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521.
T. Patrik Nordberg 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2004,42(6):413-432
A time domain simulation error method is presented in the following article for estimating the excitation of structural systems from local operational responses. The present study focuses on the case in which the location of the excitation is known a priori, as it is for the interaction of the road profile and the tyre patch for an automotive vehicle. The road profile is parameterized into coefficients using truncated sets of base functions which greatly reduce the number of unknowns in the resulting non-linear optimization problem. A complex non-linear model of a ground excited vehicle is utilized to illustrate the applicability and performance of the method. 相似文献
522.
The deficiencies in the Istanbul transportation system have led the local authorities to plan several alternative transportation projects. In this paper three alternative rail transit network proposals are evaluated by using Analytic Hierarchy Process (AHP), a multiple criteria decision support system. The AHP facilitates decision-making by organizing perceptions, experiences, knowledge and judgments, the forces that influence the decision, into a hierarchical framework with a goal, scenarios, criteria and alternatives of choice. Based on this analysis, the decision makers have developed a new alternative as a combination of the most closely competing two alternative rail transit networks. This combination rail transit network is currently under construction. 相似文献
523.
An Extended Adaptive Kalman Filter for Real-time State Estimation of Vehicle Handling Dynamics 总被引:2,自引:0,他引:2
M. C. Best T. J. Gordon P. J. Dixon 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2000,34(1):57-75
This paper considers a method for estimating vehicle handling dynamic states in real-time, using a reduced sensor set; the information is essential for vehicle handling stability control and is also valuable in chassis design evaluation. An extended (nonlinear) Kalman filter is designed to estimate the rapidly varying handling state vector. This employs a low order (4 DOF) handling model which is augmented to include adaptive states (cornering stiffnesses) to compensate for tyre force nonlinearities. The adaptation is driven by steer-induced variations in the longitudinal vehicle acceleration. The observer is compared with an equivalent linear, model-invariant Kalman filter. Both filters are designed and tested against data from a high order source model which simulates six degrees of freedom for the vehicle body, and employs a combined-slip Pacejka tyre model. A performance comparison is presented, which shows promising results for the extended filter, given a sensor set comprising three accelerometers only. The study also presents an insight into the effect of correlated error sources in this application, and it concludes with a discussion of the new observer's practical viability. 相似文献
524.
文章对预应力CFRP板双面加固钢板的轴心受拉静力行为进行了试验研究,首先采用一维线弹性理论和三维空间单元有限元模型分析预应力CFRP板双面加固钢板的轴心受拉应力分布,然后对粘贴不同预应力水平CFRP板的加固试件进行轴心受拉试验.结果表明:施加机械锚固装置后,钢板应力水平有很大降低,承载能力相应有很大提高,但刚度提高不大,而且机械锚固装置对保持高承载能力是必须的,应力分布理论值与试验值吻合得很好.试验中还观察到CFRP板高应力条件下很小的蠕变和预应力偏心作用所导致的弯曲应力.短期预应力损失主要由弹性压缩产生,循环荷载下的预应力损失很小.因此总预应力损失可简化计算为短期损失乘以一个安全系数, 相似文献
525.
With fisheries declining, coral reefs battered, mangrove forests under threat, pollution levels rising, and coastal communities experiencing increased poverty, the Philippines faces severe challenges in managing its coastal resources. Coastal management efforts began in the Philippines more than 20 years ago through various community-based projects. Now, integrated coastal management is expanding in the country and holds the potential to reverse the trends. This article analyzes the situation in relation to new approaches for coastal management being undertaken through the Coastal Resource Management Project supported by the United States Agency for International Development implemented by the Department of Environment and Natural Resources. This project, drawing on the lessons generated by past and ongoing coastal management initiatives, is emphasizing integrated approaches to management over narrowly focused fisheries management and habitat protection efforts. It highlights the increasingly important role of local governments and the changing roles of national government to effectively support integrated coastal management. Multisectoral collaboration is explained as standard procedure to achieve outcomes that are broad based and sustainable. Local and national level activities are contrasted and shown as essential complements in building institutionalization of resources management within all levels of government. A practical result framework is explained for measuring relative success at the local government level of implementing best practices for coastal management. Finally, lessons being learned related to collaboration, level of focus, education, and communication; who is responsible; and expansion of the project are highlighted. 相似文献
526.
T. H. S. Li C. J. Huang C. C. Chen 《International Journal of Automotive Technology》2010,11(4):581-592
A novel tracking and almost disturbance decoupling problem of multi-input, multi-output (MIMO) nonlinear systems based on
feedback linearization and a multi-layered feedforward neural network approach has been proposed. The feedback linearization
and neural network controller guarantees exponentially global uniform ultimate bounded stability and almost disturbance decoupling
performance without using any learning or adaptive algorithms. The new approach renders the system to be stable with the almost
disturbance decoupling property at each step when selecting weights to enhance the performance if the proposed sufficient
conditions are maintained. One example, which cannot be solved by the existing approach of the almost disturbance decoupling
problem because it requires the sufficient conditions that the nonlinearities that multiply the disturbances satisfy structural
triangular conditions, is proposed to exploit the fact that the tracking and the almost disturbance decoupling performances
are easily achieved by the proposed approach. In order to demonstrate the practical applicability, a famous half-car active
suspension system is investigated. 相似文献
527.
This paper builds up a typical model of a parallel hybrid electric vehicle and develops model predictive controllers for this
model to control the speeds and torques for fast clutch engagement with high driving comfort and low jerk. Some modified algorithms
for model predictive controllers are studied to improve their ability to track the desired speed setpoints, subject to input
and output constraints. 相似文献
528.
Peter T. Leach 《中国远洋航务》2008,(9):34-35
自巴拿马运河管理局两年前宣布修建第三组船闸以来,许多行业观察家都怀疑巴拿马运河管理局是否过于野心勃勃。为了支付修建第三组船闸的费用,巴拿马运河计划增加通行费。此举是否会增加其它航线的竞争力?巴拿马运河管理局如何将项目成本控制在52.5亿美元以下,同时又保证项目如期竣工? 相似文献
529.
Almost all researches about dynamic lane assignment were conducted to evaluate the effectiveness of applying this technique at signalized intersections. However, little attention was given to the method of identifying quickly the optimum lane group. This research suggests a quick method to find the optimum lane group for 3-lane and 4-lane approaches at junctions where each approach has green by itself in turn using the percentage of turning movements. MATLAB environment was used to build an optimization model to find the optimal lane groups at all intersection approaches for hypothetical massive traffic demand combinations using an objective function of minimizing intersection delay. This finding represents a plausible quick method to predict the optimum lane group in the field instantaneously using the percentage of turning movements at the approach without conducting massive calculations. 相似文献
530.
Simplified methods to estimate mean axial crushing forces of plated structures are reviewed and applied to a series of experimental results for axial crushing of large-scale bulbous bow models. Methods based on intersection unit elements such as L-, T- and X-type elements as well as methods based on plate unit elements are employed in the analyses. The crushing forces and the total absorbed energy obtained by the simplified analyses are compared with those obtained from large-scale bulbous bow experiments. The accuracy and the applicability of these methods are discussed in detail. 相似文献