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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    

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An improved chaotic hybrid differential evolution for the short-term hydrothermal scheduling problem

Tahir Nadeem MALIK,Salman ZAFAR,Saaqib HAROON

《信息与电子工程前沿（英文）》 2015年 第16卷 第5期   页码 404-417 doi: 10.1631/FITEE.1400189

摘要： Short-term hydrothermal scheduling (STHTS) is a non-linear and complex optimization problem with a set of operational hydraulic and thermal constraints. Earlier, this problem has been addressed by several classical techniques; however, due to limitations such as non-linearity and non-convexity in cost curves, artificial intelligence tools based techniques are being used to solve the STHTS problem. In this paper an improved chaotic hybrid differential evolution (ICHDE) algorithm is proposed to find an optimal solution to this problem taking into account practical constraints. A self-adjusted parameter setting is obtained in differential evolution (DE) with the application of chaos theory, and a chaotic hybridized local search mechanism is embedded in DE to effectively prevent it from premature convergence. Furthermore, heuristic constraint handling techniques without any penalty factor setting are adopted to handle the complex hydraulic and thermal constraints. The superiority and effectiveness of the developed methodology are evaluated by its application in two illustrated hydrothermal test systems taken from the literature. The transmission line losses, prohibited discharge zones of hydel plants, and ramp rate limits of thermal plants are also taken into account. The simulation results reveal that the proposed technique is competent to produce an encouraging solution as compared with other recently established evolutionary approaches.

关键词： Valve-point effect     Prohibited discharge zones     Differential evolution     Chaotic sequences     Constraint handling    

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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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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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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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基于混沌电路电容器连接的微分耦合同步 Regular Papers

Yu-meng XU, Zhao YAO, Aatef HOBINY, Jun MA

《信息与电子工程前沿（英文）》 2019年 第20卷 第4期   页码 571-583 doi: 10.1631/FITEE.1800499

摘要： 非线性振子和电路常用于研究耦合同步和一致性问题。完全同步是指所有振子保持相同幅度和相位，主要发生在完全相同振子之间。相位同步是指振子保持步调节律同步而幅度不同。对于无维动力学系统和振子，同步依赖于耦合变量的选择和耦合方式。非线性电路中电阻常用于连接两个或以上电路，触发电压耦合可对耦合电路反馈调制。本文采用电容器耦合两个Pikovsk-Rabinovich(PR)电路，这种电场耦合机制为微分耦合提供了依据。讨论了对称性和错位耦合下两个混沌电路的同步稳定性问题。在电阻耦合下，两个混沌电路容易完全同步。进一步讨论电容器耦合，发现当耦合电容器选择合适电容值时，两个耦合电路同步可被有效控制，且耦合电容器能量流有助于对同步的调控。混沌电路的同步实现和耦合通道有关，如对称性耦合容易完全同步，错位耦合有利于相位同步。电容器对应电场耦合能降低耦合器件能量（焦耳热）消耗，加强两个耦合电路能量输运和交换，从而实现混沌电路同步。

关键词： 同步；电压耦合；混沌电路；电容器耦合    

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利用勒让德多项式同步两种不同的混沌系统及其在安全通信中的应用 None

Saeed KHORASHADIZADEH, Mohammad-Hassan MAJIDI

《信息与电子工程前沿（英文）》 2018年 第19卷 第9期   页码 1180-1190 doi: 10.1631/FITEE.1601814

摘要： 提出一种新的由状态反馈控制器和鲁棒控制项组成的混沌同步控制器，采用勒让德多项式补偿不确定性，还考虑截断错误。由于正交函数定理，勒让德多项式可逼近任意小的近似误差的非线性函数。因此，勒让德多项式可取代模糊系统和神经网络来估计和补偿控制系统中的不确定性。勒让德多项式具有比模糊系统和神经网络更少的调整参数，它的调整过程更为简单。与模糊系统的参数类似，使用从稳定性分析获得的自适应规则在线估计勒让德系数。假设主系统和从系统分别是Lorenz混沌系统和Chen混沌系统。安全通信系统需要基于观测器同步，因为主系统通过信道只发送一个状态变量。讨论了使用基于观测器同步获得其他状态变量的方法。仿真结果表明该方法的有效性。与模糊滑模控制器的比较表明，所提的控制器表现出优异的瞬态响应。此外，解释了安全通信问题，并测试了安全通信中控制器的性能。

