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Development of a novel two-stage proportional valve with a pilot digital flow distribution

Qiang GAO, Yuchuan ZHU, Changwen WU, Yulei JIANG

《机械工程前沿（英文）》 2021年 第16卷 第2期   页码 420-434 doi: 10.1007/s11465-020-0622-2

摘要： Pilot two-stage proportional valves are widely used in high-power hydraulic systems. For the purpose of improving the dynamic performance, reliability, and digitization of the traditional proportional valve, a novel two-stage proportional valve with a pilot digital flow distribution is proposed from the viewpoint of the dual nozzle-flapper valve’s working principle. In particular, the dual nozzle-flapper is decoupled by two high-speed on/off valves (HSVs). First, the working principle and mathematical model of the proposed valve are determined. Then, the influences of the control parameters (duty cycle and switching frequency) and structural parameters (fixed orifice’s diameter and main valve’s spring) on the main valve’s motion are analyzed on the basis of theory, simulation, and experiment. In addition, in optimizing the value of the fixed orifice’s diameter, a new design criterion that considers the maximum pressure sensitivity, flow controllability, and flow linearization is proposed to improve the balance between the effective displacement and the displacement fluctuation of the main valve. The new scheme is verified by simulations and experiments. Experimental results of the closed-loop displacement tracking have demonstrated that the delay time of the main valve is always within 3.5 ms under different working conditions, and the tracking error can be significantly reduced using the higher switching frequency. The amplitude–frequency experiments indicate that a ‒3 dB-frequency of the proposed valve can reach 9.5 Hz in the case of±50% full scale and 15 Hz in the case of 0%–50% full scale. The values can be further improved by increasing the flow rate of the pilot HSV.

关键词： two-stage proportional valve     digital flow distribution     high-speed on/off valve     position tracking characteristic     dynamic performance    

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Task-space position/attitude tracking control of FAST fine tuning system

QI Lin, ZHANG Hui, DUAN Guanghong

《机械工程前沿（英文）》 2008年 第3卷 第4期   页码 392-399 doi: 10.1007/s11465-008-0056-8

摘要： This paper addresses the task-space position/attitude tracking control of a suspended parallel robot, which is being developed in the framework of a five-hundred meter aperture spherical radio telescope (FAST) project. Based on the quaternion algebra, a novel model-independent task-space PD controller that ensures end-effector position and attitude tracking is presented. The simulation and experimental results show that the new controller has better control effects than the traditional joint-space controller.

关键词： telescope     five-hundred     end-effector     controller     simulation    

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Chord error constraint based integrated control strategy for contour error compensation

Tie ZHANG, Caicheng WU, Yanbiao ZOU

《机械工程前沿（英文）》 2020年 第15卷 第4期   页码 645-658 doi: 10.1007/s11465-020-0601-7

摘要： As the traditional cross-coupling control method cannot meet the requirements for tracking accuracy and contour control accuracy in large curvature positions, an integrated control strategy of cross-coupling contour error compensation based on chord error constraint, which consists of a cross-coupling controller and an improved position error compensator, is proposed. To reduce the contour error, a PI-type cross-coupling controller is designed, with its stability being analyzed by using the contour error transfer function. Moreover, a feed rate regulator based on the chord error constraint is proposed, which performs speed planning with the maximum feed rate allowed by the large curvature position as the constraint condition, so as to meet the requirements of large curvature positions for the chord error. Besides, an improved position error compensation method is further presented by combining the feed rate regulator with the position error compensator, which improves the tracking accuracy via the advance compensation of tracking error. The biaxial experimental results of non-uniform rational B-splines curves indicate that the proposed integrated control strategy can significantly improve the tracking and contour control accuracy in biaxial contour following tasks.

关键词： cross-coupling controller     contour error     tracking error     position error compensator     feed rate regulator    

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Experimental and CFD analysis of nozzle position of subsonic ejector

Xilai ZHANG, Shiping JIN, Suyi HUANG, Guoqing TIAN

《能源前沿（英文）》 2009年 第3卷 第2期   页码 167-174 doi: 10.1007/s11708-009-0001-5

摘要： The influence of nozzle position on the performance of an ejector was analyzed qualitatively with free jet flow model. Experimental investigations and computational fluid dynamics (CFD) analysis of the nozzle position of the subsonic ejector were also conducted. The results show that there is an optimum nozzle position for the ejector. The ejecting coefficient reaches its maximum when the nozzle is positioned at the optimum and decreases when deviating. Moreover, the nozzle position of an ejector is not a fixed value, but is influenced greatly by the flow parameters. Considering the complexity of the ejector, CFD is reckoned as a useful tool in the design of ejectors.

