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Triad-displaced ULAs configuration for non-circular sources with larger continuous virtual aperture and enhanced degrees of freedom
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作者 SHAIKH Abdul Hayee DANG Xiaoyu HUANG Daqing 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2024年第1期81-93,共13页
Non-uniform linear array(NULA)configurations are well renowned due to their structural ability for providing increased degrees of freedom(DOF)and wider array aperture than uniform linear arrays(ULAs).These characteris... Non-uniform linear array(NULA)configurations are well renowned due to their structural ability for providing increased degrees of freedom(DOF)and wider array aperture than uniform linear arrays(ULAs).These characteristics play a significant role in improving the direction-of-arrival(DOA)estimation accuracy.However,most of the existing NULA geometries are primarily applicable to circular sources(CSs),while they limitedly improve the DOF and continuous virtual aperture for noncircular sources(NCSs).Toward this purpose,we present a triaddisplaced ULAs(Tdis-ULAs)configuration for NCS.The TdisULAs structure generally consists of three ULAs,which are appropriately placed.The proposed antenna array approach fully exploits the non-circular characteristics of the sources.Given the same number of elements,the Tdis-ULAs design achieves more DOF and larger hole-free co-array aperture than its sparse array competitors.Advantageously,the number of uniform DOF,optimal distribution of elements among the ULAs,and precise element positions are uniquely determined by the closed-form expressions.Moreover,the proposed array also produces a filled resulting co-array.Numerical simulations are conducted to show the performance advantages of the proposed Tdis-ULAs configuration over its counterpart designs. 展开更多
关键词 direction-of-arrival(DOA)estimation sparse array non-circular source(NCS) sum co-array difference co-array degrees of freedom(Dof)
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Degree of Freedom Analysis for Holographic MIMO Based on a Mutual-Coupling-Compliant Channel Model
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作者 SUN Yunqi JIAN Mengnan +2 位作者 YANG Jun ZHAO Yajun CHEN Yijian 《ZTE Communications》 2024年第1期34-40,共7页
Degree of freedom(DOF)is a key indicator for spatial multiplexing layers of a wireless channel.Traditionally,the channel of a multiple-input multiple-output(MIMO)half-wavelength dipole array has a DOF that equals the ... Degree of freedom(DOF)is a key indicator for spatial multiplexing layers of a wireless channel.Traditionally,the channel of a multiple-input multiple-output(MIMO)half-wavelength dipole array has a DOF that equals the antenna number.However,recent studies suggest that the DOF could be less than the antenna number when strong mutual coupling is considered.We utilize a mutual-coupling-compliant channel model to investigate the DOF of the holographic MIMO(HMIMO)channel and give a upper bound of the DOF with strong mutual coupling.Our numerical simulations demonstrate that a dense array can support more DOF per unit aperture as compared with a half-wavelength MIMO system. 展开更多
关键词 channel model degree of freedom holographic MIMO mutual coupling
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Modified Two-Degrees-of-Freedom Internal Model Control for Non-Square Systems with Multiple Time Delays 被引量:25
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作者 Jian-Chang Liu Nan Chen Xia Yu 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2014年第2期122-128,共7页
A modified two-degrees-of-freedom( M-TDOF) internal model control( IMC) method is proposed for non-square systems with multiple time delays and right-half-plane( RHP) zeros. In this method,pseudo-inverse is introduced... A modified two-degrees-of-freedom( M-TDOF) internal model control( IMC) method is proposed for non-square systems with multiple time delays and right-half-plane( RHP) zeros. In this method,pseudo-inverse is introduced to design the internal model controller,and a desired closed-loop transfer function is designed to eliminate the unrealizable factors of the derived controller. In addition,set-point tracking and load-disturbance rejection of each process are separately controlled by two controllers. The simulation results show that in addition to high decoupling performance and robustness,the proposed control method also effectively improves loaddisturbance rejection and simultaneously optimizes the input tracking performance and disturbance rejection performance by selecting the parameters of controllers. Furthermore,the higher tolerance of model mismatch is achieved in this paper. 展开更多
