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Evaluation of regenerative braking based on single-pedal control for electric vehicles

Wei LIU, Xintian LIU, Yansong WANG, Hongzhong QI

《机械工程前沿(英文)》 2020年 第15卷 第1期   页码 166-179 doi: 10.1007/s11465-019-0546-x

摘要: More than 25% of vehicle kinetic energy can be recycled under urban driving cycles. A single-pedal control strategy for regenerative braking is proposed to further enhance energy efficiency. Acceleration and deceleration are controlled by a single pedal, which alleviates driving intensity and prompts energy recovery. Regenerative braking is theoretically analyzed based on the construction of the single-pedal system, vehicle braking dynamics, and energy conservation law. The single-pedal control strategy is developed by considering daily driving conditions, and a single-pedal simulation model is established. Typical driving cycles are simulated to verify the effectiveness of the single-pedal control strategy. A dynamometer test is conducted to confirm the validity of the simulation model. Results show that using the single-pedal control strategy for electric vehicles can effectively improve the energy recovery rate and extend the driving range under the premise of ensuring safety while braking. The study lays a technical foundation for the optimization of regenerative braking systems and development of single-pedal control systems, which are conducive to the promotion and popularization of electric vehicles.

关键词: electric vehicle     single-pedal control     regenerative braking     co-simulation     dynamometer test    

An experimental study of a single-piston free piston linear generator

Jin XIAO, Yingdong CHENG, Jinlong WANG, Chengwei ZHU, Zhen HUANG

《能源前沿(英文)》 2022年 第16卷 第6期   页码 916-930 doi: 10.1007/s11708-022-0838-4

摘要: Free piston linear generator (FPLG) is a promising range extender for the electrical vehicle with unparallel advantages, such as compact structure, higher system efficiency, and reduced maintenance cost. However, due to the lack of the mechanic crankshaft, the related piston motion control is a challenge for the FPLG which causes problems such as misfire and crash and limits its widespread commercialization. Aimed at resolving the problems as misfire, a single-piston FPLG prototype has been designed and manufactured at Shanghai Jiao Tong University (SJTU). In this paper, the development process and experimental validation of the related control strategies were detailed. From the experimental studies, significant misfires were observed at first, while the FPLG operated in natural-aspiration conditions. The root cause of this misfire was then identified as the poor scavenging process, and a compressed air source was leveraged to enhance the related scavenging pressure. Afterward, optimal control parameters, in terms of scavenging pressure, air-fuel equivalence ratio, and ignition position, were then calibrated in this charged-scavenging condition. Eventually, the FPLG prototype has achieved a continuous stable operation of over 1000 cycles with an ignition rate of 100% and a cycle-to-cycle variation of less than 0.8%, produced an indicated power of 2.8 kW with an indicated thermal efficiency of 26% and an electrical power of 2.5 kW with an overall efficiency of 23.2%.

关键词: free piston linear generator (FPLG)     charged scavenging     engine control     misfire     stable operation    

A wind tunnel study on control methods for cable dry-galloping

Hung D. VO,Hiroshi KATSUCHI,Hitoshi YAMADA,Mayuko NISHIO

《结构与土木工程前沿(英文)》 2016年 第10卷 第1期   页码 72-80 doi: 10.1007/s11709-015-0309-7

摘要: The common vibration of cable caused by rain-wind combination has been known as most typical type and a lot kind of its countermeasures has been proposed for suppressing this phenomenon. Recently, stayed-cables were also proved that they could be excited in dry state (without rain), which is called dry-galloping. Recently, its mechanisms have been explained by axial flow, Reynolds number and so on. To clarify the characteristics of this galloping, wind tunnel test of a cable model with various kinds of wind angle was conducted. Then, three types of countermeasure were examined to suppress dry- galloping of bridge cable. The tests confirmed that the occurrence of dry-galloping depends on relative wind attacked angles and onset reduced wind speed. Furthermore, single spiral wire, double spiral wire and circular ring were found to have high effectiveness in mitigating this galloping when those are installed properly.

关键词: dry-galloping     wind-relative angle     single spiral wire     double spiral wire     circular rings    

Overview of the quality standard research of traditional Chinese medicine

Huimin Gao, Zhimin Wang, Yujuan Li, Zhongzhi Qian

《医学前沿(英文)》 2011年 第5卷 第2期   页码 195-202 doi: 10.1007/s11684-011-0134-x

摘要: Traditional Chinese medicine (TCM) has been widely used for the prevention and treatment of various diseases for a long time in China. Due to its proven efficacy, wide applications, and low side effect, TCM has increasingly attracted worldwide attention. However, one of the biggest challenges facing the clinical practice of TCM is the uncontrollable quality. In this review, the progress of the development and the current status of quality standard as well as new quality control techniques introduced in (2010 edition), such as liquid chromatography hyphenated mass spectrometry (LC-MS), fingerprint, quantitative analysis of multi-components by single-marker (QAMS), thin layer chromatography bio-autographic assay (TLC-BAA), and DNA molecular marker technique, are briefly overviewed.

