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Analysis and stabilization control of a voltage source controlled wind farm under weak grid conditions

《能源前沿(英文)》 2022年 第16卷 第6期   页码 943-955 doi: 10.1007/s11708-021-0793-5

摘要: This paper investigates and discusses the interaction stability issues of a wind farm with weak grid connections, where the wind turbines (WTs) are controlled by a new type of converter control strategy referred to as the voltage source (VS) control. The primary intention of the VS control method is to achieve the high-quality inertial response capability of a single WT. However, when it is applied to multiple WTs within a wind farm, its weak-grid performance regarding the stability remains concealed and needs to be clarified. To this end, a frequency domain model of the wind farm under the VS control is first developed. Based on this model and the application of a stability margin quantification index, not only the interactions between the wind farm and the weak grid but also those among WTs will be systematically assessed in this paper. A crucial finding is that the inertial response of VS control has negative impacts on the stability margin of the system, and the dominant instability mode is more related to the interactions among the WTs rather than the typical grid-wind farm interaction. Based on this knowledge, a stabilization control strategy is then proposed, aiming for stability improvements of VS control while fulfilling the demand of inertial responses. Finally, all the results are verified by time-domain simulations in power systems computer aided design/electromagnetic transients including DC(PSCAD/EMTDC).

关键词: weak grids     voltage source (VS) control     wind turbine (WT)     stabilization control     wind farm     inertial response    

Piezoelectric inertial robot for operating in small pipelines based on stick-slip mechanism: modeling

《机械工程前沿(英文)》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0697-z

摘要: Small pipes exist in industrial and biomedical fields, and require microrobots with high operational precision and large load capacity to inspect or perform functional tasks. A piezoelectric inertial pipeline robot using a “stick-slip” mechanism was proposed to address this requirement. In this study, the driving principle of the proposed robot was analyzed, and the strategy of the design scheme was presented. A dynamics model of the stick-slip system was established by combining the dynamics model of the driving foot system and the LuGre friction model, and the simulation analysis of the effect of system parameters on the operating trajectory was performed. An experimental system was established to examine the output characteristics of the proposed robot. Experimental results show that the proposed pipeline robot with inertial stick-slip mechanism has a great load capacity of carrying 4.6 times (70 g) its own mass and high positioning accuracy. The speed of the pipeline robot can reach up to 3.5 mm/s (3 mm/s) in the forward (backward) direction, with a minimum step distance of 4 μm. Its potential application for fine operation in the pipe is exhibited by a demonstration of contactless transport.

关键词: pipeline robot     piezoelectric     inertial drive     stick-slip     large load capacity     dynamics model     small pipeline    

Modeling and analysis of controllable output property of cantilever-beam inertial sensors based on magnetic

Guixiong LIU, Peiqiang ZHANG, Chen XU

《机械工程前沿(英文)》 2009年 第4卷 第2期   页码 129-133 doi: 10.1007/s11465-009-0035-8

摘要: Magnetic fluid is first introduced into the traditional cantilever-beam senor. Based on the property of the cantilever-beam and the novel controllable mag-viscosity of magnetic fluid, the output of cantilever-beam sensors is under control so that the controllable output of the sensors can be realized. The mathematical model of the sensors is established and analyzed. The dynamic control function and the following educational results, which include the two curves of the displacement ratio and phase function with the different damping ratio and frequency ratio, are obtained based on the model. The result shows that it is valid to realize the controllable output of the sensors by controlling the viscosity of the magnetic fluid, and finally the expanded measurement range can be realized.

关键词: sensors     magnetic fluid     property of mag-viscosity     controllable output    

An experimental characterization of human torso motion

Daniele CAFOLLA,I-Ming CHEN,Marco CECCARELLI

《机械工程前沿(英文)》 2015年 第10卷 第4期   页码 311-325 doi: 10.1007/s11465-015-0352-z

摘要:

The torso plays an important role in the human-like operation of humanoids. In this paper, a method is proposed to analyze the behavior of the human torso by using inertial and magnetic sensing tools. Experiments are conducted to characterize the motion performance of the human torso during daily routine operations. Furthermore, the forces acting on the human body during these operations are evaluated to design and validate the performance of a humanoid robot.

