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LOCAL CENTRAL LIMIT THEOREM AND BERRY-ESSEEN THEOREM FOR SOME NONUNIFORMLY HYPERBOLIC DIFFEOMORPHISMS 被引量:1
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作者 夏红强 《Acta Mathematica Scientia》 SCIE CSCD 2010年第3期701-712,共12页
We prove that, for non-uniformly hyperbolic diffeomorphisms in the sense of Young, the local central limit theorem holds, and the speed in the central limit theorem is O(1/√n).
关键词 Local central limit theorem Berry-Esseen theorem nonuniform hyperbolic diffeomorphism Henon map
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A MULTIDIMENSIONAL CENTRAL LIMIT THEOREM WITH SPEED OF CONVERGENCE FOR AXIOM A DIFFEOMORPHISMS
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作者 夏红强 檀大耀 《Acta Mathematica Scientia》 SCIE CSCD 2011年第3期1123-1132,共10页
Let T:X → X be an Axiom A diffeomorphism,m the Gibbs state for a Hlder continuous function ɡ. Assume that f:X → R^d is a Hlder continuous function with ∫_X^(fdm) = 0.If the components of f are cohomologously i... Let T:X → X be an Axiom A diffeomorphism,m the Gibbs state for a Hlder continuous function ɡ. Assume that f:X → R^d is a Hlder continuous function with ∫_X^(fdm) = 0.If the components of f are cohomologously independent, then there exists a positive definite symmetric matrix σ~2:=σ~2 (f ) such that S^fn √ n converges in distribution with respect to m to a Gaussian random variable with expectation 0 and covariance matrix σ~2 . Moreover, there exists a real number A 〉 0 such that, for any integer n ≥ 1,Π( m*( 1√ nS f n ),N (0,σ~2 ) ≤A√n, where m*(1√ n S^fn)denotes the distribution of 1√ n S^fn with respect to m, and Π is the Prokhorov metric. 展开更多
关键词 multidimensional central limit theorem Axiom A diffeomorphisms symbolic dynamics transfer operator
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Optimized Non-hyperbolic Stack Imaging Based on Interpretation Model
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作者 Song Wei Wang Shangxu 《Petroleum Science》 SCIE CAS CSCD 2007年第4期50-55,共6页
In complex media, especially for seismic prospecting in deep layers in East China and in the mountainous area in West China, due to the complex geological condition, the common-mid-point (CMP) gather of deep reflect... In complex media, especially for seismic prospecting in deep layers in East China and in the mountainous area in West China, due to the complex geological condition, the common-mid-point (CMP) gather of deep reflection event is neither hyperbolic, nor any simple function. If traditional normal move-out (NMO) and stack imaging technology are still used, it is difficult to get a clear stack image. Based on previous techniques on non-hyperbolic stack, it is thought in this paper that no matter how complex the geological condition is, in order to get an optimized stack image, the stack should be non time move-out stack, and any stacking method limited to some kind of curve will be restricted to application conditions. In order to overcome the above-mentioned limit, a new method called optimized non-hyperbolic stack imaging based on interpretation model is presented in this paper. Based on CMP/CRP (Common-Reflection-Point) gather after NMO or pre-stack migration, this method uses the interpretation model of reflectors as constraint, and takes comparability as a distinguishing criterion, and finally forms a residual move-out correction for the gather of constrained model. Numerical simulation indicates that this method could overcome the non hyperbolic problem and get fine stack image. 展开更多
