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Stabilization With Prescribed Instant via Lyapunov Method

IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 557-559页

作者： Jiyuan Kuang Yabin Gao Yizhuo Sun Aohua Liu Jianxing Liu Department of Control Science and Engineering Harbin Institute of TechnologyHarbin 150001China

Dear Editor,This letter presents a prescribed-instant stabilization approach to high-order integrator systems by the Lyapunov method. Under the presented controller, the settling time of controlled systems is independ... 详细信息

关键词： method. prescribed instant

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Fast fixed-time three-dimensional terminal guidance with non-concave trajectory constraint

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Chinese Journal of Aeronautics 2024年第3期37卷 208-218页

作者： Youmin GONG Yanning GUO Yueyong LYU Dongyu LI Guangfu MA Department of Control Science and Engineering Harbin Institute of TechnologyHarbin 150001China School of Cyber Science and Technology Beihang UniversityBeijing 100191China

Focusing on the non-concave trajectory constraint,a sliding-mode-based nonsingular feedback fast fixed-time three-dimensional terminal guidance of rotor unmanned aerial vehicle landing,planetary landing and spacecraft rendezvous and docking terminal phase with external disturbance is investigated in this ***,a fixed-time observer based on real-time differentiator is developed to compensate for the external disturbance,whose estimation error can converge to zero after a time independent of the initial ***,a sliding surface ensuring fixed-time convergence is *** sliding surface can guarantee that the vehicle achieves a non-concave trajectory,which is better for avoiding collision and maintaining the visibility of the landing site or docking ***,the nonsingular guidance ensuring the fixed-time convergence of the sliding surface is proposed,which is continuous and chatter *** last,three numerical simulations of Mars landing are performed to validate the effectiveness and correctness of the designed scheme.

关键词： Three-dimensional Terminal guidance Non-concave trajectory constraint Fast fixed-time control Sliding mode control

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Model-Free Current Predictive control for PMSMs With Ultra-Local Model Employing Fixed-Time Observer and Extremum-Seeking Method

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IEEE Transactions on Power Electronics 2025年第8期40卷 10682-10693页

作者： Lin, Xinpo Liu, Jianxing Liu, Zhuang Gao, Yabin Peretti, Luca Wu, Ligang Harbin Institute of Technology Department of Control Science and Engineering Weihai264209 China Harbin Institute of Technology Department of Control Science and Engineering Harbin150001 China KTH Royal Institute of Technology Division of Electric Power and Energy Systems Stockholm10044 Sweden

Conventional model predictive current control of permanent magnet synchronous machines (PMSMs) relies heavily on a precise mathematical model, which may be challenging to obtain in certain cases. To address this issue, this paper proposes a model-free predictive current controller for PMSMs. Specifically, the dynamic model of the motor currents is represented using two ultra-local models, which express the derivatives of a controlled output as the sum of an amplified control input and an unknown offset term. All system parameters, nonlinear terms, and unmodeled dynamics are encapsulated into two offset terms. Online estimation of these two offset terms is performed using a second-order fixed-time convergence observer without requiring exact knowledge of the system parameters in advance. In contrast to both the linear extended state observer and the super-twisting observer, the fixed-time observer enhances convergence speed while concurrently sustaining minimal chatting. To get rid of the need for model rated parameters, an extremum-seeking approach is utilized to tune the control gains in the ultra-local model, where the amplitude of the disturbance item in extremum-seeking approach is adaptively attenuated, resulting in effective reduction of the fluctuations of both the control gains and PMSM's currents in steady state. Subsequently, a predictive controller is designed using this ultra-local model. Finally, the effectiveness and advantages of the proposed control scheme are confirmed through experimental results. © 1986-2012 IEEE.

关键词： Permanent magnets

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Influencing factor analysis of interception probability and classification-regression neural network based estimation

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Journal of Systems engineering and Electronics 2023年第4期34卷 992-1006页

作者： NAN Yi YI Guoxing HU Lei WANG Changhong TU Zhenbiao Department of Control Science and Engineering Harbin Institute of TechnologyHarbin 150001China Beijing Electro-mechanical Engineering Institute Beijing 100074China

The interception probability of a single missile is the basis for combat plan design and weapon performance evaluation,while its influencing factors are complex and mutually *** calculation methods have very limited analysis of the influence mechanism of influencing factors,and none of them has analyzed the influence of the guidance *** paper considers the influencing factors of both the interceptor and the target more *** parameters include speed,guidance law,guidance error,fuze error,and fragment killing ability,while target performance includes speed,maneuverability,and *** this paper,an interception model is established,Monte Carlo simulation is carried out,and the influence mechanism of each factor is analyzed based on the model and simulation ***,this paper proposes a classification-regression neural network to quickly estimate the interception probability based on the value of influencing *** proposed method reduces the interference of invalid interception data to valid data,so its prediction accuracy is significantly better than that of pure regression neural networks.

