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Integrating just-in-time expansion primitives and an adaptive variable-step-size mechanism for feasible path planning of finite-wing UAVs 认领 引用
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作者 Hui GAO Yuhong JIA +2 位作者 Qingyang QIN Liwen XU Yaoming ZHOU 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2025年第12期376-403,共28页
Path planning is crucial for autonomous flight of fixed-wing Unmanned Aerial Vehicles(UAVs).However,due to the high-speed flight and complex control of fixed-wing UAVs,ensuring the feasibility and safety of planned pa... Path planning is crucial for autonomous flight of fixed-wing Unmanned Aerial Vehicles(UAVs).However,due to the high-speed flight and complex control of fixed-wing UAVs,ensuring the feasibility and safety of planned paths in complex environments is challenging.This paper proposes a feasible path planning algorithm named Closed-loop Radial Ray A*(CL-RaA*).The core components of the CL-RaA*include an adaptive variable-step-size path search and a just-in-time expansion primitive.The former enables fast path search in complex environments,while the latter ensures the feasibility of the generated paths.By integrating these two components and conducting safety checks on the trajectories to be expanded,the CL-RaA*can rapidly generate safe and feasible paths that satisfy the differential constraints that comprehensively consider the dynamics and control characteristics of six-degree-of-freedom fixed-wing UAVs.The final performance tests and simulation validations demonstrate that the CL-RaA*can generate safe and feasible paths in various environments.Compared to feasible path planning algorithms that use the rapidlyexploring random trees,the CL-RaA*not only ensures deterministic planning results in the same scenarios but also generates smoother feasible paths for fixed-wing UAVs more efficiently.In environments with dense grid obstacles,the feasible paths generated by the CL-RaA*are more conducive to UAV tracking compared to those planned using Dubins curves. 展开更多
关键词 Adaptive variable step size Differential constraint Feasible path planning Fixed-wing unmanned aerial vehicle(UAV) Just-in-time expansion primitive Path search
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Finite-difference modeling with variable grid-size and adaptive time-step in porous media 认领 引用
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作者 Xinxin Liu Xingyao Yin Guochen Wu 《Earthquake Science》 2014年第2期169-178,共10页
Forward modeling of elastic wave propagation in porous media has great importance for understanding and interpreting the influences of rock properties on characteristics of seismic wavefield. However,the finite-differ... Forward modeling of elastic wave propagation in porous media has great importance for understanding and interpreting the influences of rock properties on characteristics of seismic wavefield. However,the finite-difference forward-modeling method is usually implemented with global spatial grid-size and time-step; it consumes large amounts of computational cost when small-scaled oil/gas-bearing structures or large velocity-contrast exist underground. To overcome this handicap,combined with variable grid-size and time-step,this paper developed a staggered-grid finite-difference scheme for elastic wave modeling in porous media. Variable finite-difference coefficients and wavefield interpolation were used to realize the transition of wave propagation between regions of different grid-size. The accuracy and efficiency of the algorithm were shown by numerical examples. The proposed method is advanced with low computational cost in elastic wave simulation for heterogeneous oil/gas reservoirs. 展开更多
关键词 Staggered-grid finite-difference scheme Variable grid-size Variable time-step Porous media
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Breakdown voltage model and structure realization of a thin silicon layer with linear variable doping on a silicon on insulator high voltage device with multiple step field plates 认领 引用 被引量：5
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作者 乔明 庄翔 +4 位作者 吴丽娟 章文通 温恒娟 张波 李肇基 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第10期504-511,共8页
