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Micro-optical fabrication by ultraprecision diamond machining and precision molding

Hui LI, Likai LI, Neil J. NAPLES, Jeffrey W. ROBLEE, Allen Y. YI

《机械工程前沿（英文）》 2017年 第12卷 第2期   页码 181-192 doi: 10.1007/s11465-017-0444-z

摘要：

Ultraprecision diamond machining and high volume molding for affordable high precision high performance optical elements are becoming a viable process in optical industry for low cost high quality microoptical component manufacturing. In this process, first high precision microoptical molds are fabricated using ultraprecision single point diamond machining followed by high volume production methods such as compression or injection molding. In the last two decades, there have been steady improvements in ultraprecision machine design and performance, particularly with the introduction of both slow tool and fast tool servo. Today optical molds, including freeform surfaces and microlens arrays, are routinely diamond machined to final finish without post machining polishing. For consumers, compression molding or injection molding provide efficient and high quality optics at extremely low cost. In this paper, first ultraprecision machine design and machining processes such as slow tool and fast too servo are described then both compression molding and injection molding of polymer optics are discussed. To implement precision optical manufacturing by molding, numerical modeling can be included in the future as a critical part of the manufacturing process to ensure high product quality.

关键词： ultraprecision machining     slow tool servo     fast tool servo     compression molding     injection molding     microlens arrays     optical fabrication    

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Model-based nonlinear control of hydraulic servo systems: Challenges, developments and perspectives

Jianyong YAO

《机械工程前沿（英文）》 2018年 第13卷 第2期   页码 179-210 doi: 10.1007/s11465-018-0464-3

摘要：

Hydraulic servo system plays a significant role in industries, and usually acts as a core point in control and power transmission. Although linear theory-based control methods have been well established, advanced controller design methods for hydraulic servo system to achieve high performance is still an unending pursuit along with the development of modern industry. Essential nonlinearity is a unique feature and makes model-based nonlinear control more attractive, due to benefit from prior knowledge of the servo valve controlled hydraulic system. In this paper, a discussion for challenges in model-based nonlinear control, latest developments and brief perspectives of hydraulic servo systems are presented: Modelling uncertainty in hydraulic system is a major challenge, which includes parametric uncertainty and time-varying disturbance; some specific requirements also arise ad hoc difficulties such as nonlinear friction during low velocity tracking, severe disturbance, periodic disturbance, etc.; to handle various challenges, nonlinear solutions including parameter adaptation, nonlinear robust control, state and disturbance observation, backstepping design and so on, are proposed and integrated, theoretical analysis and lots of applications reveal their powerful capability to solve pertinent problems; and at the end, some perspectives and associated research topics (measurement noise, constraints, inner valve dynamics, input nonlinearity, etc.) in nonlinear hydraulic servo control are briefly explored and discussed.

关键词： hydraulic servo system     adaptive control     robust control     nonlinear friction     disturbance compensation     repetitive control     noise alleviation     constraint control    

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Gray-box modeling and QFT control for precision servo transmission systems

Xiulan BAO, Xuedong CHEN, Xin LUO, Haocheng ZUO

《机械工程前沿（英文）》 2011年 第6卷 第4期   页码 442-448 doi: 10.1007/s11465-011-0242-y

摘要：

Precision servo transmission systems have widely been applied in industrial equipment to achieve high accuracy and high speed motion. However, due to the presence of friction and uncertainty, the characteristics of precision servo transmission systems are variant depends on the working conditions, leading to oscillation and instability in the system performances. In this paper, a grey-box model of the system is established, the model structure derived from the theoretical modeling and the model parameters are obtained by experiments using set membership identification method. This paper proposes two-degrees of freedom (2-DOF) robust position controller for a precision servo transmission system, based on the quantitative feedback theory (QFT), to achieve high accuracy and consistent tracking performance even in presence of considerable system uncertainties and friction disturbances. The results of simulate and experiment validate the effectiveness of the proposed controller.

关键词： precision servo transmission system     modeling     set membership identification     quantitative feedback theory (QFT)     robustness    

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Modeling and analysis of steady-state vibration induced by backlash in servo rotary table

Xiao YANG,Dun LU,Sanli LIU,Jun ZHANG,Wanhua ZHAO

《机械工程前沿（英文）》 2015年 第10卷 第1期   页码 43-47 doi: 10.1007/s11465-015-0327-0

摘要：

Backlash cannot be always avoided in mechanical systems because of wear or looseness. Steady-state vibration may be induced by backlash in closed loop feed drive systems. This paper presents a mathematical model of a servo rotary table, considering the effect of backlash. The accuracy of this model is verified by an experiment. The influences of the parameters, such as position controller gain, velocity controller gain, load and the magnitude of backlash, on steady-state vibration are discussed. The steady-state vibration amplitude increases with the position controller gain, load and the magnitude of backlash. The steady-state vibration frequency increases with the position controller gain and the velocity controller gain, while an increase in load leads to a decrease in the frequency.

