不常

In our thesis, contents are organized as following In Chapter 1 we present our topic's internal and overseas research situations, theoretical and practical significance, and introduce the research object and contents, and the main contributions of this dissertation. Chapter 2 reviews the development of the stability results for nonlinear systems and some relevant recent results, which include Lyapunov and LaSalle-Yoshizawa theorems for nonlinear systems, and stochastic edition for stochastic nonlinear systems. Sontag's formula for systems affine in control is presented in the frame of CLF. The concepts of disturbance attenuation and the inverse optimality are also explained in this Chapter. In chapter 3 we present the solvable theorem of inverse optimal gain assignment problem, design the inverse optimal controller and the inverse optimal tracking controller for strict-feedback nonlinear continuous systems with unknown time-varing bounded disturbances and constant unknown parameters using an adaptive backstepping algorithm, which are nonlinear, continuous and are easier to realize. These designs are fully systematic and the algorithm can be directly coded in symbolic software. The results of simulation show the effectiveness of the control algorithms.

论文的结构如下：在第1章中，给出了本文研究课题的研究现状、理论意义和实际应用，并介绍了本文的研究对象、研究内容以及主要贡献；在第2章中，针对确定性非线性系统和随机非线性系统，分别介绍了Lyapunov定理、LaSalle-Yoshizawa定理及其随机版本；对仿射系统，在控制Lyapunov函数框架下，给出了Sontag公式；同时给出了非线性系统扰动抑制和逆最优控制问题的基本概念；在第3章中，针对具有未知时变有界扰动和未知定常参数的一类不确定非线性系统，给出并证明了逆最优增益配置可解定理，使用自适应Backstepping算法和均值定理，系统地设计了自适应逆最优控制器和逆最优跟踪器，这种设计方法可同时获得逆最优控制策略和自适应律，简单明了，仿真结果表明该控制算法的有效性，并给出了性能估计。

In Chapter 4 we discuss the solvable theorem of adaptive inverse optimal control problems, and proceed with controller designs of global asymptotic stability in probability, adaptive inverse optimal stabilization in probability and output-feedback adaptive inverse optimal stabilization in probability for strict-feedback stochastic nonlinear continuous systems with additive standard Wiener noises and constant unknown parameters using It〓's differentiation rule and an adaptive backstepping algorithm. Control laws and adaptive laws can be obtained at one time by this design scheme. Many simulations have been performed to validate the properties of the proposed adaptive control scheme.

在第4章中，针对具有标准Wiener噪声扰动和未知定常参数的不确定随机非线性系统，提出并证明了自适应逆最优控制问题可解定理，构造了适当形式的四次型随机控制Lvapunov函数，基于It〓微分规则和自适应Backstepping算法，系统地设计了全局依概率渐近稳定控制器、自适应逆最优控制器、输出反馈逆最优控制器以及在设计中如何处理二阶Hessian矩阵函数的方法，这种方法可同时获得控制律和自适应律，通过实例仿真，表明该控制算法是有效性的。

Endoscopic stone ex- traction included movable stones that could be returned into common bile duct and irremovable stones that should be intubated and extracted aided by EST.

内镜取石治疗主要采用还纳法和非还纳法，不能还纳的结石应用乳头括约肌切开术辅助插管和取石，结石常在乳头括约肌切开后自行脱出。

She used to say to me, They don't know you're kidding, Irv.

"|他以前常跟我说"Irv，他们听不懂你的笑话啦

Jabez prayed to the God of Israel:"Oh, that you may truly bless me and extend my boundaries! Help me and make me free of misfortune, without pain!"

雅贝兹呼求了以色列的天主说："若你真降福我，求你扩展我的疆域，求你常伸手扶助我，脱免灾难，不受痛苦。"

Johanna : Not usually,but I've been looking for boots like these for a while.

不是常去，但是我找这样靴子找了很久

Since the government would not pay for such a new field of science as botany, Joseph Banks, at the age of 25, had to supply about ￡10,000 of his own money to equip the expedition.

serve v。为……工作；提供搭配：在写作中，表示"提供"时，同学们常常用provide，而不熟悉serve的这种用法。

"Love on the first sight" or "Hate for an instant" are the signs for juvenility.

"一见钟情"或"瞬间成恨"常被视为不成熟的标记。

Calm and phlegmatic, with a clear eye, Mr Fogg seemed a perfect type of that English composure which Angelica Kauffmann has so skilfully represented on canvas.

安详，冷静，眼皮一眨不眨，眼珠明亮有神，简直是那种冷静的英国人最标准的典型。这种人在联合王国里是司空见惯的。昂·高夫曼的妙笔，常把他们画成多少带点学究气的人物。

The Kendal's W coefficient was used to verify the consistency of the assessment results of the different evaluation methods.

应用不同方法进行农业气象灾情评价时，常出现评价结果不一致的现象。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。