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基于多频线谱陷波的动力总成振动主动控制研究
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作者 王里达 丁荣军 +3 位作者 刘侃 杨军 雷羿含 张旗 《湖南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2024年第12期1-9,共9页
针对汽车动力总成系统振动频率存在阶次多、单个阶次振动频带窄等问题,提出了一种基于滤波-x最小均方算法改进的多频线谱陷波振动主动控制方法.首先,该方法基于转速信号来获取多个阶次振动频率的参考信号,再通过最小均方滤波器来计算获... 针对汽车动力总成系统振动频率存在阶次多、单个阶次振动频带窄等问题,提出了一种基于滤波-x最小均方算法改进的多频线谱陷波振动主动控制方法.首先,该方法基于转速信号来获取多个阶次振动频率的参考信号,再通过最小均方滤波器来计算获取这些阶次振动频率的抵消信号.其次,该方法根据不同频率阶次振动信号的正交性,进一步以线性叠加计算来获得主动悬置的控制信号,最终实现对多频线谱振动的主动控制.和传统滤波-x最小均方算法相比,本算法改进了参考信号和控制信号的获取方式,因此有着更少的计算量、更快的收敛速度等优势.仿真和试验结果显示,所提方法比传统滤波-x最小均方算法,在收敛次数方面减少了81.25%,稳态误差下降了15%.其中,在怠速工况下,和传统滤波-x最小均方算法比,最高降低了34.01 dB,在定置上升全油门工况下,总振级最高下降了17.5 dB. 展开更多
关键词 多频线谱 陷波 滤波-x最小均方算法 动力总成 振动主动控制
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一类多频线谱激励下的主动隔振控制方法 被引量:5
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作者 陈绍青 王永 +1 位作者 魏璀璨 姚太克 《振动与冲击》 EI CSCD 北大核心 2012年第23期128-131,190,共5页
研究了多频离散线谱激励下的主动隔振控制问题,提出一种多通道解耦的自适应前馈控制方法;采用窄带带通滤波器对多频振动信号进行解耦,通过多个并行的自收敛变步长归一化的LMS自适应滤波器构成前馈控制器,驱动一个单自由度的作动器对多... 研究了多频离散线谱激励下的主动隔振控制问题,提出一种多通道解耦的自适应前馈控制方法;采用窄带带通滤波器对多频振动信号进行解耦,通过多个并行的自收敛变步长归一化的LMS自适应滤波器构成前馈控制器,驱动一个单自由度的作动器对多频线谱振动进行隔离;该方法无需次级通道模型信息,具有结构简单、鲁棒性强的优点。在某型磁悬浮隔振器的隔振系统上进行了多频主动隔振实验,实验结果验证了该方法的有效性。 展开更多
关键词 振动控制 主动隔振 多频线谱 磁悬浮隔振器
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一类多频线谱振动的主动控制方法 被引量:2
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作者 张国庆 王永 陈光 《南京理工大学学报(社会科学版)》 2005年第S1期43-46,共4页
针对多频线谱振动提出一种新的主动控制方法———多通道解耦LMS自适应滤波方法。该方法以多个并行的LMS自适应滤波器结构和带通滤波器组成前馈控制器,带通滤波器对自适应滤波器进行解耦,以一个单自由度的减振器作为执行机构,对多个频... 针对多频线谱振动提出一种新的主动控制方法———多通道解耦LMS自适应滤波方法。该方法以多个并行的LMS自适应滤波器结构和带通滤波器组成前馈控制器,带通滤波器对自适应滤波器进行解耦,以一个单自由度的减振器作为执行机构,对多个频率线谱振动进行主动减振。综合了LMS算法的快速性和频域自适应滤波的有效性,物理意义清晰,易于扩展。应用于国产某型机械式制冷机的主动减振,用B&K的PULSE 7700对现场调试结果进行分析,验证了该方法的有效性。 展开更多
关键词 振动控制 主动控制 自适应滤波 多频线谱
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多频线谱激励下的混合自适应微振动主动控制 被引量:3
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作者 方昱斌 朱晓锦 +2 位作者 高志远 张合生 苗中华 《振动.测试与诊断》 EI CSCD 北大核心 2021年第1期96-104,202,共10页
针对多频线谱激励下的结构振动主动控制中的频率失配问题,以并联结构滤波⁃x最小均方(filtered⁃x least mean square,简称FxLMS)算法为基础,提出一种混合自适应振动主动控制方法。前馈通道通过多个带通滤波器将多频线谱激励振动的参考信... 针对多频线谱激励下的结构振动主动控制中的频率失配问题,以并联结构滤波⁃x最小均方(filtered⁃x least mean square,简称FxLMS)算法为基础,提出一种混合自适应振动主动控制方法。前馈通道通过多个带通滤波器将多频线谱激励振动的参考信号解耦成为多个单频线谱信号,多个独立自适应滤波器调节权值抑制单一频带上的振动,提升收敛速度;反馈通道提升了算法对于扰动信号频谱发生时变及宽频噪声扰动的鲁棒性。给出该混合自适应振动主动控制算法的稳定性及收敛性分析过程,得到算法稳定与收敛的正实条件。基于Adams与Simulink联合仿真,以及搭建结构微振动主动控制实验系统,验证了混合自适应振动主动控制算法的有效性。实验结果表明,混合自适应振动主动控制算法能够有效抑制多个目标频谱的结构微振动,并在扰动频率失配以及宽频噪声中表现出较好的鲁棒性。 展开更多
关键词 微振动控制 多频线谱激励 混合自适应控制 并联结构FxLMS
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多频波动线谱自适应控制算法及试验 被引量:2
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作者 高伟鹏 贺国 刘树勇 《哈尔滨工业大学学报》 EI CAS CSCD 北大核心 2021年第1期168-175,共8页
研究了多频波动线谱激励下的主动隔振控制问题,提出一种改进小波包自适应控制算法.传统的自适应算法难以同时控制多线谱,当线谱存在频率波动时,窄带滤波算法难以取得理想的控制效果.因此,将小波包分解算法应用在控制算法中,对信号进行... 研究了多频波动线谱激励下的主动隔振控制问题,提出一种改进小波包自适应控制算法.传统的自适应算法难以同时控制多线谱,当线谱存在频率波动时,窄带滤波算法难以取得理想的控制效果.因此,将小波包分解算法应用在控制算法中,对信号进行等间距频带划分,采取并行控制策略完成多线谱控制.分析了不同小波基函数对信号分解的影响,确定最优小波基.针对虚有线谱和子频带过多导致的控制过盈问题,改进小波包分解算法,降低了计算量,消除子频带中虚有线谱.为每个子频带设置独立步长,并根据箕舌线函数修正迭代步长.搭建控制系统开展试验研究,结果表明,本文所提改进小波包自适应算法在多频波动线谱激励下能够取得良好的控制效果,线谱振动能量显著降低. 展开更多
关键词 振动控制 多频波动线谱 dmey小波基 小波包分解改进算法 变步长
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多天线频谱共享CR-NOMA系统安全中断性能分析
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作者 吕铄 嵇建波 《电子测量技术》 北大核心 2023年第17期71-78,共8页
认知无线电(CR)非正交多址接入(NOMA)网络(记为CR-NOMA)已是无线通信领域的研究热点之一。由于无线信道的开放性,使得无线网络的安全通信成为当前急需解决的问题。该文研究了频谱共享多天线CR-NOMA网络安全中断性能,首先分析了最优天线... 认知无线电(CR)非正交多址接入(NOMA)网络(记为CR-NOMA)已是无线通信领域的研究热点之一。由于无线信道的开放性,使得无线网络的安全通信成为当前急需解决的问题。该文研究了频谱共享多天线CR-NOMA网络安全中断性能,首先分析了最优天线选择(OAS)方案的安全中断概率(SOP),并推导了其精确的闭合表达式。其次,分析了空时传输(STT)方案的SOP,并推导了其精确的闭合表达式。最后,对次用户两种方案的SOP渐近性能进行了分析,揭示了系统参数对SOP的影响。最后,采用Monte Carlo仿真验证了理论分析的正确性。研究发现,两种方案基站分别存在一个最优峰值发射功率,使得远距离次用户的安全中断性能最佳。仿真结果表明增大基站峰值发射功率,OAS方案的近距离次用户的SOP会始终优于STT方案,远距离次用户的SOP会劣于STT方案。 展开更多
