期刊文献+
共找到4,978篇文章
< 1 2 249 >
每页显示 20 50 100
Development and Application of a Power Law Constitutive Model for Eddy Current Dampers
1
作者 Longteng Liang Zhouquan Feng +2 位作者 Hongyi Zhang Zhengqing Chen Changzhao Qian 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第3期2403-2419,共17页
Eddy current dampers (ECDs) have emerged as highly desirable solutions for vibration control due to theirexceptional damping performance and durability. However, the existing constitutive models present challenges tot... Eddy current dampers (ECDs) have emerged as highly desirable solutions for vibration control due to theirexceptional damping performance and durability. However, the existing constitutive models present challenges tothe widespread implementation of ECD technology, and there is limited availability of finite element analysis (FEA)software capable of accurately modeling the behavior of ECDs. This study addresses these issues by developing anewconstitutivemodel that is both easily understandable and user-friendly for FEAsoftware. By utilizing numericalresults obtained from electromagnetic FEA, a novel power law constitutive model is proposed to capture thenonlinear behavior of ECDs. The effectiveness of the power law constitutive model is validated throughmechanicalproperty tests and numerical seismic analysis. Furthermore, a detailed description of the application process ofthe power law constitutive model in ANSYS FEA software is provided. To facilitate the preliminary design ofECDs, an analytical derivation of energy dissipation and parameter optimization for ECDs under harmonicmotionis performed. The results demonstrate that the power law constitutive model serves as a viable alternative forconducting dynamic analysis using FEA and optimizing parameters for ECDs. 展开更多
关键词 Eddy current damper constitutive model finite element analysis vibration control power law constitutive model
下载PDF
Division of Gas Accumulation System and Laws Controlling Distribution of Natural Gas in Typical Petroliferous Basins of China
2
作者 Jiang Zhenxue Pang Xiongqi Jin Zhijun Chen Dongxia Basin & Reservoir Research Center, University of Petroleum, Beijing 102249 Key Laboratory of Hydrocarbon Accumulation, Ministry of Education, Beijing 102249 《Journal of China University of Geosciences》 SCIE CSCD 2002年第4期306-312,共7页
Considering the existing problems of the petroleum system, this paper bringsforward the concept of natural gas accumulation system and presents the dividing principles. Thendetailed statistics on the accumulation fact... Considering the existing problems of the petroleum system, this paper bringsforward the concept of natural gas accumulation system and presents the dividing principles. Thendetailed statistics on the accumulation factors of the 32 typical natural gas accumulation systemsin China and studies on the laws controlling distribution of gas are collected. The research showsthat the petroleum accumulation system is the basic unit controlling petroleum generation, migrationand accumulation. Generating intensity, generating amount, accumulating efficiency and migrationdistance plays an important role in the distribution of natural gas. Through analysis on results ofresources evaluation, discovered reserves and residual reserves, potential areas in middle-scaledpetroliferous basins in China are forecasted in this paper. Ordos, Sichuan, Tarim and Qaidam basinsare found out to be the main basins developing and enriching gas accumulation systems. 展开更多
关键词 petroliferous basins in china gas accumulation system petroleum system laws controlling gas potential area
下载PDF
Overburden fracture evolution laws and water-controlling technologies in mining very thick coal seam under water-rich roof 被引量:8
3
作者 Zhang Youxi Tu Shihao +1 位作者 Bai Qingsheng Li Jianjun 《International Journal of Mining Science and Technology》 SCIE EI 2013年第5期693-700,共8页
Considering the danger of water inrush in mining very thick coal seam under water-rich roof in Majialiang Coal Mine,the universal discrete element(UDEC)software was used to simulate the overburden fracture evolution l... Considering the danger of water inrush in mining very thick coal seam under water-rich roof in Majialiang Coal Mine,the universal discrete element(UDEC)software was used to simulate the overburden fracture evolution laws when mining 4#coal seam.Besides,this study researched on the influence of face advancing length,speed and mining height on the height of the water flowing fractured zones(HWFFZ),and analyzed the correlation of face advancing length and change rules of aquifer water levels and goaf water inflow.Based on those mentioned above,this research proposed the following water-controlling technologies:draining the roof water before mining,draining goaf water,reasonable advancing speed and mining thickness.These water-controlling technologies were successfully used in the feld,thus ensured safely mining the very thick coal seam under water-rich roof. 展开更多