关键词 non-hyperbolic interpretation model stack imaging
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A Renormalizable Theory of Quantum Gravity: Renormalization Proof of the Gauge Theory of Volume Preserving Diffeomorphisms
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作者 Christian Wiesendanger 《Journal of Modern Physics》 2014年第10期959-983,共25页
Inertial and gravitational mass or energy momentum need not be the same for virtual quantum states. Separating their roles naturally leads to the gauge theory of volume-preserving diffeomorphisms of an inner four-dime... Inertial and gravitational mass or energy momentum need not be the same for virtual quantum states. Separating their roles naturally leads to the gauge theory of volume-preserving diffeomorphisms of an inner four-dimensional space. The gauge-fixed action and the path integral measure occurring in the generating functional for the quantum Green functions of the theory are shown to obey a BRST-type symmetry. The related Zinn-Justin-type equation restricting the corresponding quantum effective action is established. This equation limits the infinite parts of the quantum effective action to have the same form as the gauge-fixed Lagrangian of the theory proving its spacetime renormalizability. The inner space integrals occurring in the quantum effective action which are divergent due to the gauge group’s infinite volume are shown to be regularizable in a way consistent with the symmetries of the theory demonstrating as a byproduct that viable quantum gauge field theories are not limited to finite-dimensional compact gauge groups as is commonly assumed. 展开更多
关键词 RENORMALIZATION PROOF of GAUGE Field THEORY of Volume-Preserving diffeomorphismS
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Conservation of Gravitational Energy-Momentum and Inner Diffeomorphism Group Gauge Invariance
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作者 Christian Wiesendanger 《Journal of Modern Physics》 2013年第8期37-47,共11页
Viewing gravitational energy momentum as equal by observation, but different in essence from inertial energy-momentum requires two different symmetries to account for their independent conservations—spacetime and inn... Viewing gravitational energy momentum as equal by observation, but different in essence from inertial energy-momentum requires two different symmetries to account for their independent conservations—spacetime and inner translation invariance. Gauging the latter a generalization of non-Abelian gauge theories of compact Lie groups is developed resulting in the gauge theory of the non-compact group of volume-preserving diffeomorphisms of an inner Minkowski space M4. As usual the gauging requires the introduction of a covariant derivative, a gauge field and a field strength operator. An invariant and minimal gauge field Lagrangian is derived. The classical field dynamics and the conservation laws for the new gauge theory are developed. Finally, the theory’s Hamiltonian in the axial gauge is expressed by two times six unconstrained independent canonical variables obeying the usual Poisson brackets and the positivity of the Hamiltonian is related to a condition on the support of the gauge fields. 展开更多
关键词 GAUGE Field Theory Volume-Preserving diffeomorphism Group INNER MINKOWSKI Space
