Adaptive finite-time tracking control for parameterized nonlinear systems with full state constraints

In this article, the issue of adaptive finite-time dynamic surface control (DSC) is discussed for a class of parameterized nonlinear systems with full state constraints. Using the property of logarithmic function, a one-to-one nonlinear mapping is constructed to transform a constrained system into an unconstrained system with the same structure. The nonlinear filter is constructed to replace the first-order linear filter in the traditional DSC, and the demand on the filter time constant is reduced. Based on finite-time stable theory and using modified DSC, the finite-time controller is designed via DSC. Theoretical analysis shows that all the signals in the closed-loop system are semiglobal practical finite-time stable. Furthermore, none of the states are outside the defined open set. In the end, simulation results are presented to demonstrate the effectiveness of the proposed control schemes with both linear filters and nonlinear filters.     

基于WEP的横断山垂直带水文过程模拟研究

为了更好模拟横断山在气象、植被、土壤、水分等垂直地带性影响下的水文过程，本文采用分布式流域水文模型 WEP，提出反映空间分异特征的垂直带参数化方案，并选择横断山流域 14 个水文控制断面 1960—2015 年的逐月径流数据进行了模拟验证。结果显示，垂直带参数化方案较好地模拟了横断山区的水循环过程；通过两种对照方案和垂直带参数化方案的对比表明，“垂直带参数化方案”比“普通的参数方案”的 NS 提高 0.03、RE 降低1%，比“均一化参数方案”的 NS 提高 0.3、RE 降低 19.6%。通过考虑参数的垂直变化影响，能够提高模型模拟效果，且可更好地反映气象、植被、土壤、水分等信息的垂直地带性，弥补以往水文模型对参数的垂直变化描述不足的问题。     

流线型齿轮挤压型腔构造及图形交互加工

针对齿轮挤压模具型腔易损坏、精度和效率低等弊病,引入流曲线和Bezier曲线理论,建立挤压型腔参数化模型,利用Pro/E软件的造型和图形交互功能,实现型腔的实体模型建立及高速铣削模拟。     

A simulation‐based algorithm for optimal pricing policy under demand uncertainty

We propose a simulation‐based algorithm for computing the optimal pricing policy for a product under uncertain demand dynamics. We consider a parameterized stochastic differential equation (SDE) model for the uncertain demand dynamics of the product over the planning horizon. In particular, we consider a dynamic model that is an extension of the Bass model. The performance of our algorithm is compared to that of a myopic pricing policy and is shown to give better results. Two significant advantages with our algorithm are as follows: (a) it does not require information on the system model parameters if the SDE system state is known via either a simulation device or real data, and (b) as it works efficiently even for high‐dimensional parameters, it uses the efficient smoothed functional gradient estimator.     

基于CATIA的渐开线直齿轮的参数化建模与应用

介绍了运用三维软件CATIA建立渐开线直齿轮的参数化三维模型。通过f(x)方式输入齿轮的基本参数,通过GSD模块中的fog方式输入渐开线参数方程并生成渐开线,建立了齿轮的参数化模型,并对后继的应用加以说明。     

基于ObjectARX的标牌曲线文字绘制的研究

为了提高标牌行业的绘制标牌的工作效率,操作流程的标准化,研究标牌参数化绘制方法及技术,结合（）NectARX2008与VisualStudio2008中的c。进行了AutoCAD的二次开发,详细阐述了标牌参数化绘图系统的结构、设计流程以及应用设计结果进行参数化绘图的过程,使标牌企业绘制人员在绘制的过程中,只需输入必要参数就可以由计算机自动生成所要绘制的曲线文字,从而大大提高了工作效率并扩展了CAD二次开发的范围。     

筒辊磨系列产品参数化设计

在分析筒辊磨背景技术基础上,提出筒辊磨系列产品参数化设计的方案流程:建立筒辊磨力学模型,导出筒辊磨参数化计算公式,采用工程反求设计方法确定设计参数。应用Delphi编程方法,求解系列产品的结构参数和工艺参数值,并通过实例验证筒辊磨参数化设计软件结果。采用筒辊磨系列产品的参数化设计软件可避免类比设计的传递误差,显著降低研发和制造成本,实现面向工程、面向用户的快速响应设计。     

基于AutoLISP的AutoCAD二次开发技术

AutoLISP是AutoCAD二次开发工具之一.它容易掌握、功能强大,应用广泛.先对AutoLISP进行了简介,并介绍了这种程序的几种加载方法和参数化设计思想,通过一个实例介绍了基于AutoLISP的参数化程序设计技术.     

基于Pro/M的摆动从动件圆锥凸轮建模与NC加工

以Pro/Mechanism为平台,运用机构运动仿真原理,建立了圆柱滚子摆动从动件圆锥凸轮实体的参数化造型与NC加工.提供了一种简单实用的空间凸轮实体造型方法,易于为一般工程技术人员所掌握.该方法也可应用于其它机械零件三维实体参数化造型.     

A sufficient condition for asymptotic stability for a class of time-varying parameterized systems

We derive sufficient conditions for local asymptotic stability for a class of parameterized time-varying systems, whose dynamics are in general unbounded in time. Our main result generalizes a well known limiting-dynamics based approach due to Peuteman and Aeyels (1999) in [9] for fast time-varying systems whose dynamics are bounded in time. Its proof is based on a new result providing a Lyapunov characterization for exponential stability.