Based on the theoretical and experimental investigation of a thin silicon layer（TSL） with linear variable doping（LVD） and further research on the TSL LVD with a multiple step field plate（MSFP）,a breakdown voltag... Based on the theoretical and experimental investigation of a thin silicon layer（TSL） with linear variable doping（LVD） and further research on the TSL LVD with a multiple step field plate（MSFP）,a breakdown voltage（BV） model is proposed and experimentally verified in this paper.With the two-dimensional Poisson equation of the silicon on insulator（SOI） device,the lateral electric field in drift region of the thin silicon layer is assumed to be constant.For the SOI device with LVD in the thin silicon layer,the dependence of the BV on impurity concentration under the drain is investigated by an enhanced dielectric layer field（ENDIF）,from which the reduced surface field（RESURF） condition is deduced.The drain in the centre of the device has a good self-isolation effect,but the problem of the high voltage interconnection（HVI） line will become serious.The two step field plates including the source field plate and gate field plate can be adopted to shield the HVI adverse effect on the device.Based on this model,the TSL LVD SOI n-channel lateral double-diffused MOSFET（nLDMOS） with MSFP is realized.The experimental breakdown voltage（BV） and specific on-resistance（R on,sp） of the TSL LVD SOI device are 694 V and 21.3 ·mm 2 with a drift region length of 60 μm,buried oxide layer of 3 μm,and silicon layer of 0.15 μm,respectively. 展开更多
关键词 breakdown voltage model enhanced dielectric layer field thin silicon layer linear variable doping multiple step field plates
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Noise cancellation of a multi-reference full-wave magnetic resonance sounding signal based on a modified sigmoid variable step size least mean square algorithm 认领 引用 被引量：1
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作者 TIAN Bao-feng ZHOU Yuan-yuan +2 位作者 ZHU Hui JIANG Chuan-dong YI Xiao-feng 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第4期900-911,共12页
Nano-volt magnetic resonance sounding(MRS) signals are sufficiently weak so that during the actual measurement, they are affected by environmental electromagnetic noise, leading to inaccuracy of the extracted characte... Nano-volt magnetic resonance sounding(MRS) signals are sufficiently weak so that during the actual measurement, they are affected by environmental electromagnetic noise, leading to inaccuracy of the extracted characteristic parameters and hindering effective inverse interpretation. Considering the complexity and non-homogeneous spatial distribution of environmental noise and based on the theory of adaptive noise cancellation, a model system for noise cancellation using multi-reference coils was constructed to receive MRS signals. The feasibility of this system with theoretical calculation and experiments was analyzed and a modified sigmoid variable step size least mean square(SVSLMS) algorithm for noise cancellation was presented. The simulation results show that, the multi-reference coil method performs better than the single one on both signal-to-noise ratio(SNR) improvement and signal waveform optimization after filtering, under the condition of different noise correlations in the reference coils and primary detecting coils and different SNRs. In particular, when the noise correlation is poor and the SNR<0, the SNR can be improved by more than 8 dB after filtering with multi-reference coils. And the average fitting errors for initial amplitude and relaxation time are within 5%. Compared with the normalized least mean square(NLMS) algorithm and multichannel Wiener filter and processing field test data, the effectiveness of the proposed method is verified. 展开更多
关键词 magnetic resonance sounding signal multi-reference coils adaptive noise cancellation sigmoid variable step size least mean square (SVSLMS)
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Novel LMS adaptive filtering algorithm with variable step size 认领 引用 被引量：1
