Humidity-Induced Spectral Shift in a Cross-DispersionEchelle Spectrometer and Its Theoretical Investigation

The relationship between ambient relative humidity H and the position shift of a spectral line was investigated both experimentally and theoretically.An echelle-based ICP emission spectrometer equipped with a CID detector was used for experimental verification of the derived model.The shift of a spectral line is quantitatively described by two defined spectral shift functions: Δλx(x,λ,H)(in the x direction of the CID detector) and Δλy(y,λ,H)(in the y direction of the CID detector).Experimental results indicate that Δλx(x,λ,H) does not change with a variation in ambient relative humidity, but Δλy(y,λ,H) does.A spectral shift equation,i.e.an empirical second-order polynomial equation,can be used to describe the relationship between Δλy(y,λ,H) and H.Based on the classical dipole model,classical mechanics and electrodynamics the empirical spectral-shift equation involving Δλy(y,λ,H) and H was theoretically deduced.The theoretical result is in good agreement with the experimental findings.The theoretical results indicate that the coefficients of the empirical spectral-shift equation are related to the basic physical parameters of materials and the geometric configuration of the echelle CID ICP-AES,and also provide physical meaning to the coefficients of the empirical shift equation obtained experimentally.

Generation and Analysis of Hybrid-Electric Vehicle Transmission Shift Schedules with a Torque Split Algorithm

The increased concern over global climate change and lack of long-term sustainability of fossil fuels in the projected future has prompted further research into advanced alternative fuel vehicles to reduce vehicle emissions and fuel consumption. One of the primary advanced vehicle research areas involves electrification and hybridization of vehicles. As hybrid-electric vehicle technology has advanced, so has the need for more innovative control schemes for hybrid vehicles, including the development and optimization of hybrid powertrain transmission shift schedules. The hybrid shift schedule works in tandem with a cost function-based torque split algorithm that dynamically determines the optimal torque command for the electric motor and engine. The focus of this work is to develop and analyze the benefits and limitations of two different shift schedules for a position-3 (P3) parallel hybrid-electric vehicle. a traditional two-parameter shift schedule that operates as a function of vehicle accelerator position and vehicle speed (state of charge (SOC) independent shift schedule), and a three-parameter shift schedule that also adapts to fluctuations in the state of charge of the high voltage batteries (SOC dependent shift schedule). The shift schedules were generated using an exhaustive search coupled with a fitness function to evaluate all possible vehicle operating points. The generated shift schedules were then tested in the software-in-the-loop (SIL) environment and the vehicle-in-the-loop (VIL) environment and compared to each other, as well as to the stock 8L45 8-speed transmission shift schedule. The results show that both generated shift schedules improved upon the stock transmission shift schedule used in the hybrid powertrain comparing component efficiency, vehicle efficiency, engine fuel economy, and vehicle fuel economy.

Optimal gear shift control strategy for positive independent mechanical split path transmission with automatic shift system

An improvement strategy which controls the shift effort and the power summing planetary gear set of steering clutches and brakes have been proposed based on the dynamic model of synchroniser in order to decrease the wear of synchroniser inserts, make gear shift easy and reduce the shock noise for a positive independent mechanical split path transmission which attached an auto- matic shift system when shifting. A kinetics model for the process of synchroniser engagement is built and analyzed in the paper. Thus for optimizing the gear shift process which is divided into three phases a model reference fuzzy self-adaption system is adopted. Through a 6 000 km road experiment, the control strategy has proved feasible and dependable.

基于Mean-shift聚类算法的导航欺骗干扰源定位技术

对导航干扰的现状进行了分析,针对北斗导航面临的威胁,对现有导航欺骗干扰源的定位方法和功率预测方法进行分析总结。针对现有技术水平的不足和未来战场的需求,提出了基于Mean-shift聚类算法的干扰源定位方法,对算法进行了分析,给出算法实现与优化的过程,通过仿真与实验测试对算法的性能进行了分析。外场实测数据表明,提出的导航欺骗干扰定位算法具有较高的定位精度。提出的干扰源定位方法,将为导航对抗环境下的导航态势感知提供一种新的手段和方法。

Torque Calculation of Five-Phase Synchronous Reluctance Motors With Shifted-Asymmetrical-Salient-Poles Under Saturation Condition

In traditional analytical method(AM),the magnetic saturation is always ignored to simplify the calculation process.However,synchronous reluctance motors(SynRMs)often operate around saturation point to achieve higher torque density.Therefore,a new AM is proposed,in which the saturation of stator iron has been considered.The key of the proposed method includes a saturation factor,and an iterative method is adopted to compute the saturation factor in the SynRM by increasing the air-gap length.Especially,the proposed AM can be applied to a SynRM even with shifted-asymmetrical-salient-poles.In the process of AM,the expression of stator magnetomotive force(MMF)is built firstly.Additionally,the air-gap density including slotting effect and salient-poles is calculated.Then,the rotor MMF under saturation of the stator iron is obtained.Therefore,the precision of the instantaneous torque can be improved significantly.Eventually,by the verification of finite elements method(FEM)and experiments,the torque performance of SynRMs with shifted asymmetrical rotor can be predicted accurately by the proposed AM.

