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Mechanism of self-excited torsional vibration of locomotive driving system

Jianxin LIU, Huaiyun ZHAO, Wanming ZHAI

《机械工程前沿(英文)》 2010年 第5卷 第4期   页码 465-469 doi: 10.1007/s11465-010-0115-9

摘要: A single wheelset drive model and 2-DOFs torsional vibration model were established to investigate the self-excited torsional vibration of a locomotive driving system. The simulation results indicate that the self-excited torsional vibration occurs when the steady slip velocity is located at the descending slope of the adhesion coefficient curve. The principle of energy conservation was used to analyze the mechanism of the self-excited vibration. The factors affecting on the amplitude of the self-excited vibration are studied.

关键词: locomotive     driving system     self-excited torsional vibration     mechanism     influence factor    

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    

Spatiotemporal evolution and driving factors for GHG emissions of aluminum industry in China

《能源前沿(英文)》 2023年 第17卷 第2期   页码 294-305 doi: 10.1007/s11708-022-0819-7

摘要: China’s aluminum (Al) production has released a huge amount of greenhouse gas (GHG) emissions. As one of the biggest country of primary Al production, China must mitigate its overall GHG emission from its Al industry so that the national carbon neutrality target can be achieved. Under such a background, the study described in this paper conducts a dynamic material flow analysis to reveal the spatiotemporal evolution features of Al flows in China from 2000 to 2020. Decomposition analysis is also performed to uncover the driving factors of GHG emission generated from the Al industry. The major findings include the fact that China’s primary Al production center has transferred to the western region; the primary Al smelting and carbon anode consumption are the most carbon-intensive processes in the Al life cycle; the accumulative GHG emission from electricity accounts for 78.14% of the total GHG emission generated from the Al industry; China’s current Al recycling ratio is low although the corresponding GHG emission can be reduced by 93.73% if all the primary Al can be replaced by secondary Al; and the total GHG emission can be reduced by 88.58% if major primary Al manufacturing firms are transferred from Inner Mongolia to Yunnan. Based upon these findings and considering regional disparity, several policy implications are proposed, including promotion of secondary Al production, support of clean electricity penetration, and relocation of the Al industry.

关键词: aluminum     material flow analysis     GHG (greenhouse gas) emissions     LMDI (logarithmic mean divisa index)    

基于驾驶脑的智能驾驶车辆硬件平台架构 Article

李德毅,高洪波

《工程(英文)》 2018年 第4卷 第4期   页码 464-470 doi: 10.1016/j.eng.2018.07.015

摘要:

不同智能驾驶试验平台的传感器型号、数量、安装位置各不相同,导致传感器信息处理模块也各不相同;不同驾驶地图,其提供信息的粒度也没有固定标准,由此构成的智能驾驶系统软件模块的数量、接口各不相同。基于以驾驶脑为核心的智能驾驶车辆软件与硬件架构,决策模块将不直接与传感器信息处理模块发生关联,通过驾驶认知的形式化语言,将驾驶认知形式化,由驾驶脑认知形成决策。驾驶认知的形式化降低了传感器数量、类型、安装位置的变化对整个软件架构的影响,使得软件架构可以在不同传感器配置车辆平台上方便地移植。

关键词: 驾驶脑     智能驾驶     硬件平台架构    

自动驾驶地图有关政策的思考和建议

刘经南,董杨,詹骄,高柯夫

《中国工程科学》 2019年 第21卷 第3期   页码 92-97 doi: 10.15302/J-SSCAE-2019.03.004

摘要:

