期刊文献+
共找到21,690篇文章
< 1 2 250 >
每页显示 20 50 100
Distributed predefined-time estimator-based affine formation target-enclosing maneuver control for cooperative underactuated quadrotor UAVs with fault-tolerant capabilities 被引量:1
1
作者 Yang XU Yuanfang QU +2 位作者 Delin LUO Haibin DUAN Zhengyu GUO 《Chinese Journal of Aeronautics》 2025年第1期471-490,共20页
The paper presents a two-layer,disturbance-resistant,and fault-tolerant affine formation maneuver control scheme that accomplishes the surrounding of a dynamic target with multiple underactuated Quadrotor Unmanned Aer... The paper presents a two-layer,disturbance-resistant,and fault-tolerant affine formation maneuver control scheme that accomplishes the surrounding of a dynamic target with multiple underactuated Quadrotor Unmanned Aerial Vehicles(QUAVs).This scheme mainly consists of predefinedtime estimators and fixed-time tracking controllers,with a hybrid Laplacian matrix describing the communication among these QUAVs.At the first layer,we devise predefined time estimators for leading and following QUAVs,enabling accurate estimation of desired information.In the second layer,we initially devise a fixed-time hybrid observer to estimate unknown disturbances and actuator faults.Fixedtime translational tracking controllers are then proposed,and the intermediary control input from these controllers is used to extract the desired attitude and angular velocities for the fixed-time rotational tracking controllers.We employ an exact tracking differentiator to handle variables that are challenging to differentiate directly.The paper includes a demonstration of the control system stability through mathematical proof,as well as the presentation of simulation results and comparative simulations. 展开更多
关键词 Affine formation maneuver control Target tracking Fixed-time control Quadrotor unmanned aerial vehicle Target enclosing predefined-time estimation
原文传递
Quaternion-Based Modeling and Predefined-Time Tracking Control of a Fully Actuated Autonomous Underwater Vehicle
2
作者 Yiming Li Xiao Wang +2 位作者 Jinglong Shi Jian Liu Changyin Sun 《IEEE/CAA Journal of Automatica Sinica》 2025年第11期2275-2285,共11页
This paper investigates the modeling and the practical predefined-time(PdT)tracking control problems for a fully actuated disk-shaped autonomous underwater vehicle(AUV)with six degrees of freedom.To overcome the gimba... This paper investigates the modeling and the practical predefined-time(PdT)tracking control problems for a fully actuated disk-shaped autonomous underwater vehicle(AUV)with six degrees of freedom.To overcome the gimbal lock problem inherent in Euler angle representation,unit quaternions are adopted to model the AUV,accounting for internal uncertainties and external disturbances.Then,an improved time-varying function is introduced,which serves as the basis for designing a nonsingular sliding surface and sliding mode controller with PdT stability.This approach ensures that the tracking errors converge within a predefined time,independent of initial conditions and design parameters.Compared with traditional PdT controllers,the proposed method eliminates singularities,enhances the precision of convergence time estimation,and typically yields smaller,smoother initial control inputs,thus improving its potential for engineering applications.Numerical simulations validate the effectiveness and performance of the proposed controller. 展开更多
关键词 Autonomous underwater vehicle(AUV) nonlinear control predefined-time control tracking control unit quaternion
在线阅读 下载PDF
Predefined-time controller design for a multiple space transportation robots system based on Lp-Norm-Normalized Sign Function
3
作者 Ran TAO Yibo DING +1 位作者 Hanyu LI Xiaokui YUE 《Chinese Journal of Aeronautics》 2025年第2期432-444,共13页
