The Non-Singular Fast Terminal Sliding Mode Control of Interior Permanent Magnet Synchronous Motor Based on Deep Flux Weakening Switching Point Tracking

This paper presents a novel non-singular fast terminal sliding mode control(NFTSMC)based on the deep flux weakening switching point tracking method in order to improve the control performance of permanent interior magnet synchronous motor(IPMSM)drive systems.The mathematical model of flux weakening(FW)control is established,and the deep flux weakening switching point is calculated accurately by analyzing the relationship between the torque curve and voltage decline curve.Next,a second-order NFTSMC is designed for the speed loop controller to ensure that the system converges to the equilibrium state in finite time.Then,an extended sliding mode disturbance observer(ESMDO)is designed to estimate the uncertainty of the system.Finally,compared with both the PI control and sliding mode control(SMC)by simulations and experiments with different working conditions,the method proposed has the merits of accelerating convergence,improving steady-state accuracy,and minimizing the current and torque pulsation.

A Novel Disturbance Observer Based Fixed-Time Sliding Mode Control for Robotic Manipulators With Global Fast Convergence

This paper proposes a new global fixed-time sliding mode control strategy for the trajectory tracking control of uncertain robotic manipulators.First,a fixed-time disturbance observer(FTDO) is designed to deal with the adverse effects of model uncertainties and external disturbances in the manipulator systems.Then an adaptive scheme is used and the adaptive FTDO(AFTDO) is developed,so that the priori knowledge of the lumped disturbance is not required.Further,a new non-singular fast terminal sliding mode(NFTSM) surface is designed by using an arctan function,which helps to overcome the singularity problem and enhance the robustness of the system.Based on the estimation of the lumped disturbance by the AFTDO,a fixed-time non-singular fast terminal sliding mode controller(FTNFTSMC)is developed to guarantee the trajectory tracking errors converge to zero within a fixed time.The settling time is independent of the initial state of the system.In addition,the stability of the AFTDO and FTNFTSMC is strictly proved by using Lyapunov method.Finally,the fixed-time NFESM(FTNFTSM) algorithm is validated on a 2-link manipulator and comparisons with other existing sliding mode controllers(SMCs) are performed.The comparative results confirm that the FTNFTSMC has superior control performance.

Evolutionary Safe Padé Approximation Scheme for Dynamical Study of Nonlinear Cervical Human Papilloma Virus Infection Model

This study proposes a structure-preserving evolutionary framework to find a semi-analytical approximate solution for a nonlinear cervical cancer epidemic(CCE)model.The underlying CCE model lacks a closed-form exact solution.Numerical solutions obtained through traditional finite difference schemes do not ensure the preservation of the model’s necessary properties,such as positivity,boundedness,and feasibility.Therefore,the development of structure-preserving semi-analytical approaches is always necessary.This research introduces an intelligently supervised computational paradigm to solve the underlying CCE model’s physical properties by formulating an equivalent unconstrained optimization problem.Singularity-free safe Padérational functions approximate the mathematical shape of state variables,while the model’s physical requirements are treated as problem constraints.The primary model of the governing differential equations is imposed to minimize the error between approximate solutions.An evolutionary algorithm,the Genetic Algorithm with Multi-Parent Crossover(GA-MPC),executes the optimization task.The resulting method is the Evolutionary Safe PadéApproximation(ESPA)scheme.The proof of unconditional convergence of the ESPA scheme on the CCE model is supported by numerical simulations.The performance of the ESPA scheme on the CCE model is thoroughly investigated by considering various orders of non-singular Padéapproximants.

On non-singular GRADELA crack fields

A brief account is provided on crack-tip solutions that have recently been published in the literature by employing the so-called GRADELA model and its variants. The GRADELA model is a simple gradient elasticity theory involving one internal length in addition to the two Lame＇ constants, in an effort to eliminate elastic singularities and discontinuities and to interpret elastic size effects. The non-singular strains and non-singular （but sometimes singular or even hypersingular） stresses derived this way under different boundary conditions differ from each other and their physical meaning in not clear. This is discussed which focus on the form and physical meaning of non-singular solutions for crack-tip stresses and strains that are possible to obtain within the GRADELA model and its extensions.

