Adaptive robust sliding mode control for ship straight-line tracking in random waves

Since complex controllers do not suit for application,we design a simple controller with robustness in changeable sea state.The characteristics of ship motion are large inertia,strong nonlinearity and large time delay.This paper employs adaptive sliding mode technique.We focus on a class of underactuated ship systems with parametric uncertainties and wave efects.Random wave efects are seldom considered in former studies.Various simulations validate the adaptive characteristics and robustness of the proposed controller.The closed-loop system is stable and tracking error can be arbitrarily small by Lyapunov approach.     

混合动力汽车传动系统共振转速优化分析

为解决某混合动力汽车传动系统振动和噪声的问题,建立了复合行星轮系和整车传动系统的扭转振动力学模型对该传动系统进行扭转振动分析。在计算传动系统固有频率的基础上,通过扭转减振器的刚度匹配实现共振转速的优化。研究发现,系统在某特定转速比下出现共振特性且在一定范围内随减振器刚度增大而增大;通过减小减振器刚度可以使共振转速远离发动机怠速转速范围,从而提高整车平顺性和乘坐舒适性。     

Incentive subsidy scheme design with elastic transport demand

Huge public transport subsidies caused by deficits have become a heavy financial burden on some local governments due to the decline of bus passenger numbers. It is essential to apply the performance‐based contract to bus services considering maximization of social welfare. This paper constructs an incentive subsidy contract considering the decision‐making powers of the service level and calculating the proper frequency elasticity aiming at two problems of performance‐based contracts. Meanwhile, we consider a role of bus operators ignored by most researchers. Under the scheme, the decision‐making power of the service level is discussed based on five assumptions, and meanwhile, bus operators are motivated to reduce cost and improve service level in the scheme. The case of the bus service of Arao city indicates that the optimal frequency equals to zero when bus operators decide frequency. If bus operators determine efforts, the optimal effort also equals to zero with the goal of maximizing the profit. Also, bus operators can play their roles in lessening cost and improving service level to help bus operators and the local government achieve a win‐win situation, which maximizes the social benefit in this subsidy scheme when all factors are decided by the government. Copyright © 2013 John Wiley & Sons, Ltd.     

中小跨径混凝土桥梁结构优化

针对公路高架桥上部结构常用的结构形式,选择墩梁连接方式、温度梯度、桥墩高度等参数进行了平面有限元静力分析,得出了一些优化建议。     

便携式地空导弹脱靶量仿真研究

为了能够快速计算便携式地空导弹脱靶量,对导弹作战能力做一个初步判断,本文建立了便携式地空导弹脱靶量计算模型,并运用Simulink软件对其进行了仿真编程。编程所得Simulink模块可以清晰显示导弹与目标运动图形,并且得出弹目交会时弹脱靶量大小,为初步评价武器系统作战效能提供依据。     

数字方位仪设计与实现

根据实际需求,设计了一种新型的数字方位仪,并详细地介绍了数字方位仪的原理、硬件设计、软件设计和使用安装方法。     

高桩承台大体积混凝土裂缝控制探讨

文章结合厦门港海沧港区12#泊位液体化工码头工程实例,通过理论计算,研究在不同施工条件下,温度应力的数值和分布位置,从而科学指导确定施工中的底膜厚度和选择合适的配筋率;对于类似高桩墩式结构承台裂缝控制具有借鉴意义。     

基于成本迭代与需求迭代的四阶段交通模型双重反馈算法研究

四阶段交通模型作为最流行的交通需求预测模型理论,其计算结果存在不一致性的缺陷,反馈算法被引入模型结构中来解决不一致性的问题。研究提出了成本迭代与需求迭代的双重迭代反馈算法,并使用案例比较了它与既有反馈算法的差异。研究结果表明：成本迭代＋需求迭代的双重迭代模型结构能够在不影响预测结果的前提下减少迭代次数和系统运行时间,收敛过程更加稳定且能够适用于不同规格的交通网络。     

国家发明专利《地铁站构筑方法》的技术要点及其优势

就国家发明专利《地铁站构筑方法》的基本理念、地下空间开发方式、核心和关键技术、主要工序进行了阐释,并与传统地铁站施工方法进行了比较。提出了地基预加固条件下封闭式开发地下空间的新思路,这将为我国大城市大规模地铁站建设开辟一条新路子。     

集装箱码头35 kV变电所扩容改造

某集装箱码头35 kV变电所由于扩容需要增加1台户内式8 000 kVA变压器作为备用,增加相应的高压柜及建筑设施,并改造原有的电量监测系统(GE 90/30 PLC,简称"老系统").主变两侧新旧母线的搭接是改造项目一次部分的重点和难点.在电气二次部分的改造中要求将老系统后台全部取消,所有数据从老系统的交换机转发至南瑞RCS-9000后台,老系统的所有功能应完全满足新的综合自动化后台管理需要.图1虚线框内为本次改造增加的部分.