关键词 Water-rich roof Very thick coal seam Mining induced fracture Evolution law Water-controlling technology
下载PDF
Incidence Law and Disease Symptom of Rice Blast and Its Control Technique 被引量:1
4
作者 罗守进 《Plant Diseases and Pests》 CAS 2010年第3期1-5,18,共6页
The article systematically summarizes the pathogen, incidence law and disease symptom of rice blast, and raises the integrated control technique for the disease, which will provide the certain theoretical basis for th... The article systematically summarizes the pathogen, incidence law and disease symptom of rice blast, and raises the integrated control technique for the disease, which will provide the certain theoretical basis for the control of the disease, being benefit for the actual production of rice in field. 展开更多
关键词 RICE Rice blast Incidence law SYMPTOM control
下载PDF
Error analysis and a new steering law design for spacecraft control system using SGCMGs 被引量:7
5
作者 Jin Jin Jing-Rui Zhang Zao-Zhen Liu 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2011年第5期803-808,共6页
Based on the singular value decomposition theory,this paper analyzed the mechanism of escaping/avoiding singularity using generalized and weighted singularity-robust steering laws for a spacecraft that uses single gim... Based on the singular value decomposition theory,this paper analyzed the mechanism of escaping/avoiding singularity using generalized and weighted singularity-robust steering laws for a spacecraft that uses single gimbal control moment gyros (SGCMGs) as the actuator for the attitude control system.The expression of output-torque error is given at the point of singularity,proving the incompatible relationship between the gimbal rate and the output-torque error.The method of establishing a balance between the gimbal rate and the output-torque error is discussed,and a new steering law is designed.Simulation results show that the proposed steering law can effectively drive SGCMGs to escape away from singularities. 展开更多
关键词 Single gimbal control moment gyros (SGCMGs) Attitude control Singularity analysis Steering law
下载PDF
Impact angle control over composite guidance law based on feedback linearization and finite time control 被引量:8
6
作者 ZHANG Xiaojian LIU Mingyong +1 位作者 LI Yang ZHANG Feihu 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第5期1036-1045,共10页
The impact angle control over guidance(IACG) law against stationary targets is proposed by using feedback linearization control(FLC) and finite time control(FTC). First, this paper transforms the kinematics equation o... The impact angle control over guidance(IACG) law against stationary targets is proposed by using feedback linearization control(FLC) and finite time control(FTC). First, this paper transforms the kinematics equation of guidance systems into the feedbackable linearization model, in which the guidance law is obtained without considering the impact angle via FLC. For the purpose of the line of sight(LOS) angle and its rate converging to the desired values, the second-order LOS angle is considered as a double-integral system. Then, this paper utilizes FTC to design a controller which can guarantee the states of the double-integral system converging to the desired values. Numerical simulation illustrates the performance of the IACG, in contrast to the existing guidance law. 展开更多
关键词 guidance law impact angle feedback linearization finite time control global stabilization
下载PDF
Approximation law for discrete-time variable structure control systems 被引量:6
7
作者 Yan ZHENG Yuanwei JING 《控制理论与应用(英文版)》 EI 2006年第3期291-296,共6页
Two approximation laws of sliding mode for discrete-time variable structure control systems are proposed to overcome the limitations of the exponential approximation law and the variable rate approximation law. By app... Two approximation laws of sliding mode for discrete-time variable structure control systems are proposed to overcome the limitations of the exponential approximation law and the variable rate approximation law. By applying the proposed approximation laws of sliding mode to discrete-time variable structure control systems, the stability of origin can be guaranteed, and the chattering along the switching surface caused by discrete-time variable structure control can be restrained effectively. In designing of approximation laws, the problem that the system control input is restricted is also considered, which is very important in practical systems. Finally a simulation example shows the effectiveness of the two approximation laws proposed. 展开更多
