变速轧制下超快冷系统工艺温度在线实时修正策略

结合某现场超快速冷却系统,具体分析了带钢运行速度变化对轧后冷却过程换热系数与冷却时间的影响规律.根据速度运行机制,开发了速度在线修正计算策略,实现了轧后冷却区带钢速度计算值与实际值的吻合;并在此基础上开发的工艺温度在线循环计算策略,消除了速度波动对温度控制的影响,提高了温度控制精度.将该温度在线实时修正策略应用于现场,实现了超快冷出口温度与卷取温度的精确控制,工艺温度命中率在96%以上,有效消除速度对温度波动的影响,完全满足新产品、新工艺的工业化试制及大批量生产.     

QT工艺对一种B-Nb低碳贝氏体钢 组织及强韧性的影响

通过室温拉伸、摆锤冲击、光学及扫描电镜研究了QT(淬火+回火)工艺对实验钢晶界比例、晶粒尺寸、碳化物析出情况及强韧性的影响,并对其变体的分布及组合方式进行了分析.结果表明:随着回火温度的升高,实验钢强度逐渐降低,塑性逐渐提高;450T和500T钢断口为准解理型断裂,贝氏体板条间析出的碳化物及较低比例的大角度晶界使得冲击韧性较差;而600T和650T钢断口为韧窝断裂,组织中大角度晶界的比例增加,有效地阻碍了裂纹的扩展.变体分析表明,450T钢变体组合方式介于Bain group和CP(close packed)group之间,而600T钢变体之间呈现较明显的CP组合方式,同一CP group内的变体取向差较大,偏折了裂纹传播路径,提高了低温韧性.     

Some synchronization criteria for general complex networks with coupling delays

A general complex delayed dynamical network model with asymmetric coupling matrix is considered in this paper. For reducing the conservativeness of synchronization criteria, several novel synchronization stability conditions are presented by using delay decomposition methods. Numerical examples which are widely used to study delay-dependent synchronization stability are given to illustrate the effectiveness of the proposed methods.     

<Emphasis Type="Italic">H</Emphasis><Subscript>∞</Subscript> control for stochastic systems with Poisson jumps

This paper discusses the H _∞ control problem for a class of linear stochastic systems driven by both Brownian motion and Poisson jumps. The authors give the basic theory about stabilities for such systems, including internal stability and external stability, which enables to prove the bounded real lemma for the systems. By means of Riccati equations, infinite horizon linear stochastic state-feedback H _∞ control design is also extended to such systems.     

一种航迹约束演化新模型及其FMM实现

Fast Marching Method（FMM）是一种基于水平集理论的界面演化跟踪算法,常被应用于求解几何最短路径规划问题。在静态环境信息已知的情况下,FMM比传统的网格搜索算法得到的路径更加光滑。但是,经典FMM对规划路径的方向控制能力弱、缺乏路径曲率调控能力。基于调整Eiknoal方程中的代价函数的策略,采用人工势场方法,提出一种综合代价模型,依此实现一种改进FMM。通过定义对应于时间距离图最陡下降法所得路径的势能函数,采用变分方法分析得到含路径曲率的Euler-Lagrange方程,给出满足路径曲率约束的代价调整策略。实验结果表明该模型和方法是可行和有效的,它能够在满足转弯机动约束条件下实现航迹方向的控制,可用于机器人或无人飞行器的航迹规划。     

A sparse algorithm for adaptive pruning least square support vector regression machine based on globalrepresentative point ranking

Least square support vector regression(LSSVR)is a method for function approximation,whose solutions are typically non-sparse,which limits its application especially in some occasions of fast prediction.In this paper,a sparse algorithm for adaptive pruning LSSVR algorithm based on global representative point ranking(GRPR-AP-LSSVR)is proposed.At first,the global representative point ranking(GRPR)algorithm is given,and relevant data analysis experiment is implemented which depicts the importance ranking of data points.Furthermore,the pruning strategy of removing two samples in the decremental learning procedure is designed to accelerate the training speed and ensure the sparsity.The removed data points are utilized to test the temporary learning model which ensures the regression accuracy.Finally,the proposed algorithm is verified on artificial datasets and UCI regression datasets,and experimental results indicate that,compared with several benchmark algorithms,the GRPR-AP-LSSVR algorithm has excellent sparsity and prediction speed without impairing the generalization performance.     

Optimal combinational of quota-share and stop-loss reinsurance contracts under VaR and CTE with a constrained reinsurance premium

This paper considers the problem of minimizing the VaR and CTE of an insurer’s retained risk by controlling the combinational quota-share and stop-loss reinsurance strategy. With a constrained reinsurance premium, the authors give the explicit reinsurance forms and the minimal VaR and CTE of retained risk in the case of quota-share after stop-loss reinsurance and the case of stop-loss after-quota-share reinsurance respectively. Finally, the authors conclude that the quota-share after stop-loss is a better reinsurance strategy than stop-loss after quota-share to minimize the VaR and CTE with a same constrained reinsurance premium. And the pure stop-loss reinsurance is preferred for an insurer with a high level regulatory requirement.     

基于简单蚁群算法的载荷安装误差补偿研究

载荷的安装误差补偿在工程实践中起着十分重要的作用。已有的误差补偿方法一般只针对小误差的情形,而对大误差则没有很好的解决方法。结合空中机动平台光电载荷的安装误差,提出了一种利用简单蚁群算法来补偿载荷安装误差的方法。通过对小误差和大误差两种不同情形的数值仿真,初步验证了方法的可行性;通过对试验数据的测试分析,进一步验证了方法的有效性。     

基于PCA和SDG的传感器故障诊断方法研究及应用

针对传统基于PCA(主元分析)的传感器故障诊断方法缺乏故障推理能力,难以定位故障源的缺点,提出一种PCA与SDG(符号有向图)相结合的传感器故障诊断的方法。此方法分为2步:首先建立系统的SDG模型和PCA模型,使用PCA方法监控所有的过程变量;第二步,当故障发生的时候,通过PCA得到异常变量的状态,根据变量的状态,通过SDG模型进行反向推理,找到可能发生故障的传感器。通过液位控制系统的仿真实验以及在常减压装置(AUDU)故障诊断上的应用,结果表明方法能够及时有效地检测出单个或多个传感器故障,提高了诊断的准确性与分辨率。     

胶辊式砻谷冲击隔离系统隔振技术分析与仿真

为研究胶辊式砻谷工作时振动噪声大的问题,进行了胶辊式砻谷冲击隔离系统隔振技术的研究,通过设计实验验证砻谷装置工作时产生的机械冲击激励为砻谷作业的主要激振源,然后通过理论求解计算出激励力的力幅,再根据胶辊砻谷的工作特性和减少振动传递的要求,提出了一种在胶辊内安装由隔冲器对压并联构成的冲击隔离系统,最后在ADAMS中对冲击隔离系统进行静态下的受压特性和扭转特性仿真分析,验证了冲击隔离系统工作的稳定性;对冲击隔离系统进行脉冲冲击下的动力学仿真分析,获得了胶辊在脉冲冲击下的位移曲线和胶辊安装轴盘受力曲线,将轴盘受力最大值与理论计算出的激励力幅比较。结果表明：安装冲击隔离系统后激励力的传递率为49.5%。可见在胶辊内安装由隔冲器对压并联构成的冲击隔离系统对减少振动的传递具有有益效果。