关键词: traditional Chinese medicine     quality standard     quality control     quantitative analysis of multi-components by single-marker    

基于Lagrange方程建模的单级旋转倒立摆控制

吴爱国,张小明,张钊

《中国工程科学》 2005年 第7卷 第10期   页码 11-15

摘要:

介绍一种新型单级旋转倒立摆系统的构成,通过对其动力学特性的分析建立了基于Lagrange方程的数学模型。在平衡点附近给出系统的线性化模型,对系统的稳定性、能控性和能观性进行了分析。利用线性二次型最优控制策略LQR方法设计了控制器,并在仿真实验和实物实验中实现了倒立摆的平衡控制。实验表明,系统稳定性好、鲁棒性较强。

关键词: 旋转倒立摆     Lagrange方程     最优控制策略LQR    

单边直线感应电机纵向边缘效应的研究

徐伟,孙广生

《中国工程科学》 2007年 第9卷 第3期   页码 21-27

摘要:

单边直线感应电机(SLIM)因结构简单牢固,直接产生前进的电磁推力,在交通中得到广泛应用。 由于其磁路断续,电机运行中存在横向和纵向边缘效应;次级的入口和出口因气隙磁链守恒原理会产生涡流, 并随速度上升而加大。边缘效应和涡流大小对直线电机气隙磁链产生重要影响,造成气隙有效磁通和牵引力系 数降低。探讨直线电机工作特点,得到了电机d-q轴等效电路,通过d轴互感和电阻变化来实时反应第二纵 向边缘效应和次级涡流的影响。结合旋转电机转子磁场矢量控制方法,建立了对应的SLIM控制方程。采用转子 磁链、速度和电流三个调节器,提出了uds,uqs,iqs实时在线解耦补偿控制方法,对SLIM的推力、d-q轴电压、d-q轴磁链等进行调节和控制,对d轴互感大小进行限制。结果表明,该方法在电机速度突变时减小了力 矩脉动,定子电流过渡平滑,速度平稳,改善了SLIM的运行性能,为电机实际运行分析提供了理论依据。

关键词: 单边直线感应电机     转子磁场定向控制     边缘效应     解耦     补偿    

Crystallographic orientation effect on cutting-based single atomic layer removal

Wenkun XIE, Fengzhou FANG

《机械工程前沿(英文)》 2020年 第15卷 第4期   页码 631-644 doi: 10.1007/s11465-020-0599-x

摘要: The ever-increasing requirements for the scalable manufacturing of atomic-scale devices emphasize the significance of developing atomic-scale manufacturing technology. The mechanism of a single atomic layer removal in cutting is the key basic theoretical foundation for atomic-scale mechanical cutting. Material anisotropy is among the key decisive factors that could not be neglected in cutting at such a scale. In the present study, the crystallographic orientation effect on the cutting-based single atomic layer removal of monocrystalline copper is investigated by molecular dynamics simulation. When undeformed chip thickness is in the atomic scale, two kinds of single atomic layer removal mechanisms exist in cutting-based single atomic layer removal, namely, dislocation motion and extrusion, due to the differing atomic structures on different crystallographic planes. On close-packed crystallographic plane, the material removal is dominated by the shear stress-driven dislocation motion, whereas on non-close packed crystallographic planes, extrusion-dominated material removal dominates. To obtain an atomic, defect-free processed surface, the cutting needs to be conducted on the close-packed crystallographic planes of monocrystalline copper.

关键词: ACSM     single atomic layer removal mechanism     crystallographic orientation effect     mechanical cutting     Manufacturing III    

Design and analysis of partially decoupled translational parallel mechanisms with single-loop structures

《机械工程前沿(英文)》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0695-1

摘要: This study presents a family of novel translational parallel mechanisms (TPMs) with single-loop topological structures. The proposed mechanism consists of only revolute and prismatic joints. The novel TPMs are simpler in structure and have fewer joints and components than the well-known Delta Robot. Four types of 2-degree of freedom driving systems are applied to different limb structures to avoid the moving actuator that causes the problem of increased moving mass. Four sample TPMs are constructed using the synthesized limbs, and one of them is investigated in terms of kinematic performance. First, a position analysis is performed and validated through numerical simulation to reveal the characteristics of partially decoupled motion, which improves the controllability of TPM. Second, singular configurations are identified, and the resulting singularity curve is obtained. Lastly, the workspace of TPM is analyzed, and the relationship between the singular configurations and the reachable workspace is explored. The workspace of the 3-CRR (C denotes the cylindrical joint and R denotes the revolute joint) translational mechanism is also presented to prove that the proposed TPM has a fairly large workspace.