关键词： 基于观测器同步；混沌系统；勒让德多项式；安全通信    

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Fractal characteristic evaluation and interpolation reconstruction for surface topography of drilled

《机械工程前沿（英文）》 2021年 第16卷 第4期   页码 840-854 doi: 10.1007/s11465-021-0643-5

摘要： In this paper, an improved fractal interpolation model is proposed to reconstruct the surface topography of composite hole wall. This model adopts the maximum positive deviations and maximum negative deviations between the measured values and trend values to determine the contraction factors. Hole profiles in 24 directions are measured. Fractal parameters are calculated to evaluate the measured surface profiles. The maximum and minimum fractal dimension of the hole wall are 1.36 and 1.07, whereas the maximum and minimum fractal roughness are 4.05 × 10 −5 and 4.36 × 10 −10 m, respectively. Based on the two-dimensional evaluation results, three-dimensional surface topographies in five typical angles (0°, 45°, 90°, 135°, and 165°) are reconstructed using the improved model. Fractal parameter D s and statistical parameters Sa, Sq, and Sz are used to evaluate the reconstructed surfaces. Average error of D s, Sa, Sq, and Sz between the measured surfaces and the reconstructed surfaces are 1.53%, 3.60%, 5.60%, and 9.47%, respectively. Compared with the model in published literature, the proposed model has equal reconstruction effect in relatively smooth surface and is more advanced in relatively rough surface. Comparative results prove that the proposed model for calculating contraction factors is more reasonable.

关键词： surface topography     fractal evaluation     fractal interpolation     reconstruction     composite    

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特殊任务下基于Chebychev映射的移动机器人 Article

Cai-hong LI, Yong SONG, Feng-ying WANG, Zhi-qiang WANG, Yi-bin LI

《信息与电子工程前沿（英文）》 2017年 第18卷 第9期   页码 1305-1319 doi: 10.1631/FITEE.1601253

摘要： 本文提出一种在特殊任务下基于Chebychev映射的移动机器人混沌全覆盖路径规划器的设计新策略。所设计的混沌路径规划器包含一个二维的Chebychev映射，该映射由两个一维的Chebychev映射构建而成。对规划器所产生的时间序列，进行反正弦变换，可以改善系统的混沌特性和均匀分布特性，从而提高机器人在完成特殊任务时的覆盖率和随机特性。通过仿射变换，Chebychev混沌系统映射到机器人工作空间的可行区域内，然后设计有障碍物环境下全覆盖路径规划的通用方法。仿真结果显示，所设计的混沌路径规划器在可行空间能够安全运行，不需要设计避障算法。所设计策略能够满足特殊任务下随机性、遍历性和高效率的需求。

关键词： 移动机器人；Chebychev映射；混沌；仿射变换；全覆盖路径规划    

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Operating characteristic analysis on the ultra-thin low temperature floor-heating system

Hualing ZHANG, Xiaopeng SONG

《结构与土木工程前沿（英文）》 2013年 第7卷 第2期   页码 127-132 doi: 10.1007/s11709-013-0200-3

摘要： Prefabricated ultra-thin radiant heating panel, as a new heating terminal type, is becoming a highlight in Yangtze River Valley area, China recently. However, there is a lack of operating characteristic research in this region, especially the energy consumption and operating mode are even less. To obtain these data, a heating system was set up in a duplex house in Chongqing. The test results show that the floor heating system could almost satisfy thermal comfort requirement at supply water temperature 45°C. But the preheating time was up to 4.5 h which was 1 h longer than that at supply water temperature 50°C. Meanwhile, the energy consumption at supply water temperature 50°C increased 0.10 Nm /h, and the operating efficiency decrease about 2.6% compared to those at water temperature 45°C. Considering both the thermal lag and operating efficiency, a reasonable suggestion was proposed in this paper. That was, the standard families which just stay home at night should adopt the interim mode of partial room with part time. And the supply water temperature should be properly raised during the preheating period and lowered down in the steady heating stage.