This paper presents a predefined-time controller for Multiple Space transportation Robots System (MSRS), which can be applied in on-orbit assembly tasks to transport modules to pre-assembly configuration quickly. Firs... This paper presents a predefined-time controller for Multiple Space transportation Robots System (MSRS), which can be applied in on-orbit assembly tasks to transport modules to pre-assembly configuration quickly. Firstly, to simplify the analysis and design of predefined-time controller, a Predefined-time Stability Criterion is proposed in the form of Composite Lyapunov Function (CLF-PSC). Besides simplicity, the CLF-PSC also has the advantage of less conservativeness due to utilization of initial state information. Secondly, a concept of Lp-Norm-Normalized Sign Function (LPNNSF) is proposed based on the CLF-PSC. Different from traditional norm-normalized sign function, the Lp-norm of LPNNSF can be selected arbitrarily according to practical control task requirements, which means that the proposed LPNNSF is more generalized and more convenient for calculation. Thirdly, a predefined-time disturbance observer and predefined-time controller are designed based on the LPNNSF. The observer has the property of predefined-time convergence to achieve quicker and more accurate estimation of the lumped disturbance. The controller has less control input and chattering phenomenon than traditional predefined-time controller. In addition, by introducing the observer into the controller, the closed-loop system enjoys high precision and strong robustness. Finally, the effectiveness of the proposed controller is verified by numerical simulations. By employing the controller, the MSRS can carry assembly modules to the desired pre-assembly configuration accurately within predefined time. 展开更多
关键词 Multiple space transportation robots system On-orbit assemblypredefined-time stability criterion Composite Lyapunov function Lp-Norm-Normalized Sign Function predefined-time controller
原文传递
Neural network based adaptive nonsingular practical predefined-time fault-tolerant control for hypersonic morphing aircraft 被引量:4
4
作者 Shihao XU Changzhu WEI +1 位作者 Litao ZHANG Rongjun MU 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2024年第4期421-435,共15页
This paper develops a novel Neural Network(NN)-based adaptive nonsingular practical predefined-time controller for the hypersonic morphing aircraft subject to actuator faults. Firstly, a novel Lyapunov criterion of pr... This paper develops a novel Neural Network(NN)-based adaptive nonsingular practical predefined-time controller for the hypersonic morphing aircraft subject to actuator faults. Firstly, a novel Lyapunov criterion of practical predefined-time stability is established. Following the proposed criterion, a tangent function based nonsingular predefined-time sliding manifold and the control strategy are developed. Secondly, the radial basis function NN with a low-complexity adaptation mechanism is incorporated into the controller to tackle the actuator faults and uncertainties. Thirdly, rigorous theoretical proof reveals that the attitude tracking errors can converge to a small region around the origin within a predefined time, while all signals in the closed-loop system remain bounded. Finally, numerical simulation results are presented to verify the effectiveness and improved performance of the proposed control scheme. 展开更多
关键词 Hypersonic morphing aircraft(HMA) Neural network(NN) Adaptive control Practical predefined-time control Fault-tolerant control
原文传递
Adaptive Predefined-Time Backstepping Control for Grid Connected Photovoltaic Inverter
5
作者 Jiarui Zhang Dan Liu +4 位作者 Kan Cao Ping Xiong Xiaotong Ji Yanze Xu Yunfei Mu 《Energy Engineering》 EI 2024年第8期2065-2083,共19页
The system performance of grid-connected photovoltaic(PV)has a serious impact on the grid stability.To improve the control performance and shorten the convergence time,a predefined-time controller based on backsteppin... The system performance of grid-connected photovoltaic(PV)has a serious impact on the grid stability.To improve the control performance and shorten the convergence time,a predefined-time controller based on backstepping technology and dynamic surface control is formulated for the inverter in the grid-connected photovoltaic.The time-varying tuning functions are introduced into state-tracking errors to realize the predefined-time control effect.To address the“computational explosion problem”in the design process of backstepping control,dynamic surface control is adopted to avoid the analytical calculations of virtual control.The disturbances of the PV system are estimated and compensated by adaptive laws.The control parameters are chosen and the global stability of the closed-loop is ensured by Lyapunov conditions.Simulation results confirm the effectiveness of the proposed controller and ensure the predefined time control in the photovoltaic inverter. 展开更多