关键词 Discrete-time systems Approximation law Variable structure control (VSC) Quasi-sliding mode CHATTERING
下载PDF
Sliding mode control and Lyapunov based guidance law with impact time constraints 被引量:5
8
作者 Xiaojian Zhang Mingyong Liu Yang Li 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2017年第6期1186-1192,共7页
This paper analyses the issue of impact time control of super-cavitation weapons impact fixed targets which mainly refer to the ships or submarines who lost power, but still have combat capability. Control over impact... This paper analyses the issue of impact time control of super-cavitation weapons impact fixed targets which mainly refer to the ships or submarines who lost power, but still have combat capability. Control over impact time constraints of guidance law(ITCG) is derived by using sliding mode control(SMC) and Lyapunov stability theorem. The expected impact time is realized by using the notion of attack process and estimated time-to-go to design sliding mode surface(SMS). ITCG contains equivalent and discontinuous guidance laws, once state variables arrive at SMS,the equivalent guidance law keeps the state variables on SMS,then the discontinuous guidance law enforces state variables to move and reach SMS. The singularity problem of ITCG is also analyzed. Theoretical analysis and numerical simulation results are given to test the effectiveness of ITCG designed in this paper. 展开更多
关键词 Lyapunov stability sliding mode control impact time salvo attack TIME-TO-GO guidance law
下载PDF
A novel reaching law approach of quasi-sliding-mode control for uncertain discrete-time systems 被引量:4
9
作者 袁雷 沈建清 +1 位作者 肖飞 王恒利 《Journal of Central South University》 SCIE EI CAS 2012年第9期2514-2519,共6页
A novel discrete-time reaching law was proposed for uncertain discrete-time system,which contained process noise and measurement noise.The proposed method reserves all the advantages of discrete-time reaching law,whic... A novel discrete-time reaching law was proposed for uncertain discrete-time system,which contained process noise and measurement noise.The proposed method reserves all the advantages of discrete-time reaching law,which not only decreases the band width of sliding mode and strengthens the system robustness,but also improves the dynamic performance and stability capability of the system.Moreover,a discrete-time sliding mode control strategy based on Kalman filter method was designed,and Kalman filter was employed to eliminate the influence of system noise.Simulation results show that there is no chattering phenomenon in the output of controller and the state variables of controlled system,and the proposed algorithm is also feasible and has strong robustness to external disturbances. 展开更多
关键词 discrete-time system quasi-sliding-mode control discrete-time reaching law Kalman filter
下载PDF
Fuzzy sliding mode control guidance law with terminal impact angle and acceleration constraints 被引量:6
10
作者 Qingchun Li Wensheng Zhang +1 位作者 Gang Han Yuan Xie 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2016年第3期664-679,共16页
In this paper, a novel fuzzy sliding mode control(FSMC) guidance law with terminal constraints of miss distance, impact angle and acceleration is presented for a constant speed missile against the stationary or slow... In this paper, a novel fuzzy sliding mode control(FSMC) guidance law with terminal constraints of miss distance, impact angle and acceleration is presented for a constant speed missile against the stationary or slowly moving target. The proposed guidance law combines the sliding mode control algorithm with a fuzzy logic control scheme for the lag-free system and the first-order lag system. Through using Lyapunov stability theory, we prove the sliding surface converges to zero in finite time. Furthermore, considering the uncertain information and system disturbances, the guidance gains are on-line optimized by fuzzy logic technique. Numerical simulations are performed to demonstrate the performance of the FSMC guidance law and the results illustrate the validity and effectiveness of the proposed guidance law. 展开更多
关键词 guidance law sliding mode control fuzzy logic impact angle
下载PDF
Reaching law based sliding mode control for a frame structure under seismic load 被引量:2
11
作者 Ying Zhao Mohammad Noori Wael A.Altabey 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2021年第3期727-745,共19页