关键词 non-square system two degrees of freedom internal model control
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Nonlinear dynamics of two degree of freedom systems with linear and nonlinear stiffnesses 被引量:2
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作者 Bayat Mahmoud I.Pakar 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2013年第3期411-420,共10页
In this study, a new analytical approach is developed to analyze the free nonlinear vibration of conservative two-degree-of-freedom (TDOF) systems. The mathematical models of these systems are governed by second--or... In this study, a new analytical approach is developed to analyze the free nonlinear vibration of conservative two-degree-of-freedom (TDOF) systems. The mathematical models of these systems are governed by second--order nonlinear partial differential equations. Nonlinear differential equations were transferred into a single equation by using some intermediate variables. The single nonlinear differential equations are solved by using the first order of the Hamiltonian approach (HA). Different parameters, which have a significant impact on the response of the systems, are considered and discussed. Some comparisons are presented to verify the results between the Hamiltonian approach and the exact solution. The maximum relative error is less than 2.2124 % for large amplitudes of vibration. It has been established that the first iteration of the Hamiltonian approach achieves very accurate results, does not require any small perturbations, and can be used for a wide range of nonlinear problems. 展开更多
关键词 nonlinear vibration two-degree-of-freedom (TDof analytical approach Hamitonian approach (HA)
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Asymptotic dynamics of the alternate degrees of freedom for a two-mode system:An analytically solvable model
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作者 M.Arsenijevi J.Jekni-Dugi M.Dugi 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第2期71-75,共5页
The composite systems can be non-uniquely decomposed into parts(subsystems).Not all decompositions(structures) of a composite system are equally physically relevant.In this paper we answer on theoretical ground wh... The composite systems can be non-uniquely decomposed into parts(subsystems).Not all decompositions(structures) of a composite system are equally physically relevant.In this paper we answer on theoretical ground why it may be so.We consider a pair of mutually un-coupled modes in the phase space representation that are subjected to the independent quantum amplitude damping channels.By investigating asymptotic dynamics of the degrees of freedom,we find that the environment is responsible for the structures non-equivalence.Only one structure is distinguished by both locality of the environmental influence on its subsystems and a classical-like description. 展开更多
关键词 amplitude dissipative channel two-mode state Kraus representation alternate degrees of freedom
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Manufacture of End-micro-manipulator with Two Degrees of Freedom and its Driving System for Robot
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作者 刘劲松 蔡鹤皋 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 1995年第1期24-27,共4页
ManufactureofEnd-micro-manipulatorwithTwoDegreesofFreedomanditsDrivingSystemforRobot¥(刘劲松)(蔡鹤皋)LIUJinsong;CA... ManufactureofEnd-micro-manipulatorwithTwoDegreesofFreedomanditsDrivingSystemforRobot¥(刘劲松)(蔡鹤皋)LIUJinsong;CAIHegao(RobotReset... 展开更多
关键词 ss: two-degree-of-freedom planar SM ROBOT motor driver
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ON THE HOMOCLINIC ORBITS IN A CLASS OF TWO-DEGREE-OF-FREEDOM SYSTEMS UNDER THE RESONANCE CONDITIONS
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作者 WANG Mao-nan(王茂南) +1 位作者 XU Zhen-yuan(徐振源) 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2001年第3期340-352,共13页
A class of two-degree-of-freedom systems in resonance with an external, parametric excitation is investigated, the existence of the periodic solutions locked to Omega is proved by the use of the method of multiple sca... A class of two-degree-of-freedom systems in resonance with an external, parametric excitation is investigated, the existence of the periodic solutions locked to Omega is proved by the use of the method of multiple scales. This systems can be transformed into the systems of Wiggins under some conditions. A calculating formula which determines the existence of homoclinic orbits of the systems is given. 展开更多