自动驾驶地图作为实现汽车自动驾驶的关键基础设施,对于推动我国自动驾驶领域的商业化开发至关重要。现阶段,我国受地图测绘、应用和监管等相关法律法规的制度掣肘,在自动驾驶地图的产业化进程方面相对滞后。为此,本文着重分析了我国在自动驾驶地图开发、应用和管理中面临的主要政策法规问题:自动驾驶地图是否需加密的问题、自动驾驶地图部分地理信息表达受限的问题、自动驾驶地图地理信息采集资质和审图流程的问题、自动驾驶地图事故责任和保险问题、自动驾驶地图相关测试规范和测试场景问题。同时结合国内外自动驾驶领域的发展趋势,给出加快我国自动驾驶汽车开发和商业化进程的四点建议:制定自动驾驶地图管理模式、允许自动驾驶地图应用试点及有序开放、适当放开企业权限及优化审核流程、建立国家级自动驾驶地图平台。

关键词: 自动驾驶地图     自动驾驶法规     自动驾驶政策    

一种用于自动驾驶的车辆概率性长期轨迹预测框架 Article

刘金鑫, 罗禹贡, 钟志华, 李克强, 黄荷叶, 熊辉

《工程(英文)》 2022年 第19卷 第12期   页码 228-239 doi: 10.1016/j.eng.2021.12.020

摘要:

在混合动态交通环境中,准确地预测周围车辆长期范围内的运动轨迹是自动驾驶车辆(AV)实现合理行为决策和保障行车安全不可或缺的前提条件之一。本文提出了一种车辆长期轨迹预测的概率框架,由驾驶意图推理模型(DIM)和轨迹预测模型(TPM)组成。DIM基于动态贝叶斯网络进行设计和应用,用于准确推断车辆潜在的驾驶意图。文中所提出的DIM结合了基本的交通规则和车辆多维运动信息。为了进一步提高轨迹预测精度并实现预测不确定性识别,本文开发了基于高斯过程(GP)的TPM,综合考虑了车辆模型的短期预测结果和运动特性。最后,在高速换道场景下进行仿真验证,说明了新方法的有效性。通过与其他先进方法进行对比,展示并验证了该框架在车辆长期轨迹预测任务中的优异性能。

关键词: 自动驾驶     动态贝叶斯网络     驾驶意图识别     高斯过程     车辆轨迹预测    

Development and application prospects of piezoelectric precision driving technology

ZHAO Chunsheng, ZHANG Jiantao, ZHANG Jianhui, JIN Jiamei

《机械工程前沿(英文)》 2008年 第3卷 第2期   页码 119-132 doi: 10.1007/s11465-008-0034-1

摘要: With the rapid development of science and technology, microelectronics manufacturing, photonics technology, space technology, ultra-precision machining, micro-robotics, biomedical engineering and other fields urgently need the support of modern precision driving theory and technology. Modern precision driving technology can be generally divided into two parts: electromagnetic and non-electromagnetic driving technology. Electromagnetic driving technology is based on traditional technology, has a low thrust-weight ratio, and needs deceleration devices with a cumbrous system or a complex structure. Moreover, it is difficult to improve positioning accuracy with this technology type. Thus, electromagnetic driving technology is still unable to meet the requirements for the above applications. Non-electromagnetic driving technology is a new choice. As a category of non-electromagnetic driving technology, piezoelectric driving technology becomes an important branch of modern precision driving technology. High holding torque and acute response make it suitable as an accurate positioning actuator. This paper presents the development of piezoelectric precision driving technology at home and abroad and gives an in-depth analysis. Future perspectives on the technology’s applications in the following fields are described: 1) integrated circuit manufacturing technology; 2) fiber optic component manufacturing technology; 3) micro parts manipulation and assembly technology; 4) biomedical engineering; 5) aerospace technology; and 6) ultra-precision processing technology.

关键词: Electromagnetic     ultra-precision processing     technology     piezoelectric     cumbrous    

A driving pulse edge modulation technique and its complex programming logic devices implementation

Xiao CHEN,Dong-chang QU,Yong GUO,Guo-zhu CHEN

《信息与电子工程前沿(英文)》 2015年 第16卷 第12期   页码 1088-1098 doi: 10.1631/FITEE.1500111

摘要: With the continual increase in switching speed and rating of power semiconductors, the switching voltage spike becomes a serious problem. This paper describes a new technique of driving pulse edge modulation for insulated gate bipolar transistors (IGBTs). By modulating the density and width of the pulse trains, without regulating the hardware circuit, the slope of the gate driving voltage is controlled to change the switching speed. This technique is used in the driving circuit based on complex programmable logic devices (CPLDs), and the switching voltage spike of IGBTs can be restrained through software, which is easier and more flexible to adjust. Experimental results demonstrate the effectiveness and practicability of the proposed method.