关键词: experimental biomechanics     human torso     analysis     inertial sensor     characterization    

基于悬浮光力学的惯性传感颠覆性技术

胡慧珠,尹璋琦,李楠,车双良,舒晓武,刘承

《中国工程科学》 2018年 第20卷 第6期   页码 112-116 doi: 10.15302/J-SSCAE-2018.06.018

摘要:

悬浮光力学是光力学与量子光学结合的产物,为微纳机械振子的控制和测量提供了一种全新的量子方法,这种方法具有前所未有的观测精度,可接近甚至突破标准量子极限,具有广阔的发展和应用前景。目前国际上已在室温下利用此系统实现了力、力矩、位移、加速度等多个物理量的极高灵敏度测量。本文综述了悬浮光力学的研究现状及国内外在精密传感与测量方面的进展。作为近年来发展起来的一种前沿技术,悬浮光力学已逐渐从基础研究走向应用,特别是对惯性传感与精密测量领域有重要的应用前景。最后提出了发展基于悬浮光力学的惯性传感颠覆性技术的建议,为我国惯性传感与量子精密测量技术发展规划的制定提供参考。

关键词: 光力学     精密测量     惯性传感     颠覆性技术    

脉冲型惯性双向联想记忆神经网络新解 Research Articles

Chaouki AOUITI, Mahjouba Ben REZEG, Yang CAO

《信息与电子工程前沿(英文)》 2020年 第21卷 第2期   页码 324-339 doi: 10.1631/FITEE.1900181

摘要: 探究了具有混合时滞和脉冲效应的惯性双向联想记忆神经网络。该研究为类似系统的反周期解的存在性、唯一性和全局指数稳定性提供了新的实用条件。使用微分不等式技术证明我们的主要结果,并给出一个仿真算例证明新结果的有效性。

关键词: 惯性神经网络;反周期解;全局指数稳定;脉冲;时变延迟;双向联想记忆    

基于惯性能时空最优分布的高加速轻载机构精密定位方法 Article

陈新,白有盾,杨志军,高健,陈贡发

《工程(英文)》 2015年 第1卷 第3期   页码 391-398 doi: 10.15302/J-ENG-2015063

摘要:

高速运动精密定位是微电子封装设备中高加速轻载执行机构的基本运动需求。本文推导了高加速机构瞬态非线性动力学响应方程,揭示了刚度、频率、阻尼 (与材料空间布局相关) 和驱动频率 (与运动规划相关) 是主要影响因素。据此,在满足高加速机构精密定位的条件下,笔者提出了一种基于最优非线性动力学响应的结构优化和速度规划新方法。在结构优化中,首先分析了目前流行的基于等效静态载荷的柔性多体动力学优化方法未充分考虑惯性载荷的不足,然后提出了基于等效模态的柔性多体动力学最优动态响应优化新方法;在速度规划上,针对传统的几何光滑方法不能反映系统动态特性的缺陷,提出了基于变边界条件非线性动力学响应优化的速度规划新方法。将所提方法应用到高速固晶焊头的优化设计中,通过结构优化,降低振幅超过20%,再经非对称变加速规划,缩短定位时间超过40%。本文提出的方法为微电子封装类装备等高加速轻载机构精密定位的实现提供了有效的理论支撑和解决途径。

关键词: 高加速轻载机构     精密定位     时空分布     惯性能     等效静态载荷方法     速度规划    

Dynamic contribution of variable-speed wind energy conversion system in system frequency regulation

Yajvender Pal VERMA, Ashwani KUMAR

《能源前沿(英文)》 2012年 第6卷 第2期   页码 184-192 doi: 10.1007/s11708-012-0185-y

摘要: Frequency regulation in a generation mix having large wind power penetration is a critical issue, as wind units isolate from the grid during disturbances with advanced power electronics controllers and reduce equivalent system inertia. Thus, it is important that wind turbines also contribute to system frequency control. This paper examines the dynamic contribution of doubly fed induction generator (DFIG)-based wind turbine in system frequency regulation. The modified inertial support scheme is proposed which helps the DFIG to provide the short term transient active power support to the grid during transients and arrests the fall in frequency. The frequency deviation is considered by the controller to provide the inertial control. An additional reference power output is used which helps the DFIG to release kinetic energy stored in rotating masses of the turbine. The optimal speed control parameters have been used for the DFIG to increases its participation in frequency control. The simulations carried out in a two-area interconnected power system demonstrate the contribution of the DFIG in load frequency control.

关键词: doubly fed induction generator (DFIG)     load frequency control     inertial control     wind energy conversion system (WECS)    

Revisiting China’s response to coronavirus disease 2019

《医学前沿(英文)》 2023年 第17卷 第6期   页码 1011-1013 doi: 10.1007/s11684-024-1059-5

摘要: Revisiting China’s response to coronavirus disease 2019

Instrumented toys for assessing spatial cognition in infants

Domenico CAMPOLO, Fabrizio TAFFONI, Domenico FORMICA, Flavio KELLER, Eugenio GUGLIELMELLI

《机械工程前沿(英文)》 2011年 第6卷 第1期   页码 82-88 doi: 10.1007/s11465-011-0208-0

摘要:

This paper describes an interdisciplinary approach to the assessment on infants’ behavior, with a focus on the technology. The goal is an objective, quantitative analysis of concurrent maturation of sensory, motor and cognitive abilities in young children, in relation to the achievement of developmental milestones. An instrumented block-box toy specifically developed to assess the ability to insert objects into holes is presented. The functional specifications are derived from experimental protocols devised by neuroscientists to assess spatial cognition skills. Technological choices are emphasized with respect to ecological requirements. An ad hoc calibration procedure is also presented which is suitable to unstructured environments. Finally, preliminary tests carried out at a local day-care with 12–24 months old infants are presented which prove the in-field usability of the proposed technology.

