轮胎式变跨龙门吊的设计

我国的客运专线大量采用板式无砟轨道结构形式,在轨道板的敷设过程中需要配套专用的机械设备,即轮胎式变跨门吊。结合无砟轨道的施工特点及线路断面结构,在轨行式单梁、双梁门吊主体构架的基础上,研究开发了适应线路断面变化,具有走行转向灵活、无级变跨等功能的轮胎式变跨门吊。重点介绍了轮胎式变跨门吊的主要技术参数、结构特征以及变跨机构的设计等,为今后的轮胎式门吊、变跨式门吊的设计及改造提供了参考借鉴。     

一种改进的步长自适应EASI算法

首先定义了描述信号分离状态的一种测度，并在认真分析相关固定步长和变步长EASI算法的基础上，将其加以运用，提出一种新的步长自适应EASI算法。由于该算法步长是基于分离状态的，其学习速率由信号的分离程度自适应的选取，因而能很好地解决收敛速度和稳态误差之问的矛盾。计算机仿真结果与理论分析相一致，证实了该算法明显优于其它的EASI算法。     

一种智能化实时监测系统的研究

作者从构造一个智能化实时监测系统的关键技术入手,对系统的设计与实现作了探索性的介绍。     

Optimisation of full-toroidal continuously variable transmission in conjunction with fixed ratio mechanism using particle swarm optimisation

The aim of this research is the optimisation of full-toroidal continuously variable transmission (CVT) in conjunction with the fixed ratio (FR) mechanism, while the optimisation objective is to minimise fuel consumption (FC) of the vehicle in the new European driving cycle. After the dynamic analysis of the power train, a computer model is developed to simulate contact between CVT elements and consequently calculate its efficiency. Then an algorithm is presented to calculate FC of the vehicle in the driving cycle. Then, an optimisation using particle swarm optimisation on the CVT geometry and FR mechanism (which is embedded between CVT and final drive) is carried out to minimise FC. It is found that by utilisation of the optimised CVT; FC will be about 11% and 8% lower, compared with the application of a five-speed manual transmission and conventional CVT, respectively. Finally, effects of the roller tilt angle and oil temperature on the FC are investigated.     

Roll stabilisation of road vehicles using a variable stiffness suspension system

A variable stiffness architecture is used in the suspension system to counteract the body roll moment, thereby enhancing the roll stability of the vehicle. The variation of stiffness concept uses the ‘reciprocal actuation’ to effectively transfer energy between a vertical traditional strut and a horizontal oscillating control mass, thereby improving the energy dissipation of the overall suspension. The lateral dynamics of the system is developed using a bicycle model. The accompanying roll dynamics are also developed and validated using experimental data. The positions of the left and right control masses are sequentially allocated to reduce the effective body roll and roll rate. Simulation results show that the resulting variable stiffness suspension system has more than 50% improvement in roll response over the traditional constant stiffness counterparts. The simulation scenarios examined is the fishhook manoeuvre.     

随机横浪中船舶倾覆过程模拟与安全域计算

研讨了随机海浪中船舶非线性随机横摇运动倾覆过程和安全域问题.考虑非线性阻尼、非线性复原力矩和随机波浪,建立了随机横浪中船舶运动的随机非线性微分方程.考虑两参数海浪谱和不同的有义波高,计算随机波浪力矩,采用简谐加速度数值计算方法求解随机微分方程,进行了随机倾覆过程的数值模拟.考虑船舶运动的瞬时状态,发展了胞映射方法计算随机非线性横摇运动安全域的方法,并编制了计算机程序.模拟了一条渔船不同有义波高作用下横摇倾覆过程,考虑不同的初始条件及随机波浪参数,在初始值平面上采用胞映射法构造了渔船航行的安全域.波高较小时,安全域是一个连续的区域;随着有义波高增大,安全域面积减小并且不再连续,倾覆域和安全域相互包围.计算结果表明,船舶运动的瞬时状态对安全域具有重要影响,而且随机海浪中安全域具有随机特性.     

On the achievable performance using variable geometry active secondary suspension systems in commercial vehicles

There is a need to further improve driver comfort in commercial vehicles. The variable geometry active suspension offers an interesting option to achieve this in an energy efficient way. However, the optimal control strategy and the overal performance potential remains unclear. The aim of this paper is to quantify the level of performance improvement that can theoretically be obtained by replacing a conventional air sprung cabin suspension design with a variable geometry active suspension. Furthermore, the difference between the use of a linear quadratic (LQ) optimal controller and a classic skyhook controller is investigated. Hereto, an elementary variable geometry actuator model and experimentally validated four degrees of freedom quarter truck model are adopted. The results show that the classic skyhook controller gives a relatively poor performance while a comfort increase of 17–28% can be obtained with the LQ optimal controller, depending on the chosen energy weighting. Furthermore, an additional 75% comfort increase and 77% energy cost reduction can be obtained, with respect to the fixed gain energy optimal controller, using condition-dependent control gains. So, it is concluded that the performance potential using condition-dependent controllers is huge, and that the use of the classic skyhook control strategy should, in general, be avoided when designing active secondary suspensions for commercial vehicles.     

神经网络自适应控制算法的研究和MATLAB仿真

本文针对神经网络系统跟踪输入信号时,由于误差总是存在导致学习过程难以结束的特点,以一种用BP 网络逼近对象的学习算法为基础,结合相应的控制算法加以改进,并得到了一种快速学习因子的选择方法。结合不同对象通过MATLAB进行仿真,均获得了满意的效果。仿真和分析表明,该算法能保证系统具有良好的动态品质。     

多种概率分布的随机参数结构屈曲特征值分析

采用随机收敛的非正交的多项式展式表示未知的随机屈曲特征对,对随机结构的随机变量在服从多种概率分布情况下的屈曲特征值进行了研究.算例表明,对于服从多种概率分布的随机结构屈曲特征值问题,当参数变异性较大时,即使只采用前4阶非正交多项式展式,逼近的结果仍然较好.计算结果还表明,如果把非高斯分布的随机参数模型用高斯分布模型进行分析,将给研究带来相当大的误差,而且这种误差随参数变异性的增大而增大.     

举水河特大桥大跨悬臂梁挂篮施工过程控制

通过武汉至英山高速公路03合同段举水河特大桥主跨连续箱梁施工实例,总结悬臂梁施工过程中#0块、节段及合拢段施工中每道工序应注意的要点、方法,以及施工关键环节和重要部位的质量控制,以期保证工程质量。