Implementation of efficient vibration control schemes for seismically excited structures is becoming more and more important in recent years.In this study,the influence of different control schemes on the dynamic perf... Implementation of efficient vibration control schemes for seismically excited structures is becoming more and more important in recent years.In this study,the influence of different control schemes on the dynamic performance of a frame structure excited by El Centro wave,with an emphasis on reaching law based control strategies,is examined.Reaching law refers to the reachable problem and criteria for the sliding state of a control system.Three reaching laws are designed to present different sliding mode control strategies by incorporating a state space model that describes structural dynamic characteristics of a frame structure.Both intact and damaged structures are studied by using the aforementioned control strategies.The influence of different structural damage extents,control locations and reaching law based control methods are further investigated.The results show that the structure can be well controlled using the sliding mode strategy when the induced structural damage extent does not exceed the standard percentage for considering the structure was damaged,which is 20%reduction in structure stiffness,as reported in the literature.The control effectiveness is more satisfactory if the control location is the same as the direction of external excitation.Furthermore,to study the chattering phenomenon of the sliding mode control method,approximation and detail components extracted from the phase plots of the sliding mode control system are compared via wavelet transform at different scales.The results show that for the same type of control law,the system behaves with similar chattering phenomenon. 展开更多
关键词 reaching law sliding mode control state-space model phase plot 2-D wavelet transform
下载PDF
A hybrid proportional navigation based two-stage impact time control guidance law 被引量:1
12
作者 HUANG Jia CHANG Sijiang CHEN Shengfu 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2022年第2期461-473,共13页
To improve applicability and adaptability of the impact time control guidance(ITCG) in practical engineering, a twostage ITCG law with simple but effective structure is proposed based on the hybrid proportional naviga... To improve applicability and adaptability of the impact time control guidance(ITCG) in practical engineering, a twostage ITCG law with simple but effective structure is proposed based on the hybrid proportional navigation, namely, the pureproportional-navigation and the retro-proportional-navigation.For the case with the impact time error less than zero, the first stage of the guided trajectory is driven by the retro-proportionalnavigation and the second one is driven by the pure-proportionalnavigation. When the impact time error is greater than zero, both of the stages are generated by the pure-proportional-navigation but using different navigation gains. It is demonstrated by twoand three-dimensional numerical simulations that the proposed guidance law at least has comparable results to existing proportional-navigation-based ITCG laws and is shown to be advantageous in certain circumstances in that the proposed guidance law alleviates its dependence on the time-to-go estimation, consumes less control energy, and adapts itself to more boundary conditions and constraints. The results of this research are expected to be supplementary to the current research literature. 展开更多
关键词 missile guidance law impact time control pure-proportional-navigation retro-proportional-navigation time-to-go estimation
下载PDF
Dynamical Correction of Control Laws for Marine Ships’ Accurate Steering 被引量:1
13
作者 Evgeny I. Veremey 《Journal of Marine Science and Application》 2014年第2期127-133,共7页
The objective of this work is the analytical synthesis problem for marine vehicles autopilots design. Despite numerous known methods for a solution, the mentioned problem is very complicated due to the presence of an ... The objective of this work is the analytical synthesis problem for marine vehicles autopilots design. Despite numerous known methods for a solution, the mentioned problem is very complicated due to the presence of an extensive population of certain dynamical conditions, requirements and restrictions, which must be satisfied by the appropriate choice of a steering control law. The aim of this paper is to simplify the procedure of the synthesis, providing accurate steering with desirable dynamics of the