关键词： interception probability simulation modeling analysis of influencing factors probability estimation neural networks

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High performance of Mg_(3)Bi_(1.5)Sb_(0.5) based materials for power generation:Revealing the counter-intuitive effect of tuning Bi content on the thermoelectric properties

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Journal of Magnesium and Alloys 2024年第11期12卷 4538-4546页

作者： Nuo Qu Yuke Zhu Jianbo Zhu Kuai Yu Fengkai Guo Zihang Liu Qian Zhang Wei Cai Jiehe Sui State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin150001China Department of Materials Science and Engineering Harbin Institute of TechnologyShenzhen 518055China

Recently,Mg_(3)Sb_(2)-xBixalloys have attracted intensive attention,with the aim of maximizing the electrical transport performance via donor element doping,increasing the grain size,as well as electronic band structure ***,less attention has been paid to other significant factors,like how these intrinsic point defects and accompanied secondary phases influence thermoelectric *** this study,the microstructure and thermoelectric transport properties of Mg_(3.2)Sb_(0.5)Bi_(1.495-x)Te_(0.005)(x=0~0.2)compounds were systematically investigated,where tuning the Bi content shows the counter-intuitive impact on the thermoelectric *** was found that the Bipoor environment associated with Bi impurities facilitated the increment of cation vacancy formation energy and then increased the carrier concentration,leading to the enhancement of power ***,the reduction of Bi-rich second phase content weakened the carrier scattering by grain boundaries whereas high carrier mobility was ***,the bipolar thermal conductivity decreased obviously due to the increased majority carrier concentration to suppress the intrinsic *** synergistic optimization pushes the average ZT value(300-573 K)up to 0.95 in the Mg_(3.2)Sb_(0.5)Bi_(1.295)Te_(0.005)***,the calculated single-leg conversion efficiency is increased up to 9.7%with the hot-side temperature of 573 K,as the record-high value in this system.

关键词： Mg_(3)Sb_(2)-xBix alloys Nanoscale Bi-rich phase Bipolar thermal conductivity Thermoelectric performance

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Event-based sliding mode control under denial-of-service attacks

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science China(Information sciences) 2022年第6期65卷 125-141页

作者： Yingxin TIAN Xiang LI Bo DONG Yabin GAO Ligang WU Department of Control Science and Engineering Harbin Institute of Technology School of Software Harbin Institute of Technology

This paper deals with the problem of estimator-based sliding mode control against denial-of-service(DoS) attacks and discrete events via a time-delay approach. A networked system is considered an uncertain dynamical system with matched and mismatched perturbations and exogenous disturbance in the network environment. A network-resource-aware event-triggering mechanism is designed with aperiodically releasing system measurements. Furthermore, to describe the DoS attack duration and inter-event time, a time-delay modeling approach considers the DOS attack duration and inter-event time as a “time delay” of the measurements between the sensor and controller over the network is proposed. Consequently, an intervaltime-delay system with uncertainties is formulated. A state-observer-based sliding mode controller, by which the ideal sliding mode can be achieved, is proposed against the DoS attacks. The resulting sliding motion is proved to be robust and stable with an Lgain performance. Finally, the effectiveness and applicability of the present sliding mode control are validated in a simulated pendulum system.

关键词： sliding mode control time delay uncertain system state observer event trigger

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Stabilization controller of An Extended Chained Nonholonomic System With Disturbance:An FAS Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1262-1273页

作者： Zhongcai Zhang Guangren Duan School of Engineering Qufu Normal UniversityRizhao 276826China Center for Control Science and Technology Southern University of Science and TechnologyShenzhen 518055 Center for Control Theory and Guidance Technology Harbin Institute of TechnologyHarbin 150001China

This study examines the stabilization issue of extended chained nonholonomic systems(ECNSs)with external *** the existing approaches,we transform the considered system into a fully actuated system(FAS)model,simplifying the stabilizing controller *** implement a separate controller design and propose exponential stabilization controller and finite-time stabilization controller under finite-time disturbance observer(FTDO)for the two system *** addition,we discuss the specifics of global stabilization control *** approach demonstrates that two system states exponentially or asymptotically converge to zero under the provided switching stabilization control strategy,while all other system states converge to zero within a finite time.

