基于西门子S7-200PLC的USS通信软件设计

本文以西门子MM440变频器与S7-200PLC之间的USS通信为例,详细介绍了USS驱动装置控制功能块的软件设计。     

逆向工程技术在鞋楦设计中的应用

基于已有的鞋楦,结合逆向工程技术,对其进行逆向设计的研究.采用先进的便携式测量系统FaroArm Platinum对鞋楦进行非接触式测量,获得鞋楦表面数据,利用Imageware软件对采集的数据进行处理,并完成鞋楦模型的重构.研究表明:逆向工程技术在鞋楦设计中的应用具有显著意义.     

闸后水流运动的SPH法数值模拟

在对光滑离子流体动力学(SPH)法的基本原理、核函数及控制方程离散格式、边界处理方法等进行介绍的基础上建立了数值水槽模型,成功模拟了闸门开启后水流的界面变形、界面破碎、气泡的生成及溃灭,以及涌浪的生成过程。结果表明SPH法能够捕捉到流体的飞溅及融合现象,适于模拟具有瞬时极大变形等水流运动。     

基于层次分析法的沈阳浑北灌区闸门安全评价

以《水闸安全鉴定管理办法》的评价指标体系为基础,引入层次分析法确定了指标权重,阐述了将层次分析法运用到灌区水闸安全评价的全过程,并以沈阳浑北灌区进行验证。结果表明,运用层次分析方法能对水闸的安全性作出全面、直观的评价,在一定程度上避免了评价中的主观影响。     

数字化缺陷在超特高压输电线路巡检业务管理中的研究与应用

数字化缺陷管理,作为输电线路日常巡检工作中的一种新型信息化管理机制,其有效利用计算机科学的正则表达式技术,对巡检过程发现的缺陷进行精准化记录与标准化存储,并提供最细精度的复合结果查询,实现了对巡检缺陷的高效管理与统计,通过对重庆市电力公司检修分公司所辖水张一线、水张二线进行生产实验与扩展性应用,结果表明能够有效地提高输电线路日常巡检的工作效率和管理质量,应用前景广泛。     

缅甸敏达水电站厂房设计

结合缅甸敏达水电站地形地质条件,从厂址比选、开关站型式比选和厂房布置等几个方面介绍了该水电站厂房设计的基本思路及设计要点。     

广西农村水电站信息化建设思路探讨

本文针对农村水电站管理特点,结合水电站数量多、分布广、管理要素杂、管理手段落后的客观情况,提出了信息系统建设应从"看的清、搞的懂、有办法、能落实"四个层面入手构建技术体系、功能体系和应用体系。并结合广西农村水电站信息化建设过程,探讨了农村水电站信息化建设思路。     

Design of a modified repetitive-control system based on a continuous–discrete 2D model

This paper concerns the problem of designing a modified repetitive-control system for a class of strictly proper plants. Repetitive control involves two types of actions: control and learning; but the insertion of a low-pass filter in a modified repetitive controller, which is employed to guarantee the stability of the system, mixes the two actions together. In this paper, a continuous–discrete two-dimensional model is first constructed. Next, the continuity of repetitive control and Lyapunov stability theory are applied to the model to establish two linear-matrix-inequality (LMI) based sufficient stability conditions, one for the design of the cutoff angular frequency and one for the design of the feedback gains. The features of these conditions are exploited to develop an iterative algorithm that searches for the best combination of the maximum cutoff angular frequency of the low-pass filter and the feedback gains. A numerical example illustrates the design procedure and demonstrates the validity of the method.     

话语标记语在法庭问答中的语境制约作用

在交际过程中,为了让听话人更好地理解话语,说话人可以向听话人提供明示导向的话语标记,从而对一系列的语境假设加以制约以减少听话人处理话语所需付出的努力。以关联理论为框架,通过对一份近五万字的法庭庭审语料进行分析,阐述了话语标记语对语境的制约作用主要表现在三个方面,即加强现时语境、消除现时语境以及产生新的语境暗含。     

Comparison of two suspension control strategies for multi-axle heavy truck

Two simple and effective control strategies for a multi-axle heavy truck, modified skyhook damping (MSD) control and proportional-integration-derivative (PID) control, were implemented into functional virtual prototype (FVP) model and compared in terms of road friendliness and ride comfort. A four-axle heavy truck-road coupling system model was established using FVP technology and validated through a ride comfort test. Then appropriate passive air suspensions were chosen to replace the rear tandem suspensions of the original truck model for preliminary optimization. The mechanical properties and time lag of dampers were taken into account in simulations of MSD and PID semi-active dampers implemented using MATLAB/Simulink. Through co-simulations with Adams and MATLAB, the effects of semi-active MSD and PID control were analyzed and compared, and control parameters which afforded the best comprehensive performance for each control strategy were chosen. Simulation results indicate that compared with the passive air suspension truck, semi-active MSD control improves both ride comfort and road-friendliness markedly, with optimization ratios of RMS vertical acceleration and RMS tyre force ranging from 10.1% to 44.8%. However, semi-active PID control only reduces vertical vibration of the driver’s seat by 11.1%, 11.1% and 10.9% on A, B and C level roads respectively. Both strategies are robust to the variation of road level.