Design of Nonlinear Controllers for Active Vehicle Suspensions Using Parameter-Varying Control Synthesis

Nonlinear suspension controllers have the potential to achieve superior performance compared to their linear counterparts. A nonlinear controller can focus on maximizing passenger comfort when the suspension deflection is small compared to its structural limit. As the deflection limit is approached, the controller can shift focus to prevent the suspension deflection from exceeding this limit. This results in superior ride quality over the range of road surfaces, as well as reduced wear of suspension components. This paper presents a novel approach to the design of such nonlinear controllers, based on linear parameter-varying control techniques. Parameter-dependent weighting functions are used to design active suspensions that stiffen as the suspension limits are reached. The controllers use only suspension deflection as a feedback signal. The proposed framework easily extends to the more general case where all the three main performance metrics, i.e., passenger comfort, suspension travel and road holding are considered, and to the design of road adaptive suspensions.     

施工项目HSE管理体系建设与思想工作研究

HSE的宗旨是对工程项目实行职业健康、安全、环境的全员、全方位、全过程的管理,并使其对项目建设本身的危险、对社会的危害、对环境的破坏降到最低点,是实现工程项目建设目标的需要。该文首先介绍了研究HSE的意义,然后分析了现阶段我国HSE管理存在的问题,最后提出了HSE管理体系该怎样建设。     

港口环境承载力概念及其影响因素初探

港口环境承载力作为衡量港口可持续发展的重要指标,其概念和影响因素亟待研究。根据环境科学中有关环境容量和环境承载力的相关理论,结合港口可持续发展的要求,提出港口环境承载力的概念并对其影响因素进行了分析,认为港口环境承载力受港口的自然条件、软硬件条件、周边及腹地交通条件、社会经济条件、能源资源条件和环境污染水平的共同影响。港口环境承载力概念及其影响因素的研究将为港口承载力的定量评估提供理论基础。     

Theoretical and experimental excitation force spectra for railway-induced ground vibration: vehicle–track–soil interaction,irregularities and soil measurements

Excitation force spectra are necessary for a realistic prediction of railway-induced ground vibration. The excitation forces cause the ground vibration and they are themselves a result of irregularities passed by the train. The methods of the related analyses – the wavenumber integration for the wave propagation in homogeneous or layered soils, the combined finite-element boundary-element method for the vehicle–track–soil interaction – have already been presented and are the base for the advanced topic of this contribution. This contribution determines excitation force spectra of railway traffic by two completely different methods. The forward analysis starts with vehicle, track and soil irregularities, which are taken from literature and axle-box measurements, calculates the vehicle–track interaction and gets theoretical force spectra as the result. The second method is a backward analysis from the measured ground vibration of railway traffic. A calculated or measured transfer function of the soil is used to determine the excitation force spectrum of the train. A number of measurements of different soils and different trains with different speeds are analysed in that way. Forward and backward analysis yield the same approximate force spectra with values around 1 kN for each axle and third of octave.     

信号交叉口的环境交通容量

基于对环境交通容量和交叉口运行状况的分析,提出交叉口的环境交通容量优化模型。主要利用峡谷街道排放模型和北京工业大学修正箱式模型来确定交叉口污染物的排放。模型的优化目标是交叉口通行能力的最大化,利用了非线性规划理论,并根据一般约束条件下的广义惩罚函数法进行求解。运用实例说明在一定的污染物条件下交叉口所能达到的通行能力。该模型对交叉口的设计、管理和改善有一定的参考意义。     

Stakeholder Perspectives on the Value of Marine Spatial Planning Towards Advancing Offshore Wind in the U.S.

The United States contributes only 0.2% of the 18,814?MW of global installed offshore wind capacity. Lack of development has been attributed in part to a cumbersome regulatory process that includes the evaluation of environmental impacts. Assessments are based on biological, social, and technical data that are often incomplete. Marine spatial planning (MSP) may help fill data gaps. We conducted semi-structured interviews with key informants to understand (1) whether a lack of biological data impedes offshore wind environmental assessments, (2) whether MSP could mitigate these impediments, and (3) whether MSP could advance offshore wind development in the U.S. in other ways. Most informants stated that a lack of biological data in offshore wind environmental assessments was problematic due to incomplete data, uncertainty of data, and mismatched scales. Data issues may be mitigated by creation of data products and increased communication, outcomes of MSP that may benefit the regulatory process by increasing data availability, resolving conflicts among users, and providing a common operating picture. Challenges remain in integrating MSP into the processes of siting and permitting offshore wind, but it provides a strategic framework for the systematic identification, collection, collation, analyses, application, and management of data in the offshore wind environmental regulatory process.     

环境激励下自升式海洋平台损伤诊断

为探究适用于海洋平台结构的有效损伤诊断方法,针对某自升式平台的比例模型开展环境激励下损伤诊断试验研究。分别采用频域法中的增强频域分解法和时域法中的随机子空间法处理测试数据,提取前三阶的固有频率、振型和阻尼比等模态参数,并结合频率和振型识别结果计算节点柔度矩阵。通过分析平台模型模态参数和节点柔度矩阵的变化率,识别预先设置的结构损伤。试验结果表明,两种模态识别方法均能有效识别环境激励下的平台模型模态参数,其中利用固有频率变化率能够有效判断结构是否产生损伤,利用振型和柔度矩阵的变化率能够实现损伤的准确定位。     

面向可再生能源利用的集装箱港口环境经济效益仿真

可再生能源具有环境友好、可循环利用等优点,综合利用可再生能源是绿色集装箱港口发展的必然趋势。应用系统仿真的方法量化港口装卸生产能源消耗量,结合环境经济效益计算方法定量分析可再生能源替代传统能源的环境经济效益。以某港区采用风力发电为例,对比分析集卡、岸桥和场桥能源替代后的环境效益与经济效益。     

株洲二线船闸深基坑双排桩结构的受力特性

对株洲航电枢纽二线船闸高挡土环境中的双排桩结构变形及内力特征,采用数值计算和工程观测相结合的方法,分析不同桩径、不同开挖深度时结构的变形及受力形态。结果表明:双排桩排距取3倍桩径时,不同开挖深度的前排桩最大位移值呈现二次抛物线形态;前排桩内力呈现单锚板桩的受力特征,后排桩内力呈现悬臂板桩的受力特征;通过设置卸荷板、采用抗剪强度大的材料回填可有效控制结构变形及内力。     

高速公路施工期环境监理监测指标体系的探讨

在高速公路建设施工期的环境监理工作中开展环境监测是保证环境监理有效进行的重要手段。结合工程实例,在总结高速建设项目环境监理工作经验的基础上,提出了环境监理监测指标体系的构成,并就监测指标的选择、监测方法的选择及执行标准的确定分别进行了分析。