关键词 Photovoltaic inverter system backstepping technology predefined-time control adaptive control
在线阅读 下载PDF
Adaptive Predefined-Time Attitude Tracking Control for Quadrotor Using a Novel Terminal Sliding Mode Approach
6
作者 Tianshuo Ge Tengshuo Dong +1 位作者 Baihai Zhang Fenxi Yao 《Journal of Beijing Institute of Technology》 EI CAS 2024年第6期530-546,共17页
This paper proposes an adaptive predefined-time terminal sliding mode control(APTSMC)scheme for attitude tracking control of a quadrotor.To create this,an adaptive predefined-time stability controller based on a termi... This paper proposes an adaptive predefined-time terminal sliding mode control(APTSMC)scheme for attitude tracking control of a quadrotor.To create this,an adaptive predefined-time stability controller based on a terminal sliding mode is constructed.The upper bound of convergence time in the proposed scheme can be adjusted by the explicit parameters during the design process of the controller.In addition,it is proved that the attitude tracking error will converge within two periods of the preset time.These two periods are set between two ranges:From the initial values to the sliding mode surface and from the sliding mode surface to the region near the origin.Furthermore,an adaptive law is adopted to eliminate unknown external disturbances and the effects of the uncertainties in the quadrotor model,so it is unnecessary to require the prior knowledge of the upper bound of the perturbations.Simulation results are produced and comparative case studies are carried out to demonstrate that the proposed scheme has faster convergence speed and smaller tracking errors. 展开更多
关键词 predefined-time QUADROTOR attitude tracking control adaptive terminal sliding mode
在线阅读 下载PDF
Distributed Adaptive Predefined-Time Bipartite Containment Algorithm for Nonlinear Multi-Agent Systems with Actuator Faults
7
作者 Honghao Wu 《Journal of Electronic Research and Application》 2024年第6期15-25,共11页
Distributed adaptive predefined-time bipartite containment for a class of second-order nonlinear multi-agent systems are studied with actuator faults.The communication topology of multi-agent systems is fixed and dire... Distributed adaptive predefined-time bipartite containment for a class of second-order nonlinear multi-agent systems are studied with actuator faults.The communication topology of multi-agent systems is fixed and directed.To ensure that followers can reach the convex hull spanned by leaders under the conditions of actuator faults,the sliding mode method is introduced.Control protocol for multi-agent systems demonstrates its effectiveness.Finally,simulations are provided to verify the effectiveness of the proposed algorithm. 展开更多
关键词 Actuator faults Adaptive bipartite containment control Nonlinear multi-agent systems predefined-time
在线阅读 下载PDF
Herglotz type Noether theorems of nonholonomic systems with generalized fractional derivatives 被引量:1
8
作者 Yuan-Yuan Deng Yi Zhang 《Theoretical & Applied Mechanics Letters》 2025年第2期179-187,共9页
Fractional calculus is widely used to deal with nonconservative dynamics because of its memorability and non-local properties.In this paper,the Herglotz principle with generalized operators is discussed,and the Herglo... Fractional calculus is widely used to deal with nonconservative dynamics because of its memorability and non-local properties.In this paper,the Herglotz principle with generalized operators is discussed,and the Herglotz type equations for nonholonomic systems are established.Then,the Noether symmetries are studied,and the conserved quantities are obtained.The results are extended to nonholonomic canonical systems,and the Herglotz type canonical equations and the Noether theorems are obtained.Two examples are provided to demonstrate the validity of the methods and results. 展开更多
