A Study of Electric Vehicle Suspension Control System Based on an Improved Half-vehicle Model

An improved half-vehicle model has been proposed for active suspension control systems, in contrast to existing models, it allows to explore the nature of the effect of vehicle speed changes by introducing a state vector of vehicle pitch angle. Three control strategies of linear quadratic control （LQ）, improved LQ （ILQ） and wheelbase preview LQ （WLQ） have been implemented into the proposed model. ILQ has integrated an additional control parameter into LQ by concerning the correlation between acceleration values and their corresponding pitch angles. Simulation results have showed the effectiveness of the proposed model in terms of LQ, ILQ and WLQ control strategies.

Entanglement in the Quantum Phase Transition of the Half-Integer Spin One-Dimensional Heisenberg Model

We use the Bethe’s ansatz method to study the entanglement of spinons in the quantum phase transition of half integer spin one-dimensional magnetic chains known as quantum wires. We calculate the entanglement in the limit of the number of particles . We obtain an abrupt change in the entanglement next the quantum phase transition point of the anisotropy parameter ?from the gapped phase ?to gapless phase .

基于互Box-Cox变换和Markov链风速云模型的发电系统充裕度评估

为准确计及风速随机性和自相关性对风电并网系统充裕度的影响,建立基于互Box-Cox变换和Markov链的风速云模型,并将该模型与时序Monte Carlo模拟法结合,提出计及风速随机性和自相关性的风电并网系统充裕度评估方法。仿真结果表明,所提模型产生的仿真风速样本与实测风速样本具备相似的概率分布特性和自相关性,所提方法可较精确地评估风电并网系统充裕度及风电容量可信度。

无源核子料位计探测点γ场强度数值模型构建

无源核子料位计利用粉煤灰自身的微量天然γ射线来检测灰斗或仓泵内的灰位,是一种新型的具有较高可靠性的非接触式料位计。探测点处的γ射线强度随粉煤灰灰位的变化规律是仪表设计、使用和标定的重要依据。首先从理论上推导出点状辐射体在吸收介质中某点的γ射线强度的计算公式,然后以此为基础,构建了粉煤灰辐射体在探测点处γ射线强度的一般化数值计算模型。在数值模型构建中,提出了更加高效的折半逼近法来计算介质对γ射线的吸收厚度。该模型的构建思想和方法适用于任意的辐射体形状和探测点位置,能够满足各种工况下的计算要求。通过与圆柱形辐射体在轴线上的准确的γ射线强度进行对比,证明了此模型的建模思路与方法是正确的,模型的精度是满足要求的。

‘范艾斯汀’海棠半同胞家系苗期生长特性及子代优选

以61个‘范艾斯汀’海棠(Malus spectabilis‘Vans Eseltine’)自由授粉子代的2年生嫁接苗为实验材料,并以同年嫁接的母本‘范艾斯汀’海棠嫁接苗为对照,对‘范艾斯汀’海棠半同胞家系及母本苗期的生长、观赏和抗性指标进行观测,采用Gompertz模型拟合子代年生长过程,采用层次分析(AHP)法对‘范艾斯汀’海棠半同胞家系进行综合评价,旨在制定适宜的育苗措施,同时选育出生长迅速且表型优良的子代。结果显示:‘范艾斯汀’海棠半同胞家系的苗高和地径年生长均符合“S”型曲线,呈“慢—快—慢”的生长节律,反映了“生长前期(3月中至5月中)—速生期(4月初至9月初)—生长后期(5月中至11月中)”的生长过程,对各生长期应给予不同的育苗措施。‘范艾斯汀’海棠半同胞家系速生期可分为前期速生型(4月初至4月中)、中期速生型(4月中至5月初)和后期速生型(5月初至5月中)。不同个体苗高和地径速生期始末差异明显,呈现异速生长现象。其中,85%的子代苗高速生期属于前期、中期速生型,91%的子代地径速生期属于中期、后期速生型。V39、V49、V21、V27和V405个子代生长迅速,苗高(202.0~226.0 cm)和地径(18.96~22.04 mm)均高于母本(苗高和地径分别为197.9 cm和16.14 mm),分枝数(14~38)多于母本(9),新叶均为紫红色或棕红色,树皮光滑或较光滑。综上所述,Gompertz模型可预测‘范艾斯汀’海棠半同胞家系的苗期生长特性随时间的变化趋势,了解子代的年生长规律;V39、V49、V21、V27和V405个子代综合评价得分较高,是优良的‘范艾斯汀’海棠子代单株,今后可加强其观赏性评价,实现观赏与长势俱佳的育种目标。