VEHICULAR NODE POSITIONING BASED ON DOPPLER-SHIFTED FREQUENCY MEASUREMENT ON HIGHWAY

Vehicular node positioning needs to be quick and precise on highway for safety considera-tion.In this paper,we present a novel and practical vehicular node positioning method which can achieve a higher accuracy and more reliability than the existing global-positioning-system-based po-sitioning solutions by making use of Doppler-shifted frequency measurements taken by vehicular node itself.This positioning method uses infrastructure nodes which are placed on the roadside every several kilometers as radiation sources to estimate the relative distances of vehicle to the infrastructure node.Through coordinate conversion,we get the absolute coordinates of vehicular node based on known absolute coordinates of infrastructure node.We also analyze the optimal distance of neighbor infra-structure nodes in order to ensure a high accuracy.In addition,simulation results demonstrate that the accuracy of our method with Extended Kalman Filtering(EKF) is superior to the method without EKF.

PLL DEMODULATION TECHNIQUE FOR M-RAY POSITION PHASE SHIFT KEYING

The paper presents a kind of transmission system which employs M-ary Position Phase Shift Keying(MPPSK) to send data and Phase Locked Loop(PLL) based techniques for data retrieve.With a single PLL, MPPSK demodulation is achieved, as well as carrier recovery and symbol synchronization.Firstly, MPPSK modulation method is briefly introduced.2PPSK's PSD expression is given with its optimization result.Orthogonal Phase Detector(PD) and static threshold are used for the purpose of wider phase range and simplicity in demodulation.The data rate is alterable, which is 4.65 kbps for 2PPSK and 9.3 kbps for 4PPSK in the paper.Then some indicative comparisons in Signal to Noise Ratio Symbol Error Rate(SNR-SER) are made among 2PPSK, 3PPSK and 4PPSK, of which 4PPSK has proved to be optimal in ten slots each symbol conditions.And finally, it is demonstrated by system simulations that lower than 10-4 Symbol Error Rate(SER) performance can be obtained at 13 dB symbol SNR.

Some Notes on M-hyponormal Weighted Shifts and Hyponormalizable Weighted Shifts

Let {an}∞n=0be a weight sequence and let W denote the associated unilateral weighted shift on H. In this paper, we consider the connection between the M-hyponormal and hyponormalizable weighted shift operator. Main results are Theorems 4.1 and Theorems4.2. Theorem 4.1 gives the sufficient condition that a weighted shifts M-hyponormal operator is hyponormalizable. Theorem 4.2 gives the sufficient condition that a hyponormalizable weighted shift operator is M-hyponormal. Finally, invariant subspaces of such operators are discussed.

The Fishery Industrial Structure in China Based on the Application of Shift-Share Analysis

Taking sixteen main fishery production regions as the study objects,this paper is to examine the fishery industrial structure and investigate the correlation between the economic growth of the fishery industry and the fishery industrial structure during the period 1997-2013 by the shift-share analysis. The study results show that( i) four types of regional industrial structure exist in the fishery industry in China;( ii)all the three sectors-fishing production,fish processing( manufacturing) and fish marketing( distribution),have emerged with large potential for promoting the national fishery industry growth,especially for the latter two;( iii) the factors of industry-mix and competitive position have significantly different impacts on the growth of fishery industry in different main fishery production regions. This study is one of the comprehensive studies on the status of regional fishery industrial structure,and the competitiveness of regional fishery industry in China.

