An LTR-observer-based dynamic sliding mode control for chattering reduction

Two important approaches to alleviation of control chattering in sliding mode control are the boundary layer control (BLC) and the dynamic sliding mode control (DSMC). The DSMC is superior to the BLC since in DSMC chattering is alleviated without sacrificing the control accuracy. However, the design of DSMC is more challenging because its sliding variable contains an unknown system uncertainty. This paper proposes a robust two-dimensional LTR observer for estimation of the state-dependent uncertainty in the sliding variable. This paper also shows, via simulation examples, that the DSMC can better reduce chattering than the BLC especially in noisy environments.     

Performance of Optimal Super‐Twisting Controller for Liquid Level

Higher‐order sliding mode control algorithms and second‐order in particular have become a popular research area. This research analyzes the performance of optimally designed Super‐Twisting (STW) controllers, with application to the liquid level process. The problem of optimal design of the STW controller is formulated and a solution methodology is presented. Performance of the STW controller is compared with the performance of an optimally tuned PID controller. The study is carried out through analytical approach, simulations and experiments. From the comparison of performance, conclusions are drawn about suitability and the use of the STW controller for the process specifically considered in this research as well as other process control applications.     

不确定系统离散变结构控制及在位置伺服系统中的应用

研究有界不确定离散时间系统的变结构控制设计问题.对利用传统离散趋近律设计变结构控制器时出现的稳态抖振现象进行分析,提出一种能有效减弱抖振的控制策略,并将研究结果用于设计某位置伺服系统变结构控制器.理论分析及仿真结果表明,所设计的控制器可以有效减弱抖振,并使伺服系统具有良好的跟踪能力和很强的鲁棒性.     

二阶动态滑模控制在磁悬浮控制系统中的应用

磁悬浮是典型的非线性、不稳定系统.为了实现其控制,本文采用了一种结合二阶滑模和动态滑模两种设计思想的二阶动态滑模控制器的设计方法,首先推导了磁悬浮系统的线性化状态空间模型;然后针对被控对象设计了二阶动态滑模控制器;最后与普通滑模控制器进行对比仿真试验.仿真结果表明,所设计的二阶动态滑模控制器在使小球快速稳定到达平衡点的同时,大大削弱了普通滑模控制器中存在的严重抖振现象.     

Robust MRAC to disturbance using VS‐type adaptive identifier

It is well known that variable structure (VS)‐type model reference adaptive controls (MRAC) are robust to disturbances. However, almost all conventional design schemes of VS‐MRAC may cause chattering because of the switching function used in the control synthesis input. In this paper, we propose a new design scheme of MRAC which uses a VS‐type adaptive identifier. This design scheme can avoid occurrence of chattering. Furthermore, this design scheme is robust to disturbances. © 1999 Scripta Technica, Electr Eng Jpn, 130(2): 80–87, 2000     

基于ESO 的复合滑模面非奇异terminal 滑模控制

针对传统非奇异terminal 滑模控制存在的收敛缓慢和控制输入抖振的问题, 提出采用复合滑模面函数和扩张状态观测器的控制器设计方法. 首先, 结合复合滑模面, 采用分阶段控制律提高系统收敛速度; 然后, 在此基础上使用扩张状态观测器在线估计并补偿系统的不确定量, 以有效削弱系统未建模动力学导致的抖振; 最后, 分别证明了以上两种方法的有限时间收敛特性. 仿真结果验证了所提出方法的有效性, 体现了系统的快速收敛和强鲁棒性等特点.     

Position control of synchronous motor drive by modified adaptive two-phase sliding mode controller

A modified adaptive two-phase sliding mode controller for the synchronous motor drive that is highly robust to uncertain-ties and external disturbances is proposed in this paper. The proposed controller uses two-phase sliding mode control (SMC) where the 1st phase mainly controls the system in steady states and disturbed states-it is a smoothing phase. The 2nd phase is used mainly in the case of disturbed states. Also, it is an autotuning phase and uses a simple adaptive algorithm to tune the gain of conventional variable structure control (VSC). The modified controller is useful in position control of a permanent magnet synchronous drive.     

基于神经网络的PMSM自适应滑模控制

结合滑模控制和神经网络各自的优点,对永磁同步电机(PMSM)提出了一种基于神经网络的PMSM自适应滑模控制方案.首先设计了带积分操作的滑模变结构位置控制器,通过递归神经网络的在线学习来实时估计系统参数变化和外部负载扰动等不确定性的界限,减小滑模控制器的控制量.进而,在滑模控制器中又引入饱和函数取代符号函数,进一步减弱"抖振"现象.理论分析和实验仿真对比研究的结果表明所提出方法具有优越的动态性能和鲁棒性.     

建筑结构的准滑模控制研究

结合饱和函数和继电特性连续函数的优点,提出了含饱和函数的指数趋近律形成的控制律和含继电特性连续函数的指数趋近律形成的控制律。基于这两种控制律,采用准滑模控制方法对地震作用下建筑结构的振动控制问题进行了研究。以一个多层剪切型建筑结构模型为例验证所提控制方法的有效性,算例数值分析结果表明,所提出的准滑模控制方法,控制效果明显,能有效地减小结构的地震峰值响应,且在控制参数ε值较大的情况下,控制系统的抖振很小。     

低抖振非奇异终端滑模控制

为了解决常规滑模控制中产生的抖振,同时利用终端滑模控制中快速收敛的优良特性,针对一类二阶仿射非线性系统,将非奇异终端滑动流形和终端到达律同时应用到滑模控制设计中,得到低抖振非奇异终端滑模控制,并证明其具有较强的鲁棒性.