Search | Engineering

订阅投稿

首页工程期刊工程焦点工程成就工程前沿关于我们 English

资源类型

期刊论文 55

会议视频 1

年份

2023 1

2022 3

2021 1

2020 7

2019 1

2018 4

2017 3

2016 4

2015 1

2013 4

2012 3

2011 2

2010 2

2009 4

2008 2

2007 7

2006 3

2005 2

2004 1

2001 1

展开︾

关键词

DX桩 2

CMAC神经网络 1

Lagrange方程 1

一致性哈希表；副本布局；能源管理；键值存储系统；可靠性 1

三轴转台 1

上限法 1

交流位置伺服系统 1

交流永磁同步电机；滑模控制器；扩张状态观测器；鲁棒控制；运动控制 1

传热过程 1

伺服驱动 1

元素亲和性 1

元素周期表 1

六自由度并联平台 1

农业科学 1

决策表 1

决策规则 1

冶金学 1

分布柔度簧片 1

切削碾压 1

展开︾

检索范围：

排序：展示方式：

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

HTML PDF 收藏

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

HTML PDF 收藏

交流伺服直驱式旋锻机的动力学理论研究

宋涛,赵升吨,闫观海,刘红宝

《中国工程科学》 2013年第15卷第1期页码 63-67

摘要：

提出了高速伺服直驱式旋锻机结构，分析设计了基于摆线运动曲线的锤头轮廓曲线，采用上限法确定了旋锻机在极限工况下的最大输出载荷上限的变化规律。研究表明，随着进料角的增大，锻机负载有所降低，但同时工件需要更大的推进力，因此实际中采用的进料角的范围为5°~15°。

关键词：旋转锻造伺服驱动上限法

HTML PDF 收藏

Dynamic characteristics of an NC table with phase space reconstruction

Linhong WANG, Bo WU, Runsheng DU, Shuzi YANG

《机械工程前沿（英文）》 2009年第4卷第2期页码 179-183 doi: 10.1007/s11465-009-0018-9

摘要： The dynamic properties of a numerical control (NC) table directly interfere with the accuracy and surface quality of work pieces machined by a computer numerical control (CNC) machine. Phase space reconstruction is an effective approach for researching dynamic behaviors of a system with measured time series. Based on the theory and method for phase space reconstruction, the correlation dimension, maximum Lyapunov exponent, and dynamic time series measured from the NC table were analyzed. The characteristic quantities such as the power spectrum, phase trajectories, correlation dimension, and maximum Lyapunov exponent are extracted from the measured time series. The chaotic characteristic of the dynamic properties of the NC table is revealed via various approaches. Therefore, an NC table is a nonlinear dynamic system. This research establishes a basis for dynamic system discrimination of a CNC machine.

关键词： NC table chaotic characteristic phase-space reconstruction correlation dimension maximum Lyapunov exponent

HTML PDF 收藏

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

HTML PDF 收藏

Soybean drying characteristics in microwave rotary dryer with forced convection

Ruifang WANG, Zhanyong LI, Yanhua LI, Jingsheng YE

《化学科学与工程前沿（英文）》 2009年第3卷第3期页码 289-292 doi: 10.1007/s11705-009-0022-y

摘要： A new hybrid drying technique by combining microwave and forced convection drying within a rotary drum, i.e., microwave rotary drying, was developed with the purpose to improve the uniformity of microwave drying. In a laboratory microwave rotary dryer, rewetted soybean was utilized as experimental material to study the effects of drum rotating speed, ventilation flow rate, and specific microwave power on the drying kinetics and cracking ratio of soybean. It was found that, with rotation, the cracking ratio can be lowered but without distinct improvement in the drying rate. Increasing ventilation flow rate and specific microwave power can improve the drying rate, but the cracking ratio also increases as a negative result. The cracking ratio lower than 10% can be attained for ventilation flow rate lower than 2.0 m ·h or specific microwave energy lower than 0.4 kW·kg in the present experiments.

关键词： cracking microwave rotary drying soybean

HTML PDF 收藏

Dynamic characteristics of NC table with SVD

WANG Linhong, WU Bo, DU Runsheng, YANG Shuzi

《机械工程前沿（英文）》 2008年第3卷第4期页码 385-391 doi: 10.1007/s11465-008-0052-z

摘要： This paper employs the SVD (singular value decomposition) method to study dynamic characteristics of a numerical control (NC) table. Acceleration signals of the NC table at three directions are tested; the singular spectrum of the signals is acquired with SVD; principal components of the signals are found out; dynamic characteristics of the signals and their contributing factors are studied by extracting dynamic characteristics of principal components; and signals and principal components are quantitatively analyzed by calculating signal energy. Results indicate that signal characteristics of the previous two principal components are apparent, based on which dynamic characteristics of chaotic signal can be extracted. Signal at the perpendicular direction of the table is significantly correlated with that at the horizontal motion direction, which indicates that they are excited from the same vibration source. However, signals perpendicular to each other in terms of the motion direction at the horizontal level are rarely correlated; the total signal energy is maximum at the motion direction, minimum at the horizontal non-motion direction, and medium at the perpendicular non-motion direction. Bending vibration of the lead screw at the perpendicular direction is far more violent than that at the horizontal direction.