Non-Singular Trees, Unicyclic Graphs and Bicyclic Graphs

We called graph G non-singular if adjacency matrix A (G) of G is non-singular. A connected graph with n vertices and n-1, n and n+1 edges are called the tree, the unicyclic graph and the bicyclic graph. Respectively, as we all know, each connected bicyclic graph must contain ∞(a,s,b) or?θ(p,l,q) as the induced subgraph. In this paper, by using three graph transformations which do not change the singularity of the graph, the non-singular trees, unicyclic graphs and bicyclic graphs are obtained.

THE SQUARE ROOT OF H-MATRIX

1 IntroductionLet A∈Cn×n, B∈Cn×n.We say B is a square root of A if A=B×B i.e.A=B2.It is well-known that any symmetric positive definite matrix exists one and only onesquare root which is a symmetric positive definite matrix,too（e.g.see[5]）.Higham[4]studied carefully the relation of a real nonsingular matrix between its real square rootsand its eigenvalues.Alefeld and Schneider[1]pointed out that for any nonsingular M-ma-trix there is one and only one M-matrix as its square root.In this paper,we study on

Inconsistence of Non-Singular Spherically Symmetric Solution and a Satisfactory Energy-Momentum Complex

Two spherically symmetric non-singular black hole solutions in Moiler tetrad theory of gravitation have been obtained. Although the two solutions have the same form of metric （spherically symmetric nonsingular black hole）, their energy contents are different. We use another method given by Gibbons and Hawking to calculate the energy content of these solutions. We also obtained different value of energy. Study the requirements of a satisfactory energymomentum complex given by Moiler we find that the second solution, which behaves as 1/√r, is not transformed as a four-vector under Lorentz transformation.

A Proof of the Non-Singularity of the <i>D</i>Matrix Used in Deriving the Two—Step Butcher’s Hybrid Scheme for the Solution of Initial Value Problems

In this paper, we state and prove the conditions for the non-singularity of the D matrix used in deriving the continuous form of the Two-step Butcher’s hybrid scheme and from it the discrete forms are deduced. We also show that the discrete scheme gives outstanding results for the solution of stiff and non-stiff initial value problems than the 5th order Butcher’s algorithm in predictor-corrector form.

Creation of a Non-Expanding, Non-Singular Universe

A theory of gravitation in flat space-time is applied to homogeneous, isotropic cosmological models. There are non-singular cosmological models. A natural interpretation is a non-expanding universe. The redshift is an intrinsic effect and not a Doppler effect. The universe contains only energy in the beginning, i.e. no matter exists. In the course of time matter and radiation are created from energy where the whole energy is conserved. Matter increases with time but a certain time after the beginning of the universe the creation of matter is finished and the universe appears like a static one. A modified Hubble law is considered which may explain the high redshifts of objects in the universe without the assumption of dark energy.

非奇异H-矩阵的细分迭代直接判定新条件

通过细分矩阵非占优行指标集,以及构造新的递进式放缩迭代因子,寻找合适的正对角变换因子的方法,得到了一类非奇异H矩阵直接判定新条件.

α-双对角占优与H矩阵的判定

设A=(aij)∈Cn×n,若 α∈[0,1],使对 i≠j(i,j∈N)均有｜aiiajj｜≥(Λi,Λj)α(SiSj)1-α,则称A为α 双对角占优矩阵.本文利用矩阵回路给出了A为H阵的新的判定准则,即A=(aij)∈Cn×n,若对任意i∈N和v∈S(A)有:ΠΛi)α(ΠSi)1-α,α∈[0,1],则A为H阵,改进和推广了已有的结果.｜aii｜>

α-对角占优与非奇异H-矩阵新判据

广泛用于计算数学、矩阵理论、数值分析、数学物理、控制理论中的非奇异H-矩阵,一直是国内外学者们所关注的研究课题.特别是对于非奇异H-矩阵的判定条件的探讨,更是一些学者讨论的热门课题,近几年,取得了一些很好的充分条件.从矩阵自己所含元素为基本点,联系某些结果,并对其适量改造,得出了非奇异H-矩阵新的判定方法,并给出数值例子说明新判据具有比原有定理更大的适用范围.