关键词 a two-degree-of-freedom system method of multiple scales periodic solution homoclinic orbit CHAOS
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Set-point Filter Design for a Two-degree-of-freedom Fractional Control System
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作者 Fabrizio Padula Antonio Visioli 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI 2016年第4期451-462,共12页
This paper focuses on a new approach to design(possibly fractional) set-point filters for fractional control systems.After designing a smooth and monotonic desired output signal,the necessary command signal is obtaine... This paper focuses on a new approach to design(possibly fractional) set-point filters for fractional control systems.After designing a smooth and monotonic desired output signal,the necessary command signal is obtained via fractional input-output inversion.Then,a set-point filter is determined based on the synthesized command signal.The filter is computed by minimizing the 2-norm of the difference between the command signal and the filter step response.The proposed methodology allows the designer to synthesize both integer and fractional setpoint filters.The pros and cons of both solutions are discussed in details.This approach is suitable for the design of two degreeof-freedom controllers capable to make the set-point tracking performance almost independent from the feedback part of the controller.Simulation results show the effectiveness of the proposed methodology. 展开更多
关键词 Fractional control systems two-degree-of-freedom control set-point following system inversion
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Trimming the Degrees of Freedom via a K^(+) Flux Rectifier for Safe and Long‑Life Potassium‑Ion Batteries 被引量:1
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作者 Xianhui Yi Apparao MRao +1 位作者 Jiang Zhou Bingan Lu 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第11期157-171,共15页
High degrees of freedom(DOF)for K^(+)movement in the electrolytes is desirable,because the resulting high ionic conductivity helps improve potassium-ion batteries,yet requiring support from highly free and flammable o... High degrees of freedom(DOF)for K^(+)movement in the electrolytes is desirable,because the resulting high ionic conductivity helps improve potassium-ion batteries,yet requiring support from highly free and flammable organic solvent molecules,seriously affecting battery safety.Here,we develop a K^(+)flux rectifier to trim K ion’s DOF to 1 and improve electrochemical properties.Although the ionic conductivity is compromised in the K^(+)flux rectifier,the overall electrochemical performance of PIBs was improved.An oxidation stability improvement from 4.0 to 5.9 V was realized,and the formation of dendrites and the dissolution of organic cathodes were inhibited.Consequently,the K||K cells continuously cycled over 3,700 h;K||Cu cells operated stably over 800 cycles with the Coulombic efficiency exceeding 99%;and K||graphite cells exhibited high-capacity retention over 74.7%after 1,500 cycles.Moreover,the 3,4,9,10-perylenetetracarboxylic diimide organic cathodes operated for more than 2,100 cycles and reached year-scale-cycling time.We fabricated a 2.18 Ah pouch cell with no significant capacity fading observed after 100 cycles. 展开更多
关键词 Electrolytes degrees of freedom SAFE Coulombic efficiency Potassium-ion batteries
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System Identification Modeling of Ship Manoeuvring Motion in 4 Degrees of Freedom Based on Support Vector Machines 被引量:5
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作者 王雪刚 邹早建 +1 位作者 余龙 蔡韡 《China Ocean Engineering》 SCIE EI CSCD 2015年第4期519-534,共16页
Based on support vector machines, three modeling methods, i.e., white-box modeling, grey-box modeling and black-box modeling of ship manoeuvring motion in 4 degrees of freedom are investigated. With the whole-ship mat... Based on support vector machines, three modeling methods, i.e., white-box modeling, grey-box modeling and black-box modeling of ship manoeuvring motion in 4 degrees of freedom are investigated. With the whole-ship mathematical model for ship manoeuvring motion, in which the hydrodynamic coefficients are obtained from roll planar motion mechanism test, some zigzag tests and turning circle manoeuvres are simulated. In the white-box modeling and grey-box modeling, the training data taken every 5 s from the simulated 20°/20° zigzag test are used, while in the black-box modeling, the training data taken every 5 