履带车辆磁流变阻尼器动力学模拟实验台研究

基于磁流变液(M RF)构造出的半主动悬挂系统可以用于对车辆振动的实时控制,半主动悬挂系统模拟实验台是实行实车动力学分析进而实现上述目标的基础性设备。首先,按照相似定理,进行了履带车辆磁流变液半主动悬挂系统动力学模拟实验的台架设计,实现了动力学模拟;进而,结合履带车辆行驶的典型越野路面,提出一种路面激励输入设计方案;最后叙述了基于L abV IEW虚拟仪器的磁流变振动实验台状态监测系统的构成。     

基于磁流变阻尼器的半主动悬挂控制实验研究

将磁流变阻尼器应用于半主动悬挂系统。建立了基于磁流变半主动悬挂系统的二自由度1/2车体的履带车辆振动模型。应用LQR最优控制理论,提出了一种基于磁流变阻尼器的履带车辆半主动控制策略,并在振动实验台上进行了半主动控制实验,模拟了车辆通过正弦路面的情形,结果表明,应用该控制策略能得到良好的减振效果。     

履带车辆磁流变半主动悬挂系统控制算法研究

将磁流变阻尼器这种智能阻尼减振装置应用于车辆悬挂系统中，构成了新型的半主动悬挂系统。建立了1／2车体动力学动模型。研究了瞬时最优控制（IOC）和经典线性最优控制（COC）两种控制算法及其实现问题。通过对某型履带车辆在典型沙土路面激励下的振动响应进行仿真，得出了不同控制策略下车体的响应情况。比较分析表明，两种控制策略下磁流变半主动悬挂系统都有着较好的减振效果。     

基于磁流变阻尼器的履带车辆悬挂系统半主动控制

将磁流变阻尼器应用于履带车辆的悬挂系统中,研究了磁流变阻尼器在不同电流下的力学特性和耗能特性。建立了履带车辆二自由度车体振动模型,提出了基于线性二次型(LQR)最优控制理论的半主动控制算法。对典型沙土路面激励下履带车辆悬挂系统的半主动控制效果进行了仿真,与被动及开关控制的减振效果进行比较,得出了车体振动加速度、线位移、角加速度和角位移的响应曲线。结果表明,该控制算法对基于磁流变阻尼器的履带车辆悬挂系统有着很好的控制效果。     

加速度输入的履带车辆悬挂系统LQR控制建模与仿真

建立了以加速度作为路面激励输入信号,且考虑非悬置质量的履带车辆二自由度二分之一车辆力学模型,选定状态变量,推导出悬挂系统状态方程和振动微分方程。基于线性二次型(LQR)最优控制理论的主动控制算法得出最优控制力,依据磁流变阻尼器半主动限界Hrovat控制算法追踪最优控制力,实现悬挂系统磁流变阻尼半主动控制。对典型正弦路面激励下履带车辆悬挂系统的主动、半主动控制效果进行了仿真,并与被动控制效果进行比较。结果表明,建立的力学模型可信,算法能很好控制车体位移和加速度。     

磁流变阻尼器力学特性及其在车辆悬挂系统中的应用

对磁流变阻尼器的力学特性进行了理论分析和实验研究，得出了其阻尼力与电流、振动速度和振幅等因素之间的变化关系，并将该阻尼器应用于车辆悬挂系统中，建立了基于该阻尼器的履带车辆振动模型，提出了相应的半主动控制算法，对路面激励下悬挂系统的控制效果进行了仿真，结果表明，将磁流变阻尼器应用于履带车辆的悬挂系统可以大大减小车体响应，有着广阔的工程应用前景。     

履带车辆半主动悬挂二自由度计算机仿真实验

基于磁流变(MRF)减振器的履带车辆半主动悬挂系统，其阻尼力根据环境可控可调，从而能够完成对履带车辆振动的有效抑制。选用履带车辆二自由度1／2的车体模型，分别针对被动悬挂和半主动悬挂，建立了相应的数学模型。加上瞬时最优控制算法后，得出了悬挂系统的最优控制力。采用控制系统的分析和仿真软件Matlab中的Simulink工具箱进行了被动及半主动仿真实验。     

履带车辆主动悬挂多点布置优化

为实现履带车辆主动悬挂减振性能和能耗达到综合最优,基于正交试验方法开展履带车辆主动悬挂多点布置优化设计。首先,建立了履带车辆悬挂系统动力学模型,并通过道路模拟试验验证了该模型的合理性;其次,开展了履带车辆悬挂系统正交试验,分析了4种典型路面下各子悬挂对悬挂系统减振性能影响的敏感性;最后,设计了主动悬挂作动器的6个布置方案,通过建立基于线性二次最优（linear quadratic regulator,简称LQR）控制的履带车辆主动悬挂动力学模型,分析了典型路面下各布置方案对悬挂系统减振性能的影响规律及能耗变化规律。结果表明,通过对履带车辆主动悬挂作动器的布置优化,可以实现悬挂减振性能和能耗之间的平衡。     

基于磁流变液减振器的履带车辆悬挂振动控制研究

选用履带车辆二自由度1/4的车体模型,分别针对被动悬挂系统和基于磁流变液(MRF)减振器的半主动悬挂系统建立了相应的数学模型,并在加上H∞控制算法后,得出了半主动悬挂系统的阻尼控制力。采用控制系统的分析和仿真软件MATLAB中的SIMULINK工具箱进行了被动及半主动控制的仿真,并将两次仿真结果进行了比较。结果表明,采用基于H∞控制算法的半主动悬挂系统的车身振动得到了明显控制。     

基于磁流变阻尼器的半主动悬挂系统模糊控制策略

建立了磁流变阻尼器和1/2车辆半主动悬挂系统模型,并对该系统设计了一种模糊控制策略。充分利用Mat-lab/Simulink仿真平台对基于磁流变阻尼器的半主动悬挂系统进行仿真分析。结果表明,较被动悬挂系统,该半主动悬挂系统很好地抑制了车身浮沉振动加速度,显著改善了车辆乘坐舒适性。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.