汽车半主动座椅悬架主要参数优化研究

半主动座椅悬架能有效改善驾驶平顺性,减少人体垂向振动,提升车内驾乘人员的乘坐体验.其中,半主动悬架的初始性能参数对悬架性能起到决定性作用.为此,本文针对半主动座椅悬架的初始性能参数(弹簧刚度和阻尼系数)的优化问题展开研究,在使用了随机路面模型、六自由度半车模型的基础上,以优化前后座椅垂向加速度之比作为适应度函数,利用遗传算法对半主动座椅悬架的刚度及阻尼系数进行优化.最后,利用MATLAB软件对优化结果进行仿真分析.结果表明,经算法优化后,座椅垂向加速度的均方根减少了16.4%,最大值下降了11.3%;座椅相对位移的均方根减少了36%,最大值下降了39.2%.

基于稀疏鲁棒M-投资选择模型的鲁棒Half算法

为得到鲁棒、稀疏的投资组合,提出稀疏鲁棒M-投资选择模型,并且基于L1/2正则化理论和Half阈值算法,构建鲁棒Half阈值算法求解稀疏鲁棒M-投资选择问题.数值实验表明,该算法不仅比Lasso算法收敛速度更快,而且在期望值固定的情况下得到的风险更小、更平稳.

基于谐波磁化响应半峰宽模型的非零场点磁性纳米粒子距离层析测量

磁粒子成像技术是一种以生物功能化超顺磁性纳米粒子为示踪剂的全新人体功能层析成像技术,其通常必须构建基于梯度场的零磁场点/线并对其进行空间扫描以实现示踪剂定位,其空间分辨率正比于梯度场强度。而高强度梯度场需大体积电/永磁体构建,使其无法用于微创淋巴结术中定位。本研究在不使用梯度定位场条件下,提出基于朗之万函数和激励-磁化场空间分布计算的窄带磁纳米粒子深度定位理论,推导不同深度磁性纳米粒子产生的磁化响应与空间方位角的函数关系,建立半峰宽-距离检测与真实浓度解析模型,并进一步开发了磁粒子深度层析装置(即非梯度式一维磁粒子成像仪),体外实验测量结果表明其空间定位分辨率为15 mm,误差5.21%,浓度模型还原误差为2.61%。对比已获批上市的欧洲Sentimag等静磁场磁粒子定位装置具有显著性能优势,可完全满足术中淋巴结定位等创新临床应用需求。

Adaptive Backstepping Control Design for Semi-Active Suspension of Half-Vehicle With Magnetorheological Damper

This paper investigates the problem of controlling half-vehicle semi-active suspension system involving a magnetorheological(MR)damper.This features a hysteretic behavior that is presently captured through the nonlinear Bouc-Wen model.The control objective is to regulate well the heave and the pitch motions of the chassis despite the road irregularities.The difficulty of the control problem lies in the nonlinearity of the system model,the uncertainty of some of its parameters,and the inaccessibility to measurements of the hysteresis internal state variables.Using Lyapunov control design tools,we design two observers to get online estimates of the hysteresis internal states and a stabilizing adaptive state-feedback regulator.The whole adaptive controller is formally shown to meet the desired control objectives.This theoretical result is confirmed by several simulations demonstrating the supremacy of the latter compared to the skyhook control and passive suspension.