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General Relativity as the Classical Limit of the Renormalizable Gauge Theory of Volume Preserving Diffeomorphisms
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作者 Christian Wiesendanger 《Journal of Modern Physics》 2014年第10期948-958,共11页
The different roles and natures of spacetime appearing in a quantum field theory and in classical physics are analyzed implying that a quantum theory of gravitation is not necessarily a quantum theory of curved spacet... The different roles and natures of spacetime appearing in a quantum field theory and in classical physics are analyzed implying that a quantum theory of gravitation is not necessarily a quantum theory of curved spacetime. Developing an alternative approach to quantum gravity starts with the postulate that inertial energy-momentum and gravitational energy-momentum need not be the same for virtual quantum states. Separating their roles naturally leads to the quantum gauge field theory of volume-preserving diffeomorphisms of an inner four-dimensional space. The classical limit of this theory coupled to a quantized scalar field is derived for an on-shell particle where inertial energy-momentum and gravitational energy-momentum coincide. In that process the symmetry under volume-preserving diffeomorphisms disappears and a new symmetry group emerges: the group of coordinate transformations of four-dimensional spacetime and with it General Relativity coupled to a classical relativistic point particle. 展开更多
关键词 QUANTUM Gravity QUANTUM Gauge Theory of Volume-Preserving diffeomorphism Group GR Emerging AS the Classical LIMIT of Above Different Roles of Inertial and Gravitational Momentum Observability of Spacetime at Microscopic Level
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基于状态反馈精确线性化的双馈异步风机最优控制策略 被引量:1
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作者 韩金龙 袁枭添 +3 位作者 江晗 戴耀辉 杨锐 杜正春 《中国电机工程学报》 EI CSCD 北大核心 2024年第9期3508-3517,I0014,共11页
该文基于微分几何理论,从状态空间的角度出发对双馈异步风机(doubly fed induction generator,DFIG)的机侧变换器和网侧变换器独立设计,通过构造微分同胚变换将其动态模型精确线性化并设计相应的非线性控制律,实现了多目标最优控制。通... 该文基于微分几何理论,从状态空间的角度出发对双馈异步风机(doubly fed induction generator,DFIG)的机侧变换器和网侧变换器独立设计,通过构造微分同胚变换将其动态模型精确线性化并设计相应的非线性控制律,实现了多目标最优控制。通过仿真验证表明,基于状态反馈精确线性化的双馈异步风机最优控制策略能有效抵御外界风况和电网电压的剧烈变动并快速恢复稳定,呈现优良的抗扰特性。 展开更多
关键词 双馈异步风机 状态反馈精确线性化 非线性控制 多目标最优控制 微分同胚
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Katok’s Entropy Formula of Unstable Metric Entropy for Partially Hyperbolic Diffeomorphisms
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作者 Ping Huang Chenwei Wang Ercai Chen 《Communications in Mathematics and Statistics》 SCIE CSCD 2024年第2期339-355,共17页
Katok’s entropy formula is an important formula in entropy theory.It plays significant roles in large deviation theories,multifractal analysis,quantitative recurrence and so on.This paper is devoted to establishing K... Katok’s entropy formula is an important formula in entropy theory.It plays significant roles in large deviation theories,multifractal analysis,quantitative recurrence and so on.This paper is devoted to establishing Katok’s entropy formula of unstable metric entropy which is the entropy caused by the unstable part of partially hyperbolic systems.We also construct a similar formula which can be used to study the quantitative recurrence in the unstable manifold for partially hyperbolic diffeomorphisms. 展开更多
关键词 Katok’s entropy formula Unstable metric entropy Measure decomposition Partially hyperbolic diffeomorphisms