关键词： ejector     nozzle position     ejecting coefficient     CFD    

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Robust energy-efficient train speed profile optimization in a scenario-based position–time–speed network

《工程管理前沿（英文）》 2021年 第8卷 第4期   页码 595-614 doi: 10.1007/s42524-021-0173-1

摘要： Train speed profile optimization is an efficient approach to reducing energy consumption in urban rail transit systems. Different from most existing studies that assume deterministic parameters as model inputs, this paper proposes a robust energy-efficient train speed profile optimization approach by considering the uncertainty of train modeling parameters. Specifically, we first construct a scenario-based position–time–speed (PTS) network by considering resistance parameters as discrete scenario-based random variables. Then, a percentile reliability model is proposed to generate a robust train speed profile, by which the scenario-based energy consumption is less than the model objective value at α confidence level. To solve the model efficiently, we present several algorithms to eliminate the infeasible nodes and arcs in the PTS network and propose a model reformulation strategy to transform the original model into an equivalent linear programming model. Lastly, on the basis of our field test data collected in Beijing metro Yizhuang line, a series of experiments are conducted to verify the effectiveness of the model and analyze the influences of parameter uncertainties on the generated train speed profile.

关键词： robust train speed profile     percentile reliability model     scenario-based position–time–speed network     mixed-integer programming    

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Analysis of the dynamic hysteresis characteristic of finger seal

LEI Yanni, CHEN Guoding

《机械工程前沿（英文）》 2007年 第2卷 第1期   页码 32-36 doi: 10.1007/s11465-007-0005-y

摘要： The research about hysteresis characteristic of finger seal (FS), which was carried out based on the model with static loads, could not reflect the dynamics behavior of FS system when the rotor runs at high speed. To solve this problem, the relations between the dynamics parameters, structure parameters as well as working parameters in the system were given out through the analysis of finite element analysis result. A mass spring damper dynamics model of FS system was proposed and the hysteresis characteristic of the FS system was analyzed. This work shows that the dynamics characteristic analysis of the FS is necessary and the dynamics model proposed in this paper is valid. This dynamics model is the basis for the optimization design of FS system.

关键词： FS     necessary     hysteresis characteristic     optimization     spring    

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Strategic position and development prospects of nuclear energy in China

SHEN Wenquan

《能源前沿（英文）》 2007年 第1卷 第2期   页码 125-128 doi: 10.1007/s11708-007-0015-9

摘要： By analyzing the challenges of China s energy supply, an excellent perspective of nuclear power development in the country has been described. Taking into account the near-, mid-, and long-term development requirements, a comprehensive, coordinated and sustainable nuclear power program is proposed. Thus, our national nuclear industry can not only catch up with the world s advanced level in proper time, but also possess enough stamina for sustainability.

关键词： development     excellent perspective     long-term development     comprehensive     national    

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Output tracking control of mobile manipulators based on dynamical sliding-mode control

WUYuxiang, FENG Ying, HU Yueming

《机械工程前沿（英文）》 2007年 第2卷 第1期   页码 110-115 doi: 10.1007/s11465-007-0019-5

摘要： A dynamical sliding-mode controller is devised to track the output of mobile manipulators. During the investigation, firstly a reduced dynamic model considering the dynamics of the driving motor is developed for mobile manipulators. Then, the system is decomposed into four lower-dimensional subsystems by means of diffeomorphism and nonlinear input transformation. Moreover, a design method of the dynamical sliding-mode controller that is applied to the output tracking of mobile manipulators is proposed. The simulation results indicate that the dynamical sliding-mode controller can not only track the given trajectory correctly but also reduce the chattering of sliding-mode control system considerably.

关键词： lower-dimensional     nonlinear     trajectory     tracking     diffeomorphism    

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Flow characteristic and wastewater treatment performance of a pilot-scale airlift oxidation ditch

Hongtao PANG, Hanchang SHI, Huiming SHI,

《环境科学与工程前沿（英文）》 2009年 第3卷 第4期   页码 470-476 doi: 10.1007/s11783-009-0143-z

摘要： A pilot-scale airlift oxidation ditch using bubble diffuser and baffle as aerator was operated in a wastewater treatment plant (WWTP) to investigate its flow characteristic and wastewater treatment performance. Compared with the conventional oxidation ditch process, effective depth and oxygen utilization efficiency of this new process was improved by underwater aeration. Furthermore, it had a reversed velocity distribution, which decreased from the bottom to the top on vertical section. Velocity measurement showed that a velocity over 0.2m/s at the bottom was sufficient to prevent sludge settlement during long term operation. Application of these concepts would save land area and energy consumption by about 25%―50% and 55%, respectively. In this new system, organic biodegradation and nitrification could be well achieved. Denitrification could occur steadily in the straight part by adjusting the airflow rate. An average TN removal rate of 63% was achieved with dissolved oxygen (DO) concentrations between 0.6mg/L and 1.5mg/L. The main pollutants in the effluent could meet the strictest discharge standard (COD<50mg/L, NH―N<5mg/L, and TN<15mg/L) in China now.