关键词 Nonholonomic system Herglotz principle Noether theorem Generalized operators
在线阅读 下载PDF
The Paley-Wiener Theorem for General Weighted Hardy Spaces on Tube Domains
9
作者 HUANG Yun ZHANG Dawei 《应用数学》 北大核心 2025年第3期841-849,共9页
In this paper,the Paley-Wiener theorem is extended to the analytic function spaces with general weights.We first generalize the theorem to weighted Hardy spaces Hp(0<p<∞)on tube domains by constructing a sequen... In this paper,the Paley-Wiener theorem is extended to the analytic function spaces with general weights.We first generalize the theorem to weighted Hardy spaces Hp(0<p<∞)on tube domains by constructing a sequence of L^(1)functions converging to the given function and verifying their representation in the form of Fourier transform to establish the desired result of the given function.Applying this main result,we further generalize the Paley-Wiener theorem for band-limited functions to the analytic function spaces L^(p)(0<p<∞)with general weights. 展开更多
关键词 Paley-Wiener theorem Fourier transform Weighted Hardy space Tube domain
在线阅读 下载PDF
A Metamodeling Approach to Enforcing the No-Cloning Theorem in Quantum Software Engineering
10
作者 Dae-Kyoo Kim 《Computers, Materials & Continua》 2025年第8期2549-2572,共24页
Quantum software development utilizes quantum phenomena such as superposition and entanglement to address problems that are challenging for classical systems.However,it must also adhere to critical quantum constraints... Quantum software development utilizes quantum phenomena such as superposition and entanglement to address problems that are challenging for classical systems.However,it must also adhere to critical quantum constraints,notably the no-cloning theorem,which prohibits the exact duplication of unknown quantum states and has profound implications for cryptography,secure communication,and error correction.While existing quantum circuit representations implicitly honor such constraints,they lack formal mechanisms for early-stage verification in software design.Addressing this constraint at the design phase is essential to ensure the correctness and reliability of quantum software.This paper presents a formal metamodeling framework using UML-style notation and and Object Constraint Language(OCL)to systematically capture and enforce the no-cloning theorem within quantum software models.The proposed metamodel formalizes key quantum concepts—such as entanglement and teleportation—and encodes enforceable invariants that reflect core quantum mechanical laws.The framework’s effectiveness is validated by analyzing two critical edge cases—conditional copying with CNOT gates and quantum teleportation—through instance model evaluations.These cases demonstrate that the metamodel can capture nuanced scenarios that are often mistaken as violations of the no-cloning theorem but are proven compliant under formal analysis.Thus,these serve as constructive validations that demonstrate the metamodel’s expressiveness and correctness in representing operations that may appear to challenge the no-cloning theorem but,upon rigorous analysis,are shown to comply with it.The approach supports early detection of conceptual design errors,promoting correctness prior to implementation.The framework’s extensibility is also demonstrated by modeling projective measurement,further reinforcing its applicability to broader quantum software engineering tasks.By integrating the rigor of metamodeling with fundamental quantum mechanical principles,this work provides a structured,model-driven approach that enables traditional software engineers to address quantum computing challenges.It offers practical insights into embedding quantum correctness at the modeling level and advances the development of reliable,error-resilient quantum software systems. 展开更多
关键词 METAMODELING no-cloning theorem quantum software software engineering
在线阅读 下载PDF