关键词 认知无线电 非正交多址接入 安全中断性能 安全中断概率
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Coordinated Multi-User Spectrum Sharing in Distributed Antenna-Based Cognitive Radio Systems 被引量:6
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作者 ZHAO Juntao FENG Wei +1 位作者 ZHAO Ming WANG Jing 《China Communications》 SCIE CSCD 2016年第1期57-67,共11页
Spectrum sharing for efficient reuse of licensed spectrum is an important concept for cognitive radio technologies.In a spectrum-sharing system(SSS),deploying the antennas in a distributed manner can offer a new spati... Spectrum sharing for efficient reuse of licensed spectrum is an important concept for cognitive radio technologies.In a spectrum-sharing system(SSS),deploying the antennas in a distributed manner can offer a new spatial dimension for the efficient reuse of licensed frequency bands.To improve the whole performance of multiple secondary users(SUs),this paper addresses the problem of coordinated multi-SU spectrum sharing in a distributed antenna-based SSS.By adopting the Hungarian method,the primal decomposition method and pricing policy,we propose a coordinated multi-user transmission scheme,so as to maximize the sum-rate of SUs.Simulation results show that the proposed method can significantly enhance the system performance,and the computational complexity is low. 展开更多
关键词 cognitive radio distributed anten-na spectrum-sharing system antenna selec-tion power allocation
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A K-means clustering based blind multiband spectrum sensing algorithm for cognitive radio 被引量:2
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作者 LEI Ke-jun TAN Yang-hong +1 位作者 YANG Xi WANG Han-rui 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第10期2451-2461,共11页
In this paper,a blind multiband spectrum sensing(BMSS)method requiring no knowledge of noise power,primary signal and wireless channel is proposed based on the K-means clustering(KMC).In this approach,the KMC algorith... In this paper,a blind multiband spectrum sensing(BMSS)method requiring no knowledge of noise power,primary signal and wireless channel is proposed based on the K-means clustering(KMC).In this approach,the KMC algorithm is used to identify the occupied subband set(OSS)and the idle subband set(ISS),and then the location and number information of the occupied channels are obtained according to the elements in the OSS.Compared with the classical BMSS methods based on the information theoretic criteria(ITC),the new method shows more excellent performance especially in the low signal-to-noise ratio(SNR)and the small sampling number scenarios,and more robust detection performance in noise uncertainty or unequal noise variance applications.Meanwhile,the new method performs more stablely than the ITC-based methods when the occupied subband number increases or the primary signals suffer multi-path fading.Simulation result verifies the effectiveness of the proposed method. 展开更多
关键词 cognitive radio(CR) blind multiband spectrum sensing(BMSS) K-means clustering(KMC) occupied subband set(OSS) idle subband set(ISS) information theoretic criteria(ITC) noise uncertainty
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Demodulation spectrum analysis for multi-fault diagnosis of rolling bearing via chirplet path pursuit 被引量:1
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作者 LIU Dong-dong CHENG Wei-dong WEN Wei-gang 《Journal of Central South University》 SCIE EI CAS CSCD 2019年第9期2418-2431,共14页
