Observer design for matrix second order linear systems with uncertain disturbance input-a parametric approach

A simple parametric approach to design a full-order observer for matrix second-order linear systems with uncertain disturbance input in the matrixsecond-order framework is proposed. The basic idea is to minimize the H2 norm of the transfer function from disturbance to estimation error using the design degrees of freedom provided by a parametric approach in the observer design. Besides the design parameters, the eigenvalues of the closed-loop system are also optimized within desired regions on the left-half of the complex plane. Using the proposed approach, additional specifications can be easily achieved. A spring-mass system is using to show the effect of the proposed approaches.

Parametric approach to track following control of FFSM

A robust task space tracking scheme is proposed for the free-flying space manipulator system. The dynamic equations of the system are derived via the law of momentum conservation, and then a linear state space representation is formulated by local linearization. A parametric approach is applied by using the eigenstructure assignment theory and the model reference method. A feedback stabilizing controller and a feedforward compensation controller are built based on the approach. Then an optimization procedure is followed after that to obtain the desired requirement and characteristics. Simulation results are presented to show the effectiveness of the proposed method.

Exploration of nature-based biomimetic approach in landscape architectural design: parametric study of candelabra model design

This research provides an exploration of a biomimetic approach in the process of designing a candelabra model using linear shaped leaves of a Bell flower.The design process described in this research contains two steps:biological and geometrical.In the first biological step,a proper model for the creation of an urban element was found from nature in a Bell flower(Campanula persicifolia L.).The upper leaves of the selected plant,which are small with a linear spear and sharpening at the top,were chosen for the modeling process.The second step included applying two geometrical methods,i.e.,Voronoi diagrams and Delaunay triangulation.A geometrical leaf form of the selected plant species and the modeling process were obtained using aparametric modeling software,Blender.Using different Blender plug-ins and modifiers,Delaunay triangulation and Voronoi diagram were implemented by marking the starting points on the leaf form in the image data source,adjusting the Delaunay triangulation parameters,and creating Voronoi diagrams in which the Voronoi points were located at the shortest distance from the edges of the Voronoi polygon.Consequently,a three dimensional model of a candelabra was developed through this study.

Robust parametric approach for tracking control of an air-breathing hypersonic cruise vehicle

To realize the stabilization and the tracking of flight control for an air-breathing hypersonic cruise vehicle, the linearization of the longitudinal model under trimmed cruise condition is processed firstly. Furthermore, the flight control problem is formulated as a robust model tracking control problem. And then, based on the robust parametric approach, eigenstructure assignment and reference model tracking theory, a parametric optimization method for robust controller design is presented. The simulation results show the effectiveness of the proposed approach.

A novel approach towards parametric assessment of reliability and resilience of high voltage mica-based insulation systems by statistical analysis of experimental failure data

Insulation systems in high-voltage electric machines play a pivotal role in the reliable operation and longevity of the equipment.Mica-based insulation materials have proven to possess and maintain excellent dielectric properties in the long run and prevent premature insulation degradation.Numerous qualifications tests,such as voltage endurance,are outlined in IEC and IEEE standards.The authors,however,take a different parametric approach,opting for reliability assessment of insulation systems using derived three-parameter Weibull models.Therefore,instead of simple pass–fail criteria,empirical data is employed to determine failure rate probabilities quantitatively and objectively.Experimental data,including breakdown,dissipation factor,and partial discharge mea-surements,are used to construct the Weibull distribution model to predict fault and failure rates and calculate hazard functions.The rigorous examinations interpreted through the analytical model help assess insulation system resilience and particularly the impact of electrical field stress and mica content.Variation of electrical stress from 66.75 to 71.20 V/mil demonstrated how the mean time to failure of the system changed from 146.4 to 85.1 at 3 Un,hence identifying opportunities for design improvement and uncovering performance boundaries.Ultimately,the developed framework enhances comprehension of insulation system failure probabilities,guiding design decisions and ensuring a secure and reliable operation of electrical machines across applications.

Solvability Condition for a Class of Parametric Robust Stabilization Problem

The robust stabilization problem (RSP) for a plant family P(s,δ,δ) having real parameter uncertainty δ will be tackled. The coefficients of the numerator and the denominator of P(s,δ,δ) are affine functions of δ with ‖δ‖p≤δ. The robust stabilization problem for P(s,δ,δ) is essentially to simultaneously stabilize the infinitely many members of P(s,δ,δ) by a fixed controller. A necessary solvability condition is that every member plant of P(s,δ,δ) must be stabilizable, that is, it is free of unstable pole-zero cancellation. The concept of stabilizability radius is introduced which is the maximal norm bound for δ so that every member plant is stabilizable. The stability radius δmax(C) of the closed-loop system composed of P(s,δ,δ) and the controller C(s) is the maximal norm bound such that the closed-loop system is robustly stable for all δ with ‖δ‖p<δmax(C). Using the convex parameterization approach it is shown that the maximal stability radius is exactly the stabilizability radius. Therefore, the RSP is solvable if and only if every member plant of P(s,δ,δ) is stabilizable.