关键词: Driving pulse edge modulation     Switching voltage spike     Complex programmable logic device (CPLD)     Active gate drive    

Reverse driving character of 2-DOF closed chain haptic device

GUO Wei-dong, GUO Xin, ZHANG Yu-ru

《机械工程前沿(英文)》 2006年 第1卷 第3期   页码 356-359 doi: 10.1007/s11465-006-0029-8

摘要: Reverse driving character plays an important role in evaluating the performance of a haptic device, and it is the primary rule in the mechanical design. This article mainly investigates the problem of 2-DOF haptic device design f

Driving mechanism and boundary control of urban sprawl

Dongmei JIANG,Xiaoshun LI,Futian QU,Mingyan LI,Shaoliang ZHANG,Yunlong GONG,Xiaoping SHI,Xin CHEN

《环境科学与工程前沿(英文)》 2015年 第9卷 第2期   页码 298-309 doi: 10.1007/s11783-014-0639-z

摘要: Since the reform and opening-up, China’s economy has achieved remarkable development and so does the urbanization. However, there is an unavoidable contradiction between urban sprawl and the protection of arable land and the environment. By redefining the urban sprawl boundary, this paper is to provide a solution for the conflict above on the China’s urbanization context. The ideal boundary, moderate boundary and limit boundary are defined for urban sprawl in space. Taking Nanjing city as a case, the three urban sprawl boundaries are estimated in this paper based on the calculation of agricultural land resources value in Nanjing. The results show that 1) the integrated value of agricultural (cultivated) land resources in Nanjing is 1.55 × 10 CNY·hm , the economic value accounts for only 8.74% of the integrated value, while 91.26% of the integrated value has not revealed itself due to the existing institutional arrangements, policy distortions, and imperfect land market; 2) it is difficult to define the ideal and moderate boundaries due to the relatively low price of North Nanjing. In South Nanjing the land price is expensive and the ideal, moderate and limit boundaries are expanded to Jiangning, Qixia, and Yuhuatai; 3) the city scale of South Nanjing should be limited within 5.82 × 10 hm , which is roughly the same as the designated size of 5.81 × 10 hm in the urban planning. It is suggested that the rational scope of urban expansion should be controlled within the moderate boundary.

关键词: urban sprawl     rational expansion     driving forces     boundary control     Nanjing    

静液驱动二次调节扭矩加载系统实验

战兴群,张炎华,赵克定

《中国工程科学》 2001年 第3卷 第11期   页码 70-73

摘要:

针对柔性航天器动力学模型的降阶问题,综述了动力学建模中几种常用的模态集,介绍了用于选择系统保留模态的有关准则。通常的模态价值分析和内平衡理论是用于航天器系统模态的选取,而不是直接用于动力学建模时的部件模态或系统结构弹性变形模态的选取,因而存在如何应用上述准则于动力学建模的问题。为此,提出了一个动力学建模时的降阶策略;还提供了一个数值例子,以对采用不同的模态集建模时的结果进行比较,并表明如何采用上述准则于航天器的动力学建模。

关键词: 航天器     柔性体     动力学     模型降阶    

Evolutionary Decision-Making and Planning for Autonomous Driving Based on Safe and Rational Exploration

