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针对异步电动机矢量控制系统常规等效滑模控制存在扰动稳态误差大、抖振大、跟踪快速性差的问题,设计了一种改进的等效滑模控制器。该控制器采用改进的切换控制函数,提高了电动机的动态控制性能。仿真试验结果表明,与传统的PI控制器和常规的等效滑模控制器相比,该控制器能有效降低系统抖振,提高了系统的动态响应速度,增强了系统的鲁棒性。 相似文献
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针对船舶直线航迹控制的非线性特性,设计一种基于输入输出线性化的自适应模糊滑模控制器,并利用Lyapunov理论,证明该系统在所设计控制器作用下全局渐近稳定,Simulink仿真结果表明,所设计控制器能够有效抑制常规滑模所固有的稳态抖振现象,且在参数摄动及风浪干扰下具有强鲁棒性,较好的实现了对设定航迹的跟踪。 相似文献
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为提高可控励磁直线磁悬浮同步电动机进给系统的快速性与鲁棒性,提出全局积分Terminal滑模控制策略.构造新型的全局积分Terminal滑模面,对系统状态任意初值可在有限时间内收敛到零点,在趋近律中引入衰减因子,可减小系统抖振;在构造滑模面和趋近律的基础上设计全局积分Terminal滑模速度控制器;为进一步削弱滑模控制的抖振,减小切换增益,用径向基函数神经网络设计扰动观测器,并对扰动进行前馈补偿控制.仿真结果表明全局积分Terminal滑模控制策略能够明显改善系统的动态性能,缩短误差的收敛时间,提高系统抑制扰动的能力,削弱系统的抖振,增强系统的鲁棒性. 相似文献
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为了克服传统永磁同步电机(Permanent magnet synchronous motor,PMSM)的滑模控制增益大容易产生抖振的问题,提出基于模糊观测器的PMSM积分滑模控制策略。采用新型趋近律设计积分滑模控制器取代传统的滑模控制器,提高系统的动态响应性能。结合模糊控制与自适应控制的特点,设计模糊扰动观测器,能够迅速有效地观测系统内部参数变化和外部扰动,并对积分滑模速度控制器进行前馈补偿,削弱系统抖振的同时提高了系统的鲁棒性。通过李雅普诺夫理论证明了该控制系统的稳定性。仿真及实验结果验证了该方法具有较强的鲁棒性,可以实现良好的跟踪效果并且无抖动。 相似文献
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针对传统ST滑模控制算法在DC–DC变换系统到达段存在快速性和抑制抖振之间的矛盾问题,提出一种三相交错双向DC–DC变换器的模糊高阶滑模(FZST)控制算法.该算法依据李雅普诺夫函数求解出系统稳定需要满足的收敛条件,然后基于当前误差进行模糊逻辑推算,进一步在线调整收敛条件下的滑模面系数,保证对误差项加速抑制的同时完成对静态误差的积分,保留了ST滑模控制的动态性,并抑制系统的抖振.最后对双向DC–DC半桥回路中的电压环和电流内环,进行双FZST滑模控制的仿真与实验验证,结果表明:系统在电压跟随,输入端电压与输出端负载大扰动情况下, FZST滑模控制算法具有较强的鲁棒性,能够改善系统的动态品质,并有效地解决抖振问题. 相似文献
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《控制理论与应用》2021,(6)
针对脉宽调制型Buck变换器的内外干扰和滑模控制的抖振等问题,本文提出了一种基于降阶扩张状态观测器和无抖振滑模的新型控制策略.首先,建立新型的跟踪误差状态空间模型,将匹配和不匹配干扰定义为统一的匹配干扰;然后,设计降阶扩张状态观测器提高跟踪误差微分和系统干扰的估计速度,并抵消负载和输入端的电压变化、系统参数不确定性对控制系统的影响;其次,利用跟踪误差微分的估计值设计滑模控制器抑制干扰估计误差,使得切换项近似为零,实现滑模技术的无抖振控制,提高Buck变换器系统电压跟踪的快速性和准确性.利用李雅普诺夫稳定判据从理论上证明了所提控制器的闭环稳定性.最后,仿真结果表明所提方法通过抑制抖振和内外干扰有效改善Buck变换器的鲁棒性和动态性能. 相似文献
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European Community policy and the market 总被引:1,自引:0,他引:1
C. Lloyd 《Journal of Computer Assisted Learning》1993,9(2):86-91
Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven. 相似文献
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融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。 相似文献
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David Poole 《Computational Intelligence》1989,5(2):97-110
Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given. 相似文献
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Watts S. Humphrey 《Annals of Software Engineering》2002,14(1-4):39-72
This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)SM and Team Software Process (TSP){SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical. 相似文献
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基于复小波噪声方差显著修正的SAR图像去噪 总被引:4,自引:1,他引:3
提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。 相似文献
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R. NOSS 《Journal of Computer Assisted Learning》1987,3(1):2-12
Abstract This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development. 相似文献
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C. Xiang 《控制理论与应用(英文版)》2014,12(3):217-217
正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where 相似文献
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《浙江大学学报:C卷英文版》2014,(7)
正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere. 相似文献
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潘丽 《自动化与仪器仪表》2014,(7):80-82
自然界的绝大部分信号都是以模拟的形式存在,因此模拟信号的采集转换存储在数字时代十分关键。文章讨论了在雷达信号处理领域基于AD9626的AD采集存储卡的设计原理、硬件结构和程序设计与芯片配置等问题,为今后相关领域的研究提供了可参考的方案。 相似文献