关键词： ultra-thin floor heating panel     the preheating time     thermal comfort     energy saving    

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Design and characteristic research of a novel electromechanical-hydraulic hybrid actuator with two transmission

《机械工程前沿（英文）》 2023年 第18卷 第2期 doi: 10.1007/s11465-022-0735-x

摘要： Servo-hydraulic actuators (SHAs) are widely used in mechanical equipment to drive heavy-duty mechanisms. However, their energy efficiency is low, and their motion characteristics are inevitably affected by uncertain nonlinearities. Electromechanical actuators (EMAs) possess superior energy efficiency and motion characteristics. However, they cannot easily drive heavy-duty mechanisms because of weak bearing capacity. This study proposes and designs a novel electromechanical-hydraulic hybrid actuator (EMHA) that integrates the advantages of EMA and SHA. EMHA mainly features two transmission mechanisms. The piston of the hydraulic transmission mechanism and the ball screw pair of the electromechanical transmission mechanism are mechanically fixed together through screw bolts, realizing the integration of two types of transmission mechanisms. The control scheme of the electromechanical transmission mechanism is used for motion control, and the hydraulic transmission mechanism is used for power assistance. Then, the mathematical model, structure, and parameter design of the new EMHA are studied. Finally, the EMHA prototype and test platform are manufactured. The test results prove that the EMHA has good working characteristics and high energy efficiency. Compared with the valve-controlled hydraulic cylinder system, EMHA exhibits a velocity tracking error and energy consumption reduced by 49.7% and 54%, respectively, under the same working conditions.

关键词： electromechanical-hydraulic hybrid actuator (EMHA)     integration     transmission mechanisms     power assistance     energy efficiency     working characteristics    

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Mesh relationship modeling and dynamic characteristic analysis of external spur gears with gear wear

《机械工程前沿（英文）》 2022年 第17卷 第1期   页码 9-9 doi: 10.1007/s11465-021-0665-z

摘要： Gear wear is one of the most common gear failures, which changes the mesh relationship of normal gear. A new mesh relationship caused by gear wear affects meshing excitations, such as mesh stiffness and transmission error, and further increases vibration and noise level. This paper aims to establish the model of mesh relationship and reveal the vibration characteristics of external spur gears with gear wear. A geometric model for a new mesh relationship with gear wear is proposed, which is utilized to evaluate the influence of gear wear on mesh stiffness and unloaded static transmission error (USTE). Based on the mesh stiffness and USTE considering gear wear, a gear dynamic model is established, and the vibration characteristics of gear wear are numerically studied. Comparison with the experimental results verifies the proposed dynamic model based on the new mesh relationship. The numerical and experimental results indicate that gear wear does not change the structure of the spectrum, but it alters the amplitude of the meshing frequencies and their sidebands. Several condition indicators, such as root-mean-square, kurtosis, and first-order meshing frequency amplitude, can be regarded as important bases for judging gear wear state.

关键词： gear wear     mesh relationship     mesh stiffness     transmission error     vibration characteristics    

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Chaotic behavior of LNG after stratification in main stream region of storage tank

WANG Jingjing, MA Xiaoqian

《能源前沿（英文）》 2008年 第2卷 第4期   页码 514-518 doi: 10.1007/s11708-008-0076-4

摘要： A study of the chaotic behavior of liquefied natural gas (LNG) after stratification in the main stream region of a storage tank was conducted. Based on non-linear dynamics, a 2-dimensional Rayleigh-Benard convection model was developed to simulate the convection, Lorenz equations of LNG convection were deduced from conservation equations, and the Runge-Kutta method was used to solve the equations. The results showed that when = 1.33, 106 < < 1470, chaos was obtained, which meant that the velocity field and the temperature field were highly unsteady. In addition, the influence of temperature and scale factor on the solutions and the corresponding range of parameters were studied. The results revealed that the chaos in LNG convection resulted from the interaction of buoyancy and viscid forces. A small quantity of heat impacting the storage tank would lead to a strong and unstable convection of LNG in the main stream region.