关键词: inertial-magnetic sensing     in-field calibration     neuro-developmental engineering     ecological assessment    

Development of a seismic design method based on response spectra for building structures

ZHOU Xiyuan, YU Ruifang

《结构与土木工程前沿(英文)》 2007年 第1卷 第2期   页码 129-141 doi: 10.1007/s11709-007-0014-2

摘要: The assumption and problem of the mode-superposition response spectrum method in seismic design code is discussed based on a brief review of the development of the seismic design method for building structures. The scope of application for the classical damping theory is analyzed and the necessity of the research on mode-superposition method for non-classical damping is presented. The progresses on the mode superposition response spectrum theory are discussed. This includes: 1) the complex mode superposition method (in real form) for the non-classically damped linear system and the general calculation formula for the application of code; 2) the complex complete quadratic combination (CCQC) method for the non-classically damped linear system, which is based on the same assumptions as in deducing the complete quadratic combination (CQC) method which is popularly used in seismic design codes of many countries; 3) the complex complete quadratic combination with three components (CCQC3) method, which is a generalization of the CCQC method to the case of multi-components and multiple-support seismic excitations and deducing corresponding method; 4) the approach for calculation of seismic response of the non-classically damped system with overcritical damping and the calculation method of seismic response for the linear system with multiple eigenvalues; 5) the time-dependent CCQC (t) algorithm considering nonstationary earthquake ground motion; 6) an applied and effective method to solve the low order complex vector basis for the large linear non-classically damped system, which can be expediently used in practice to avoid the unknown errors coming from the forced uncoupling method; 7) bringing forward the concept of partial quadratic combination in order to reduce the calculation amount of CQC and CCQC methods, and studying the primary estimation-criterion. The reasonability and applicable scope of these methods are also briefly discussed in this paper.

关键词: generalization     classical damping     mode-superposition response     calculation formula     damping theory    

Trajectory of COVID-19 response and management strategy in China: scientific rationale driven strategy

《医学前沿(英文)》 2024年 第18卷 第1期   页码 19-30 doi: 10.1007/s11684-024-1074-6

摘要: The pneumonia caused by novel coronavirus SARS-CoV-2 infection in early December 2019, which was later named coronavirus disease 2019 (COVID-19) by the World Health Organization (WHO), rapidly spread across the world. China has made extraordinary efforts to this unprecedented pandemic, put its response and control at a very high level of infectious disease management (Category B but with measures for Category A), given top priority to the people and their lives, and balanced the pandemic control and socio-economic development. After more than three years’ fighting against this disease, China downgraded the management of COVID-19 to Category B infectious disease on January 8, 2023 and the WHO declared the end of public health emergency on May 5, 2023. However, the ending of pandemic does not mean that the disease is no longer a health threat. Experiences against COVID-19 from China and the whole world should be learned to prepare well for the future public health emergencies. This article gives a systematic review of the trajectory of COVID-19 development in China, summarizes the critical policy arrangements and provides evidence for the adjustment during policy making process, so as to share experiences with international community and contribute to the global health for all humanity.

关键词: COVID-19     public health     response and control strategy     science-based policy making    

Confining pressure effect on dynamic response of high rockfill dam

Xuexing CAO, Yunlong HE, Kun XIONG,

《结构与土木工程前沿(英文)》 2010年 第4卷 第1期   页码 116-126 doi: 10.1007/s11709-010-0014-5

摘要: Studies show that the dynamic properties of rockfill are strongly dependent on the confining pressure. Therefore, confining pressure effect has become a very important factor in the seismic analysis of high rockfill dam. The relationships of dynamic shear modulus versus dynamic shear strain and damping ratio versus dynamic shear strain had been improved to a certain degree on the basic of widely used Hardin-Drnevich constitutive model in this paper. Then a new model that could consider confining pressure effect has been established. Regression analysis was carried out of the dynamic triaxial experimental data of the damming materials in the Changheba hydropower station of Sichun Province, China. The results show that, the new model can fit the test data well under various confining pressures. A corresponding computational procedure was compiled and applied in the dynamic response analysis of the Changheba Dam. Comparing the calculation results between the new constitutive model and the ordinary Hardin-Drnevich model, it can be seen that the result is conservative to some extent without considering confining pressure effect.