半门刮板取料机无人化平料作业技术研究

针对C型料场堆型复杂、平料效率低、环境恶劣等问题,提出了一种半门刮板取料机无人化平料作业技术。基于激光建模,扫描堆场料堆3D模型,实现堆型动态感知,结合料堆3D模型,计算平料过程中的关键参数,以指导半门刮板机平料作业。研究了子料堆分割技术,建立了子料堆初平料和整体终平料的控制流程,降低了平料过程中的空刮率。为了提高平料效率,防止刮板过载,根据刮板与物料的接触长度动态调整刮板的步进下降角度。本技术已应用于实际生产过程中,缩减了人工成本,降低了半门刮板机的故障发生率,取得了较好的平料作业效果。

Experimental investigation on single person's jumping load model

This paper presents a modified half-sine-squared load model of the jumping impulses for a single person. The model is based on a database of 22,921 experimentally measured single jumping load cycles from 100 test subjects. Threedimensional motion capture technology in conjunction with force plates was employed in the experiment to record jumping loads. The variation range and probability distribution of the controlling parameters for the load model such as the impact factor, jumping frequency and contact ratio, are discussed using the experimental data. Correlation relationships between the three parameters are investigated. The contact ratio and jumping frequency are identified as independent model parameters, and an empirical frequency-dependent function is derived for the impact factor. The feasibility of the proposed load model is established by comparing the simulated load curves with measured ones, and by comparing the acceleration responses of a single-degree-of-freedom system to the simulated and measured jumping loads. The results show that a realistic individual jumping load can be generated by the proposed method. This can then be used to assess the dynamic response of assembly structures.

A new model for the formation of contact angle and contact angle hysteresis

The formation mechanism of the contact angle and the sliding angle for a liquid drop on a solid surface plays an important role in producing hydrophobic surfaces. A new half soakage model is established in this paper as a substitute for Wenzel （complete soakage） and Cassie （no soakage） models. The model is suited to many solid surfaces, whether they are hydrophilic or hydrophobic, or even superhydrophobic. Based on the half soakage model, we analyse two surfaces resembling lotus, i.e. taper-like surface and corona-like surface. Furthermore, this new model is used to establish a quantitative relationship between the sliding angle and the parameters of surface morphology.

基于半模型的高速列车远场气动噪声计算方法

随着高速列车运行速度的提高,其气动噪声问题逐渐凸显,如何准确快速预测高速列车的远场气动噪声成为关键.利用半自由空间的Green函数求解FW-H方程,推导了考虑半模型时的远场声学积分公式,提出通过半模型的数值计算结果预测全模型高速列车远场气动噪声的方法;建立了全模型和半模型高速列车的气动噪声数值计算模型,应用改进延迟的分离涡模拟方法对不同模型高速列车表面的气动噪声源进行求解;通过风洞试验进行了全模型高速列车的数值仿真计算方法验证;对比分析了全模型和半模型高速列车周围的流场结构、气动噪声源和远场气动噪声特性.结果表明:半模型高速列车数值计算得到的列车周围流场结构、气动噪声源以及远场气动噪声特性与全模型的一致;采用半模型计算会过高估计列车尾车流线型区域表面压力的波动程度和噪声源的辐射强度,但通过半模型预测整车模型的远场噪声平均声压级误差小于1 dBA;相比于全模型高速列车,半模型计算时的网格总量减少一半.

Exploring the sensitivity of α-decay half-life to neutron skin thickness for nuclei around ^(208)Pb

Based on the newest experimentally extracted nuclear density distributions for double-magic nucleus208Pb(Tarbert et al. in Phys Rev Lett 112:242502, 2014),the sensitivity of α-decay half-life to nuclear skin thickness is explored in the vicinity of the shell closure region around208 Pb, i.e., isotopes of Z ? 82 and isotones of N ? 126.With the two-parameter Fermi(2PF) density distributions and an analytically derived formula, the α-decay half-life is found to be closely related to the magnitude of nuclear skin thickness. For a decays to the Z ? 82 isotopes, the α-decay half-life is found to decrease with the increasing neutron skin thickness, while the opposite behavior is found for a decays to the N ? 126 isotones. Therefore, it could be a possible way to extract the nuclear skin thickness from measured α-decay half-lives.