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作者 李继明 马骥 +1 位作者 王洋 程学珍 《Journal of Measurement Science and Instrumentation》 CAS 2012年第3期239-242,共4页
By analyzing algorithms available for variable step size least mean square(LMS)adaptive filter,a new modified LMS adaptive filtering algorithm with variable step size is proposed,along with performance analysis based ... By analyzing algorithms available for variable step size least mean square(LMS)adaptive filter,a new modified LMS adaptive filtering algorithm with variable step size is proposed,along with performance analysis based on different parameters.Compared with the existing algorithms through the simulation,the proposed algorithm has faster convergence speed and smaller steady state error. 展开更多
关键词 adaptive filter variable step size least mean square(LMS)
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Joint receiving mechanism based on blind equalization with variable step size for M-QAM modulation 认领 引用 被引量：1
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作者 卢继华 Abdallah Elhirtsia AHMED +1 位作者 王晓华 Kheddar BOUDJEMAA 《Journal of Beijing Institute of Technology》 EI CAS 2015年第3期381-386,共6页
The problem of inter symbol interference（ ISI） in wireless communication systems caused by multipath propagation when using high order modulation like M-Q AMis solved. Since the wireless receiver doesn＇t require a ... The problem of inter symbol interference（ ISI） in wireless communication systems caused by multipath propagation when using high order modulation like M-Q AMis solved. Since the wireless receiver doesn＇t require a training sequence,a blind equalization channel is implemented in the receiver to increase the throughput of the system. To improve the performances of both the blind equalizer and the system,a joint receiving mechanismincluding variable step size（ VSS） modified constant modulus algorithms（ MC-MA） and modified decision directed modulus algorithms（ MD DMA） is proposed to ameliorate the convergence speed and mean square error（ MSE） performance and combat the phase error when using high order QAM modulation. The VSS scheme is based on the selection of step size according to the distance between the output of the equalizer and the desired output in the constellation plane. Analysis and simulations showthat the performance of the proposed VSS-MCMA-MD DMA mechanismis better than that of algorithms with a fixed step size. In addition,the MCMA-MDDMA with VSS can performthe phase recovery by itself. 展开更多
关键词 inter symbol interference（ISI） modified constant modulus algorithm（MCMA） modified decision directed modulus algorithm（MDDMA） variable step size blind equalization phase rotation
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Study of Variable Step Size LMS Adaptive Algorithm Based on Variable Region 认领 引用
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作者 曲永印 邵世煌 +1 位作者 姜林 周振雄 《Journal of Donghua University(English Edition)》 EI CAS 2006年第4期32-35,共4页
This paper puts forward a new variable step size LMS adaptive algorithm based on variable region. The step size p（k） in the algorithm varies with the variation of the region of deviation e （k） to ensure the optimi... This paper puts forward a new variable step size LMS adaptive algorithm based on variable region. The step size p（k） in the algorithm varies with the variation of the region of deviation e （k） to ensure the optimization of the three performance objectives including initial convergent speed, trace ability of the time-varying system and steady disregulation. The paper demonstrates the convergence of the algorithm accompanied by random noise, 展开更多
关键词 variable step size LMS algorithm variable region convergence model identification.
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Active micro-vibration control based on improved variable step size LMS algorithm 认领 引用 被引量：1
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作者 Li Xiangmin Fang Yubin +2 位作者 Zhu Xiaojin Huang Yonghui Zhou Yijia 《High Technology Letters》 EI CAS 2020年第2期178-187,共10页