关键词： design stabilization system

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Facial Expression Recognition via Closed-Loop Transcription 50

Facial Expression Recognition via Closed-Loop Transcription

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50th Annual Conference of the IEEE Industrial Electronics Society, IECON 2024

作者： Liu, Xuan Ma, Jiachen Wang, Qiang Department of Control Science and Engineering Harbin Institute of Technology Harbin China Department of Control Science and Engineering Harbin Institute of Technology Weihai China

ISBN: (纸本)9781665464543

Convolutional Neural Networks (CNNs) are the most widely used and successful approaches for accomplishing the Facial Expression Recognition (FER) task. However, these technologies appear to have reached a bottleneck since the networks are becoming increasingly complex and heavier, yet the performance improvements remain minimal. The "black box" nature of CNNs makes it challenging to identify and address this crux. This paper aims to address the issue by utilizing the principles of data compression and discriminative representation within a plausible theoretical framework. We are employing an innovative computational framework, drawing inspiration from feedback loop control systems, to develop an interpretable closed-loop transcription model to generate a Linear Discriminative Representation (LDR) for multi-class real-world datasets. This model, comprised of an encoder and decoder that facilitates data mapping between the data space and the feature space, employs the output of the transcription system as feedback or guidance, with the objective of improving the accuracy and efficiency of the transcription process. The optimal LDR is learned jointly for all data classes through a two-player minimax game between the encoder and decoder for the learned representation over a single rate reduction-based objective. The studies conducted on the FER2013 dataset show promising results for the proposed closed-loop formulation. The visual quality of the learned decoder and the classification performance of the encoder are comparable to those of large and complex networks. An accuracy of 70.97% was attained on the FER2013 dataset by applying Principal Component Analysis (PCA) to the learned representation. © 2024 IEEE.

关键词： Decoding

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Microstructure and magnetocaloric properties of melt-extracted SmGdDyCoAl high-entropy amorphous microwires

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Rare Metals 2024年第3期43卷 1234-1242页

作者： Shi-Jie Wei Hong-Xian Shen Lun-Yong Zhang Lin Luo Xin-Xing Tang Jian-Fei Sun Xiao-Qing Li School of Materials Science and Engineering Harbin Institute of TechnologyHarbin150001China Applied Materials Physics Department of Materials Science and EngineeringKTH-Royal Institute of Technology10044StockholmSweden

This paper presents a systematic investigation of the microstructure and magnetocaloric properties of melt-extracted Sm_(20)Gd_(20)Dy_(20)Co_(20)Al_(20)high-entropy *** fabricated wires exhibited an amorphous structure,and the temperature interval of the undercooled liquid AT was 45 *** microwires underwent a second-order magnetic transition from a ferromagnetic to a paramagnetic state near the Curie temperature(T_(C)=52 K),The maximum magnetic entropy change(-ΔS_M^(max)),the relative cooling power and the refrigeration capacity reached 6.34 J·kg^(-1)·K^(-1).422.09 J·kg^(-1)and 332.94 J·kg^(-1),respectively,under a magnetic field change of 5 *** addition,the temperature-averaged entropy changes with two temperature lifts(3 and 10 K)were 6.32 and 6.27 J·kg^(-1)·K^(-1),*** good magnetocalorie performance highlights the significant potential for the Sm_(20)Gd_(20)Dy_(20)Co_(20)Al_(20)microwires to be used as magnetic refrigerant materials in low-temperature region *** work will serve as a valuable reference for future investigations on low-temperature high-entropy magnetocaloric materials.

关键词： Melt-extraction High-entropy amorphous microwires Magnetocaloric effect Magnetic refrigeration

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Indoor Uncertain Semantic Trajectory Similarity Join

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Journal of Computer science & technology 2024年第6期39卷 1441-1465页

作者： Hong-Bo Yin Dong-Hua Yang Kai-Qi Zhang Hong Gao Jian-Zhong Li Faculty of Computing Harbin Institute of TechnologyHarbin 150001China Center of Analysis Measurement and ComputingHarbin Institute of TechnologyHarbin 150001China Faculty of Computer Science and Control Engineering Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China

With the widespread deployment of indoor positioning systems, an unprecedented scale of indoor trajectories is being produced. By considering the inherent uncertainties and the text information contained in such an indoor trajectory, a new definition named Indoor Uncertain Semantic Trajectory is defined in this paper. In this paper, we focus on a new primitive, yet quite essential query named Indoor Uncertain Semantic Trajectory Similarity Join (IUST-Join for short), which is to match all similar pairs of indoor uncertain semantic trajectories from two sets. IUST-Join targets a number of essential indoor applications. With these applications in mind, we provide a purposeful definition of an indoor uncertain semantic trajectory similarity metric named IUS. To process IUST-Join more efficiently, both an inverted index on indoor uncertain semantic trajectories named 3IST and the first acceleration strategy are proposed to form a filtering-and-verification framework, where most invalid pairs of indoor uncertain semantic trajectories are pruned at quite low computation cost. And based on this filtering-and-verification framework, we present a highly-efficient algorithm named Indoor Uncertain Semantic Trajectory Similarity Join Processing (USP for short). In addition, lots of novel and effective acceleration strategies are proposed and embedded in the USP algorithm. Thanks to these techniques, both the time complexity and the time overhead of the USP algorithm are further reduced. The results of extensive experiments demonstrate the superior performance of the proposed work.

关键词： filtering-and-verification framework indoor uncertain semantic trajectory inverted index trajectory similarity join

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