关键词： Runge-Kutta     non-linear     corresponding     temperature     addition    

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Macro-architectured cellular materials: Properties, characteristic modes, and prediction methods

Zheng-Dong MA

《机械工程前沿（英文）》 2018年 第13卷 第3期   页码 442-459 doi: 10.1007/s11465-018-0488-8

摘要：

Macro-architectured cellular (MAC) material is defined as a class of engineered materials having configurable cells of relatively large (i.e., visible) size that can be architecturally designed to achieve various desired material properties. Two types of novel MAC materials, negative Poisson’s ratio material and biomimetic tendon reinforced material, were introduced in this study. To estimate the effective material properties for structural analyses and to optimally design such materials, a set of suitable homogenization methods was developed that provided an effective means for the multiscale modeling of MAC materials. First, a strain-based homogenization method was developed using an approach that separated the strain field into a homogenized strain field and a strain variation field in the local cellular domain superposed on the homogenized strain field. The principle of virtual displacements for the relationship between the strain variation field and the homogenized strain field was then used to condense the strain variation field onto the homogenized strain field. The new method was then extended to a stress-based homogenization process based on the principle of virtual forces and further applied to address the discrete systems represented by the beam or frame structures of the aforementioned MAC materials. The characteristic modes and the stress recovery process used to predict the stress distribution inside the cellular domain and thus determine the material strengths and failures at the local level are also discussed.

关键词： architectured material     cellular materials     multi-scale modeling     homogenization method     effective material properties     computational method    

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用于非线性混沌系统的基于分岔分数阶PID控制器设计方法 None

Karima RABAH, Samir LADACI, Mohamed LASHAB

《信息与电子工程前沿（英文）》 2018年 第19卷 第2期   页码 180-191 doi: 10.1631/FITEE.1601543

摘要： 提出一个新的鲁棒分数阶比例-积分-微分（FOPID）控制器，以其中一个不稳定的固定点来稳定一个扰动非线性混沌系统。基于使用分岔图的比例-积分-微分行为，分析非线性混沌系统的稳定性。提取控制器参数的初始集，其后续可通过二次准则优化。积分和微分分数阶也被二次准则识别。在两个非线性系统（陈氏多涡卷混沌系统和Genesio-Tesi混沌系统）中应用数值模拟，结果表明分数阶比例-积分-微分控制器在稳定非稳定固定点过程中，甚至在随机扰动情况下，能够提供最好的闭环系统性能。

关键词： 分数阶系统；分岔图；分数PID控制器；陈氏多涡卷混沌系统；Genesio-Tesi混沌系统    

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标题 作者 时间 类型 操作

Dynamic characteristics of an NC table with phase space reconstruction

Linhong WANG, Bo WU, Runsheng DU, Shuzi YANG

期刊论文

An improved chaotic hybrid differential evolution for the short-term hydrothermal scheduling problem

Tahir Nadeem MALIK,Salman ZAFAR,Saaqib HAROON

期刊论文

Analysis of the dynamic hysteresis characteristic of finger seal

LEI Yanni, CHEN Guoding

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

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

Xiaoli XU, Xiuli LIU

期刊论文

基于混沌电路电容器连接的微分耦合同步

Yu-meng XU, Zhao YAO, Aatef HOBINY, Jun MA

期刊论文

利用勒让德多项式同步两种不同的混沌系统及其在安全通信中的应用

Saeed KHORASHADIZADEH, Mohammad-Hassan MAJIDI

期刊论文

Fractal characteristic evaluation and interpolation reconstruction for surface topography of drilled

期刊论文

特殊任务下基于Chebychev映射的移动机器人

Cai-hong LI, Yong SONG, Feng-ying WANG, Zhi-qiang WANG, Yi-bin LI

期刊论文

Operating characteristic analysis on the ultra-thin low temperature floor-heating system

Hualing ZHANG, Xiaopeng SONG

期刊论文

Design and characteristic research of a novel electromechanical-hydraulic hybrid actuator with two transmission

期刊论文

Mesh relationship modeling and dynamic characteristic analysis of external spur gears with gear wear

期刊论文

Chaotic behavior of LNG after stratification in main stream region of storage tank

WANG Jingjing, MA Xiaoqian

期刊论文

Macro-architectured cellular materials: Properties, characteristic modes, and prediction methods

Zheng-Dong MA

期刊论文

用于非线性混沌系统的基于分岔分数阶PID控制器设计方法

Karima RABAH, Samir LADACI, Mohamed LASHAB

期刊论文