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基于拟共形理论的分数阶多尺度微分同胚图像配准
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作者 王慧楠 韩欢 《数学物理学报(A辑)》 CSCD 北大核心 2024年第6期1665-1688,共24页
图像配准领域存在着两大挑战:(1)网格重叠现象;(2)贪婪配准问题不适定.针对这两大挑战,该文提出了一个基于拟共形理论的多尺度分数阶微分同胚图像配准模型,该模型在无网格重叠及先验正则项的前提下,得到了相似性度量泛函的一个光滑极小... 图像配准领域存在着两大挑战:(1)网格重叠现象;(2)贪婪配准问题不适定.针对这两大挑战,该文提出了一个基于拟共形理论的多尺度分数阶微分同胚图像配准模型,该模型在无网格重叠及先验正则项的前提下,得到了相似性度量泛函的一个光滑极小值点.此外,该文证明了所提模型解的存在性及多尺度方法的收敛性,并通过数值实验验证了所提算法能有效避免网格重叠并得到较好的配准结果. 展开更多
关键词 微分同胚 多尺度 拟共形理论 分数阶 图像配准
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Ashtekar-Kodama Gravity as a Classical and Quantum Extension of Loop Quantum Gravity
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作者 Jan Helm 《Journal of Modern Physics》 2024年第6期864-937,共74页
This paper presents a new theory of gravity, called here Ashtekar-Kodama (AK) gravity, which is based on the Ashtekar-Kodama formulation of loop quantum gravity (LQG), yields in the limit the Einstein equations, and i... This paper presents a new theory of gravity, called here Ashtekar-Kodama (AK) gravity, which is based on the Ashtekar-Kodama formulation of loop quantum gravity (LQG), yields in the limit the Einstein equations, and in the quantum regime a full renormalizable quantum gauge field theory. The three fundamental constraints (hamiltonian, gaussian and diffeomorphism) were formulated in 3-dimensional spatial form within LQG in Ashtekar formulation using the notion of the Kodama state with positive cosmological constant Λ. We introduce a 4-dimensional covariant version of the 3-dimensional (spatial) hamiltonian, gaussian and diffeomorphism constraints of LQG. We obtain 32 partial differential equations for the 16 variables E<sub>mn</sub> (E-tensor, inverse densitized tetrad of the metric) and 16 variables A<sub>mn</sub> (A-tensor, gravitational wave tensor). We impose the boundary condition: for large distance the E-generated metric g(E) becomes the GR-metric g (normally Schwarzschild-spacetime). The theory based on these Ashtekar-Kodama (AK) equations, and called in the following Ashtekar-Kodama (AK-) gravity has the following properties. • For Λ = 0 the AK equations become Einstein equations, A-tensor is trivial (constant), and the E-generated metric g(E) is identical with the GR-metric g. • When the AK-equations are developed into a Λ-power series, the Λ-term yields a gravitational wave equation, which has only at least quadrupole wave solutions and becomes in the limit of large distance r the (normal electromagnetic) wave equation. • AK-gravity, as opposed to GR, has no singularity at the horizon: the singularity in the metric becomes a (very high) peak. • AK-gravity has a limit scale of the gravitational quantum region 39 μm, which emerges as the limit scale in the objective wave collapse theory of Gherardi-Rimini-Weber. In the quantum region, the AK-gravity becomes a quantum gauge theory (AK quantum gravity) with the Lie group extended SU(2) = ε-tensor-group(four generators) as gauge group and a corresponding covariant derivative. • AK quantum gravity is fully renormalizable, we derive its Lagrangian, which is dimensionally renormalizable, the normalized one-graviton wave function, the graviton propagator, and demonstrate the calculation of cross-section from Feynman diagrams. 展开更多
关键词 Quantum Gravity Loop Quantum Gravity General Relativity Gravitational Wave Gauge Field Theory Graviton Hamiltonian Constraint Gaussian Constraint diffeomorphism Constraint
