【作者】 刁晨；

【导师】 陈希平；

【作者基本信息】 兰州理工大学 ， 控制理论与控制工程， 2007， 硕士

【摘要】 变结构控制是五十年代末发展起来的一类控制算法，由于它对系统参数摄动和外干扰具有鲁棒性，因而受到了世界范围的重视。变结构控制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，这不利于工程实际应用。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。本文在变速趋近律、指数趋近律和可拓控制的基础上提出了一种新的控制策略，其主要内容包括如下几个方面：1．回顾了离散变结构控制与可拓控制的产生背景及意义，以及两者结合产生的基于可拓控制的离散变结构系统组合控制策略研究的必要性。2．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。3．给出了可拓控制的基本概念、基本结构、可拓集合的性质和可拓控制的基本算法。4．将可拓控制与离散变结构控制相结合，针对离散变结构控制系统提出了一种新的控制策略。通过对指数趋近律、变速趋近律和本文提出的控制策略仿真对比说明，新的组合控制策略能够有效的减小抖振提高系统的动态性能。5．论文最后，对全文进行总结，对后续工作进行了展望。更多还原

【Abstract】 Variable structure control (VSC) is well known for its robustness to system parameter variations and external disturbances developed in the late 1950’s. VSC has been widely used in many applications, such as robots、 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 its 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 dissertation, on the basis of the variable rate reaching law、 exponential rate and extension control, a new control strategy is formed. The contents in this dissertation are as follows:1. Review the developing of DVSC and extension control. And tell of the necessary of combine the two algorithms as a new algorithm named hybrid control strategies for discrete variable structure control systems via extension control.2. The related definitions of DVSC are proposed. The arrival condition, the existence condition and stabilization of sliding mode in DVSC are analyzed.3. Present the related basic concepts of extension control, the structure of canonical extension control, extension set of character status of basic extension controller, and general extension control algorithm.4. In chapter four, apply extension control into the DVSC and present a new hybrid control strategies for discrete variable structure control systems. The simulations are made between variable rate reaching law、 exponential rate and extension control for DVSC. The results show that the new hybrid control strategies are effective in reducing the chattering and improving dynamic performances of system effectively.5. In the end, a conclusion is made and the future researches are prospected.更多还原