广义性能驱动的机械产品方案设计方法

将产品广义性能作为驱动整个机械产品方案设计过程的有效工具,利用'对象结构'公理推导并结合'P-E'体系给出了产品广义性能的定义,将产品广义性能划分为结构性能和行为性能两类。针对两类广义性能分别进行形式化表述,构建产品广义性能相关的产品符号模型。提出一种广义性能驱动的机械产品方案设计方法,分析性能结构映射可能出现的理想映射、冗余映射和耦合映射关系,给出广义性能驱动机械产品方案设计的过程图解与算法。以注塑机产品重要组成部分之一的注射装置方案设计为例,说明该方法在实际机械产品方案设计中的应用,证明了该方法的正确性、有效性与实用性。

广义性能指标下T-S模糊系统的鲁棒可靠控制

针对一类具有输入及输出端扰动的T-S模糊系统,在线性矩阵不等式区域内定义了非线性系统的稳态及动态广义性能指标,提出了线性矩阵不等式(LMI)方法下可靠输出反馈控制器存在的充分条件,从而保证闭环系统在传感器或执行器发生结构性故障时的稳态及动态性能,且始终满足基于L2/L∞范数理论的鲁棒性能,并利用投射引理引入附加阵,解耦该充分条件中的控制器变量与相关Lyapunov函数变量,增加设计的自由度.F-16歼击机的纵向通道控制仿真表明了方法的有效性.

广义性能化结构加固设计方法之经济指标分析

在探索广义性能化结构加固设计方法基础上,进行了经济指标分析.建筑性能目标的实施,需要建筑经济指标分析为指导,研究的目的是通过功能定位和经济分析,达到节约资源,实现经济利益最大化.采用财务净现值方法对建筑的投入和支出进行了分析,给出了广义性能化结构加固框架与流程.研究表明,广义性能化结构加固设计方法是可行和经济的,但仍需要不断深入研究、完善和发展.

具有时变不确定性的广义系统的鲁棒H_∞控制

研究具有一般形式的不确定广义系统的鲁棒H∞状态反馈和动态输出反馈控制器的设计问题·基于广义二次H∞性能概念,利用线性矩阵不等式,首先证明了如果存在鲁棒H∞动态状态反馈控制器,则必存在鲁棒H∞静态状态反馈控制器,然后给出鲁棒H∞静态状态反馈控制器存在的充要条件及构造方法,最后给出鲁棒H∞动态输出反馈控制器存在的充分条件以及相应的控制器构造·

时滞系统的非脆弱广义H_2控制

针对状态反馈控制器所具有的加性和乘性摄动不确定性,设计无记忆的状态反馈控制器,使得对于所允许的不确定性,对应的闭环系统是稳定的,同时具有指定的广义H2性能指标.以线性矩阵不等式的形式,给出了时滞系统存在非脆弱广义H2控制器的充分条件.当对应的线性矩阵不等式可解时,系统的非脆弱广义控制器可以通过凸优化求解而得到.所得到的结果可以拓展得到不确定的时滞系统的控制器.

具有热阻和热漏的再热布雷顿循环性能分析

用有限时间热力学方法建立了一个工作在恒温热源TH、TL之间,存在热阻、热漏和再热的定常流空气标准闭式布雷顿循环模型。导出了其功率、效率的一般关系并对其进行优化,得到循环的基本优化关系;分析了在傅立叶导热定律下再热对循环最优性能的影响。

无线传感器网络LEACH协议的Petri网模型及性能分析

Petri网是分析网络协议一种有效的形式化建模工具,基于对无线传感器网络LEACH协议运行机制的分析,为协议建立广义随机Petri网(GSPN)性能模型,并用SPNP软件对建立的性能模型进行分析,模型数据验证了模型的有效性,同时讨论了性能模型对协议的低功耗改进所起的指导作用。