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Dynamical Properties of a Discrete Lesley-Gower Prey-Predator Model with Holling-II Type Functional Response
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作者 Kaile Qiu Wanying Li +2 位作者 Donghuan He Guoqiang Qian Xiaoliang Zhou 《Journal of Applied Mathematics and Physics》 2024年第11期3912-3922,共11页
In this paper, we will study a class of discrete Leslie-Gower prey-predator models, which is a discretization of the continuous model proposed by Leslie and Gower in 1960. First, we find all fixed points, use hyperbol... In this paper, we will study a class of discrete Leslie-Gower prey-predator models, which is a discretization of the continuous model proposed by Leslie and Gower in 1960. First, we find all fixed points, use hyperbolic and non-hyperbolic conditions to give the types of fixed points, and then analyze the bifurcation properties of non-hyperbolic fixed points. The generating conditions of Flip bifurcation and Neimark-Sacker bifurcation at fixed points are studied. Finally, numerical simulations of Flip bifurcation and Neimark-Sacker bifurcation are given. 展开更多
关键词 Leslie-Gower Prey-Predator Model non-hyperbolic Fixed Point Flip Bifurcation Neimark-Sacker Bifurcation
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Qualitative Properties of Equilibrium Point in a Discrete Predator-Prey Model
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作者 Weijie Lin Minhong Yang +2 位作者 Chenhao Sun Kaiwen Guan Xiaoliang Zhou 《Journal of Applied Mathematics and Physics》 2024年第8期2920-2927,共8页
In this paper, the dynamic properties of a discrete predator-prey model are discussed. The properties of non-hyperbolic fixed points and hyperbolic fixed points of the model are analyzed. First, by using the classic S... In this paper, the dynamic properties of a discrete predator-prey model are discussed. The properties of non-hyperbolic fixed points and hyperbolic fixed points of the model are analyzed. First, by using the classic Shengjin formula, we find the existence conditions for fixed points of the model. Then, by using the qualitative theory of ordinary differential equations and matrix theory we indicate which points are hyperbolic and which are non-hyperbolic and the associated conditions. 展开更多
关键词 Discrete Predator-Prey Model non-hyperbolic Fixed Point NODE Saddle Point
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The Dynamical Properties of a Class of Discrete Smith Diffusion Model
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作者 Yu-Ming Yan Min-Hong Yang +2 位作者 Ying Lin Lu-Di Chen Xiao-Liang Zhou 《International Journal of Modern Nonlinear Theory and Application》 2024年第1期1-10,共10页
In this paper, the dynamical properties of Smith type diffusion model with Dirichlet boundary conditions are studied. The properties of hyperbolic fixed points and non-hyperbolic fixed points of the model are analyzed... In this paper, the dynamical properties of Smith type diffusion model with Dirichlet boundary conditions are studied. The properties of hyperbolic fixed points and non-hyperbolic fixed points of the model are analyzed. By using the central manifold theorem, the bifurcation phenomenon of the model is studied. The results show that flip, transcritical, pitchfork and Fold-flip bifurcations exist at non-hyperbolic fixed points. 展开更多
关键词 Hyperbolicfixed Point non-hyperbolic Fixed Point Central Manifold Theorem BIFURCATION
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大形变微分同胚图像配准快速算法 被引量:7