Kang Yuan,Yanjun Huang,Shuo Yang,Zewei Zhou,Yulei Wang,Dongpu Cao,Hong Chen,

《工程(英文)》 doi: 10.1016/j.eng.2023.03.018

摘要: Decision-making and motion planning are extremely important in autonomous driving to ensure safe driving in a real-world environment. This study proposes an online evolutionary decision-making and motion planning framework for autonomous driving based on a hybrid data- and model-driven method. First, a data-driven decision-making module based on deep reinforcement learning (DRL) is developed to pursue a rational driving performance as much as possible. Then, model predictive control (MPC) is employed to execute both longitudinal and lateral motion planning tasks. Multiple constraints are defined according to the vehicle’s physical limit to meet the driving task requirements. Finally, two principles of safety and rationality for the self-evolution of autonomous driving are proposed. A motion envelope is established and embedded into a rational exploration and exploitation scheme, which filters out unreasonable experiences by masking unsafe actions so as to collect high-quality training data for the DRL agent. Experiments with a high-fidelity vehicle model and MATLAB/Simulink co-simulation environment are conducted, and the results show that the proposed online-evolution framework is able to generate safer, more rational, and more efficient driving action in a real-world environment.

关键词: Autonomous driving     Decision-making     Motion planning     Deep reinforcement learning     Model predictive control    

Research on Anthropomorphic Obstacle Avoidance Trajectory Planning for Adaptive Driving Scenarios Based

Jian Wu,Yang Yan,Yulong Liu,Yahui Liu,

《工程(英文)》 doi: 10.1016/j.eng.2023.07.018

摘要: The forward design of trajectory planning strategies requires preset trajectory optimization functions, resulting in poor adaptability of the strategy and an inability to accurately generate obstacle avoidance trajectories that conform to real driver behavior habits. In addition, owing to the strong time-varying dynamic characteristics of obstacle avoidance scenarios, it is necessary to design numerous trajectory optimization functions and adjust the corresponding parameters. Therefore, an anthropomorphic obstacle-avoidance trajectory planning strategy for adaptive driving scenarios is proposed. First, numerous expert-demonstrated trajectories are extracted from the HighD natural driving dataset. Subsequently, a trajectory expectation feature-matching algorithm is proposed that uses maximum entropy inverse reinforcement learning theory to learn the extracted expert-demonstrated trajectories and achieve automatic acquisition of the optimization function of the expert-demonstrated trajectory. Furthermore, a mapping model is constructed by combining the key driving scenario information that affects vehicle obstacle avoidance with the weight of the optimization function, and an anthropomorphic obstacle avoidance trajectory planning strategy for adaptive driving scenarios is proposed. Finally, the proposed strategy is verified based on real driving scenarios. The results show that the strategy can adjust the weight distribution of the trajectory optimization function in real time according to the “emergency degree” of obstacle avoidance and the state of the vehicle. Moreover, this strategy can generate anthropomorphic trajectories that are similar to expert-demonstrated trajectories, effectively improving the adaptability and acceptability of trajectories in driving scenarios.

关键词: Obstacle avoidance trajectory planning     Inverse reinforcement theory     Anthropomorphic     Adaptive driving scenarios    

Hyperosmolarity promotes macrophage pyroptosis by driving the glycolytic reprogramming of corneal epithelial

《医学前沿(英文)》 2023年 第17卷 第4期   页码 781-795 doi: 10.1007/s11684-023-0986-x

摘要: Tear film hyperosmolarity plays a core role in the development of dry eye disease (DED) by mediating the disruption of ocular surface homeostasis and triggering inflammation in ocular surface epithelium. In this study, the mechanisms involving the hyperosmolar microenvironment, glycolysis mediating metabolic reprogramming, and pyroptosis were explored clinically, in vitro, and in vivo. Data from DED clinical samples indicated that the expression of glycolysis and pyroptosis-related genes, including PKM2 and GSDMD, was significantly upregulated and that the secretion of IL-1β significantly increased. In vitro, the indirect coculture of macrophages derived from THP-1 and human corneal epithelial cells (HCECs) was used to discuss the interaction among cells. The hyperosmolar environment was found to greatly induce HCECs’ metabolic reprogramming, which may be the primary cause of the subsequent inflammation in macrophages upon the activation of the related gene and protein expression. 2-Deoxy-d-glucose (2-DG) could inhibit the glycolysis of HCECs and subsequently suppress the pyroptosis of macrophages. In vivo, 2-DG showed potential efficacy in relieving DED activity and could significantly reduce the overexpression of genes and proteins related to glycolysis and pyroptosis. In summary, our findings suggested that hyperosmolar-induced glycolytic reprogramming played an active role in promoting DED inflammation by mediating pyroptosis.