离散区间二型Tagaki-Sugeno模型时滞系统广义耗散控制设计

对带有时变时滞和外部扰动的一类离散区间二型Tagaki-Sugeno(T–S)模型非线性系统,研究了其广义耗散性能分析与状态反馈控制器的设计问题.与一型T–S模糊系统相比,区间二型模糊系统能更好地处理隶属函数中的不确定信息.首先,通过模型转换的方法,对系统的滞后状态进行变换,从而将时变时滞的不确定性从原系统中分离出.根据转换后的仅含定常时滞和具有有界误差范数的两个子系统,利用时滞依赖的李雅普诺夫-克拉索夫斯基泛函方法推导出了使系统渐近稳定并具有广义耗散性能的充分条件.接着,设计了保证闭环系统渐近稳定并具有广义耗散性能指标的状态反馈控制器.最后由数值仿真验证了设计方法的有效性.

不确定区间二型离散系统的广义H2控制器设计

研究了一类不确定区间二型离散系统的广义H2控制问题,根据Lyapunov稳定性理论和矩阵不等式放缩技巧,建立了使闭环系统渐近稳定且具有广义H2范数界的充分条件.利用二型模糊基函数的特性引入松弛矩阵,并使用矩阵分解技巧对具有不确定性的参数矩阵进行了处理.最后,通过仿真实例验证了设计方法的可行性.

T-S模糊多项式奇异系统的广义耗散滑模控制

文章研究了T-S模糊多项式奇异系统的滑模控制问题.针对被控制对象的T-S模糊多项式奇异模型,设计一种带有奇异矩阵的分段切换面的滑模控制器,并利用SOS技术和含有非正定项的分段李雅普诺夫函数,给出滑动模态广义耗散可容许的充分条件,设计滑模控制器使系统状态保持在切换面上.最后,通过一个数值算例证明所提方法的有效性.

基于LMI优化的主动悬架多目标控制

首先将汽车主动悬架的控制问题归结为有时域硬约束的鲁棒干扰抑制问题．在多目标控制框架下,基于线性矩阵不等式(LMI)优化技术,提出了一种H_2/广义H_2混合控制策略：利用广义H_2范数描述系统的时域硬约束,同时选择H_2范数最小化系统的性能输出,最终将系统的控制律归结为求解具有LMI约束的半定规划问题．以半车模型为例设计了主动悬架控制器,并给出了较全面的分析和仿真结论．最后利用快速原型(RCP)和硬件在回路仿真(HILS)一体化技术进一步验证所提方法的有效性和可行性．

Application of the generalized quasi-complementary energy principle to the fluid-solid coupling problem

The fluid-solid coupling theory, an interdisciplinary science between hydrodynamics and solid mechanics, is an important tool for response analysis and direct design of structures in naval architecture and ocean engineering. By applying the corresponding relations between generalized forces and generalized displacements, convolutions were performed between the basic equations of elasto-dynamics in the primary space and corresponding virtual quantities. The results were integrated and then added algebraically. In light of the fact that body forces and surface forces are both follower forces, the generalized quasi-complementary energy principle with two kinds of variables for an initial value problem is established in non-conservative systems. Using the generalized quasi-complementary energy principle to deal with the fluid-solid coupling problem and to analyze the dynamic response of structures, a method for using two kinds of variables simultaneously for calculation of force and displacement was derived.

The optimal performance of a generalized Carnot cycle for a generalized heat transfer law

The finite time thermodynamic performance of a generalized Carnot cycle, in which the heat transfer between the working fluid and the heat reservoirs obeys the generalized law Q∝( Δ T) m , is studied. The optimal configuration and the fundamental optimal relation between power and efficiency of the cycle are derived. Some special examples are discussed. The results can provide some theoretical guidance for the design a practical engine.

Classification and Functional Separable Solutions to Extended Nonlinear Wave Equations

The generalized conditional symmetry approach is applied to study the variable separation of the extended wave equations. Complete classification of those equations admitting functional separable solutions is obtained and exact separable solutions to some of the resulting equations are constructed.