The contradiction of variable step size least mean square(LMS)algorithm between fast convergence speed and small steady-state error has always existed.So,a new algorithm based on the combination of logarithmic and sym... The contradiction of variable step size least mean square(LMS)algorithm between fast convergence speed and small steady-state error has always existed.So,a new algorithm based on the combination of logarithmic and symbolic function and step size factor is proposed.It establishes a new updating method of step factor that is related to step factor and error signal.This work makes an analysis from 3 aspects:theoretical analysis,theoretical verification and specific experiments.The experimental results show that the proposed algorithm is superior to other variable step size algorithms in convergence speed and steady-state error. 展开更多
关键词 adaptive filtering variable step size least mean square(LMS)algorithm logarithmic and symbolic functions convergence and steady state error active control of micro vibration
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Establishment of Dynamic Model for Axle Box Bearing of High-Speed Trains Under Variable Speed Conditions 认领 引用 被引量：14
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作者 Yongqiang Liu Baosen Wang +1 位作者 Bin Zhang Shaopu Yang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2022年第4期340-351,共12页
In this study,a dynamic model for the bearing rotor system of a high-speed train under variable speed conditions is established.In contrast to previous studies,the contact stress is simplifed in the proposed model and... In this study,a dynamic model for the bearing rotor system of a high-speed train under variable speed conditions is established.In contrast to previous studies,the contact stress is simplifed in the proposed model and the compensation balance excitation caused by the rotor mass eccentricity considered.The angle iteration method is used to overcome the challenge posed by the inability to determine the roller space position during bearing rotation.The simulation results show that the model accurately describes the dynamics of bearings under varying speed profles that contain acceleration,deceleration,and speed oscillation stages.The order ratio spectrum of the bearing vibration signal indicates that both the single and multiple frequencies in the simulation results are consistent with the theoretical results.Experiments on bearings with outer and inner ring faults under various operating conditions are performed to verify the developed model. 展开更多
关键词 Variable speed conditions High-speed train Bearing model Angle iteration Order ratio spectrum
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Artificial intelligence-driven enhanced CBR modeling of sandy soils considering broad grain size variability 认领 引用
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作者 Zia ur Rehman Zeeshan Aziz +3 位作者 Usama Khalid Nauman Ijaz Sadaqat ur Rehman Zain Ijaz 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2025年第5期3161-3179,共19页
The soil packing,influenced by variations in grain size and the gradation pattern within the soil matrix,plays a crucial role in constituting the mechanical properties of sandy soils.However,previous modeling approach... The soil packing,influenced by variations in grain size and the gradation pattern within the soil matrix,plays a crucial role in constituting the mechanical properties of sandy soils.However,previous modeling approaches have overlooked incorporating the full range of representative parameters to accurately predict the soaked California bearing ratio(CBRs)of sandy soils by precisely articulating soil packing in the modeling framework.This study presents an innovative artificial intelligence(AI)-based approach for modeling the CBRsof sandy soils,considering grain size variability meticulously.By synthesizing extensive data from multiple sources,i.e.extensive tailored testing program undertaking multiple tests and extant literature,various modeling techniques including genetic expression programming(GEP),multi-expression programming(MEP),support vector machine(SVM),and multi-linear regression(MLR)are utilized to develop models.The research explores two modeling strategies,namely simplified and composite,with the former incorporating only sieve analysis test