s from the simulated 15°/15°, 20°/20° zigzag tests and 15°, 25° turning manoeuvres are used; and the trained support vector machines are used to predict the whole 20°/20° zigzag test. Comparisons between the simulated and predicted 20°/20° zigzag tests show good predictive ability of the proposed methods. Besides, all mathematical models obtained by the proposed modeling methods are used to predict the 10°/10° zigzag test and 35° turning circle manoeuvre, and the predicted results are compared with those of simulation tests to demonstrate the good generalization performance of the mathematical models. Finally, the proposed modeling methods are analyzed and compared with each other in aspects of application conditions, prediction accuracy and computation speed. The appropriate modeling method can be chosen according to the intended use of the mathematical models and the available data needed for system identification. 展开更多
关键词 ship manoeuvring 4 degrees of freedom system identification support vector machines
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Physical Modeling and Parametric Study on Two-Degree-of-Freedom VIV of A Cylinder near Rigid Wall 被引量:3
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作者 杨兵 高福平 +1 位作者 李东晖 吴应湘 《China Ocean Engineering》 SCIE EI 2009年第1期119-132,共14页
Unlike most previous studies on the transverse vortex-induced vibration(VlV) of a cylinder mainly under the wallfree condition (Williamson & Govardhan, 2004), this paper experimentally investigates the vortex-ind... Unlike most previous studies on the transverse vortex-induced vibration(VlV) of a cylinder mainly under the wallfree condition (Williamson & Govardhan, 2004), this paper experimentally investigates the vortex-induced vibration of a cylinder with two degrees of freedom near a rigid wall exposed to steady flow. The amplitude and frequency responses of the cylinder are discussed. The lee wake flow patterns of the cylinder undergoin^g VIV were visualized by employing the hydrogen bubble technique. The effects of the gap-to-diameter ratio (eo/D) and the mass ratio on the vibration amplitude and frequency are analyzed. Comparisons of VIV response of the cylinder are made between one degree (only transverse) and two degrees of freedom (streamwise and transverse) and those between the present study and previous ones. The experimental observation indicates that there are two types of streamwise vibration, i.e. the first streamwise vibration (FSV) with small amplitude and the second streamwise vibration (SSV) which coexists with transverse vibration. The vortex shedding pattern for the FSV is approximately syrmnetric and that for the SSV is ahernate. The first streamwise vibration tends to disappear with the decrease of eo/D. For the case of large gap-to-dianeter ratios ( e.g. eo/D = 0. 54 ~ 1.58), the maximum amplitudes of the second streamwise vibration and transverse one increase with the increasing gap- to-diameter ratio. But for the case of small gap-to-diameter ratios (e. g. eo/D= 0. 16, 0.23), the vibration amplitude of the cylinder increases slowly at the initial stage (i.e. at small reduced velocity Vr), and across the maximum amplitude it decreases quickly at the last stage (i.e. at large Vr). Within the range of the examined small mass ratio (m 〈 4), both streamwise and transverse vibration amplitude of the cylinder decrease with the increase of mass ratio for the fixed value of Vr- The vibration range ( in terms of Vr) tends to widen with the decrease of the mass ratio. In the second streamwise vibration region, the vibration frequency of the cylinder with a small mass ratio ( e.g. mx = 1.44) undergoes a jump at a certain Vr+ The maximum amplitudes of the transverse vibration for two-degree-of-freedom case is larger than that for one-degree-of-freedom case, but the transverse vibration frequency of the cylinder with two degrees of freedom is lower than that with one degree of freedom(transverse). 展开更多
关键词 vortex-induced vibration cylinder near a wall two degrees of freedom steady flow gap-to-diameter ratio mass ratio
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Type Synthesis of Two-Degrees-of-Freedom Rotational Parallel Mechanism with Two Continuous Rotational Axes 被引量:17
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作者 XU Yundou ZHANG Dongsheng +2 位作者 WANG Min YAO Jiantao ZHAO Yongsheng 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第4期694-702,共9页