关键词: translational parallel mechanism     single loop     multiple driving system     workspace analysis     singularity    

Moving policy and regulation forward for single-use plastic alternatives

《环境科学与工程前沿(英文)》 2021年 第15卷 第3期 doi: 10.1007/s11783-021-1423-5

摘要: Single-use plastics are often used once or cannot be reused for extended periods. They are widely consumed with the rapid development of social economy. The waste generated by single-use plastics threatens ecosystem health by entering the environment and ultimately restricts sustainable human development. The innovation of sustainable and environmentally friendly single-use plastic alternative materials and the joint participation of governments, enterprises and the public are promising technologies and management approaches that can solve the problem of single-use plastics wastes. The development of single-use plastic alternative products can be promoted fundamentally only by improving relevant legislation and standards, providing differentiated industrial policies, encouraging scientific and technological innovation and expanding public participation.

关键词: Single-use plastic alternatives     Policy     Regulation     Sustainable development    

Damage propagation and strength prediction of a single-lap interference-fit laminate structure

Peng ZOU, Xiangming CHEN, Hao CHEN, Guanhua XU

《机械工程前沿(英文)》 2020年 第15卷 第4期   页码 558-570 doi: 10.1007/s11465-020-0591-5

摘要: Experimental and finite element research was conducted on the bolted interference fit of a single-lap laminated structure to reveal the damage propagation mechanism and strength change law. A typical single-lap statically loading experiment was performed, and a finite element damage prediction model was built based on intralaminar progress damage theory. The model was programmed with a user subroutine and an interlaminar cohesive zone method. The deformation and damage propagation of the specimen were analyzed, and the failure mechanism of intralaminar and interlaminar damage during loading was discussed. The effect of secondary bending moment on load translation and damage distribution was revealed. The experimental and simulated load–displacement curves were compared to validate the developed model’s reliability, and the ultimate bearing strengths under different fit percentages were predicted. An optimal percentage was also recommended.

关键词: single-lap     interference fit     secondary bending moment     damage mechanism     bearing strength    

Novel casting processes for single-crystal turbine blades of superalloys

Dexin MA

《机械工程前沿(英文)》 2018年 第13卷 第1期   页码 3-16 doi: 10.1007/s11465-018-0475-0

摘要:

This paper presents a brief review of the current casting techniques for single-crystal (SC) blades, as well as an analysis of the solidification process in complex turbine blades. A series of novel casting methods based on the Bridgman process were presented to illustrate the development in the production of SC blades from superalloys. The grain continuator and the heat conductor techniques were developed to remove geometry-related grain defects. In these techniques, the heat barrier that hinders lateral SC growth from the blade airfoil into the extremities of the platform is minimized. The parallel heating and cooling system was developed to achieve symmetric thermal conditions for SC solidification in blade clusters, thus considerably decreasing the negative shadow effect and its related defects in the current Bridgman process. The dipping and heaving technique, in which thin-shell molds are utilized, was developed to enable the establishment of a high temperature gradient for SC growth and the freckle-free solidification of superalloy castings. Moreover, by applying the targeted cooling and heating technique, a novel concept for the three-dimensional and precise control of SC growth, a proper thermal arrangement may be dynamically established for the microscopic control of SC growth in the critical areas of large industrial gas turbine blades.

关键词: superalloy     investment casting     Bridgman process     directional solidification     single crystal     turbine blade    

Numerical analysis of bearing behaviors of single batter piles under horizontal loads in various directions

《结构与土木工程前沿(英文)》 2023年 第17卷 第2期   页码 224-237 doi: 10.1007/s11709-022-0914-1

摘要: The horizontal bearing behavior of a single batter pile (SBP) is vital to its application in practical engineering; however, the horizontal responses of SBPs change with the directions of horizontal loads, and this phenomenon is rarely investigated. Therefore, the directional differences in the horizontal bearing behaviors of SBPs are investigated in this study. Four model tests are conducted to preliminarily examine the effects of the skew angle of horizontal loads on the horizontal bearing capacities and distributions of the bending moments of the SBPs. Subsequently, the differences in the responses of the SBPs under horizontal loads in various directions at full scale are analyzed comprehensively via finite-element (FE) analysis. The effects of the skew angle on SBP-soil interaction are discussed. Moreover, an empirical design method is proposed based on the FE analysis results to predict the bearing ratios of SBPs in medium-dense and dense sand while considering the effects of the skew angle, batter angle, and pile diameter. The method is confirmed to be effective, as confirmed by the close agreement between the predicting results with the model test (reported in this study) and centrifuge model test results (reported in the literature).