parameters,while the latter includes compaction test parameters alongside sieve analysis data.The models'performance is assessed using statistical key performance indicators(KPIs).Results indicate that genetic AI-based algorithms,particularly GEP,outperform SVM and conventional regression techniques,effectively capturing complex relationships between input parameters and CBRs.Additionally,the study reveals insights into model performance concerning the number of input parameters,with GEP consistently outperforming other models.External validation and Taylor diagram analysis demonstrate the GEP models'superiority over existing literature models on an independent dataset from the literature.Parametric and sensitivity analyses highlight the intricate relationships between grain sizes and CBRs,further emphasizing GEP's efficacy in modeling such complexities.This study contributes to enhancing CBRsmodeling accuracy for sandy soils,crucial for pertinent infrastructure design and construction rapidly and cost-effectively. 展开更多
关键词 California bearing ratio(CBR) Grain size variability Sandy soil matrix AI-Based modeling Genetic algorithm
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Fixed Points and Crossovers for the Hysteresis Scaling of Dynamic Mean-Field Models 认领 引用
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作者 Jiapeng Yang Fan Zhong 《Chinese Physics Letters》 SCIE EI CAS CSCD 2026年第7期5-11,共7页
Phase transitions are divided into first-order and continuous ones in the current classification.While the latter shows striking phenomena of scaling and universality,the former is typically characterized by discontin... Phase transitions are divided into first-order and continuous ones in the current classification.While the latter shows striking phenomena of scaling and universality,the former is typically characterized by discontinuous jumps in extensive variables and pronounced hysteresis.Recent studies have demonstrated universal scaling behavior controlled by a cubic fixed point in first-order phase transitions.However,more recent investigations of hysteresis in a dynamic mean-field quartic model driven across its first-order phase transitions have revealed new scaling exponents for different driving rates.Here,we discover a new exponent for large driving rates arising surprisingly from critical phenomena and show that,depending on the magnitude of the driving rates and the absence or presence of noise,the same mean-field model remarkably exhibits several universality classes with definite universal scaling exponents governed by their corresponding fixed points,as revealed through a systematic scaling analysis based on renormalization group theory.The theories,the various crossovers between different fixed points,and the complete universal scaling of full curve collapse,are all verified by numerical results.This further confirms universal scaling in first-order phase transitions. 展开更多
关键词 pronounced hysteresisrecent first order phase transitions fixed points scaling exponents phase transitions discontinuous jumps extensive variables quartic model cubic fixed point
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Variable Step Filtered-X Least Mean Square Algorithm Based on Piecewise Logarithmic Function 认领 引用
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作者 Zeyi Ding Jianan Bian +1 位作者 Xinyuan Jiang Xi Chen 《Journal of Physical Science and Application》 2024年第1期16-24,共9页
In order to improve the problem that the filtered-x least mean square(FxLMS)algorithm cannot take into account the convergence speed,steady-state error during active noise control.A piecewise variable step size FxLMS ... In order to improve the problem that the filtered-x least mean square(FxLMS)algorithm cannot take into account the convergence speed,steady-state error during active noise control.A piecewise variable step size FxLMS algorithm based on logarithmic function(PLFxLMS)is proposed,and the genetic algorithm are introduced to optimize the parameters of logarithmic variable step size FxLMS(LFxLMS),improved logarithmic variable step size Films(IFxLMS),and PLFxLMS algorithms.Bandlimited white noise is used as the input signal,FxLMS,LFxLMS,ILFxLMS,and PLFxLMS algorithms are used to conduct active noise control simulation,and the convergence speed and steady-state characteristic of four algorithms are comparatively analyzed.Compared with the other three algorithms,the PLFxLMS algorithm proposed in this paper has the fastest convergence speed,and small steady-state error.The PLFxLMS algorithm can effectively improve the convergence speed and steady-state error of the FxLMS algorithm that cannot be controlled at the same time,and achieve the optimal effect. 展开更多