Multivariable Control Performance Assessment Based on Generalized Minimum Variance Benchmark

This paper is concerned with the control performance assessment based on the multivariable generalized minimum variance benchmark.An explicit expression for the feedback controller-invariant(the generalized minimum variance)term of the multivariable control system is obtained,which is used as a standard benchmark for the assessment of the control performance for multi input multi output(MIMO)process.The proposed approach is based on the multivariable minimum variance benchmark.In comparison with the minimum variance benchmark, the developed method is more reasonable and practical for the control performance assessment of multivariable systems.The approach is illustrated by a simulation example and an industrial application.

Modeling hot strip rolling process under framework of generalized additive model

This research develops a new mathematical modeling method by combining industrial big data and process mechanism analysis under the framework of generalized additive models(GAM)to generate a practical model with generalization and precision.Specifically,the proposed modeling method includes the following steps.Firstly,the influence factors are screened using mechanism knowledge and data-mining methods.Secondly,the unary GAM without interactions including cleaning the data,building the sub-models,and verifying the sub-models.Subsequently,the interactions between the various factors are explored,and the binary GAM with interactions is constructed.The relationships among the sub-models are analyzed,and the integrated model is built.Finally,based on the proposed modeling method,two prediction models of mechanical property and deformation resistance for hot-rolled strips are established.Industrial actual data verification demonstrates that the new models have good prediction precision,and the mean absolute percentage errors of tensile strength,yield strength and deformation resistance are 2.54%,3.34%and 6.53%,respectively.And experimental results suggest that the proposed method offers a new approach to industrial process modeling.

Energy dissipation of cavity expansion based on generalized non-linear failure criterion under high stresses

Based on the compression mechanism for analyzing the cavity expansion problem in soil under high stresses,generalized non-linear failure criterion and large strain and energy conservation in plastic region during the cavity expanding were adopted.The energy conservation equation was established and the limited pressure of cavity expansion under high stresses was given based on the energy dissipation analysis method,in which the energy generated from cavity expansion is absorbed by the volume change and shear strain caused in soil.The factors of large strain and dilatation were considered by the proposed method.The analysis shows that the limited pressure is determined by failure criterion,stress state,large deformation characteristic,dilatation and strength of soil.It is shown from the comparison that the results with the proposed method approximate to those of the in-situ method.The cavity expansion pressure first decreases and then increases nonlinearly with both of shear modulus and dilatation increasing.

Performance Comparison Between Logistic and Generalized Surplus-Production Models Applied to the Sillago sihama Fishery in Pakistan

The catch and effort data of Sillago sihama fishery in Pakistani waters were used to investigate the performance of two closely related stock assessment models: logistic and generalized surplus-production models. Compared with the generalized production model, the logistic model produced more reasonable estimates for parameters such as maximum sustainable yield. The Akaike's Information Criterion values estimated at 4.265 and -51.152 respectively by the logistic and generalized models. Simulation analyses of the S. sihama fishery showed that the estimated and observed abundance indices for the logistic model were closer than those for the generalized production model. Standardized residuals were distributed closer for logistic model, but exhibited a slightly increasing trend for the generalized model. Statistical outliers were seen in 1989 and 1993 for the logistic model, and in 1981 and 1999 for the generalized model. Simulated results revealed that the logistic estimates were close to the true value for low CVs (coefficients of variation) but widely dispersed for high CVs. In contrast, the generalized model estimates were loose for all CV levels. The estimated production model curve parameter was not reasonable at all the tested levels of white noise. With the increase in white noise R2 for the catch per unit effort decreased. Therefore, we conclude that the logistic model performs more reasonably than the generalized production model.

A Generalized Hankel Transformation Derived by Parametrized Entangled State Representations

Using the parametrized entangled state representations we have found a generalized Hankel transformationwith the integral kernel being a combination of Bessel functions.This generalized Hankel transformation corresponds tothe appropriate quantum mechanical representation transformation.