Scaling Rule,Energy Distribution and Energy Level Analysis for Morse Oscillator by Virtue of Hermann-Feynman Theorem
11
作者 Zhi-Long Wan Jun-Hua Chen Hong-Yi Fan 《Chinese Journal of Chemical Physics》 2025年第3期368-372,I0109,共6页
We propose the scaling rule of Morse oscillator,based on this rule and by virtue of the Her-mann-Feymann theorem,we respectively obtain the distribution of potential and kinetic ener-gy of the Morse Hamiltonian.Also,w... We propose the scaling rule of Morse oscillator,based on this rule and by virtue of the Her-mann-Feymann theorem,we respectively obtain the distribution of potential and kinetic ener-gy of the Morse Hamiltonian.Also,we derive the exact upper limit of physical energy level.Further,we derive some recursive relations for energy matrix elements of the potential and other similar operators in the context of Morse oscillator theory. 展开更多
关键词 Morse oscillator Scaling rule Hermann-Feynman theorem
在线阅读 下载PDF
ECHOS OF THE STEINER-LEHMUS EQUAL BISECTORS THEOREM
12
作者 Christoph BÖRGERS Eric L.GRINBERG +1 位作者 Mehmet ORHON Junhao SHEN 《Acta Mathematica Scientia》 2025年第1期257-263,共7页
The Steiner-Lehmus equal bisectors theorem originated in the mid 19th century.Despite its age,it would have been accessible to Euclid and his contemporaries.The theorem remains evergreen,with new proofs continuing to ... The Steiner-Lehmus equal bisectors theorem originated in the mid 19th century.Despite its age,it would have been accessible to Euclid and his contemporaries.The theorem remains evergreen,with new proofs continuing to appear steadily.The theorem has fostered discussion about the nature of proof itself,direct and indirect.Here we continue the momentum by providing a trigonometric proof,relatively short,based on an analytic estimate that leverages algebraic trigonometric identities.Many proofs of the theorem exist in the literature.Some of these contain key ideas that already appeared in C.L.Lehmus’1850 proofs,not always with citation.In the aim of increasing awareness of and making more accessible Lehmus’proofs,we provide an annotated translation.We conclude with remarks on different proofs and relations among them. 展开更多
关键词 Steiner-Lehmus theorem equal bisectors
在线阅读 下载PDF
LIOUVILLE THEOREM FOR 3D STATIONARY Q-TENSOR SYSTEM OF LIQUID CRYSTAL
13
作者 HU Li-li ZHOU Yan-ping BIE Qun-yi 《数学杂志》 2025年第4期283-292,共10页
In this paper,we study Liouville theorem for the 3D stationary Q-tensor system of liquid crystal in Lorentz and Morrey spaces.Under some additional hypotheses,stated in terms of Lorentz and Morrey spaces,using energy ... In this paper,we study Liouville theorem for the 3D stationary Q-tensor system of liquid crystal in Lorentz and Morrey spaces.Under some additional hypotheses,stated in terms of Lorentz and Morrey spaces,using energy estimation,we obtain that the trivial solution u=Q=0 is the unique solution.Our theorems correspond to improvements of some recent results and contain some known results as particular cases. 展开更多
关键词 Lorentz spaces Morrey spaces Q-tensor liquid crystal Liouville theorem
在线阅读 下载PDF
VANISHING THEOREMS OF THE BASIC P-HARMONIC FORMS ON COMPLETE FOLIATED RIEMANNIAN MANIFOLDS
14
作者 NIE Yan-ci SHEN Zheng-han 《数学杂志》 2025年第3期195-204,共10页
In this paper,we study the basic p-harmonic forms on the complete foliated Riemannian manifolds.By using the method in[1],we show that if the basic mean curvature form is bounded and co-closed,and the transversal curv... In this paper,we study the basic p-harmonic forms on the complete foliated Riemannian manifolds.By using the method in[1],we show that if the basic mean curvature form is bounded and co-closed,and the transversal curvature operator is nonnegative and positive at least one point,then we obtain a vanishing theorem for L^(p)-integrably p-harmonic r-forms. 展开更多
关键词 basic p-harmonic form vanishing theorem foliated Riemannian manifold
在线阅读 下载PDF
A VECTOR BUNDLE VALUED MIXED HARD LEFSCHETZ THEOREM
15
作者 Zeng CHEN Guanxiang WANG 《Acta Mathematica Scientia》 2025年第2期514-524,共11页
In this paper,we obtain a vector bundle valued mixed hard Lefschetz theorem.The argument is mainly based on the works of Tien-Cuong Dinh and Viet-Anh Nguyen.