关键词 Active noise control filtered-x least mean square algorithm variable step size genetic algorithm
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On the Cosmic Evolution of the Quantum Vacuum Using Two Variable G Models and Winterberg’s Thesis 认领 引用
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作者 Christopher Pilot 《Journal of High Energy Physics, Gravitation and Cosmology》 CAS 2023年第4期1134-1160,共27页
We work within a Winterberg framework where space, i.e., the vacuum, consists of a two component superfluid/super-solid made up of a vast assembly (sea) of positive and negative mass Planck particles, called planckion... We work within a Winterberg framework where space, i.e., the vacuum, consists of a two component superfluid/super-solid made up of a vast assembly (sea) of positive and negative mass Planck particles, called planckions. These material particles interact indirectly, and have very strong restoring forces keeping them a finite distance apart from each other within their respective species. Because of their mass compensating effect, the vacuum appears massless, charge-less, without pressure, net energy density or entropy. In addition, we consider two varying G models, where G, is Newton’s constant, and G-1, increases with an increase in cosmological time. We argue that there are at least two competing models for the quantum vacuum within such a framework. The first follows a strict extension of Winterberg’s model. This leads to nonsensible results, if G increases, going back in cosmological time, as the length scale inherent in such a model will not scale properly. The second model introduces a different length scale, which does scale properly, but keeps the mass of the Planck particle as, ± the Planck mass. Moreover we establish a connection between ordinary matter, dark matter, and dark energy, where all three mass densities within the Friedman equation must be interpreted as residual vacuum energies, which only surface, once aggregate matter has formed, at relatively low CMB temperatures. The symmetry of the vacuum will be shown to be broken, because of the different scaling laws, beginning with the formation of elementary particles. Much like waves on an ocean where positive and negative planckion mass densities effectively cancel each other out and form a zero vacuum energy density/zero vacuum pressure surface, these positive mass densities are very small perturbations (anomalies) about the mean. This greatly alleviates, i.e., minimizes the cosmological constant problem, a long standing problem associated with the vacuum. 展开更多
关键词 Winterberg Model Planck Particles Positive and Negative Mass Planck Particles Planckions Quantum Vacuum Space as a Superfluid/Supersolid Extended Models for Space Cosmological Constant Higgs Field as a Composite Particle Higgs Boson Inherent Length Scale for the Vacuum Dark Energy Cosmological Scaling Behavior for the Quantum Vacuum Variable G Models Extended Gravity Newton’s Constant as an Order Parameter High Energy Behavior for the Vacuum
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Multi-Material Topology Optimization of Structures Using an Ordered Ersatz Material Model 认领 引用 被引量：2
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作者 Baoshou Liu Xiaolei Yan +2 位作者 Yangfan Li Shiwei Zhou Xiaodong Huang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2021年第8期523-540,共18页