关键词： airlift oxidation ditch     flow characteristic     wastewater treatment    

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Air-bearing position optimization based on dynamic characteristics of ultra-precision linear stages

CHEN Xuedong, LI Zhixin

《机械工程前沿（英文）》 2008年 第3卷 第4期   页码 400-407 doi: 10.1007/s11465-008-0060-z

摘要： Air-bearings are installed between the stator and the mover of ultra-precision linear stages to suppress vibration and mechanical contact. Spring-damping elements are used to emulate the complex interaction of the finite element model (FEM) developed in this paper and the system dynamic behaviors are analyzed. Through the experimental modal test, the validity and reliability of the model are proven. However, the dynamic characteristics including mode frequency, mode shape, and response amplitude are obviously changed with the position of air-bearings. The combined optimization method is used to optimize the air-bearings position. The best and worst positions are obtained using the dynamic characteristic analysis. The method can be generalized to the connection position of different components in manufacture elements and to implement the system dynamic characteristics optimization when the connection position can be changed.

关键词： manufacture     different     interaction     air-bearings     response amplitude    

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Weak characteristic information extraction from early fault of wind turbine generator gearbox

Xiaoli XU, Xiuli LIU

《机械工程前沿（英文）》 2017年 第12卷 第3期   页码 357-366 doi: 10.1007/s11465-017-0423-4

摘要：

Given the weak early degradation characteristic information during early fault evolution in gearbox of wind turbine generator, traditional singular value decomposition (SVD)-based denoising may result in loss of useful information. A weak characteristic information extraction based on µ-SVD and local mean decomposition (LMD) is developed to address this problem. The basic principle of the method is as follows: Determine the denoising order based on cumulative contribution rate, perform signal reconstruction, extract and subject the noisy part of signal to LMD and µ-SVD denoising, and obtain denoised signal through superposition. Experimental results show that this method can significantly weaken signal noise, effectively extract the weak characteristic information of early fault, and facilitate the early fault warning and dynamic predictive maintenance.

关键词： wind turbine generator gearbox     µ-singular value decomposition     local mean decomposition     weak characteristic information extraction     early fault warning    

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我国致密砂岩气资源潜力、分布与未来发展地位

张国生,邓松涛

《中国工程科学》 2012年 第14卷 第6期   页码 87-93

摘要：

系统分析了我国鄂尔多斯、四川和塔里木等主要盆地致密砂岩气成藏条件和主控因素，提出斜坡岩性型和深层构造型是两种最重要的致密砂岩气藏。采用多因素叠合法预测有利含气范围，并通过对已知重点致密砂岩气田的解剖研究，刻度出储量丰度、含气面积系数等关键参数，采用类比法来计算主要盆地的致密砂岩气资源量。研究表明，我国致密砂岩气技术可采资源量为9.2万亿～13.4万亿m3，主要分布于含煤系地层的盆地中；致密砂岩气资源开发利用现实性最好，在国家政策扶持和工程技术进步的推动下，再经过10～20年的发展，有望成为我国天然气开发利用的主导资源之一。

关键词： 致密砂岩气     分布特征     资源潜力     发展地位    

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Dynamic Target Tracking of Unmanned Aerial Vehicles Under Unpredictable Disturbances

Yanjie Chen,Yangning Wu,Limin Lan,Hang Zhong,Zhiqiang Miao,Hui Zhang,Yaonan Wang,

《工程（英文）》 doi: 10.1016/j.eng.2023.05.017

摘要： This study proposes an image-based visual servoing (IBVS) method based on a velocity observer for an unmanned aerial vehicle (UAV) for tracking a dynamic target in Global Positioning System (GPS)-denied environments. The proposed method derives the simplified and decoupled image dynamics of underactuated UAVs using a constructed virtual camera and then considers the uncertainties caused by the unpredictable rotations and velocities of the dynamic target. A novel image depth model that extends the IBVS method to track a rotating target with arbitrary orientations is proposed. The depth model ensures image feature accuracy and image trajectory smoothness in rotating target tracking. The relative velocities of the UAV and the dynamic target are estimated using the proposed velocity observer. Thanks to the velocity observer, translational velocity measurements are not required, and the control chatter caused by noise-containing measurements is mitigated. An integral-based filter is proposed to compensate for unpredictable environmental disturbances in order to improve the anti-disturbance ability. The stability of the velocity observer and IBVS controller is analyzed using the Lyapunov method. Comparative simulations and multistage experiments are conducted to illustrate the tracking stability, anti-disturbance ability, and tracking robustness of the proposed method with a dynamic rotating target.