基于磁链相移原理的不对称交替极永磁辅助同步磁阻电机设计与分析

传统永磁辅助同步磁阻电机(PMaSynRM)无法充分利用永磁转矩和磁阻转矩,该文提出一种新型不对称交替极永磁辅助同步磁阻电机(ACP-PMaSynRM)。基于永磁磁链相移原理,将交替极永磁阵列、不对称磁极和磁障相结合,实现永磁转矩和磁阻转矩的最大值在相同电流相位下叠加,不但提高了永磁转矩和磁阻转矩的利用率,增强了电机输出转矩能力,而且减少了永磁体用量。采用有限元法对比分析了传统和新型ACP-PMaSynRM的电磁性能,验证了所提电机拓扑的可行性。最后,制造了一台48槽14极样机并对其进行了实验验证。

基于动态理论模型的电液伺服加载前馈补偿复合控制系统

针对一般电液伺服系统存在的非预期负载扰动和非线性干扰等问题,为了提高系统的自适应能力和动态响应的品质,减小系统跟踪和输出响应的误差,提出了一种基于动态理论模型的电液伺服加载前馈补偿复合控制方法。首先,阐释了电液伺服试验台的结构组成及其数学模型,分析了系统力矩控制和位置控制的结构关系;然后,论证了自适应前馈补偿复合控制的伺服原理,阐述了以调速理论模型和实际模型的误差函数作为调速依据的前馈补偿和复合控制的原理和方法;最后,进行了系统仿真,同时为了验证基于动态理论模型的自适应前馈补偿复合控制策略的合理性和有效性,对伺服系统进行了加载试验。研究结果表明:采用该复合控制策略可以精确算出对伺服马达进行转速补偿的基准值和调整参数,系统动态响应速度比采用传统闭环控制算法提高了8%以上;系统控制器自适应能力和抗扰动性能也明显优于采用传统PI闭环控制及模糊PI闭环控制算法的系统;通过对比分析0.2 Hz和0.5 Hz的正弦响应曲线可知,该系统的位置跟踪曲线性能最优,控制精度最高,实际输出值的误差也最小。

风力叶片自动合模装置双液压缸铰点位置设计

叶片模具是风力叶片制造的关键设备,当前风电叶片模具的开合主要有机械起重机吊装翻转和全自动液压翻转2种方式,采用机械行车提吊翻转过程不连续且精度较差,而现有的自动合模装置主要采用对称布置的2个液压缸,翻转过程中会碰到死点且对液压缸损害很大。针对上述问题,文中介绍了一种新型双液压缸风力叶片自动合模装置,描述了其结构和工作原理,并建立了该装置的几何模型,推导了翻转过程中液压系统主副液压缸力矩计算的数学模型,通过Matlab遗传算法工具箱对该自动合模装置双液压缸的铰点位置进行优化设计,使翻转过程中液压缸动力矩变化尽可能拟合负载的阻力矩,优化设计结果表明,通过该方法可以进一步优化该装置的结构尺寸,提高叶片合模的效率和精度。

一种基于快速傅里叶建模方法的开关磁阻电机模型预测控制

为快速准确地建立开关磁阻电机模型,提高模型预测控制性能,该文提出一种基于快速傅里叶建模方法的模型预测控制策略。一方面采用傅里叶级数对磁链和转矩特性进行解析建模,并推导转矩预测模型;另一方面结合分扇区的思想控制电机换相进而简化代价函数,并在每个扇区内只设计两个预选电压矢量,有效减小了预测控制的计算负担。另外,扇区的位置和宽度可根据转速和负载的变化而变化,增强了算法的适用性。仿真和实验与传统的模型预测控制方法进行对比,并考虑到低、高速以及转速和负载突变的不同工况,结果表明所提算法的转矩脉动更低,转矩电流比更高。

变负载直驱力矩电机位置误差预测模型研究

为提高直驱力矩电机在变外载荷工况下的位置精度,使用基于狼群算法(WPA)优化支持向量回归(SVR)神经网络,建立直驱力矩电机位置误差预测模型。搭建试验台,将磁粉制动器与力矩电机用联轴器连接,利用磁粉制动器对直驱力矩电机施加变化外载荷。以可变外载荷数据和直驱力矩电机运行时电流数据作为输入,以直驱力矩电机位置误差作为输出。实验结果表明:所建立的WPA—SVR预测模型精度高于SVR预测模型,能够有效预测直驱力矩电机变负载下位置误差。

基于关节双位置反馈的柔性协作机械臂零力控制

零力控制是协作机械臂实现拖动示教的核心问题之一,目前方法多依赖于附加力/力矩传感器,其虽能保证测量精度,但会增加系统复杂程度及成本。提出一种基于关节双位置反馈的柔性协作机械臂零力控制方法,该方法可在无外加传感器条件下实现机械臂零力控制。首先,基于波发生器与柔轮柔性特性,建立了谐波传动关节的动力学模型;其次,基于谐波传动关节刚度辨识方法,建立了基于双位置反馈的柔性关节力矩估测方法;再次,建立了简化重力矩补偿模型,并考虑关节转动过程中的粘滞摩擦和Stribeck库伦摩擦,完善了关节摩擦力矩模型,基于此,实现对关节重力矩和摩擦力矩补偿,实现机械臂零力控制;最后,搭建谐波传动一体化关节和机械臂样机平台,并进行了实验研究,结果表明,所提方法可有效实现无附加力/力矩传感器条件下的谐波传动机械臂零力控制。