This paper proposes a new element-based multi-material topology optimization algorithm using a single variable for minimizing compliance subject to a mass constraint.A single variable based on the normalized elemental... This paper proposes a new element-based multi-material topology optimization algorithm using a single variable for minimizing compliance subject to a mass constraint.A single variable based on the normalized elemental density is used to overcome the occurrence of meaningless design variables and save computational cost.Different from the traditional material penalization scheme,the algorithm is established on the ordered ersatz material model,which linearly interpolates Young’s modulus for relaxed design variables.To achieve a multi-material design,the multiple floating projection constraints are adopted to gradually push elemental design variables to multiple discrete values.For the convergent element-based solution,the multiple level-set functions are constructed to tentatively extract the smooth interface between two adjacent materials.Some 2D and 3D numerical examples are presented to demonstrate the effectiveness of the proposed algorithm and the possible advantage of the multi-material designs over the traditional solid-void designs. 展开更多
关键词 Multi-material topology optimization ordered ersatz material model mass constraint single variable
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Estimation Method of State-of-Charge For Lithium-ion Battery Used in Hybrid Electric Vehicles Based on Variable Structure Extended Kalman Filter 认领 引用 被引量：18
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作者 SUN Yong MA Zilin +2 位作者 TANG Gongyou CHEN Zheng ZHANG Nong 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2016年第4期717-726,共10页
Since the main power source of hybrid electric vehicle（HEV） is supplied by the power battery,the predicted performance of power battery,especially the state-of-charge（SOC） estimation has attracted great attention ... Since the main power source of hybrid electric vehicle（HEV） is supplied by the power battery,the predicted performance of power battery,especially the state-of-charge（SOC） estimation has attracted great attention in the area of HEV.However,the value of SOC estimation could not be greatly precise so that the running performance of HEV is greatly affected.A variable structure extended kalman filter（VSEKF）-based estimation method,which could be used to analyze the SOC of lithium-ion battery in the fixed driving condition,is presented.First,the general lower-order battery equivalent circuit model（GLM）,which includes column accumulation model,open circuit voltage model and the SOC output model,is established,and the off-line and online model parameters are calculated with hybrid pulse power characteristics（HPPC） test data.Next,a VSEKF estimation method of SOC,which integrates the ampere-hour（Ah） integration method and the extended Kalman filter（EKF） method,is executed with different adaptive weighting coefficients,which are determined according to the different values of open-circuit voltage obtained in the corresponding charging or discharging processes.According to the experimental analysis,the faster convergence speed and more accurate simulating results could be obtained using the VSEKF method in the running performance of HEV.The error rate of SOC estimation with the VSEKF method is focused in the range of 5% to 10% comparing with the range of 20% to 30% using the EKF method and the Ah integration method.In Summary,the accuracy of the SOC estimation in the lithium-ion battery cell and the pack of lithium-ion battery system,which is obtained utilizing the VSEKF method has been significantly improved comparing with the Ah integration method and the EKF method.The VSEKF method utilizing in the SOC estimation in the lithium-ion pack of HEV can be widely used in practical driving conditions. 展开更多
关键词 state of charge estimation hybrid electric vehicle general lower-order model variable structure EKF
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Variable-step-size second-order-derivative multistep method for solving first-order ordinary differential equations in system simulation 认领 引用
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作者 Lei Zhang Chaofeng Zhang Mengya Liu 《International Journal of Modeling, Simulation, and Scientific Computing》 EI 2020年第1期42-57,共16页