一类时滞广义系统的非脆弱H_∞控制

针对一类时滞广义系统,讨论其时滞相关非脆弱H_∞控制问题。通过构造Lyapunov-Krasovskii泛函,利用线性矩阵不等式方法和最新建立的积分不等式,给出了时滞广义系统的鲁棒H_∞控制的时滞相关判据,设计非脆弱记忆反馈控制器,使得时滞广义系统正则、无脉冲、渐近稳定且满足H_∞范数小于给定界γ。数值例子与已有文献进行比较,说明了所给方法的有效性及优越性。

非奇异H-矩阵的一组判定条件

本文首先推广α-对角占优矩阵的概念到广义α-对角占优矩阵;然后构造出两个乘积因子,利用α-对角占优矩阵的概念及性质,给出非奇异H-矩阵几个简捷的判别定理,并利用数值实例验证了它们的有效性,从而丰富和完善了α-对角占优矩阵与非奇异H-矩阵的理论,更为计算数学、矩阵论、控制论、经济数学等相关领域的研究奠定了基础.

α-次对角占优矩阵与非奇异次H矩阵的判定

利用α-次对角占优矩阵的一些性质,通过选取正对角因子元素和放缩不等式的技巧,获得了广义严格次对角占优矩阵的几个判定定理,从而将一些已有的结论推广到非奇异次H矩阵中,并用数值例子说明了所得结果的实用性.

非奇异H-矩阵的一类迭代判别法

非奇异H-矩阵应用广泛,但在实用中其判定十分困难。根α-对角占优矩阵与非奇异H-矩阵的关系,给出一类非奇异H-矩阵的迭代判定准则,对已有的相关结果进行推广和改进,并用数值算例验证了该判定准则的有效性。

一类离散奇异Markovian跳变系统的非脆弱H_∞控制

本文研究了一类离散奇异Markovian跳变系统的非脆弱H∞问题.首先针对标称离散奇异Markovian跳变系统,得到考虑控制器参数摄动后不确定闭环系统的关于鲁棒随机可容许性及H∞扰动衰减性能分析的结论;然后推导出标称离散奇异Markovian跳变系统非脆弱H∞控制器的设计方法,该方法表明可通过求解一组耦合线性矩阵不等式来构建非脆弱H∞控制器;最后将标称系统的结果进一步推广到考虑系统不确定性的鲁棒非脆弱H∞控制器设计.

广义Delta算子系统的非脆弱H_∞控制

针对广义Delta算子系统的非脆弱控制问题,本文主要对广义Delta算子系统的非脆弱状态反馈H_∞控制问题进行研究,其控制器增益矩阵分别包含加法摄动和乘法摄动两种不同的形式。利用线性矩阵不等式方法,给出广义Delta算子系统在上述两种摄动的影响下,非脆弱H_∞控制器存在的充要条件,并通过解线性矩阵不等式,得到了相应的控制器的设计方法,从而使闭环系统是广义二次容许的,且具有指定的H_∞性能,并通过数值算例,对文中的理论结果进行仿真验证。仿真结果表明,本文所设计的非脆弱控制器具有可行性和有效性。该研究具有实际应用价值。

不确定离散广义时滞系统的鲁棒非脆弱H_∞控制

针对一类参数不确定离散时滞广义系统,研究其鲁棒非脆弱H∞状态反馈控制器的设计问题。系统中的不确定项参数与控制器的增益变化同时具有线性分式形式的范数有界。首先,利用Lyapunov函数理论,研究该标称系统的鲁棒H∞控制问题;其次,以线性矩阵不等式(LMI)形式给出该系统的鲁棒非脆弱H∞控制器存在的充分条件及设计方法。该控制器既能使闭环系统是允许的,又能保证系统具有一定的H∞性能.最后,通过数值算例说明该方法的有效性。

基于有限元模型的三维集成电路热分析

基于有限元理论,对三维集成电路(3D-IC)进行了建模和仿真,研究了不同模型的热分布和计算复杂度。通过Gmsh软件创建3D-IC模型并生成网格化文件。利用Matlab软件提取有限元参数,获到模型的刚度矩阵。用层次矩阵(Hierarchical matrix,H-matrix)表示刚度矩阵,得到了不同模型刚度矩阵的求逆所消耗的存储空间和运算时间。结果表明:随着模型刚度矩阵行列数目的增加,所需要的运算时间和存储空间呈现线性变化关系。