基于多岛遗传算法的翼型多目标优化设计

[目的]针对大型水平轴水轮机叶片运行工况复杂的问题,提出一种多目标优化算法。[方法]基于多岛遗传算法建立翼型优化模型,采用类形函数变换(CST)法对翼型进行参数化拟合,整个优化过程集成于Isight平台,实现自动优化。[结果]采用上述方法,选用NACA 63813/63815/63816翼型作为初始翼型进行多目标优化,利用Fluent转捩模型对得到的翼型进行CFD数值验证,选择翼型攻角5°时的升阻比、升力等为优化目标参数,得到优化后的翼型升力系数分别增大了14%,15%,20%,升阻比分别增大了14%,16%,28%。[结论]数值验证结果表明,优化后的翼型在多个工况点下的升阻比均高于同厚度原始翼型,在具有良好的水动力动性能的同时还提高了叶片的结构强度,相比于传统的翼型更适用于大型潮流能水平轴水轮机。

Solution for generalized fuzzy fractional Kortewege-de Varies equation using a robust fuzzy double parametric approach

The nonlinear Kortewege-de Varies(KdV)equation is a functional description for modelling ion-acoustic waves in plasma,long internal waves in a density-stratified ocean,shallow-water waves and acoustic waves on a crystal lattice.This paper focuses on developing and analysing a resilient double parametric analytical approach for the nonlinear fuzzy fractional KdV equation(FFKdVE)under gH-differentiability of Caputo fractional order,namely the q-Homotopy analysis method with the Shehu transform(q-HASTM).A triangular fuzzy number describes the Caputo fractional derivative of orderα,0<α≤1,for modelling problem.The fuzzy velocity profiles with crisp and fuzzy conditions at different spatial positions are in-vestigated using a robust double parametric form-based q-HASTM with its convergence analysis.The ob-tained results are compared with existing works in the literature to confirm the efficacy and effectiveness of the method.

A Direct Parametric Approach to Spacecraft Attitude Tracking Control

Through the direct parameter approach, a solution for spacecraft attitude tracking is presented. First of all, the spacecraft attitude tracking control model is built up by the error equation of the second-order nonlinear quaternion-based attitude system. Based on the control model, a suitable controller is designed by the direct parameter approach. Compared with other control strategies, the direct parameter approach can offer all degrees of freedom for the controller to satisfy the requirements for system properties and turn the original nonlinear system into closed-loop linear system. Furthermore, this paper optimizes the controller according to the robustness, limitation of controller output and closed-loop eigenvalue sensitivity. Putting the controller into the original system, the state response of the closed-loop system and the output of controller are plotted in Matlab to verify the availability and robustness of the controller. Therefore, the controlled spacecraft can achieve the goal of tracking on the mobile target with the external disturbance torque.

ParametricVibration Analysis of Pipes Conveying Fluid by Nonlinear Normal Modes and a Numerical Iterative Approach

Nonlinear normal modes and a numerical iterative approach are applied to study the parametric vibrations of pipes conveying pulsating fluid as an example of gyroscopic continua.The nonlinear non-autonomous governing equations are transformed into a set of pseudo-autonomous ones by employing the harmonic balance method.The nonlinear normal modes are constructed by the invariant manifold method on the state space and a numerical iterative approach is adopted to obtain numerical solutions,in which two types of initial conditions for the modal coefficients are employed.The results show that both initial conditions can lead to fast convergence.The frequency-amplitude responses with some modal motions in phase space are obtained by the present iterative method.Quadrature phase difference and traveling waves are found in the time-domain complex modal analysis.

转轨时期中国工业的效率与生产率——动态非参数生产前沿面理论及其应用

本文采用非参数生产率指数方法对转轨时期中国工业经济增长方式的转变程度进行定量研究。文中采用分区域的工业统计数据生产资源配置效率的变化和技术水平的变化两个方面测算了工业生产率的演化 ,并对生产率增长的内涵、经济增长方式转变的判据、区域性工业经济增长的特征等问题阐述了作者的观点。

模糊需求和模糊能力约束的集约生产计划

通过对模糊需求量和模糊等式及模糊需求环境下生产＿库存平衡方程两种等价的描述方法的基础上,建立了具有模糊需求量和模糊能力约束集约生产计划问题的最佳平衡模型(BAPP)、交互式集约计划模型(IAPP)和交互式求解方法.