关键词: confining pressure effect     high rockfill dam     dynamic response     Hardin-Drnevich constitutive model    

Topology optimization of transient problem with maximum dynamic response constraint using SOAR scheme

《机械工程前沿(英文)》 2021年 第16卷 第3期   页码 593-606 doi: 10.1007/s11465-021-0636-4

摘要: This paper proposes a novel method for the continuum topology optimization of transient vibration problem with maximum dynamic response constraint. An aggregated index in the form of an integral function is presented to cope with the maximum response constraint in the time domain. The density filter solid isotropic material with penalization method combined with threshold projection is developed. The sensitivities of the proposed index with respect to design variables are conducted. To reduce computational cost, the second-order Arnoldi reduction (SOAR) scheme is employed in transient analysis. Influences of aggregate parameter, duration of loading period, interval time, and number of basis vectors in the SOAR scheme on the final designs are discussed through typical examples while unambiguous configuration can be achieved. Through comparison with the corresponding static response from the final designs, the optimized results clearly demonstrate that the transient effects cannot be ignored in structural topology optimization.

关键词: topology optimization     solid isotropic material with penalization     transient response     aggregation function     second-order Arnoldi reduction    

Dynamic response of precast segmental bridge columns under heavy truck impact

《结构与土木工程前沿(英文)》 2023年 第17卷 第3期   页码 327-349 doi: 10.1007/s11709-023-0911-z

摘要: Considering the wide application of precast segmental bridge columns (PSBCs) in engineering practice, impact-resistant performance has gained significant attention. However, few studies have focused on PSBCs subjected to high-energy impacts caused by heavy truck collisions. Therefore, the behavior of PSBCs under a heavy truck impact was investigated in this study using high-fidelity finite element (FE) models. The detailed FE modeling methods of the PSBCs and heavy trucks were validated against experimental tests. The validated modeling methods were employed to simulate collisions between PSBCs and heavy trucks. The simulation results demonstrated that the engine and cargo caused two major peak impact forces during collision. Subsequently, the impact force, failure mode, displacement, and internal force of the PSBCs under heavy truck impacts were scrutinized. An extensive study was performed to assess the influence of the section size, truck weight, impact velocity, and number of precast segments on the impact responses. The truck weight was found to have a minor effect on the engine impact force. Damage was found to be localized at the bottom of the three segments, with the top remaining primarily undamaged. This parametric study demonstrated that larger cross-sections may be a preferred option to protect PSBCs against the impact of heavy trucks.

关键词: precast segmental bridge columns     heavy truck     collision     dynamic response    

标题 作者 时间 类型 操作

Analysis and stabilization control of a voltage source controlled wind farm under weak grid conditions

期刊论文

Piezoelectric inertial robot for operating in small pipelines based on stick-slip mechanism: modeling

期刊论文

Modeling and analysis of controllable output property of cantilever-beam inertial sensors based on magnetic

Guixiong LIU, Peiqiang ZHANG, Chen XU

期刊论文

An experimental characterization of human torso motion

Daniele CAFOLLA,I-Ming CHEN,Marco CECCARELLI

期刊论文

基于悬浮光力学的惯性传感颠覆性技术

胡慧珠,尹璋琦,李楠,车双良,舒晓武,刘承

期刊论文

脉冲型惯性双向联想记忆神经网络新解

Chaouki AOUITI, Mahjouba Ben REZEG, Yang CAO

期刊论文

基于惯性能时空最优分布的高加速轻载机构精密定位方法

陈新,白有盾,杨志军,高健,陈贡发

期刊论文

Dynamic contribution of variable-speed wind energy conversion system in system frequency regulation

Yajvender Pal VERMA, Ashwani KUMAR

期刊论文

Revisiting China’s response to coronavirus disease 2019

期刊论文

Instrumented toys for assessing spatial cognition in infants

Domenico CAMPOLO, Fabrizio TAFFONI, Domenico FORMICA, Flavio KELLER, Eugenio GUGLIELMELLI

期刊论文

Development of a seismic design method based on response spectra for building structures

ZHOU Xiyuan, YU Ruifang

期刊论文

Trajectory of COVID-19 response and management strategy in China: scientific rationale driven strategy

期刊论文

Confining pressure effect on dynamic response of high rockfill dam

Xuexing CAO, Yunlong HE, Kun XIONG,

期刊论文

Topology optimization of transient problem with maximum dynamic response constraint using SOAR scheme

期刊论文

Dynamic response of precast segmental bridge columns under heavy truck impact

期刊论文