According to the relationship between truncation error and step size of two implicit second-order-derivative multistep formulas based on Hermite interpolation polynomial,a variable-order and variable-step-size numeric... According to the relationship between truncation error and step size of two implicit second-order-derivative multistep formulas based on Hermite interpolation polynomial,a variable-order and variable-step-size numerical method for solving differential equations is designed.The stability properties of the formulas are discussed and the stability regions are analyzed.The deduced methods are applied to a simulation problem.The results show that the numerical method can satisfy calculation accuracy,reduce the number of calculation steps and accelerate calculation speed. 展开更多
关键词 Numerical method variable step size variable order hermite interpolation ordinary differential equations
一种基于信号分解质量多目标评价的VMD参数寻优新方法 认领 引用 被引量：2
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作者 李贺 查志华 吴杰 《振动与冲击》 EI CSCD 北大核心 2026年第3期88-96,共9页
模态数K和惩罚因子α设置不当,会严重影响信号变分模态分解(variational mode decomposition,VMD)的性能,已有的改进VMD法参数寻优时,无法同时兼顾速度和准确性,也未将避免信号欠分解和过分解以及分量与原信号的信息量差异最小都作为寻... 模态数K和惩罚因子α设置不当,会严重影响信号变分模态分解(variational mode decomposition,VMD)的性能,已有的改进VMD法参数寻优时,无法同时兼顾速度和准确性,也未将避免信号欠分解和过分解以及分量与原信号的信息量差异最小都作为寻优的目标,导致所确定的K和α最优组合未能充分提升信号分解性能。针对此问题,提出了一种信号变步长VMD (variable step size-VMD,VSS-VMD)算法对K和α寻优,采用能量损失系数评价信号欠分解,互相关系数和峭度相结合评价信号过分解,分量与原信号的信息熵差评价分量表征原信号能力,α以较大初始步长逐渐变小,先以较大步长快速找到较优参数组合并缩小寻优范围,然后以较小步长精确找到最优参数组合。与最近报道的3种改进VMD法相比,VSS-VMD法确定的最优K和α对仿真信号和多个实测信号分解结果表明,提取信号分量完备,未发生欠分解,有效避免了过分解,同时表现出更优的噪声抑制效果,分量与原信号的能量差异值以及分量之间的正交指数都低,分量表征原信号的能力强。该方法在参数寻优范围很大的情况下,确保准确寻优的同时,寻优时间明显减少,为信号VMD性能提升以及有关应用研究提供了重要参考和借鉴。 展开更多
关键词 变分模态分解(VMD) 惩罚因子 变步长 过分解 欠分解 信号分量信息
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温-力耦合环境效应下土工格栅蠕变特性及分数阶损伤本构模型研究 认领 引用 被引量：1
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作者 靳静 陈何塘 +3 位作者 梁小勇 杨广庆 周诗广 寇凌曦 《铁道学报》 EI CAS CSCD 北大核心 2026年第2期146-155,共10页
为研究温-力耦合环境效应下土工格栅蠕变全过程的变形特征,开展温-力耦合环境效应下的土工格栅室内蠕变试验,基于试验结果,考虑土工格栅蠕变过程中随时间产生劣化效应引入损伤变量,修正分数阶损伤本构模型,并进行参数敏感性分析。结果表... 为研究温-力耦合环境效应下土工格栅蠕变全过程的变形特征,开展温-力耦合环境效应下的土工格栅室内蠕变试验,基于试验结果,考虑土工格栅蠕变过程中随时间产生劣化效应引入损伤变量,修正分数阶损伤本构模型,并进行参数敏感性分析。结果表明,当温度一定时,随着应力比提高,土工格栅蠕变较快进入加速蠕变阶段;当温度升高时,土工格栅蠕变速率显著增大,达到相同应变所施加的应力比有所降低;当温度为40℃,应力比从43%增至50%时,蠕变应变增幅为363.77%,所需时间由1098 h缩短至6.21 h;在温-力耦合环境效应下,土工格栅的割线模量随时间呈反比递减趋势,而应力比的提高加速了时效割线模量的衰减;研究提出的修正损伤本构模型,能有效表征土工格栅在高温环境下的蠕变行为,泊松比ν随温度的升高急剧上升,流阻因子A与温度呈现负相关。 展开更多
关键词 温-力耦合环境效应 土工格栅 蠕变特性 损伤变量 分数阶本构模型
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采用d-q同步旋转坐标系的永磁同步电机无位置传感器控制 认领 引用 被引量：1
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作者 宋哲 周威宏 肖曦 《西安交通大学学报》 EI CAS CSCD 北大核心 2026年第5期174-184,共11页
在永磁同步电机(PMSM)无位置传感器控制系统中,针对传统基于α-β两相静止坐标系的滑模观测器(SMO)存在转速和转子位置估计误差较大的问题,提出了一种基于d-q同步旋转坐标系的PMSM无位置传感器控制方法。根据改进快速超螺旋算法设计了基... 在永磁同步电机(PMSM)无位置传感器控制系统中,针对传统基于α-β两相静止坐标系的滑模观测器(SMO)存在转速和转子位置估计误差较大的问题,提出了一种基于d-q同步旋转坐标系的PMSM无位置传感器控制方法。根据改进快速超螺旋算法设计了基于d-q坐标系的快速超螺旋滑模观测器(FST-SWO),实现对转速和转子位置的估计,减小了抖振和估计反电动势中的纹波。为了消除观测位置角的相位波动和漂移问题,构建了基于d-q坐标系的锁相环提取估计信息,避免了低通滤波器的使用和位置误差重构,提高了动态性能和观测精度。针对控制延时、安装误差和参数时变等非理想因素,在d-q坐标系下采用智能变步长爬山法对观测的误差角进行寻优补偿,进一步提高了观测精度。实验结果表明,该方法能够实现转速和转子位置的精确观测,与传统基于α-β坐标系的SMO相比,在稳态运行时,速度波动和谐波含量分别降低了33.33%和26.07%,位置观测精度提高了40%,在动态运行时,速度突增突减的调节时间分别缩短了78.18%和72.73%,展现出较好的动静态性能。 展开更多
关键词 永磁同步电机 快速超螺旋 滑模观测器 变步长爬山法 d-q坐标系
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含脉冲负载的船舶非线性周期时变系统暂态功角轨迹及稳定边界计算方法 认领 引用
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作者 林鸿彬 黄文焘 +1 位作者 余墨多 王良秀 《中国电机工程学报》 EI CSCD 北大核心 2026年第11期4553-4565,I0014,共13页
雷达等大功率脉冲负载(pulsed power load,PPL)接入船舶综合电力系统,导致低惯量系统出现周期性冲击振荡,其非线性周期时变特征加剧了系统响应的不确定性,进而导致系统暂态越限甚至失稳。为分析系统非线性周期时变特征及动态行为,明晰... 雷达等大功率脉冲负载(pulsed power load,PPL)接入船舶综合电力系统,导致低惯量系统出现周期性冲击振荡,其非线性周期时变特征加剧了系统响应的不确定性,进而导致系统暂态越限甚至失稳。为分析系统非线性周期时变特征及动态行为,明晰周期扰动的暂态稳定机理,提出暂态功角轨迹与稳定边界计算方法。该方法构建含PPL船舶综合电力系统的变步长变阶数Dormand-Prince解析模型,解决非线性周期时变状态量建模问题,并刻画暂态功角相空间轨迹;构造Lyapunov周期指数作为系统周期时变状态量收敛性的判据,提取状态轨迹特征并辨识系统参数的收敛稳定、亚稳定及发散失稳区域边界。以该判据为基础,提出参数灵敏度计算方法,量化分析系统暂态现象多时间尺度参量特征。利用RT-LAB平台建立含脉冲负载的典型船舶综合电力系统模型,仿真结果表明所提方法能够精确判断船舶综合电力系统稳定状态,且暂态稳定边界的误差约为4%。 展开更多
关键词 脉冲功率负载 变步长变阶数模型 暂态稳定边界 Lyapunov周期指数 综合电力系统
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