【作者】 赵秀华；

【导师】 韩莉；

【作者基本信息】 东北电力大学 ， 模式识别与智能系统， 2008， 硕士

【摘要】 变结构控制自产生以来,因其对参数摄动和外界干扰的不敏感性,受到了控制界的广泛关注。近年来,随着计算机技术的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,离散系统变结构控制中的切换不再是连续光滑的,而只是一个准滑动模态。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。本文首先介绍了变结构控制的历史及现状及存在的问题。而后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。着重讨论了利用离散趋近律设计离散时间系统的变结构控制问题,在衰减控制的基础上,针对衰减变速趋近律的抖振问题,给出了两种改进方案。而后利用全程滑模变结构控制理论,提出了基于衰减控制的全程滑模变结构控制器,充分利用了全程滑动模态鲁棒性强的优点,并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。最后,针对不确定性问题,分别利用干扰观测器和利用时延性估计未知干扰的方法设计了两种鲁棒性控制器,通过数例仿真验证了其良好的鲁棒性。更多还原

【Abstract】 Variable structure control (VSC) is well known for its robustness to system parameter variations and external disturbances.VSC has been widely used in many applications.In recent years,with the development of microcomputer technology and the needs of industrial automation,we use computer to realize the control algor- ithm.But during the time of realizing the VSC,because of the limits of sampling, the ideal sliding mode does not exist,and the switching control is not smooth any more,it is only a quasi-sliding mode.It is significant to study discrete-time VSC (DVSC) to reduce chattering of sliding mode.Firstly,in this dissertation,a detailed analysis of the history and current situation of study on variable structure and a discussion about the discrete-time systems VSC are stressed.Secondly,the related definitions of DVSC are proposed. After analyzing the arrival condition,the existence condition and stabilization of sliding mode in DVSC.It is discussed that the design of variable structure control for discrete time system using discrete reaching law.Based on the he attenuating variable rate and the attenuating power reaching law,two improved discrete reaching law are developed. Using global sliding mode variable structure control theory,a global sliding mode variable structure controller based on the attenuating power reaching law is developed.It used the advantage for robustness of the sliding mode. The simulation results show that the approach is effective.Finally,A discrete-time variable structure controller with a decoupled disturbance compensator its application to a CNC servomechanism is designed.And another kind of controller is designed by applying delay characteristic to estimate the uncertainty on-line.Both theory analysis and simulation can prove the validity of these methods.更多还原