control system. The approach proposed here is based on the usage of a special unified multipurpose control law structure that allows decoupling a synthesis into simpler particular optimization problems. In particular, this structure includes a dynamical corrector to support the desirable features for the vehicle's motion under the action of sea wave disturbances. As a result, a specialized new method for the corrector design is proposed to provide an accurate steering or a trade-off between accurate steering and economical steering of the ship. This method guaranties a certain flexibility of the control law with respect to an actual environment of the sailing;its corresponding turning can be realized in real time onboard. 展开更多
关键词 marine ships control law dynamical corrector accurate steering autopilot sea wave
下载PDF
Practical Survey on Design and Testing of Flight Control Laws for Helicopter Engineering Simulators
14
作者 Gu Hongbin Hu Jinshuo Fu Jun 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2017年第5期465-476,共12页
A practical survey on engineering implementation of flight control laws on helicopter engineering simulators is proposed.Advances of helicopter engineering simulators are introduced.Practical flight control technologi... A practical survey on engineering implementation of flight control laws on helicopter engineering simulators is proposed.Advances of helicopter engineering simulators are introduced.Practical flight control technologies are reviewed,with an emphasis on discussing the corresponding engineering simulation programs.Finally,the difficulties of implementing advanced control technologies are addressed,and the future development of helicopter engineering simulators are highlighted. 展开更多
关键词 HELICOPTER helicopter engineering simulator flight control law flight control technology
下载PDF
Remote Control Guidance Law Design Using Variable Structure Control
15
作者 孟秀云 王奇 《Journal of Beijing Institute of Technology》 EI CAS 2006年第1期81-84,共4页
A method of sliding mode variable structure control for the missile body being a time varying system is presented. A remote control guidance law is designed. The method has strong robustness to target' s maneuver. To... A method of sliding mode variable structure control for the missile body being a time varying system is presented. A remote control guidance law is designed. The method has strong robustness to target' s maneuver. To reduce the chattering phenomena, quasi-sliding mode variable structure control method is used. Simulation results show that the proposed method has small miss distance for any kind of maneuvering targets and requires small control energy. 展开更多
关键词 remote control guidance law variable structure control sliding mode reaching mode
下载PDF
Improving the Control Energy in Model Reference Adaptive Controllers Using Fractional Adaptive Laws
16
作者 Norelys Aguila-Camacho Manuel A.Duarte-Mermoud 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI 2016年第3期332-337,共6页
This paper presents the analysis of the control energy consumed in model reference adaptive control(MRAC)schemes using fractional adaptive laws, through simulation studies. The analysis is focused on the energy spent ... This paper presents the analysis of the control energy consumed in model reference adaptive control(MRAC)schemes using fractional adaptive laws, through simulation studies. The analysis is focused on the energy spent in the control signal represented by means of the integral of the squared control input(ISI). Also, the behavior of the integral of the squared control error(ISE) is included in the analysis.The orders of the adaptive laws were selected by particle swarm optimization(PSO), using an objective function including the ISI and the ISE, with different weighting factors. The results show that, when ISI index is taken into account in the optimization process to determine the orders of adaptive laws,the resulting values are fractional, indicating that control energy of the scheme might be better managed if fractional adaptive laws are used. 展开更多
关键词 control energy fractional adaptive laws modelreference adaptive control
下载PDF
Model Predictive Control Based Defensive Guidance Law in Three-Body Engagement
17
作者 Jinglei Ren Zhenya Wang Feng Fang 《Journal of Beijing Institute of Technology》 EI CAS 2022年第6期559-569,共11页