The two-rotational-degrees-of-freedom(2R) parallel mechanism(PM) with two continuous rotational axes(CRAs) has a simple kinematic model.It is therefore easy to implement trajectory planning,parameter calibration... The two-rotational-degrees-of-freedom(2R) parallel mechanism(PM) with two continuous rotational axes(CRAs) has a simple kinematic model.It is therefore easy to implement trajectory planning,parameter calibration,and motion control,which allows for a variety of application prospects.However,no systematic analysis on structural constraints of the 2R-PM with two CRAs has been performed,and there are only a few types of 2R-PM with two CRAs.Thus,a theory regarding the type synthesis of the 2R-PM with two CRAs is systematically established.First,combining the theories of reciprocal screw and space geometry,the spatial arrangement relationships of the constraint forces applied to the moving platform by the branches are explored,which give the 2R-PM two CRAs.The different distributions of the constraint forces in each branch are also studied.On the basis of the obtained structural constraints of branches,and considering the geometric relationships of constraint forces in each branch,the appropriate kinematic chains are constructed.Through the reasonable configuration of branch kinematic chains corresponding to every structural constraint,a series of new 2R-PMs with two CRAs are finally obtained. 展开更多
关键词 type synthesis continuous rotational axes two rotational degrees of freedom parallel mechanism constraint force
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Generalized Parallel Coprime Array for Two-Dimensional DOA Estimation:A Perspective from Maximizing Degree of Freedom 被引量:3
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作者 Luo Chen Xinping Lin +1 位作者 Beizuo Zhu Xiaofei Zhang 《China Communications》 SCIE CSCD 2021年第4期14-26,共13页
Parallel arrays with coprime subarrays have shown its potential advantages for two dimensional direction of arrival(DOA)estimation.In this paper,by introducing two flexible coprime factors to enlarge the inter-element... Parallel arrays with coprime subarrays have shown its potential advantages for two dimensional direction of arrival(DOA)estimation.In this paper,by introducing two flexible coprime factors to enlarge the inter-element spacing of parallel uniform subarrays,we propose a generalized parallel coprime array(GPCA)geometry.The proposed geometry enjoys flexible array layouts by the coprime factors and enables to extend the array aperture to achieve great improvement of estimation performance.Meanwhile,we verify that GPCA always can obtain M2 degrees of freedom(DOFs)in co-array domain via 2M sensors after optimization,which outperforms sparse parallel array geometries,such as parallel coprime array(PCA)and parallel augmented coprime array(PACA),and is the same as parallel nested array(PNA)with extended aperture.The superiority of GPCA geometry has been proved by numerical simulations with sparse representation methods. 展开更多
关键词 direction of arrival estimation generalized parallel coprime array degrees of freedom array aperture coprime factors
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Behavior of Vortex-Induced Vibration of A Circular Cylinder Near A Deformable Wall with Two Degrees of Freedom in Steady Flow 被引量:1
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作者 杨兵 马建林 +1 位作者 崔金声 徐万海 《China Ocean Engineering》 SCIE EI 2011年第4期549-564,共16页
The behavior of vortex-induced vibration of a two-degree-of-freedom cylinder near a deformable wall in steady flow is investigated experimentally. The typical phenomenon of the two-degree-of-freedom cylinder's VIV is... The behavior of vortex-induced vibration of a two-degree-of-freedom cylinder near a deformable wall in steady flow is investigated experimentally. The typical phenomenon of the two-degree-of-freedom cylinder's VIV is discussed. The influences of initial gap between the cylinder and the wall on the dynamic responses of the cylinder are analyzed. The comparison is made about dynamic responses of the cylinder with one and two degrees of freedom. Experimental results show that the vibration of the cylinder near a deformable wall with a small value of initial gap-to-diameter ratios can generally be divided into two phases. The initial gap-to-diameter ratios have a noticeable influence on the occurrence of transverse vibration. The transverse maximum amplitude of the cylinder with two degrees of freedom is larger than that of the cylinder with one degree of freedom under the condition with the same values of other parameters. However, the vibration frequency of the cylinder for the two degrees of freedom case is smaller than that for the one degree of freedom case at the same value of Vr number 展开更多