关键词： backlash     servo rotary table     steady-state vibration    

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Control algorithm of a servo platform

Shouyong XIE, Xiwen LI, Shuzi YANG, Mingjin YANG,

《机械工程前沿（英文）》 2010年 第5卷 第3期   页码 353-355 doi: 10.1007/s11465-010-0098-6

摘要： According to the characteristics of the movement of a special-purpose three-axis servo platform, this paper presents an improved grey prediction proportional integral derivative (PID) control algorithm. Different weights at different time are given to different sampling moments in the algorithm, and the time meanings of the sample data are paid more attention. Simulation results show that the performance of response and stability of the platform of the improved algorithm is better than that of the traditional one. The control algorithm meets all requirements of the control system of the special-purpose three-axis servo platform.

关键词： grey prediction     proportional integral derivative (PID) control     improved algorithm     weight     servo platform    

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Energy saving design of the machining unit of hobbing machine tool with integrated optimization

《机械工程前沿（英文）》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0694-2

摘要： The machining unit of hobbing machine tool accounts for a large portion of the energy consumption during the operating phase. The optimization design is a practical means of energy saving and can reduce energy consumption essentially. However, this issue has rarely been discussed in depth in previous research. A comprehensive function of energy consumption of the machining unit is built to address this problem. Surrogate models are established by using effective fitting methods. An integrated optimization model for reducing tool displacement and energy consumption is developed on the basis of the energy consumption function and surrogate models, and the parameters of the motor and structure are considered simultaneously. Results show that the energy consumption and tool displacement of the machining unit are reduced, indicating that energy saving is achieved and the machining accuracy is guaranteed. The influence of optimization variables on the objectives is analyzed to inform the design.

关键词： energy saving design     energy consumption     machining unit     integrated optimization     machine tool    

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Effect of magneto rheological damper on tool vibration during hard turning

P. Sam PAUL, A. S. VARADARAJAN

《机械工程前沿（英文）》 2012年 第7卷 第4期   页码 410-416 doi: 10.1007/s11465-012-0341-4

摘要：

Recently, the concept of hard turning has gained considerable attention in metal cutting as it can apparently replace the traditional process cycle of turning, heat treating, and finish grinding for assembly of hard wear resistant steel parts. The present investigation aims at developing a magneto rheological (MR) fluid damper for suppressing tool vibration and promoting better cutting performance during hard turning. The magneto rheological Fluid acts as a viscoelastic spring with non-linear vibration characteristics that are controlled by the composition of the magneto rheological fluid, the shape of the plunger and the electric parameters of the magnetizing field. Cutting experiments were conducted to arrive at a set of electrical, compositional and shape parameters that can suppress tool vibration and promote better cutting performance during turning of AISI 4340 steel of 46 HRC with minimal fluid application using hard metal insert with sculptured rake face. It was observed that the use of MR fluid damper reduces tool vibration and improves the cutting performance effectively. Also commercialization of this idea holds promise to the metal cutting industry.

关键词： tool vibration     magneto rheological damper     hard turning     surface finish     tool wear    

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Variable identification and automatic tuning of the main module of a servo system of parallel mechanism

YANG Zhiyong, XU Meng, HUANG Tian, NI Yanbing

《机械工程前沿（英文）》 2007年 第2卷 第1期   页码 82-88 doi: 10.1007/s11465-007-0014-x

摘要： The variables of the main module of a servo system for miniature reconfigurable parallel mechanism were identified and automatically tuned. With the reverse solution module of the translation, the module with the exerted translation joint was obtained, which included the location, velocity and acceleration of the parallelogram carriage-branch. The rigid dynamic reverse model was set as the virtual work principle. To identify the variables of the servo system, the triangle-shaped input signal with variable frequency was adopted to overcome the disadvantages of the pseudo-random number sequence, i.e., making the change of the vibration amplitude of the motor dramatically, easily impact the servo motor and make the velocity loop open and so on. Moreover, all the variables including the rotary inertia of the servo system were identified by the additive mass. The overshoot and rise time were the optimum goals, the limited changing load with the attitude was considered, and the range of the controller variables in the servo system was identified. The results of the experiments prove that the method is accurate.