对我国建筑业生产技术效率的评估与分析

建立一种非参数方法的经济计量分析模型，对１９８１～１９９６年间我国建筑业的生产技术 效率进行评估分析．结果表明，我国建筑业在这十几年的发展呈良好上升态势，生产技术效率有 显著提高，其平均年增长率达到 １０． ０６％．这种计量分析方法为其它经济效率的研究提供了有益 的借鉴。

地区性因素、集约性特征与工业经济增长——中国工业经济省际差异成因的经验研究

在中国经济快速增长的过程中,各地区经济增长呈现出显著的差异性。工业经济的地区差距是各地经济差距的一个最重要的表现。初始禀赋等工业地区性因素、工业增长的集约性特征和要素的投入水平是可能导致工业经济的地区差距的主要原因。本文采用生产率的非参数测度方法计算得到1992-2002年期间七个截面30个省市自治区直辖市的反映工业增长集约性特征的技术进步率和资源配置效率,并结合面板数据(PanelData)的固定效应计量经济模型(FEM),揭示出了在所研究时间区间内造成工业经济省际差异的成因。本文的研究表明,代表集约型增长特征的技术变革和效率演化对各地工业的增长也呈现波动交替作用的乘数效应,1992-1999年期间,中国工业经济呈现出粗放性特征,资金的投入和各地区的工业基础与初始禀赋因素是导致东、中、西部地区工业经济的地区差异的重要原因,初始禀赋的"遗传效应"很明显。从1999年起中国工业经济进入了一个集约化增长的新阶段,导致省际工业差异的决定性因素变为各地区工业发展形成的新的资金、效率和技术实力,即呈现出典型的禀赋"遗忘效应"。

任意初值非线性不确定系统的迭代学习控制

为解决任意初态下的轨迹跟踪问题,针对一类含参数和非参数不确定性的非线性系统,提出基于滤波误差初始修正的自适应迭代学习控制方法.利用修正滤波误差信号设计学习控制器,并以Lyapunov方法进行收敛性能分析.依据类Lipschitz条件处理非参数不确定性,对于处理过程中出现的未知时变参数向量,利用自适应迭代学习机制进行估计.经过足够多次迭代后,藉由修正滤波误差在整个作业区间收敛于零,实现滤波误差本身在预设的作业区间也收敛于零.仿真结果表明了本文所提控制方法的有效性.

模型参考控制系统设计的一种完全参数化方法

本文进一步深入研究了文［１］中提出的前馈加反馈模型参考输出跟踪控制方案的存在性和求解问题。建立了该控制方案存在的充要条件，并给出了该控制方案的完全参数表示。使得整个控制系统的设计工作只包含设计参数的选取和一些简单的代数运算。两个数值算例说明了该方法的有效性和简单、实用性。

非参数统计理论与人工智能技术在水土空间变异中的应用研究

采用非参数统计理论中的指示克立格与BP神经网络技术,以河套灌区内一典型实验区的土壤水盐预测为例,在一条采样基线上比较了指示克立格与BP神经网络技术的优劣,发现指示克立格与BP神经网络技术在一维空间的土壤水盐预测中能改进普通克立格平滑效应,具有条件模拟的仿真功能,可用于空间水盐插值与预测。

轴心受压钢构件高温下局部稳定设计方法

为了得到钢构件高温下局部稳定设计方法,通过试验对建立的有限元模型进行了验证。采用验证后的有限元模型,分析了温度、板件宽厚比、初始几何缺陷、腹板和翼缘相互作用等因素对H形截面轴心受压钢构件局部屈曲应力的影响,提出了Q235钢和Q460钢H形截面轴心受压构件高温下的局部稳定承载力简化计算公式和高温下防止局部屈曲的翼缘宽厚比和腹板高厚比限值。研究表明:当板件宽厚比较小时,构件的局部屈曲应力随宽厚比的增大迅速减小,宽厚比较大时,构件屈曲应力降低不明显;初始几何缺陷对构件局部屈曲应力影响较小;高温下翼缘对腹板屈曲的约束作用比常温下明显;高温下防止局部屈曲的宽厚比限值与常温下宽厚比限值不同。

我国省级碳排放绩效评价及边际减排成本估计:基于非参数距离函数方法

本文利用非参数距离函数方法研究了能源消费结构约束下的我国省级地区碳排放绩效水平和二氧化碳边际减排成本。计算结果表明:各地区二氧化碳边际减排成本差异较大,一般碳强度越低的地区,所要付出的宏观经济成本越高,减排难度也更大。与传统不考虑能源消费结构的评价结果进行比较发现,忽略能源消费结构的制约会低估碳排放绩效水平,并且导致二氧化碳边际减排成本计算结果出现偏差。

应用半参数法计算石油市场风险价值

由于石油价格收益存在厚尾性特征,采用通常的GARCH参数估计风险价值(VaR)会严重低估风险,对此提出了一种半参数方法,实证表明这种半参数方法在99%的置信度下VaR的计算结果大大改善.