Systematic Calculations of α-Decay Half-Lives Using Microscopic Deformed Potentials

A new version of the generalized density-dependent cluster model （GDDCM） is developed to describe an α particle tunneling through a deformed potential barrier. The microscopic deformed potential is numerically constructed in the double-folding model using the multipole ex- pansion method. The decay width of an α-cluster state is evaluated using the integral of the quasi-bound state wave function, the scattering state wave function, and the difference of poten- tials. We perform a systematic calculation of α-decay half-lives for favored transitions in even-even nuclei ranging from Z=52 to Z=104. The calculated half-lives are in good agreement with the experimental values. The relation between nuclear deformations and α-decay half-lives is also discussed in details.

a-Decay half-life screened by electrons

In this paper,by considering the electrons in different external environments,including neutral atoms,a metal,and an extremely strong magnetic-field environment,the screened a-decay half-lives of the a emitters with proton number Z = 52–105 are systematically calculated.In the external environment,the decay energy and the interaction potential between a particle and daughter nucleus are both changed due to the electron screening effect and their variations are both very important for the electron screening effect.Besides,the electron screening effect is found to be closely related to the decay energy and its proton number.

基于抗损性的钢筋混凝土摇摆柱力学性能研究

抗震韧性将震后建筑的功能维持或快速恢复作为最终目标。构件层次的摇摆机制是实现主体结构功能可恢复的有效途径,但应以构件的抗损性为前提。以钢筋混凝土摇摆柱为对象,比拟弹性半空间局部受载经典拉芒(Flamant)理论,推导摇摆柱轴向应力分布弹性力学解答,以此为基础,假定摇摆柱侧移由柱端接触面转角和柱身弯剪变形引起,建立钢筋混凝土摇摆柱荷载-侧移力学模型,与有限元模拟结果对比验证合理性。开展轴压比和柱端强度分析,结果表明,在柱体抗损的前提下,单纯提高轴压比可提高柱体承载能力,但对侧移能力提升不显著;随着柱端材料强度提升,柱体承载力和侧移能力均显著改善,因此,采用柱端局部增强的方法改善钢筋混凝土摇摆柱工作性能具有可行性。

TBM掌子面力学模型与滚刀破岩力推力预测

以掌子面岩体破坏前状态建立了滚刀推力作用的双集中力模型,采用弹性半空间理论的Boussinesq解答和叠加原理,给出了双滚刀协同作用下岩体应力分布的解析解。根据应力分布的特点和TBM破岩要求,提出了TBM破岩的必要条件;采用单轴强度理论和多轴强度理论,分别给出了滚刀破岩推力的预测公式。工程实例表明,采用本文提出的基于多轴强度理论的预测公式计算出的滚刀破岩推力与TBM工作时实际使用的推力非常吻合。

基于驾驶员模型的六足机器人自主/协同决策

重载六足机器人在野外地形环境移动作业时的决策智能水平亟待提高。然而,当机器人在尚未形成合理的决策结构层次时,直接采用其与环境进行交互方式进行常规的强化学习训练,将导致机器人的行为决策过于发散。因此,本文首先利用一种符合驾驶员决策逻辑的分步训练神经网络,得到驾驶员的决策经验模型,使机器人快速形成自主决策智能。此外,为融合人机决策优势,本文基于合作博弈理论,提出一种消除人机协同决策指令冲突的方法。搭建面向重载六足机器人人机协同决策的半物理仿真实验系统,开展实验的结果表明,机器人通过学习驾驶员先验模型和自主训练,其决策效果可接近驾驶员决策水平,同时人机协同决策指令可有效弥补单智能体决策指令的缺陷,在规则沟壑地形下协同决策指令的碰撞率指标优于驾驶员单智能体指令23.8%,障碍地形下协同决策指令的能量消耗指标优于机器自主单智能体指令34.1%。

Fuzzy optimization of pneumatic half-floating slide ways

Dynamic modeling was carried on by combining the dynamic of machinery with composite triology, and the critical condition in which the ways would not produce composite-friction self-excited vibration was obtained. The movement regularity and characteristic of the airflow in exhaust gas slit were analyzed, and the relationship between pressure lost and geometry parameters of exhaust gas slit was obtained. A dynamic model and a mathematical model were established for pneumatic half-floating slide ways by combining the dynamics of machinery with hydrokinetics. The objective function for the optimization of slide ways was established based on the fuzzy optimization theory. The membership function of fuzzy constraint was deduced, the fuzzy constraint limit was established by amplification coefficient method, and the optimal value was resolved by the multilevel fuzzy comprehensive evaluation method. By combining the internal penalty function method with the variable metric method, the fuzzy optimization design program of ways was designed based on the Matlab platform. The validation was carried on by an example, and ideal results of fuzzy optimization design of slide ways were obtained.