数值算法

Firstly,BEM can be used to accurately calculate the expanding stress at the tip of reamers,with regarding the soil medium as the elastomer.

采用轴对称数值方法，将三维模型转化为二维模型，再采用弹性体边界元边界方法，精确计算扩孔器端面的扩张应力，在此基础上求得扩孔器工作过程中所受的阻力和阻力矩，并通过遗传算法，以阻力和阻力矩最小为优化目标函数，对扩孔器的形状、尺寸进行优化。

The results of simulation show that through CFPSO algorithm component level model can get convergence in a large scale of precision.

数值仿真表明，CFPSO算法能够在比较广泛的精度范围内收敛。

Firstly, based on the sliding mode control and backstepping technique, a new attitude tracking controller is derived to control the attitude motion of spacecraft, the stability of the system is analyzed via Lyapunov method and the reaction wheel dynamics is also considered from the real applications point of view. The whole design process is divided into two steps: the first step is to use sliding control technique to design suppositional adaptive variable structure controller; and the second step is to design attitude tracking controller based on SMC and backstepping technique. Numerical simulations are performed to show that both tracking maneuver and vibration suppression can be accomplished effectively.

首先，采用自适应后步法结合主动振动控制技术设计了姿态跟踪鲁棒控制器，基于Lyapunov方法分析了系统的渐近稳定性；在此基础上，显性地考虑了执行机构动态特性问题，将整个设计过程分为两个步骤：第一步采用滑模控制技术设计了变结构虚拟控制器，给出自适应控制律的设计方法；第二步，将后步法与滑模控制技术相结合，设计了姿态跟踪鲁棒控制器，给出飞轮电压的输入算法及稳定性分析；最后，将提出的控制方法应用于挠性航天器的姿态跟踪控制，通过数值仿真对所提方法的可行性与有效性进行分析和验证。

An art of numerical analysis is to find a stable algorithm for solving a well-posed mathematical problem.

一种艺术的数值分析是找到一种稳定算法求解良好的数学问题提出的。

Based on these, an improving μ-synthesis is presented, with which the high-purity distillation is designed well. 2. The robust performance problem of MIMO plant is explained with the plant direction angle, which shows that the robust performance varies with different input uncertainties and the μ-synthesis should be applied correctly according to the uncertainty structure. 3. Condition number and bandwidth are the important items for robust performance design in MIMO system. The H〓 two-block problems can not deal with the robust performance design of MIMO system because of the condition number cancellation. A general μ-synthesis procedure for MIMO system with uncertainties is presented. 4. For the SISO system, the object function in robust performance is amplified by at most 〓 than that of H〓 two-block problems in value: So the robust performance of SISO system can be done with the H〓 two-block problems to avoid the complicated μ-synthesis procedure. 5. All the conclusions and methods presented in this paper are demonstrated by some typical design examples.

从而形成一种改进的μ综合方去，并对精馏塔病态对象进行了鲁棒性能设计，得到令人满意的结果；（2）利用对象的方向角解释了MIMO对象鲁棒性能设计出现问题的原因，并提出不同输入摄动形式下系统的鲁棒性能问题也并不相同，因此利用μ综合处理鲁棒性能设计时，应根据不同的摄动情况采用不同的结构进行设计：（3）条件数问题和带宽问题是MIMO系统鲁棒性能设计的两个主要问题，指出由于条件数对消的存在使得一般H〓两块问题无法处理MIMO系统的鲁棒性能设计，而μ综合方法则是处理MIMO系统鲁棒性能设计的有效方法，并给出了其处理MIMO系统鲁棒性能设计的一般性方法；（4）提出对于SISO系统H〓两块问题（S/T问题、S/KS问题）的设计指标函数与鲁棒性能设计的μ指标函数在数值上最大差〓倍，因此对于一般SISO系统的鲁棒性能设计可以简单地用一般的H〓的两块问题处理，而避免μ综合设计的复杂过程；（5）本文中提出的结论和算法都利用H〓/μ发展中的典型例子：Doyle-Stein问题，Safonov的战斗机模型，精馏塔对象等进行了设计验证。

By finite element software ANSYS, the process of twin-wire submerged arc welding was performed and the rule of calculation and loading of mobile heat source was studied.

中文摘要：利用有限元软件ANSYS对中厚板的双丝埋弧焊进行了数值分析，对其移动热源的加载算法规律进行了研究。

For improving the maneuver stability,safety and decreasing the tire wear,the combination of the optimization software,modefrontier and msc.adams,is applied to design the steering mechanism,with bottom angle of steering trapezoid,arm length,kingpins distance and axles distance as design parameters,transmit angle as constraint,minimum error between theoretical and practical steering angle as objective function,and simulated annealing as the optimization algorithm.

为了提高汽车操纵稳定性、安全性及减少轮胎磨损，将数值优化软件modefrontier同机械动力学仿真分析软件m sc.adam s集成，以转向梯形底角、转向臂长度、主销中心距和轴距为设计参数，传动角为约束，以转向时内轮实际转角与理论转角的误差最小为目标函数，采用模拟退火算法对转向机构进行最优化设计。

Then confirm the validity of the controller through simulation algorithm.Here we realized the stable control of chaos system through the mutual effect of state variable which is extremely simple and easy to realize.

本文结合反馈控制方法，提出了一种基于系统状态变量的错位线性控制器设计策略，用李雅普诺夫稳定性方法证明了该控制策略的稳定性，并设计了数值仿真算法验证了控制器的有效性。

By using explicit central difference algorithm and finite element software ANSYS/LS-DYNA, the numerical simulation of involute spline shaft's cold-rolling forming was realized.

利用显式中心差分算法，借助有限元分析软件ANSYS/LS-DYNA，通过数值模拟，实现了花键冷滚轧成形过程的可视化。

Using Brian ADI algorithm, the model is solved numerically and a snow-melting simulation program is developed based on the compiler of Visual Basic. This program can output some important results including the pavement temperature field, the height of snow layers, the height of liquid film and the idling characteristic curve.

通过Brian ADI格式算法，对上述模型进行数值求解，并基于Visual Basic平台，开发了一个通用型的道路融雪模拟分析软件，可输出路面温度场、雪层厚度、液膜厚度以及路面待融特征曲线等重要结果。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。