The vibration signals of multi-fault rolling bearings under nonstationary conditions are characterized by intricate modulation features,making it difficult to identify the fault characteristic frequency.To remove the ... The vibration signals of multi-fault rolling bearings under nonstationary conditions are characterized by intricate modulation features,making it difficult to identify the fault characteristic frequency.To remove the time-varying behavior caused by speed fluctuation,the phase function of target component is necessary.However,the frequency components induced by different faults interfere with each other.More importantly,the complex sideband clusters around the characteristic frequency further hinder the spectrum interpretation.As such,we propose a demodulation spectrum analysis method for multi-fault bearing detection via chirplet path pursuit.First,the envelope signal is obtained by applying Hilbert transform to the raw signal.Second,the characteristic frequency is extracted via chirplet path pursuit,and the other underlying components are calculated by the characteristic coefficient.Then,the energy factors of all components are determined according to the time-varying behavior of instantaneous frequency.Next,the final demodulated signal is obtained by iteratively applying generalized demodulation with tunable E-factor and then the band pass filter is designed to separate the demodulated component.Finally,the fault pattern can be identified by matching the prominent peaks in the demodulation spectrum with the theoretical characteristic frequencies.The method is validated by simulated and experimental signals. 展开更多
关键词 rolling bearing demodulation spectrum multi-fault detection NONSTATIONARY chirplet path pursuit
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Throughput optimization for multi-channel cooperative CR under reporting channel errors
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作者 Wang Cong Jiang Wei +2 位作者 Song Tiecheng Bao Xu Hu Jing 《Journal of Southeast University(English Edition)》 EI CAS 2020年第3期245-251,共7页
To overcome the problem of channel fading and noise uncertainty,cooperative spectrum sensing(CSS)is developed to enhance the sensing performance in cognitive radio networks(CRNs).Considering that the non-ideal reporti... To overcome the problem of channel fading and noise uncertainty,cooperative spectrum sensing(CSS)is developed to enhance the sensing performance in cognitive radio networks(CRNs).Considering that the non-ideal reporting channels of CSS can cause an adverse impact on the detection performance,the throughput maximization problem for multi-channel CSS cognitive radio under reporting channel errors is investigated.While providing all the primary users with sufficient protection,the average throughput of secondary users(SUs)is maximized by jointly optimizing the sensing duration,detection threshold and SU assignment.To address the non-convex optimization problem,the optimal energy detection threshold is derived first.Then,a sub-optimal greedy algorithm is proposed to obtain the optimal sensing duration and the optimal SU assignment.Analysis and simulation results show that the proposed algorithm can output the same performance as the exhaustive search algorithm at a much lower level of complexity.It is also shown that the impact of imperfect reporting channels should be considered especially in low signal-to-noise ratio environments and the reporting channel errors significantly reduce the performance of CSS. 展开更多
关键词 cognitive radio MULTI-CHANNEL cooperative spectrum sensing reporting channel errors
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Nonlinear distortion analysis for multisine excitation constrained by power spectral density
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作者 ZHOU Kun-li QU Ji-feng ZHOU Zhen-yu 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2016年第4期350-357,共8页