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作者 闫德勤 刘彩凤 +1 位作者 刘胜蓝 刘德山 《自动化学报》 EI CSCD 北大核心 2015年第8期1461-1470,共10页
本文提出一种研究大形变图像配准算法.大形变使得图像信息和拓扑结构有较大的改变,目前该方面的研究仍然是一个难点.基于严密数学理论的微分同胚Demons算法是图像配准的著名算法,为解决大形变配准问题提供了重要基础.基于对微分同胚Dem... 本文提出一种研究大形变图像配准算法.大形变使得图像信息和拓扑结构有较大的改变,目前该方面的研究仍然是一个难点.基于严密数学理论的微分同胚Demons算法是图像配准的著名算法,为解决大形变配准问题提供了重要基础.基于对微分同胚Demons算法的研究结合流形学习的思想提出一种大形变图像配准的新算法(MRL算法).新算法通过挖掘图像的局部和全局流形信息改进微分同胚Demons速度场的更新,更好地保持图像的拓扑结构.对比实验结果表明,本文所提出的算法能够快速高精度地实现大形变图像的配准. 展开更多
关键词 图像配准 微分同胚Demons 流形 大形变
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欠驱动船舶的光滑时变指数镇定 被引量:13
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作者 赵国良 韩冰 《控制理论与应用》 EI CAS CSCD 北大核心 2006年第5期787-790,共4页
船舶水平面运动的欠驱动特性使船舶运动控制的研究具有了新的内涵.本文在船舶水平面运动的运动学及动力学模型基础上,将其演化为二阶系统方程组.针对其欠驱动的特性,借助微分同胚变换及控制输入变换将其转化为两个子系统,分别设计状... 船舶水平面运动的欠驱动特性使船舶运动控制的研究具有了新的内涵.本文在船舶水平面运动的运动学及动力学模型基础上,将其演化为二阶系统方程组.针对其欠驱动的特性,借助微分同胚变换及控制输入变换将其转化为两个子系统,分别设计状态反馈控制律,从而得到了原系统的具有指数收敛速率的时变光滑反馈镇定律,实现闭环系统所有状态全局指数收敛至平衡点.该方法可用于欠驱动船舶动力定位或自动泊位控制.最后的仿真试验验证表明本方法是有效的. 展开更多
关键词 欠驱动 船舶 微分同胚变换 指数镇定
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三相有源电力滤波器精确反馈线性化空间矢量PWM复合控制 被引量:33
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作者 乐江源 谢运祥 +1 位作者 张志 陈林 《中国电机工程学报》 EI CSCD 北大核心 2010年第15期32-39,共8页
提出一种基于精确反馈线性化的三相有源电力滤波器空间矢量脉宽调制控制方法。在三相并联型有源电力滤波器的仿射非线性模型基础上,推导出其状态反馈精确线性化非线性控制律,实现三相并联型有源电力滤波器有功补偿电流和无功补偿电流的... 提出一种基于精确反馈线性化的三相有源电力滤波器空间矢量脉宽调制控制方法。在三相并联型有源电力滤波器的仿射非线性模型基础上,推导出其状态反馈精确线性化非线性控制律,实现三相并联型有源电力滤波器有功补偿电流和无功补偿电流的解耦控制。选取适当的反馈系数可确定交流侧指令电压,利用空间矢量脉宽调制技术对所需的指令电压进行逼近。与PI控制的三角载波控制方案进行仿真对比分析,验证了所提出的控制方案的动、静性能指标均优于PI控制方案。研制了一台小功率样机,验证了所提方案的正确性和可行性。 展开更多
关键词 有源电力滤波器 解耦控制 精确反馈线性化 空间矢量脉宽调制 微分同胚
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基于微分同胚变换的故障重构算法 被引量:4
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作者 何静 邱静 张昌凡 《控制理论与应用》 EI CAS CSCD 北大核心 2010年第4期481-487,共7页
针对一类含有未知输入扰动的不确定非线性系统提出一种鲁棒故障重构方案.采用全局微分同胚变换,将非线性系统变换为二个子系统,使得其中一子系统不受故障影响,状态部分可观,另一子系统受故障影响但状态完全可观.利用滑模变结构原理对两... 针对一类含有未知输入扰动的不确定非线性系统提出一种鲁棒故障重构方案.采用全局微分同胚变换,将非线性系统变换为二个子系统,使得其中一子系统不受故障影响,状态部分可观,另一子系统受故障影响但状态完全可观.利用滑模变结构原理对两个子系统分别设计状态观测器消除扰动对系统的影响后,再利用等值控制方法实现对故障的重构.应用案例验证了所提方法的有效性. 展开更多
关键词 微分同胚 故障重构 观测器 滑模
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关于非线性两点边界值问题u″+g(t,u)=f(t),u(0)=u(2π)=0的解的存在性和唯一性 被引量:7
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作者 黄文华 曹菊生 沈祖和 《应用数学和力学》 CSCD 北大核心 1998年第9期821-826,共6页
本文给出了max_min原理的一个非变分形式,证明了非线性两点边界值问题u″+g(t,u)=f(t),u(0)=u(2π)=0的解的一个存在性和唯一性定理·
关键词 非线性 存在性 两点边值问题 唯一性
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非完全对称欠驱动高速无人艇轨迹跟踪控制 被引量:14
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作者 万磊 董早鹏 +1 位作者 李岳明 何斌 《电机与控制学报》 EI CSCD 北大核心 2014年第10期95-103,共9页
研究一类非完全对称欠驱动无人艇的轨迹跟踪控制问题,考虑系统阻尼系数矩阵和惯性系数矩阵非对角线元素存在非零项,且阻尼系数随着航速变化的情况,首先通过两次全局微分同胚变换将系统矩阵变换为级联系统的形式,使控制模型得以简化;然... 研究一类非完全对称欠驱动无人艇的轨迹跟踪控制问题,考虑系统阻尼系数矩阵和惯性系数矩阵非对角线元素存在非零项,且阻尼系数随着航速变化的情况,首先通过两次全局微分同胚变换将系统矩阵变换为级联系统的形式,使控制模型得以简化;然后基于简化后的模型构建轨迹跟踪误差模型,将轨迹跟踪问题转化为误差的镇定问题,同时基于级联系统理论和Lyapunov直接法设计了误差镇定控制器,该控制器能够实现非完全对称欠驱动高速无人艇的任意参考轨迹的跟踪控制,包括原点的镇定控制。最后通过仿真实验验证了所设计控制器的有效性。 展开更多
关键词 非完全对称 高速无人艇 轨迹跟踪 欠驱动控制 全局微分同胚变换 级联系统
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有关流形上Poisson结构的几点讨论 被引量:6
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作者 王宝勤 刘亚军 《工程数学学报》 CSCD 北大核心 2002年第3期140-142,132,共4页
讨论了微分同胚对Poisson流形上Poisson结构的保持 ,得到了微分同胚所诱导的Poisson括号的一些性质 ,最后 。
关键词 流形 POISSON结构 微分同胚 广义Poisson括号 POISSON流形 CASIMIR函数
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