采用模式搜索法对磁悬浮列车轨道梁的加工实现精确定位

磁悬浮列车轨道梁体积大、质量重,无法适用传统机加工定位方式,需由机床进行测量并与理论模型进行拟合以确定其加工位置。针对定位过程中的拟合问题,文章基于最小二乘原理,采用模式搜索法对理论模型和实际模型进行拟合,使其满足每个实测点与其对应理论点的距离的平方和为最小,从而实现对加工位置的精确定位,并得到从理论模型到加工模型的坐标变换参数和转换矩阵。     

不锈钢焊管抛磨新设备

PG圆管和PF方管系列抛光机的抛光质量及效率能满足生产需要。介绍了这种不锈钢圆管及方管抛光机的工作原理。着重分析了抛磨轮的选用。     

斜拉桥肋板式主梁剪力滞效应研究

大跨度斜拉桥剪力滞效应十分突出,在设计和施工过程中应考虑剪力滞效应的影响。根据能量变分原理,推导出肋板式主梁截面的剪力滞系数简易计算公式。以某460米主跨预应力混凝土斜拉桥为研究对象,采用大型空间有限元分析程序MIDAS FEA 3.3进行三维实体有限元数值分析,并与通过能量变分法计算得到的剪力滞系数比较发现,宽度较大的肋板式主梁剪力滞效应突出,且跨中处截面剪力滞系数小,而塔根处的截面剪力滞系数大,在设计和施工过程中应采取必要的措施保证结构安全。     

A revisit to stochastic near-optimal controls: The critical case

This paper revisits the stochastic near-optimal control problem considered in Zhou (1998), where the stochastic system is given by a controlled stochastic differential equation with the control variable taking values in a general control space and entering both the drift and diffusion coefficients. A necessary condition of near-optimality is derived using Ekeland’s variational principle, spike variation techniques, and some delicate estimates for the state and the adjoint processes. We improve the error bound of order from “almost” ${\epsilon }^{\frac{1}{3}}$ in Zhou (1998) to “exactly” ${\epsilon }^{\frac{1}{3}}$.     

高压开关柜温度远程在线监测系统设计

针对现有高压开关柜测温系统的缺陷,设计了一种温度远程在线监测系统.系统由6只SAW温度传感器和1个基于雷达原理的无线询问器组成,询问器通过向传感器发射高频激励信号(497～503 MHz)并接收带有温度信息的回波信号实现温度测量,同时,系统利用GSM模块进行短信报警、即时温度查询以及系统参数设置实现了远程在线监测.经过大量的实验和测试表明:该系统工作稳定,抗干扰能力强,测量误差在0.5℃以内,采用10 Ah锂电池供电,可持续工作超过35天,相比传统设备,更适合于高压开关柜的温度监测.     

一种低噪声分离装置研究

低噪声分离装置的主要功能是实现段间连接和可靠的低噪声分离。其工作原理主要为杠杆原理,主体采用完全机械结构,执行机构由小型机电结合件限位控制,在采用了适当的降噪措施后,其动作可靠,静音效果良好。     

Probability‐weighted nonlinear stochastic optimal control strategy of quasi‐integrable Hamiltonian systems with uncertain parameters

The nonlinear stochastic optimal control problem of quasi‐integrable Hamiltonian systems with uncertain parameters is investigated. The uncertain parameters are described by using a random vector with λ probability density function. First, the partially averaged Itô stochastic differential equations are derived by using the stochastic averaging method for quasi‐integrable Hamiltonian systems. Then, the dynamical programming equation is established based on stochastic dynamical programming principle. By minimizing the dynamical programming equation with respect to control forces, the optimal control forces can be derived, which are functions of the uncertain parameters. The final optimal control forces are then determined by probability‐weighted average of the obtained control forces with the probability density of the uncertain parameters as weighting function. The mean control effectiveness and mean control efficiency are used to evaluate the proposed control strategy. The robustness of the proposed control is measured by using the ratios of the variation coefficients of mean control effectiveness and mean control efficiency to the variation coefficients of uncertain parameters. Finally, two examples are given to illustrate the proposed control strategy and its effectiveness and robustness. Copyright © 2014 John Wiley & Sons, Ltd.     

关于Hamilton原理

Hamilton发展了Lagrange分析力学,他对分析力学的主要贡献是一个原理—Hamilton原理和一个方程-Hamilton方程.本文给出Hamilton原理的经过史,包括Hamilton原著的表述,以及后人对这个原理的理解和发展.     

黄河下游引黄涵闸清淤设备的设计方案研究

本文解决了快速清除引黄涵闸淤积泥沙设备的设计方案问题。该设备的工作原理是将高压水喷射到闸门前淤积的泥沙层,靠高压水的冲击力清除闸门前的淤积泥沙。它主要由高压供水喷水系统和喷水装置牵引支撑系统两部分构成,被固定地安放在闸门上方,其构造简单、安装维护方便,具有良好的实用价值,有利于推广应用。     

A Maximum Principle via Malliavin calculus for combined stochastic control and impulse control of forward‐backward systems

We consider a combined stochastic control and impulse control problem of forward‐backward systems driven by Lévy processes, where both the system coefficients and the objective performance functional are allowed to be random, non‐Markovian; the information available to the controller is partial information. Applying a Malliavin calculus approach, we derive a maximum principle for this control problem, where the adjoint processes are explicitly represented by the parameters and the states of the system. Finally, we give two examples of applications. © 2015 Chinese Automatic Control Society and Wiley Publishing Asia Pty Ltd