Model predictive control(MPC)has been widely used in process industry,but its appli-cations to missile guidance law are relatively rare.In this paper,MPC is introduced to design defen-sive guidance law in a three-body... Model predictive control(MPC)has been widely used in process industry,but its appli-cations to missile guidance law are relatively rare.In this paper,MPC is introduced to design defen-sive guidance law in a three-body engagement,where a defending missile(i.e.,defender)is employed to protect a target aircraft from an attacking missile.Based on nonlinear kinematic equa-tions,an explicit linear discrete-time model is derived as the predictive model.Then the defensive guidance problem is formulated as a quadratic programming problem,and a fast algorithm for the MPC guidance law is developed.The advantages of the MPC guidance law include the applicabil-ity to scenarios with unknown guidance strategy of attacking missile,nonlinear kinematics and mul-tiple constraints.Another key feature is that the proposed approach does not require alteration in the target maneuver.Simulation results show that the MPC guidance law works well and can meet real-time requirements. 展开更多
关键词 defensive guidance law model predictive control three-body engagement
下载PDF
Sliding mode control of three-phase AC/DC converters using exponential rate reaching law
18
作者 JEERANANTASIN Narin NUNGAM Suksun 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2022年第1期210-221,共12页
Sliding mode control(SMC) becomes a common tool in designing robust nonlinear control systems, due to its inherent characteristics such as insensitivity to system uncertainties and fast dynamic response.Two modes are ... Sliding mode control(SMC) becomes a common tool in designing robust nonlinear control systems, due to its inherent characteristics such as insensitivity to system uncertainties and fast dynamic response.Two modes are involved in the SMC operation, namely reaching mode and sliding mode.In the reaching mode, the system state is forced to reach the sliding surface in a finite time.The major drawback of the SMC approach is the occurrence of chattering in the sliding mode, which is undesirable in most applications.Generally, the trade-off between chattering reduction and fast reaching time must be considered in the conventional SMC design.This paper proposes SMC design with a novel reaching law called the exponential rate reaching law(ERRL) to reduce chattering, and the control structure of the converter is designed based on the multiinput SMC that is applied to a three-phase AC/DC power converter.The simulation and experimental results show the effectiveness of the proposed technique. 展开更多
关键词 exponential rate reaching law(ERRL) multi-input sliding mode control(SMC) chattering reduction three-phase AC-to-DC converter
下载PDF
The law of anti-VCAM-1 targeted microbubbles adhesion to activated endothelial cells under controlled shear flow
19
作者 Lie Zhang,Hong Yang,Yiyao Liu(Department of Biophysics,School of Life Science and Technology,University of Electronic Science and Technology of China,Chengdu 610054,Sichuan,China) 《医用生物力学》 EI CAS CSCD 2009年第S1期11-11,共1页
Microbubbles can enhance the detection in noninvasive ultrasound imaging.Recently,targeted microbubbles have been developed to selectively adhere to specific and overexpressed p molecules in endothelial cells in some ... Microbubbles can enhance the detection in noninvasive ultrasound imaging.Recently,targeted microbubbles have been developed to selectively adhere to specific and overexpressed p molecules in endothelial cells in some pathologic conditions.However,the law of 展开更多
关键词 HUVECs The law of anti-VCAM-1 targeted microbubbles adhesion to activated endothelial cells under controlled shear flow
下载PDF
Analysis of Laws and Regulations on Vaccine Quality Control in China
20
作者 Zhi Yuanyuan Wang Shuling He Yalan 《Asian Journal of Social Pharmacy》 2019年第3期92-99,共8页
Objective To analyze laws, regulations and the responsibilities of relevant authorities for vaccine quality control and to provide suggestions for improving vaccine quality control system in China. Methods Laws and ru... Objective To analyze laws, regulations and the responsibilities of relevant authorities for vaccine quality control and to provide suggestions for improving vaccine quality control system in China. Methods Laws and rules issued by related authorities were classified and studied. Results and Conclusion There are still some problems in the basic laws and regulations, including the lack of legal basis, the unclear responsibilities of relevant authorities and so on. We should improve the current laws, regulations as well as the responsibilities of the authorities so as to build up a sound system of vaccine traceability gradually. 展开更多
关键词 VACCINE QUALITY control law and REGULATION RELEVANT AUTHORITY
下载PDF
上一页 1 2 249 下一页 到第
使用帮助 返回顶部