Two-port network based bilateral control of a steer-bywire system

Steer-by-wire (SBW) system which is characterized by variable steering feel, better active safety, unmanned drive, has been widely studied to realize a distinctive driving experience. Control strategy acts as a key part of SBW system to achieve the goals. In this paper, a control strategy by bilateral control structure for steer-by-wire system is proposed. To make SBW system has the same function of conventional steering systems, the controller is designed to realize desired tracking control and realistic road feel feedback. The control of position and torque for each actuator is taken as two ports for the control network. Based on different control loop, two kinds of bilateral control is investigated respectively. The hardwarein- the-loop experiment platform of SBW is developed by the reconfiguration of electric power steering system. The test results are compared to show the performance of different control loops.     

New tension mechanism for high-speed tensile testing machine

As concerns of dynamic tensile measuring, a new tension mechanism driven by liner motor in high-speed tensile testing machine is presented. It satisfies the requirements for testing the dynamic tensile properties of plastic materials with strain rates from 1 to 100 s^-1, which is relatively difficult to test for currently available machines. For this purpose the idle stroke principle is used to realize the dynamic load of plastic material with static grip. Computer aided engineering is used: i) to analyze and optimize the tension mechanism thus allowing reducing the system shock caused by collisions. ii) to avoid the influence of plastic materials specimen stress and strain uniformity on the measuring system. The analysis results agreed well with the established empirical relationships based on experimental evidence. Two sets of experiments for different strain rate tensile were conducted thus allowing proving the reliability and credibility of the designed tension mechanism.     

关于悬挂点焊机焊点过烧的分析

在汽车的制造生产过程中,白车身总成的焊接通常使用悬挂点焊机进行驾驶室的焊接,点焊属于压力焊的一种,然而在焊接过程中易出现焊点过烧(俗称炸点)的现象,对焊接质量造成一定的影响,也会对人身安全造成一定的伤害.本文主要介绍在悬挂电焊机出现过烧问题时的分析与故障排查.     

网络搜索链接技术的研究

介绍了近几年来互联网络搜索中链接分析技术的进展,并为进一步的研究反对易式出了几个可行的方向。     

岸桥大车液压系统的防风改造

当大车液压系统故障时,现场手动强制作业,存在严重安全隐患。分析了对大车液压系统工况及问题,找出故障原因,并提出合理的解决方案,提高岸桥的安全性和可靠性。     

二齿差针摆行星传动中摆线轮等效代换齿廓的试验研究

通过样机试验的手段来检验,用一条整枝短幅外摆线的等距贡线来代换二齿差摆线轮齿廓的正确性和可行性。采用比较的方法,即在试验台上对装有两种不同齿廓摆线轮的样机,分别进行温升,噪音,振动和效率等参数的对比试验。试验结果表明,等效代换齿廓与原齿廓的传动性能比较,基本相同或略优。从而进一步验证了该理论的正确性,并为该技术的应用提供了依据。     

太平天国的水军太平军水营

以洪秀全为首的农民军自金田起义后,更名为太平军。他们不断与清军作战,转战长江南北,并设立“水路军”,分别在陆上和水中与清军展丌了作战。虽然轰轰烈烈的太平天国运动最终以失败告终,但是“水军”从兴起到结束的十余年时间却在太平天困的战斗史上占据了非常重要的地位。     

考虑跨肩管土作用的悬跨管道涡激振动特性研究

海底悬跨管道涡激振动是一个复杂的流场-管道结构-跨肩土体耦合问题,其发生机理和振动特性十分复杂,特别是两端跨肩处管土作用对涡激振动的影响有待深入讨论。为此,文章引入了P-y曲线描绘跨肩处管土耦合作用,提出了基于管道位移和速度的新非线性土体弹簧模型,根据能量平衡原理计算土体阻尼,采用尾流振子模型模拟悬跨管段流固耦合作用,建立了考虑流—固—土多场耦合作用的海底悬跨管道涡激振动预报模型,并重点研究了考虑跨肩管土作用时,悬跨管道涡激振动的诸多特性。     

Port competition with accessibility and congestion: a theoretical framework and literature review on empirical studies

This review interprets recent studies of the interactions between the competition of gateway seaports and the accessibility of landside transportation links to inland regions. Port competition is treated as part of a rivalry between two transportation chains. This article identifies the main modeling approaches and defines the different types of hinterland access systems described in the literature. A general theoretical framework is then proposed to incorporate those key components. The importance of the proposed framework is revealed by comparing and extending results from the literature. Major assumptions that need further empirical verification are identified and discussed, and related empirical studies are reviewed. Finally, avenues for further research are discussed.     

特种半潜式无人航行器的优化设计

提出一种新型特种半潜式无人航行器方案,并对该航行器方案开展主尺度初步拟定和舱室划分等总体设计工作。基于STAR CCM+软件对该型航行器的水动力性能进行数值仿真分析,分析结果可作为推进系统设计及船型主尺度优化的依据。结合实际工程产品需求分析制约航行器推进系统设计的影响因素,分析续航力、航速、主机功率及电池质量之间的匹配关系,同时提出基于约束关系的主尺度优化方法。最后针对性能校核及数值仿真中发现的问题,提出半潜式无人航行器的进一步优化方案。