any building facility manager has to face many decision-making situations. One of the most important to be mentioned is the arbitration of a multi-year maintenance plan for buildings. Deciding between proposed maintenance actions, according to several constraints, so as to aim at satisfying corporate strategy is a complex choice. Risk approaches can be particularly effective because of their ability to handle complexity and uncertainties. The problem is then to be able to propose a method considering risks, adapted to the specific context of building facility management. Our method, regarded as a traditional approach, includes needed resources (i.e. costs) according to constraints (i.e. budget), but it also considers several risk domains (safety, technical preservation, client satisfaction, etc.), through the consequences (gain and loss). It proposes an ergonomic arbitration system based on filters following two complementary approaches: a selection of the fundamental actions and then an optimization of the plan (in a global view). The aim, for decision-makers, is to build their own solution by testing multiple angles of vision in simulation logic.This article presents the principles of the method, illustrated by an example of a real case conducted for a leading French company.     

申嘉湖高速公路双壁路堑开挖爆破安全管理

阐述申嘉湖高速公路双壁路堑开挖爆破的安全问题,以及如何加强和细化人员、爆破器材及施工过程中的安全管理工作,以确保在工程爆破中取得良好的爆破效果,保证爆破工程的安全.     

Piezo patch sensor/actuator control of the vibrations of a cantilever under axial load

The effect of axial force in the vibration control of beams is studied by means of an integral equation formulation, which facilitates the numerical solution of the problem of finding the eigenfrequencies and eigenfunctions of a freely vibrating beam controlled by piezo patch sensors and actuators. The basic formulation of the problem is given in terms of a differential equation which is converted to an equivalent integral equation formulation by introducing an explicit Green’s function. After approximating the kernel of the integral equation in terms of Fourier series based on the eigenfrequencies of the host structure, a method of solution is outlined which consists of expressing the integral equation as an infinite series of linear equations and using a finite of number of these equations in the numerical solution. Numerical results are obtained for different values of the gain, the axial load and for three patch sizes. The first three vibration frequencies of the controlled and uncontrolled beam are given. The tip deflections of the beam for different axial loads are also plotted to compare transient behaviour.     

网络环境下实时图像信息处理传输系统

基于 MPEG-IV 编解码技术和 RTP/RTCP 网络传输协议,设计出一种以高速 DSPTMS320C6205 为核心处理器的实时图像信息处理传输系统(IPTS)。系统的总体构架采用Client/Server 模式,由现场视频信息采集前端、信息中心和视频信息传输网络构成。该系统融合了先进图像处理技术、信息技术、数据通信传输技术及自动控制技术等,能实时地采集和处理图像信息,并进行网络传输和控制,是一种范围大、方位全、实时、准确和高效信息综合处理系统。     

基于智能天线的动态时隙指派技术研究

针对TDMA/TDD公众蜂窝移动通信系统的特征,运用了一种智能天线的解决方案,研究并提出一种动态时隙指派的算法。目的是让无线资源指派根据空时最佳特性进行量化评估并优选,然后把最优载波和时隙分配给需要的移动终端。系统级仿真表明,本算法和传统时隙分配算法相比,移动通信网络的综合性能指标得到的显著的改善。     

Inverse methodology as applied to reconstruct local textile features from measured pressure field

One can compute the final deformation of a known geometry under specific boundary conditions using the constitutive laws of mechanics that describe their stress strain behavior.In such cases the initial geometry is known,and all operators mapping the deformation are defined on the reference domain.However,there are situations in which the final configuration of a deformation might be known but not the initial.The inverse formulation allows one to determine the initial geometry of a domain,given its final deformation state,the material behavior law and a set of boundary conditions.In the present work we propose a method to reconstruct the mesoscale geometry of a textile based on its mechanical response during compaction.To do so,stress boundary conditions are acquired by means of a pressuresensitive film.By adopting an appropriate material law,the thickness and width information of the yarns are deduced from the pressure field experienced by the compacted textile.Unlike 3D scanning techniques such asβ-CT,the proposed method can be applied on any domain size,allowing long-range variability to be captured.To the best of the authors' knowledge,there are no previous works that use a pressure-sensitive film on a large domain to capture the input data for a shape reconstruction.This example application serves as a demonstration of a methodology which could be applied to other classes of materials.     

Vibration and damping characteristics of beams with active constrained layer treatments under parametric variations

Hybrid damping designs with active piezoelectric materials and passive viscoelastic materials (VEMs) combine the advantages of both active and passive constrained layer damping (ACLD/PCLD) treatments.Researchers have established the standards for the extent and placement of the PCLD treatment for common structures. However for ACLD treatment, such detailed studies are not available. This study is aimed to examine, the effect of parametric variation of active constrained layer on the vibration control of the beams treated with optimally placed active or passive constrained layer damping patches. Finite element model is developed to model the open-loop and close-loop dynamics of active/passive constrained layer damping treated beam. The placement strategies of ACLD patches are devised using the modal strain energy (MSE) approach. Extensive experimentation studies are conducted by making twenty one separate samples of ACLD/PCLD treated beams with variations in viscoelastic material layer thickness, ACLD/PCLD patch coverage and location of the patch. Effects of key parameters, such as control gain, viscoelastic material thickness, coverage and location variation of ACLD patch on the system loss factor have been investigated. The careful analysis of results from partially covered ACLD treated beam suggests that the maximum damping of the first mode can be achieved by attaching the ACLD patch only up to 50% coverage. It also reveals that with proper choice of the control voltage and thickness, the effective loss factor can be almost doubled. The present study suggests the potential use of parametric studies that establish some guide lines for the extent and placement of the ACLD patches on the cantilevered beam.     

空调系统运行能效及运行监测参数探讨

空调系统运行能效比对于判定空调系统是否节能运行十分重要。通过对5个工程运行管理和运行记录的调查分析,从计算空调系统运行能效比的角度出发,分别提出冷水机组＋燃气锅炉,直燃机,水环热泵三种空调系统重点用能设备必要运行监测参数和记录频率,并将实际工程参数的记录情况与之比较,发现实际工程运行记录和运行管理中存在的一些问题,提出一些意见和需要注意的问题,为健全企业运行记录管理提供参考。     

压电智能结构有限元动力模型及其振动主动控制的研究

推导了压电智能结构的有限元动力方程;应用模态控制理论对结构振动主动控制的原理和策略进行了讨论,利用两种反馈控制律研究了智能结构振动抑制的问题,最后应用本文方法对一新型2—DOF平面并联压电智能杆机构进行了振动主动控制实验研究,结果表明系统的稳定时间从抑振前的488ms缩短到了抑振后的115ms,验证了本文方法的有效性。     

Real-time routing in flexible flow shops: a self-adaptive swarm-based control model

This paper presents a self-adaptive, swarm-based control model for real-time part routing in a flexible flow-shop environment. The proposed control model is a multi-agent system that exhibits adaptive behaviour, which has been inspired from the natural system of the wasp colony. The production problem, which has been previously studied in the literature by several researchers, involves assigning trucks to paint booths in real-time in a flexible flow-shop environment with the objective of throughput maximization and minimization of number of paint flushes accrued by the production system, assuming no a priori knowledge of the colour sequence or colour distribution of trucks is available. The proposed control model is benchmarked with the results of previous studies reported in the literature in solving the same production problem. The proposed control model uses self-adapting threshold parameters to facilitate the production flow in real time. A simulation-based software environment is designed and developed to investigate its performance. The simulation results show that the proposed control model is more robust to environmental changes, and it outperforms the previously reported studies on the basis of throughput, number of setups, and cycle time performance measures.