关键词: single batter pile     skew horizontal load     model test     finite-element analysis     empirical design method    

Promising approach for preparing metallic single-atom catalysts: electrochemical deposition

《能源前沿(英文)》 2022年 第16卷 第4期   页码 537-541 doi: 10.1007/s11708-022-0837-5

Ionic strength directed self-assembled polyelectrolyte single-bilayer membrane for low-pressure nanofiltration

《化学科学与工程前沿(英文)》 2022年 第16卷 第5期   页码 699-708 doi: 10.1007/s11705-021-2093-3

摘要: Layer-by-layer assembly is a versatile technique for fabricating nanofiltration membranes, where multiple layers of polyelectrolytes are usually required to achieve reasonable separation performance. In this work, an ionic strength directed self-assembly procedure is described for the preparation of nanofiltration membranes consisting of only a single bilayer of poly(diallyldimethylammoniumchloride) and poly(sodium-4-styrenesulfoate). The influence of background ionic strength as well as membrane substrate properties on the formation of single-bilayer membranes are systematically evaluated. Such a simplified polyelectrolyte deposition procedure results in membranes having outstanding separation performance with permeating flux of 14.2 ± 1.5 L∙m–2∙h–1∙bar–1 and Na2SO4 rejection of 97.1% ± 0.8% under a low applied pressure of 1 bar. These results surpass the ones for conventional multilayered polyelectrolyte membranes. This work encompasses an investigation of ionic strength induced coiling of the polyelectrolyte chains and emphasizes the interplay between-polyelectrolyte chain configuration and substrate pore profile. It thus introduces a new concept on the control of membrane fabrication process toward high performance nanofiltration.

关键词: layer-by-layer self-assembly     single bilayer     nanofiltration membrane     desalination    

Computer-Aided Design System for CP Single-Screw Compressor

SHEN Jing-feng, YAO Fu-sheng

《机械工程前沿(英文)》 2006年 第1卷 第1期   页码 21-25 doi: 10.1007/s11465-005-0018-3

摘要:

To design various optimum parameters and simulate the working process of CP single-screw compressor, the Computer-Aided Design (CAD) system for the CP single-screw compressor has been established. A new method based on computer graphics technology, database technology, object-oriented programming technology, and visual simulation technology has been adopted in this CAD system. The system has integrated solid modeling function with parameterization design function and animator simulation function based on analyzing the working principle of the CP single-screw compressor. The experimental results show that the CAD system for the CP single-screw compressor is practical and feasible.

关键词: CP single-screw     database technology     simulation technology     programming technology     animator simulation    

标题 作者 时间 类型 操作

Evaluation of regenerative braking based on single-pedal control for electric vehicles

Wei LIU, Xintian LIU, Yansong WANG, Hongzhong QI

期刊论文

An experimental study of a single-piston free piston linear generator

Jin XIAO, Yingdong CHENG, Jinlong WANG, Chengwei ZHU, Zhen HUANG

期刊论文

A wind tunnel study on control methods for cable dry-galloping

Hung D. VO,Hiroshi KATSUCHI,Hitoshi YAMADA,Mayuko NISHIO

期刊论文

Overview of the quality standard research of traditional Chinese medicine

Huimin Gao, Zhimin Wang, Yujuan Li, Zhongzhi Qian

期刊论文

基于Lagrange方程建模的单级旋转倒立摆控制

吴爱国,张小明,张钊

期刊论文

单边直线感应电机纵向边缘效应的研究

徐伟,孙广生

期刊论文

Crystallographic orientation effect on cutting-based single atomic layer removal

Wenkun XIE, Fengzhou FANG

期刊论文

Design and analysis of partially decoupled translational parallel mechanisms with single-loop structures

期刊论文

Moving policy and regulation forward for single-use plastic alternatives

期刊论文

Damage propagation and strength prediction of a single-lap interference-fit laminate structure

Peng ZOU, Xiangming CHEN, Hao CHEN, Guanhua XU

期刊论文

Novel casting processes for single-crystal turbine blades of superalloys

Dexin MA

期刊论文

Numerical analysis of bearing behaviors of single batter piles under horizontal loads in various directions

期刊论文

Promising approach for preparing metallic single-atom catalysts: electrochemical deposition

期刊论文

Ionic strength directed self-assembled polyelectrolyte single-bilayer membrane for low-pressure nanofiltration

期刊论文

Computer-Aided Design System for CP Single-Screw Compressor

SHEN Jing-feng, YAO Fu-sheng

期刊论文