关键词： Acceleration vibration source chaotic energy dynamic

HTML PDF 收藏

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

HTML PDF 收藏

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

HTML PDF 收藏

DX挤扩灌注桩技术在铁路桥梁工程中的应用

张德华,王梦恕

《中国工程科学》 2009年第11卷第7期页码 92-96

摘要：

DX桩是近年来新兴的一种变截面新桩型。是在钻孔灌注桩的基础上，使用专用挤扩设备在桩底和桩身挤扩成为支盘状，然后浇灌混凝土后形成的桩身、分承力盘和桩根共同承载的桩型。DX桩可较大幅度提高单桩承载力。试验表明单桩承载力比同等条件下的直孔灌注桩提高80 %以上。DX桩可在粘性土、粉土、砂土层、强风化岩、残积土中挤扩承力盘，也可在卵砾石层的上层面挤扩成盘，更适宜在粘性土、粉土或砂土交互分层的地基中使用。DX桩的桩身直径可为400～2 000 mm,桩长可达60多米。是一种值得推广应用的新桩型，已在高层建筑、公路桥

关键词： DX桩旋挖挤扩灌注桩承载力

HTML PDF 收藏

Effectiveness analysis and optimum design of the rotary regenerator for thermophotovoltaic (TPV) system

Xi WU, Hong YE, Jianxiang WANG, Jie HE, Jian YANG

《能源前沿（英文）》 2012年第6卷第2期页码 193-199 doi: 10.1007/s11708-012-0184-z

摘要： The influence of the period of rotation on the effectiveness of the thermophotovoltaic (TPV) rotary regenerator was theoretically and experimentally investigated. It was found that the deviations of the theoretical results from the experimental ones decrease with the increase of the period of rotation. To the TPV system of 10 kW combustion power, the deviation is 3.5% when the rotation period is 3 s; while the deviation decreases to 1.5% when the rotation period increases to 15 s. The deviation could be mainly attributed to the cold and hot fluids carryover loss which was not considered in the model. With a new model taking account of the carryover loss established, the predicted results were greatly improved. Based on the modified model, the influence of geometrical parameters of rotary regenerator on the effectiveness was analyzed for TPV systems of various combustion power. The results demonstrate that the effectiveness increases with the increase of the rotary regenerator diameter and height, while fluid carryover loss increases at the same time, which weakens the impact of geometrical parameters.

关键词： thermophotovoltaic (TPV) system rotary regenerator effectiveness carryover loss

HTML PDF 收藏

Performance of rolling piston type rotary compressor using fullerenes (C70) and NiFe

Ruixiang WANG,Yihao ZHANG,Yi LIAO

《能源前沿（英文）》 2020年第14卷第3期页码 644-648 doi: 10.1007/s11708-017-0453-y

摘要： A novel way for a compressor to improve its coefficient of performance was proposed in this paper. Fullerenes (C70) and NiFe O nanocomposites were modified by span 80 and dispersed in refrigeration oil by solid grinding (SG). Besides, the tribological properties of the nanocomposites were investigated using a four ball friction tester. The results show that when the mass concentration of fullerenes nanocomposite is higher than 60 ppm and the concentration of nano-oil is 2 g/L, the friction coefficient decreases from 0.13 to 0.06 which means the wear is reduced. The coefficient of performance of the compressor under the air conditioning test condition can be raised by 1.23%.

关键词： rotary compressor friction coefficient nanocomposite materials coefficient of performance fullerenes (C70)

HTML PDF 收藏

Co-pyrolysis of sludge and kaolin/zeolite in a rotary kiln: Analysis of stabilizing heavy metals

《环境科学与工程前沿（英文）》 2022年第16卷第7期 doi: 10.1007/s11783-021-1488-1

摘要：

• Adding kaolin/zeolite promotes the formation of stable heavy metals.

关键词： Co-pyrolysis Sewage sludge Heavy metals Rotary kiln Immobilization mechanism

HTML PDF 收藏

Air bearing center cross gap of neutron stress spectrometer sample table support system

Yang LI,Yunxin WU,Hai GONG,Xiaolei FENG

《机械工程前沿（英文）》 2016年第11卷第4期页码 403-411 doi: 10.1007/s11465-016-0405-y

摘要：

A support system is the main load-bearing component of sample table for neutron stress spectrometer, and air bearing is an important element of a support system. The neutron stress spectrometer sample table was introduced, and the scheme for air bearing combination was selected. To study the performance of air bearing center cross gap, finite element models (FEMs) were established based on air motion and Reynolds equations, effects of air supply pressure, and gap parameters on the overturning moment and bearing capacity of air bearing center cross gap were analyzed. Results indicate that the width, depth, and height differences of the marble floor gap played important roles in the performance of the air bearing. When gap width is lesser than 1 mm and gap depth is lower than 0.4 mm, bearing capacity and overturning moment would vary rapidly with the variation of the width and depth. A gap height difference results in the bearing capacity dropping rapidly. The FEM results agree well with experimental results. Further, findings of the study could guide the design of the support system and marble floor.

关键词： neutron stress spectrometer sample table support system air bearing center cross gap simulation experiment

HTML PDF 收藏

Novel precision piezoelectric step rotary actuator

LIU Jianfang, YANG Zhigang, ZHAO Hongwei, CHENG Guangming

《机械工程前沿（英文）》 2007年第2卷第3期页码 356-360 doi: 10.1007/s11465-007-0062-2

摘要： A novel piezoelectric (PZT) precision step rotary actuator was developed on the basis of PZT technology. It adopts the principle of bionics and works with an inside anchoring/loosening of the stator and a distortion structure of the uniformly distributed thin flexible hinge to solve problems such as ineffective anchoring/loosening, low step rotary frequency, small travel, poor resolution, low speed and unsteady output. The developed actuator is characterized by high frequency (30 Hz), high speed (380 μrad/s), large travel (>270º), high resolution (1 μrad/step), and work stability. It greatly improves the ability to drive the existing PZT step rotary actuator. The new actuator can be applied in the field of micromanipulation and precision engineering, including precision driving and positioning and optics engineering.

关键词： developed stability ineffective anchoring/loosening technology piezoelectric