关键词： acceleration     reconfigurable parallel     additive     sequence     parallel mechanism    

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Preliminary design of an SCO conversion system applied to the sodium cooled fast reactor

《能源前沿（英文）》 2021年 第15卷 第4期   页码 832-841 doi: 10.1007/s11708-021-0777-5

摘要： The supercritical carbon dioxide (SCO2) Brayton cycle has become an ideal power conversion system for sodium-cooled fast reactors (SFR) due to its high efficiency, compactness, and avoidance of sodium-water reaction. In this paper, the 1200 MWe large pool SFR (CFR1200) is used as the heat source of the system, and the sodium circuit temperature and the heat load are the operating boundaries of the cycle system. The performance of different SCO2 Brayton cycle systems and changes in key equipment performance are compared. The study indicates that the inter-stage cooling and recompression cycle has the best match with the heat source characte-ristics of the SFR, and the cycle efficiency is the highest (40.7%). Then, based on the developed system transient analysis program (FR-Sdaso), a pool-type SFR power plant system analysis model based on the inter-stage cooling and recompression cycle is established. In addition, the matching between the inter-stage cooling recompression cycle and the SFR during the load cycle of the power plant is studied. The analysis shows that when the nuclear island adopts the flow-advanced operation strategy and the carbon dioxide flowrate in the SCO2 power conversion system is adjusted with the goal of maintaining the sodium-carbon dioxide heat exchanger sodium side outlet temperature unchanged, the inter-stage cooling recompression cycle can match the operation of the SFR very well.

关键词： sodium-cooled fast reactor (SFR)     supercritical carbon dioxide (SCO2)     brayton cycle     load cycle    

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Experimental Study on the Piezoelectric Prestage Driver of Electrohydraulic Servo Valves

CHENG Guang-ming, SHEN Chuan-liang, YANG Zhi-gang

《机械工程前沿（英文）》 2006年 第1卷 第1期   页码 56-59 doi: 10.1007/s11465-005-0017-4

摘要：

A piezoelectric actuated prestage driver of hydraulic servo valves for the low-frequency response of electrohydraulic servo valve electromagnetic prestage driver was presented. The new driver was driven by piezoelectric multilayer actuators. The displacement of a piezoelectric multilayer actuator was amplified by a flexure-hinged amplifier based on the principles of triangle amplification. Static and dynamic characteristics were tested on the model machine. The characteristics of good linearity, high resolution, and high-frequency response were approved. The natural frequency reached 1.201 kHz using finite element analysis, and the practice measurement result was 1 kHz.

关键词： flexure-hinged amplifier     kHz     amplification     high-frequency     electromagnetic    

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Kinematic Model Building and Servo Parameter Identification of 3-HSS Parallel Mechanism

YANG Zhi-yong, WU Jiang, HUANG Tian, NI Yan-bing

《机械工程前沿（英文）》 2006年 第1卷 第1期   页码 60-66 doi: 10.1007/s11465-005-0019-2

摘要：

Aiming at a parallel mechanism with three degrees of freedom, a method for dynamic model building and the parameter identification of its servosystem is presented. First, the reverse solution models of position, velocity, and acceleration of parallelogram branch structure are deduced, and then, its dynamic model of a rigid body is set up by using the virtual work principle. Based on the above model, a method to identify the servo parameter of the parallel mechanism is put up. In this method, the triangle-shaped input with variable frequency is adopted to offset the disadvantages of pseudorandom number sequence in parameter identification, such as dramatically changing the vibration amplitude of the motor, easily impacting the motor that results in its velocity loop to easily open, and so on. Moreover, the rotary inertia can also be identified by the additive mass. The abovementioned data will lay a solid foundation for the optimum performance of the system in the whole workspace.

关键词： building     acceleration     additive     workspace     optimum performance    

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EAP-FAST在公共无线局域网安全接入控制中的研究及实现

曹萍,裴文江

《中国工程科学》 2005年 第7卷 第12期   页码 78-82

摘要：

Cisco公司于2004年提出基于隧道的灵活认证协议（EAP-FAST）以替代存在安全漏洞的LEAP认证协议，该协议具有安全性和易部署性的特点。文章论述了基于802.1x协议的EAP-FAST认证协议及其实现技术，并在公共无线局域网(PWLAN)综合实验平台上实现了EAP-FAST认证的客户端、认证者、认证服务器端功能。

关键词： 公共无线局域网     端口访问控制协议（802.1x）     基于隧道的灵活认证协议（EAP-FAST）    

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A novel six-legged walking machine tool for