基于有效特征筛选的Mean shift运动目标跟踪算法

针对现有Mean shift跟踪算法在目标被遮挡、跟踪场景变化时,跟踪误差变大甚至丢失目标的问题,提出了一种基于有效特征筛选的Mean shift运动目标跟踪算法。首先通过对目标特征的优化筛选,改善了现有Mean shift算法因目标特征多而造成计算时间较长,在目标发生较大变化时跟踪精度降低的情况。更能有效地表征目标特征,减少跟踪误差,增强特征集对目标的描述能力。同时给出目标模板更新的方法,在目标发生明显变化时,能自适应地更新特征集,进一步提高跟踪精度。仿真结果表明:文中方法具有更好的跟踪精度,计算时间较小,对遮挡、场景变化有更好的鲁棒性。

Effective assignment of positional isomers in dimeric shikonin and its analogs by ^(1)H NMR spectroscopy

An approach for distinguishing two types of positional isomers of dimeric shikonin and its analogs was explored with ^(4)JC,H long-range correlation by prolonging the acquisition time at ^(2,3)JC,H values of 2.0 and 8.0Hz.Furthermore,the ^(1)H(proton)nuclear magnetic resonance(NMR)pattern of phenolic hydroxyl protons was developed as a“diagnosis signal”to ascertain the relative location of each side chain in DMSO-d_(6) at sample concentrations of 0.022-0.034 mol/L.The chemical shift differences of 0.6ppm between OH-5' and OH-1 and between OH-8'and OH-4 are assigned to Type A and Type B,respectively.All reported ambiguous structures were corrected by this pattern.Additionally,the steric structures of isolated compounds were elucidated by quantum chemical calculations of electronic circular dichroism(ECD)spectra.

基于铱星/INS组合定位技术在船舶中的应用研究

GNSS拒止环境下惯性/GNSS组合导航系统的性能会严重恶化,通过利用并提取机会信号中的有用观测量,可以实现机会信号和惯性系统的联合动态定位。提出了利用铱星/INS组合定位技术实现船舶的动态定位。首先深入研究了铱星的信号体制,建立了利用铱星瞬时多普勒频移进行定位的算法模型;然后,提出了利用基于扩展卡尔曼滤波(EKF)技术的铱星机会信号与INS组合定位算法;最后,通过船舶航行实测数据对所提算法进行了试验验证。结果表明,提出的利用铱星机会信号和INS组合定位方法可以有效改善无GNSS信号条件下的INS定位精度,在GNSS信号拒止环境下解决了船舶定位问题,具有重要的研究意义和实用价值。

Instantaneous velocity determination and positioning using Doppler shift from a LEO constellation

To provide backup and supplementation for the Global Navigation Satellite System(GNSS),Doppler shift from Low Earth Orbit(LEO)satellites can be used as signals of opportunity to provide positioning,navigation,and timing service.In this contribution,we frst investigate the model and performance of instantaneous velocity determination and positioning with LEO satellites.Given a LEO constellation with 288 satellites,we simulate Doppler shift observations at nine multi-GNSS experiment stations.Owing to the lower orbit,the performance of LEO velocity determination is much more sensitive to the initial receiver position error than that of GNSS.Statistical results show that with the initial receiver position error increased from 0.1 to 10 m,the Root Mean Square Errors(RMSEs)increase from 0.73 to 2.65 cm/s,0.68 to 2.96 cm/s,and 1.67 to 4.15 cm/s in the east,north,and up directions,respectively.The performances with GPS are compared with GPS+LEO,and it is found that LEO Doppler shift observations contribute to GPS velocity determination.As for LEO Doppler positioning,even if more than 30 visible LEO satellites are available,the position dilution of precision values can reach several hundreds.Assuming that the error of LEO Doppler measurements is 0.01 m/s,the instantaneous Doppler positioning accuracy can achieve about a few meters,which is comparable to that of GNSS pseudorange positioning.A constant velocity model is adopted for state transition.Static LEO Doppler positioning results show that an accuracy at centimeter to decimeter level can be achieved after solution convergence.For a static simulated kinematic positioning test,the RMSEs range from a few decimeters to several meters in diferent regions by giving diferent constraints.For a dynamic positioning test,the RMSEs are about 2–3 m in high latitude region.