关键词 vortex-induced vibration two degrees of freedom deformable wall circular cylinder steady flow
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A novel two-degree-of-freedom spherical ultrasonic motor using three travelling-wave type annular stators 被引量:5
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作者 王剑 胡锡幸 +1 位作者 王班 郭吉丰 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第4期1298-1306,共9页
In order to promote the tolerance and controllability of the multi-degree-of-freedom(M-DOF) ultrasonic motor, a novel two-degree-of-freedom(2-DOF) spherical ultrasonic motor using three traveling-wave type annular sta... In order to promote the tolerance and controllability of the multi-degree-of-freedom(M-DOF) ultrasonic motor, a novel two-degree-of-freedom(2-DOF) spherical ultrasonic motor using three traveling-wave type annular stators was put forward. Firstly,the structure and working principle of this motor were introduced, especially a spiral spring as the preload applied component was designed for adaptive adjustment. Then, the friction drive model of 2-DOF spherical motor was built up from spatial geometric relation between three annular stators and the spherical rotor which was used to analyze the mechanical characteristics of the motor.The optimal control strategy for minimum norm solution of three stators' angular velocity was proposed, using Moore-Penrose generalized inverse matrix. Finally, a 2-DOF prototype was fabricated and tested, which ran stably and controllably. The maximum no-load velocity and stall torque are 92 r/min and 90 m N·m, respectively. The 2-DOF spherical ultrasonic motor has compact structure, easy assembly, good performance and stable operation. 展开更多
关键词 球形电动机 超声波马达 电机定子 两自由度 行波型 环形 2自由度 最优控制策略
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An experimental investigation of one-and two-degree of freedom VIV of cylinders 被引量:3
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作者 Zhuang Kang Lu-Sheng Jia 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2013年第2期284-293,共10页
In the paper,an experiment investigation was conducted for one-and two-degree of freedom vortex-induced vibration(VIV) of a horizontally-oriented cylinder with diameter of 11 cm and length of 120 cm.In the experimen... In the paper,an experiment investigation was conducted for one-and two-degree of freedom vortex-induced vibration(VIV) of a horizontally-oriented cylinder with diameter of 11 cm and length of 120 cm.In the experiment,the spring constants in the cross-flow and in-line flow directions were regulated to change the natural vibration frequency of the model system.It was found that,in the one-degree of freedom VIV experiment,a "double peak" phenomenon was observed in its amplitude within the range of the reduced velocities tested,moreover,a "2T" wake appeared in the vicinity of the second peak.In the two-degree of freedom VIV experiment,the trajectory of cylinder exhibited a reverse "C" shape,i.e.,a "new moon" shape.Through analysis of these data,it appears that,besides the non-dimensional in-line and cross-flow natural vibration frequency ratios,the absolute value of the natural vibration frequency of cylinder is also one of the important parameters affecting its VIV behavior. 展开更多
关键词 One- and two-degree of freedom VIV “2T” wake “New moon” trajectory Natural vibration frequency ratio
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Temperature Control Based on Fuzzy Logic Two-degree-of-freedom Smith Internal Model 被引量:4
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作者 WANG Zhigang HE Meng 《Instrumentation》 2020年第2期1-8,共8页
According to the characteristics of the large time delay,nonlinearity and the great inertia of temperature control system in biomass pyrolysis reactor,a two-degree-of-freedom Smith internal model controller based on f... According to the characteristics of the large time delay,nonlinearity and the great inertia of temperature control system in biomass pyrolysis reactor,a two-degree-of-freedom Smith internal model controller based on fuzzy control is proposed.Firstly,the mathematical model of the temperature control system is established by using the step response method,and then the two-degree-of-freedom Smith internal model controller is designed,and the good tracking performance and disturbance suppression performance can be obtained by designing the set value tracking controller and interference rejection capability.Secondly,the fuzzy control algorithm is used to realize the on-line tuning of the control parameters of the two-degree-of-freedom Smith internal model algorithm.The simulation results show that,compared with the traditional internal model control,fuzzy internal model PID control and two-degree-of-freedom Smith internal model control,the algorithm proposed in this paper improves the influence of lag time on the control system,realizes the separation control of set point tracking and anti-jamming performance and the self-tuning of control parameters,and improves the control performance of the system. 展开更多