Jimu LIU, Yuan TIAN, Feng GAO

《机械工程前沿（英文）》 2020年 第15卷 第3期   页码 351-364 doi: 10.1007/s11465-020-0594-2

摘要： The manufacture and maintenance of large parts in ships, trains, aircrafts, and so on create an increasing demand for mobile machine tools to perform operations. However, few mobile robots can accommodate the complex environment of industrial plants while performing machining tasks. This study proposes a novel six-legged walking machine tool consisting of a legged mobile robot and a portable parallel kinematic machine tool. The kinematic model of the entire system is presented, and the workspace of different components, including a leg, the body, and the head, is analyzed. A hierarchical motion planning scheme is proposed to take advantage of the large workspace of the legged mobile platform and the high precision of the parallel machine tool. The repeatability of the head motion, body motion, and walking distance is evaluated through experiments, which is 0.11, 1.0, and 3.4 mm, respectively. Finally, an application scenario is shown in which the walking machine tool steps successfully over a 250 mm-high obstacle and drills a hole in an aluminum plate. The experiments prove the rationality of the hierarchical motion planning scheme and demonstrate the extensive potential of the walking machine tool for operations on large parts.

关键词： legged robot     parallel mechanism     mobile machine tool     in-situ machining    

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Design and analysis of a new high frequency double-servo direct drive rotary valve

Muzhi ZHU,Shengdun ZHAO,Jingxiang LI

《机械工程前沿（英文）》 2016年 第11卷 第4期   页码 344-350 doi: 10.1007/s11465-016-0406-x

摘要：

Researchers have investigated direct drive valve for many years to solve problems, such as fluid force imbalance and switching frequency. The structure of the rotary valve has received considerable research interest because of its favorable dynamic properties and simple structure. This paper studied the high frequency double-servo direct drive rotary valve (DDRV), and proposed a novel structure and drive method satisfying high reversing frequency and adequate quantity of flow. Servo motors are integrated into the valve by the innovative structure, which is designed to equilibrate the unbalanced radial fluid force with the symmetric distributed oil ports. Aside from the fast reversing function of the valve, the DDRV presented high performance in linearity of the flow quantity and valve opening as a result of the fan-shaped flow ports. In addition, a computational fluid dynamics (CFD) method based on Fluent was conducted to verify the flux regulation effect of the height change of the adjustable boss.

关键词： direct drive rotary valve     computational fluid dynamics (CFD)     flow regulation    

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Green catalytic engineering: A powerful tool for sustainable development in chemical industry

Kequan Chen, Dangguo Cheng, Chong Peng, Dan Wang, Jintao Zhang

《化学科学与工程前沿（英文）》 2018年 第12卷 第4期   页码 835-837 doi: 10.1007/s11705-018-1756-1

摘要：
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标题 作者 时间 类型 操作

Micro-optical fabrication by ultraprecision diamond machining and precision molding

Hui LI, Likai LI, Neil J. NAPLES, Jeffrey W. ROBLEE, Allen Y. YI

期刊论文

Model-based nonlinear control of hydraulic servo systems: Challenges, developments and perspectives

Jianyong YAO

期刊论文

Gray-box modeling and QFT control for precision servo transmission systems

Xiulan BAO, Xuedong CHEN, Xin LUO, Haocheng ZUO

期刊论文

Modeling and analysis of steady-state vibration induced by backlash in servo rotary table

Xiao YANG,Dun LU,Sanli LIU,Jun ZHANG,Wanhua ZHAO

期刊论文

Control algorithm of a servo platform

Shouyong XIE, Xiwen LI, Shuzi YANG, Mingjin YANG,

期刊论文

Energy saving design of the machining unit of hobbing machine tool with integrated optimization

期刊论文

Effect of magneto rheological damper on tool vibration during hard turning

P. Sam PAUL, A. S. VARADARAJAN

期刊论文

Variable identification and automatic tuning of the main module of a servo system of parallel mechanism

YANG Zhiyong, XU Meng, HUANG Tian, NI Yanbing

期刊论文

Preliminary design of an SCO conversion system applied to the sodium cooled fast reactor

期刊论文

Experimental Study on the Piezoelectric Prestage Driver of Electrohydraulic Servo Valves

CHENG Guang-ming, SHEN Chuan-liang, YANG Zhi-gang

期刊论文

Kinematic Model Building and Servo Parameter Identification of 3-HSS Parallel Mechanism

YANG Zhi-yong, WU Jiang, HUANG Tian, NI Yan-bing

期刊论文

EAP-FAST在公共无线局域网安全接入控制中的研究及实现

曹萍,裴文江

期刊论文

A novel six-legged walking machine tool for

Jimu LIU, Yuan TIAN, Feng GAO

期刊论文

Design and analysis of a new high frequency double-servo direct drive rotary valve

Muzhi ZHU,Shengdun ZHAO,Jingxiang LI

期刊论文

Green catalytic engineering: A powerful tool for sustainable development in chemical industry

Kequan Chen, Dangguo Cheng, Chong Peng, Dan Wang, Jintao Zhang

期刊论文