关键词 hard Lefschetz theorem holomorphic vector bundle Hermitian fat vector bundle
在线阅读 下载PDF
Sub-Riemannian Limits,Connections with Torsion and the Gauss-Bonnet Theorem for Four Dimensional Twisted BCV Spaces
16
作者 LI Hong-feng LIU Ke-feng WANG Yong 《Chinese Quarterly Journal of Mathematics》 2025年第2期111-134,共24页
In this paper,we compute sub-Riemannian limits of some important curvature variants associated with the connection with torsion for four dimensional twisted BCV spaces and derive a Gauss-Bonnet theorem for four dimens... In this paper,we compute sub-Riemannian limits of some important curvature variants associated with the connection with torsion for four dimensional twisted BCV spaces and derive a Gauss-Bonnet theorem for four dimensional twisted BCV spaces. 展开更多
关键词 Gauss-Bonnet theorem Sub-Riemannian limit Twisted BCV spaces Orthogonal connections with torsion
在线阅读 下载PDF
Liouville Theorem for 3D Steady Q-Tensor System of Liquid Crystal in Mixed Lorentz Spaces
17
作者 WAN Mengru DENG Xuemei BIE Qunyi 《Wuhan University Journal of Natural Sciences》 2025年第3期235-240,共6页
this paper,we study Liouville theorem for 3D steady Q-tensor system of liquid crystal in mixed Lorentz spaces.We obtain u=0,Q=0 on the conditions that μ∈L^(p,∞x_(1)L^(q,∞x_(2)L^(r,∞x_(3)(R^(4)∩H^(1)(R^(3),Q∈H^(... this paper,we study Liouville theorem for 3D steady Q-tensor system of liquid crystal in mixed Lorentz spaces.We obtain u=0,Q=0 on the conditions that μ∈L^(p,∞x_(1)L^(q,∞x_(2)L^(r,∞x_(3)(R^(4)∩H^(1)(R^(3),Q∈H^(2)(R^(3),p,q,r∈(3,∞],and 1/p+1/q+1/r≥2/3, which extends some known results. 展开更多
关键词 mixed Lorentz spaces Q-tensor system of liquid crystal Liouville theorem
原文传递
三维稳态向列型液晶系统的Liouville型定理
18
作者 王静 别群益 曹志杰 《应用数学》 北大核心 2026年第1期22-31,共10页
本文研究三维稳态向列型液晶系统的Liouville型定理.利用能量估计方法,证明了若光滑解(u,w,P)满足一些适当条件,则该系统仅有唯一解u=0,▽w=0.本文将Jarrin(2020)的结果推广到混合局部Morrey空间.
关键词 向列型液晶系统 LIOUVILLE型定理 混合局部Morrey空间
在线阅读 下载PDF
随机变量和的分布及其正态分布近似
19
作者 王福昌 靳志同 《高等数学研究》 2026年第1期45-48,共4页
本文给出均匀分布、指数分布和0-1分布的和的分布及其正态分布近似的计算与模拟,帮助学生正确理解和应用中心极限定理.
关键词 中心极限定理 均匀分布 指数分布 0-1分布
在线阅读 下载PDF
贝叶斯方法的基本原理及其哲学意蕴
20
作者 陈晓平 《哲学分析》 北大核心 2026年第1期155-168,199,共15页
贝叶斯方法现已成为一种新的科学范式,尤其体现于当前迅速发展的人工智能领域,它为AI系统提供了处理不确定性和动态更新概率的推理框架。从基本原理上讲,贝叶斯定理为人们从验前概率过渡到验后概率提供了逻辑依据,成为人们根据经验证据... 贝叶斯方法现已成为一种新的科学范式,尤其体现于当前迅速发展的人工智能领域,它为AI系统提供了处理不确定性和动态更新概率的推理框架。从基本原理上讲,贝叶斯定理为人们从验前概率过渡到验后概率提供了逻辑依据,成为人们根据经验证据来改变置信度的理性指导。然而,贝叶斯定理本身的合理性何在?这是休谟的归纳问题在贝叶斯方法中的体现,具体呈现为贝叶斯条件化规则的合理性问题。对此可提出“最小初始概率原则”给以回答。贝叶斯方法在科学推理的应用上,一个显著方面是用多理论检验模型取代传统的单理论检验模型即假设—演绎法,这不仅符合科学史的实际案例,而且通过“意见收敛定理”得到理论上的辩护。意见收敛定理的前提条件是可交换性,对之加以分析和澄清,可使该定理的应用范围从简单的重复独立试验扩展到复杂的科学验证。 展开更多
关键词 贝叶斯方法 假设—演绎法 意见收敛定理 归纳问题 贝叶斯条件化规则
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部