关键词 Smith Predictive Controller Internal Model Control two degrees of freedom Fuzzy Control Algorithm
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Primary resonance of multiple degree-of-freedom dynamic systems with strong non-linearity using the homotopy analysis method 被引量:1
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作者 原培新 李永强 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2010年第10期1293-1304,共12页
A homotopy analysis method(HAM)is presented for the primary resonance of multiple degree-of-freedom systems with strong non-linearity excited by harmonic forces.The validity of the HAM is independent of the existenc... A homotopy analysis method(HAM)is presented for the primary resonance of multiple degree-of-freedom systems with strong non-linearity excited by harmonic forces.The validity of the HAM is independent of the existence of small parameters in the considered equation.The HAM provides a simple way to adjust and control the convergence region of the series solution by means of an auxiliary parameter.Two examples are presented to show that the HAM solutions agree well with the results of the modified Linstedt-Poincar'e method and the incremental harmonic balance method. 展开更多
关键词 homotopy analysis method primary resonance series solution strong nonlinearity MULTI-degree-of-freedom
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HAMILTONIANS WITH TWO DEGREES OF FREEDOM ADMITTING A SINGLEVALUED GENERAL SOLUTION
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作者 R.Conte M.Musette C.Verhoeven 《Analysis in Theory and Applications》 2005年第2期188-200,共13页
Following the basic principles stated by Painlevé, we first revisit the process of selecting the admissible time-independent Hamiltonians H = (p1^2 + p2^2)/2 + V(q1, q2) whose some integer power qj^nj (t)... Following the basic principles stated by Painlevé, we first revisit the process of selecting the admissible time-independent Hamiltonians H = (p1^2 + p2^2)/2 + V(q1, q2) whose some integer power qj^nj (t) of the general solution is a singlevalued function of the complez time t. In addition to the well known rational potentials V of Hénon-Heiles, this selects possible cases with a trigonometric dependence of V on qj. Then, by establishing the relevant confluences, we restrict the question of the explicit integration of the seven (three “cubic” plus four “quartic”) rational Hénon-Heiles cases to the quartic cases. Finally, we perform the explicit integration of the quartic cases, thus proving that the seven rational cases have a meromorphic general solution explicitly given by a genus two hyperelliptic function. 展开更多
关键词 two degree of freedom Hamiltonians Painlevé test Painlevé property Hdnon-Heiles Hamiltonian hyperelliptic
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Design for Two-degree-of-freedom PID Regulator Based on Improved Generalized Extremal Optimization Algorithm
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作者 霍海波 朱新坚 曹广义 《Journal of Shanghai Jiaotong university(Science)》 EI 2007年第2期148-152,158,共6页
A kind of new design method for two-degree-of-freedom(2DOF)PID regulator was presented,in which,a new global search heuristic--improved generalized extremal optimization(GEO)algorithm is applied to the parameter optim... A kind of new design method for two-degree-of-freedom(2DOF)PID regulator was presented,in which,a new global search heuristic--improved generalized extremal optimization(GEO)algorithm is applied to the parameter optimization design of 2DOF PID regulator.The simulated results show that very good dynamic response performance of both command tracking and disturbance rejection characteristics can be achieved simultaneously.At the same time,the comparisons of simulation results with the improved GA,the basic GEO and the improved GEO were given.From the comparisons,it is shown that the improved GEO algorithm is competitive in performance with the GA and basic GEO and is an attractive tool to be used in the design of two-degree-of-freedom PID regulator. 展开更多
关键词 控制器 参数 优化设计 动力反应
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