渐近特性

In consideration of the nonlinear characters of driving chain, with the general perturbation method, the asympototical solution to the nonlinear dynamic equation of the valve train with multinomial timing cam of symmetrical type is reached in this paper.

本文在考虑到传动键的非线性特性情况下，用普通小参数法求出了具有对称多项式凸轮的配气机构气门的渐近解。

Modeling and stability analysis problem of linear switched system are emphasized in this part and main results include:(1) Through investigation in the projection of 〓 on x, where x denotes continuous state vector, a series of sufficient conditions for stability, asymptotic stability and unstability of linear switched system's equilibrium in the sense of Lyapunov are achieved. And also, a sufficient and necessary condition for state bounded stability of linear switched system is received.(2) For a class of periodical linear switched system whose switching sets are a group of ordinal lines starting from the original point, it's proved that state bounded stability can be defined by the running characteristic in a single period (3) Based on linear switched system, the concept of linear switched system network is put forward. Linear switched system network is a complex network interconnected by many linear switched systems.

这部分着重研究线性切换系统的建模与稳定性分析问题，主要成果包括：（1）通过考察〓在x上的投影，得到线性切换系统的平衡点在Lyapunov意义下稳定、渐近稳定及不稳定的一系列充分条件，并得到了线性切换系统状态有界稳定的一个充要条件；（2）证明了对于一类切换集为从原点出发的一组射线的周期线性切换系统，其状态有界稳定可根据一个周期内的系统运行特性来判定；（3）在线性切换系统的基础上提出了线性切换系统网络的概念，线性切换系统网络是由多个线性切换系统交互作用而形成的复杂网络。

A nonlinear adaptive speed controller based on adaptive backstepping approach for permanent magnet synchronous motors with nonlinear coupling and parameter uncertainties is presented. With the preposed controller, the parameter uncertainties are compensated and high performance speed controller for permanent magnet synchronous motors is shown to be globally asymptotically stable. The scheme is robust to the parameter uncertainties and load torque disturbance.

针对永磁同步电动机系统的非线性耦合特性以及参数的不确定性，采用自适应反步控制实现永磁同步电动机的非线性控制，在补偿参数不确定性影响，提高系统的抗干扰能力的同时，实现了永磁同步电动机的高性能全局渐近稳定速度跟踪控制。

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。

Moreover, a sensitivity redistribution method in combination with the above method is also used to control checkerboard patterns so as to have a smooth transition of each element＇s contribution to the whole structural performances.

算例表明，本文的单元材料特性更改的结构渐近拓扑优化方法与灵敏度再分配棋盘格式控制技术相结合的方法，可以得到边界清晰、结构合理的拓扑优化构形。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