离散时间变结构控制及其仿真研究

【作者】 李忠娟；

【导师】 张新政；

【作者基本信息】 广东工业大学 ， 控制理论与控制工程， 2004， 硕士

【摘要】 变结构控制从20世纪50年代产生至今，因它对系统参数摄动和外干扰具有鲁棒性，而受到了世界范围的重视。已成功地应用到了许多方面，如机器人手臂、发电机及电力电子系统。近年来，随着计算机技术的飞速发展和工业自动化领域的实际需要，控制算法的实现经常利用数字计算机，但当采用数字计算机实现变结构控制算法时，由于采样过程的限制，理想的滑动模态不存在，状态轨迹以抖振的形式沿着滑动平面运动，这是不利于工程的实际应用的。同时，在离散的情况下，滑动模态的性质、存在条件及其到达条件都已经改变，因此研究离散时间系统变结构控制方法对降低抖振具有重要的理论价值和实际意义。 本文详细分析了变结构控制的现状，着重研究了离散时间系统的变结构控制问题。主要内容包括如下几个方面： 一、论述与本文有关的背景； 二、给出了离散时间系统变结构控制的有关概念，分析了离散时间系统滑动模态的到达条件、存在条件和稳定性问题。 三、给出了滑动模态存在的充分条件，在此基础上给出了控制器的设计方法。其次，详细分析了离散指数趋近律抖振产生的原因，给出两种改进方案，并与其它方法进行了比较。最后，分别给出了每种方案的数例仿真，仿真结果表明所提方案是有效的、可行的。 四、研究了不确定系统的离散时间变结构控制，利用灰色系统理论，对不确定部分建立灰色估计模型，给出仿真数例，结果表明此方法是合理的。更多还原

【Abstract】 Variable structure control(VSC) are well known for their robustness to system parameter variations and external disturbances. VSC have been widely used in many applications, such as robots, aircrafts, power generator and DC and AC motors and so on. In the recent years, with the development of microcomputer technology and the needs of industrial automation. We use computer to realize the control algorithm. But during the time of realizing the VSC, because of the limits of sampling, the ideal sliding mode does not exist. The state trajectory of system is chattering, which restrict it’s actual applications. In the circumstances, the arrival condition and the existence condition have been changed. It is significant to study discrete-time VSC (DVSC) to reduce chattering of sliding mode.In this thesis, a detailed analysis of the current situation of study on variable structure and a discussion about the discrete-time systems VSC are stressed. The main contents in this thesis are as follows.1. The background related to the subject is summarized2. The related definitions of DVSC are proposed. After analyzing the arrival condition, the existence condition and stabilization of sliding mode in DVSC.3. Detailed analyzing the reason for the discrete reaching law to cause system chattering is given and three improved discrete reaching law is developed. At last, several simple examples are given to illustrate the proposed methods, simulation results are compared with those of some other design methods, which justifies the conclusion obtained.4. The design of VSC for uncertain discrete time systems is discussed. A grey estimating model is built for the uncertain part and thus values of parameters are obtained. Simulation results are presented to illustrate that the method in the thesis is rational.更多还原