Nonlinear distortion introduced by an amplifier when subjected to a multisine excitation decreases the measurement accuracy in many metrological and measurement areas. In this paper, we performed qualitative and quant... Nonlinear distortion introduced by an amplifier when subjected to a multisine excitation decreases the measurement accuracy in many metrological and measurement areas. In this paper, we performed qualitative and quantitative analyses of the nonlinear distortion with the multisine excitations constrained by a constant power spectral density. We present the numerical results with respect to different tone spacings,nonlinear orders, harmonic phases and tone distributions. Moreover, three as-pects of contributions are made to further reveal the distortion mechanism. First, we find that the type Ⅱ components for Schr- oeder-phase multisines distribute uniformly but not all in anti-phase to the type I components for the second order nonlinearity. Second,we simulate the variance of the type I and Ⅱ components and their summation to explain the principle of reducing the type Ⅱ distortion by averaging the results obtained using multiple realizations of random-phase multisines. Third, we observe a special distortion distribution mechanism for the Schroeder-phase multisine excitation The results contribute to a better estima-tion and understanding of the nonlinear distortion. 展开更多
关键词 multisine excitation nonlinear distortion power spectral density type I and contributions
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Optimization of Multiband Spectrum Sensing for Cognitive Radio Networks under Sensing Capability Constrains
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作者 Zhao Chenglin Yao Haipeng Zhou Zheng 《China Communications》 SCIE CSCD 2010年第5期129-136,共8页
This paper addresses the problem of joint optimization of subchannel selection and spectrum sensing time for multiband cognitive radio networks under the sensing capability constrains. In particular, we construct a mu... This paper addresses the problem of joint optimization of subchannel selection and spectrum sensing time for multiband cognitive radio networks under the sensing capability constrains. In particular, we construct a multiband spectrum sensing framework, and derive the probabilities of detection and false alarm taking the different subchannel gain into account. Furthermore, we formulate the multi- band sensing as a two-parameter optimization prob- lem under the sensing capability constrains and guaranteeing the QoS of the secondary user. Moreover, we develop a semi-analytical optimization scheme to achieve the optimal solution. 展开更多
关键词 multlbiand sensing cognitive radio detection probability false alarm probability
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Application of wavelet transform in-ray spectra analysis
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作者 YU GuoLiang GU JianZhong +3 位作者 HOU Long LI ZhenYu WANG YanZhao ZHANG YiYun 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2013年第9期1735-1739,共5页
The frequency distribution of different ingredients in-ray spectra,e.g.,photo-peak,fluctuations of counts and Compton region,is separately analyzed.After wavelet transform of-ray spectra,the wavelet coefficients of a ... The frequency distribution of different ingredients in-ray spectra,e.g.,photo-peak,fluctuations of counts and Compton region,is separately analyzed.After wavelet transform of-ray spectra,the wavelet coefficients of a photo-peak increase with transforming scales and these coefficients show direct proportion with intensity of peak at determinate scale.A novel algorithm based on wavelet transform is proposed and studied.The results indicate that most of the photo-peaks in multi-spectra can be determined accurately,the-rays energy and intensity of the peak can also be determined.This method has the prospect of being applied in on-line multi-spectra analysis in such fields as radioprotection and nuclear safety monitoring. 展开更多
关键词 wavelet transform -ray spectra photo-peak
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