关键词: dry eye disease     glycolytic reprogramming     pyroptosis     inflammation     2-DG    

Evaluation of measurement uncertainty of the high-speed variable-slit system based on the Monte Carlo

Yin ZHANG, Jianwei WU, Kunpeng XING, Zhongpu WEN, Jiubin TAN

《机械工程前沿(英文)》 2020年 第15卷 第4期   页码 517-537 doi: 10.1007/s11465-020-0589-z

摘要: This paper presents a dynamic and static error transfer model and uncertainty evaluation method for a high-speed variable-slit system based on a two-dimensional orthogonal double-layer air-floating guide rail structure. The motion accuracy of the scanning blade is affected by both the moving component it is attached to and the moving component of the following blade during high-speed motion. First, an error transfer model of the high-speed variable-slit system is established, and the influence coefficients are calculated for each source of error associated with the accuracy of the blade motion. Then, the maximum range of each error source is determined by simulation and experiment. Finally, the uncertainty of the blade displacement measurement is evaluated using the Monte Carlo method. The proposed model can evaluate the performance of the complex mechanical system and be used to guide the design.

关键词: air-floating guide rail     error transfer model     driving and following structure     dynamic error     uncertainty evaluation     Monte Carlo method    

标题 作者 时间 类型 操作

Mechanism of self-excited torsional vibration of locomotive driving system

Jianxin LIU, Huaiyun ZHAO, Wanming ZHAI

期刊论文

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

期刊论文

Spatiotemporal evolution and driving factors for GHG emissions of aluminum industry in China

期刊论文

基于驾驶脑的智能驾驶车辆硬件平台架构

李德毅,高洪波

期刊论文

自动驾驶地图有关政策的思考和建议

刘经南,董杨,詹骄,高柯夫

期刊论文

一种用于自动驾驶的车辆概率性长期轨迹预测框架

刘金鑫, 罗禹贡, 钟志华, 李克强, 黄荷叶, 熊辉

期刊论文

Development and application prospects of piezoelectric precision driving technology

ZHAO Chunsheng, ZHANG Jiantao, ZHANG Jianhui, JIN Jiamei

期刊论文

A driving pulse edge modulation technique and its complex programming logic devices implementation

Xiao CHEN,Dong-chang QU,Yong GUO,Guo-zhu CHEN

期刊论文

Reverse driving character of 2-DOF closed chain haptic device

GUO Wei-dong, GUO Xin, ZHANG Yu-ru

期刊论文

Driving mechanism and boundary control of urban sprawl

Dongmei JIANG,Xiaoshun LI,Futian QU,Mingyan LI,Shaoliang ZHANG,Yunlong GONG,Xiaoping SHI,Xin CHEN

期刊论文

静液驱动二次调节扭矩加载系统实验

战兴群,张炎华,赵克定

期刊论文

Evolutionary Decision-Making and Planning for Autonomous Driving Based on Safe and Rational Exploration

Kang Yuan,Yanjun Huang,Shuo Yang,Zewei Zhou,Yulei Wang,Dongpu Cao,Hong Chen,

期刊论文

Research on Anthropomorphic Obstacle Avoidance Trajectory Planning for Adaptive Driving Scenarios Based

Jian Wu,Yang Yan,Yulong Liu,Yahui Liu,

期刊论文

Hyperosmolarity promotes macrophage pyroptosis by driving the glycolytic reprogramming of corneal epithelial

期刊论文

Evaluation of measurement uncertainty of the high-speed variable-slit system based on the Monte Carlo

Yin ZHANG, Jianwei WU, Kunpeng XING, Zhongpu WEN, Jiubin TAN

期刊论文