关键词： Unmanned aerial vehicle     Visual servoing     Velocity observer     Target tracking    

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Wheel tracking methods to evaluate moisture sensitivity of hot-mix asphalt mixtures

Jie HAN,Harihar Shiwakoti

《结构与土木工程前沿（英文）》 2016年 第10卷 第1期   页码 30-43 doi: 10.1007/s11709-016-0318-1

摘要： Existing test methods to determine moisture sensitivity in hot-mix asphalt (HMA) mixtures are time consuming and inconsistent. This research focused on wheel tracking devices to evaluate moisture sensitivity. The Asphalt Pavement Analyzer (APA) and the Hamburg Wheel Tracking Device (HWTD) were used for this research. Compacted cylindrical samples were fabricated using a Superpave Gyratory compactor. This study selected two most commonly used mixtures, SM-12.5A with PG 64-22 binder in overlay projects and SM-19A mixtures with PG 64-22 binder for major modification projects at Kansas Department of Transportation. Test results show that APA tests could induce stripping in most samples without any anti-stripping agent, which could be identified visually. However, APA results did not indicate any stripping inflection point while the HWTD results showed stripping inflection points, which are important to identify stripping potential of mixtures. The APA results show that wet tests are severe at lower temperatures. The HWTD results show improvement in the performance using anti-stripping agents at later stage. The HWTD test is more effective as a rapid test method in case of determining moisture sensitivity. Laboratory results from this study should be verified and correlated with field performance.

关键词： hot-mix asphalt     moisture sensitivity     rutting     wheel tracking test    

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适用于混合动力汽车的表贴式永磁同步电机初始位置估算 Article

Bing TIAN,Qun-tao AN,Li SUN,Dong-yang SUN,Jian-dong DUAN

《信息与电子工程前沿（英文）》 2016年 第17卷 第8期   页码 803-813 doi: 10.1631/FITEE.1500298

摘要： 霍尔开关位置传感器初始位置测量精度为±30度，使得永磁同步电机在汽车启动阶段提供的最大电磁转矩受到限制。因此，对表贴式永磁同步电机非线性（磁饱和）模型进行了研究，并依据非线性模型进行较准确的初始位置估算。本文采用混合注入法（注入高频电压矢量和直流电压矢量）估算转子位置，其中直流电压用于改变铁芯饱和度，而铁芯饱和度又将调制高频电流响应。结合一种特殊的解调算法便可从高频电流响应中获得磁饱和特征函数以及转子位置信息。通过MATLAB/simulink和实验进行了转子位置估算。

关键词： 表贴式永磁同步电机；初始位置估算；非线性模型；混合注入法；位置观测器    

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标题 作者 时间 类型 操作

Development of a novel two-stage proportional valve with a pilot digital flow distribution

Qiang GAO, Yuchuan ZHU, Changwen WU, Yulei JIANG

期刊论文

Task-space position/attitude tracking control of FAST fine tuning system

QI Lin, ZHANG Hui, DUAN Guanghong

期刊论文

Chord error constraint based integrated control strategy for contour error compensation

Tie ZHANG, Caicheng WU, Yanbiao ZOU

期刊论文

Experimental and CFD analysis of nozzle position of subsonic ejector

Xilai ZHANG, Shiping JIN, Suyi HUANG, Guoqing TIAN

期刊论文

Robust energy-efficient train speed profile optimization in a scenario-based position–time–speed network

期刊论文

Analysis of the dynamic hysteresis characteristic of finger seal

LEI Yanni, CHEN Guoding

期刊论文

Strategic position and development prospects of nuclear energy in China

SHEN Wenquan

期刊论文

Output tracking control of mobile manipulators based on dynamical sliding-mode control

WUYuxiang, FENG Ying, HU Yueming

期刊论文

Flow characteristic and wastewater treatment performance of a pilot-scale airlift oxidation ditch

Hongtao PANG, Hanchang SHI, Huiming SHI,

期刊论文

Air-bearing position optimization based on dynamic characteristics of ultra-precision linear stages

CHEN Xuedong, LI Zhixin

期刊论文

Weak characteristic information extraction from early fault of wind turbine generator gearbox

Xiaoli XU, Xiuli LIU

期刊论文

我国致密砂岩气资源潜力、分布与未来发展地位

张国生,邓松涛

期刊论文

Dynamic Target Tracking of Unmanned Aerial Vehicles Under Unpredictable Disturbances

Yanjie Chen,Yangning Wu,Limin Lan,Hang Zhong,Zhiqiang Miao,Hui Zhang,Yaonan Wang,

期刊论文

Wheel tracking methods to evaluate moisture sensitivity of hot-mix asphalt mixtures

Jie HAN,Harihar Shiwakoti

期刊论文

适用于混合动力汽车的表贴式永磁同步电机初始位置估算

Bing TIAN,Qun-tao AN,Li SUN,Dong-yang SUN,Jian-dong DUAN

期刊论文