改进快速全局滑模控制方法

针对全局滑模控制的动态滑模面不能在有限时间内演化为线性滑模面的缺点, 提出一种改进的全局滑模控制方法, 其动态滑模面的衰减函数由3个指数函数项组成一阶可导函数, 并能在有限时间内衰减为零. 这样, 该方法不仅具有了全局滑模控制的全局鲁棒性, 而且能够使动态滑模面在有限时间内演化为线性滑模面, 从而加快了系统的响应速度. 利用该方法实现了二阶电力系统的混沌控制, 仿真结果验证了所提出方法的有效性.     

Fuzzy sliding mode control for an under-actuated system with mismatched uncertainties

This article presents a robust fuzzy sliding mode controller. The methodology of sliding mode control provides an easy way to control under-actuated nonlinear systems with uncertainties. The structure of the sliding surface is designed as follows. First, decouple the entire system into second-order systems so that each subsystem has a separate control target expressed in terms of a sliding surface. Second, from the sliding surface of subsystems, organize the main sliding surface system. Third, generate a control input for the main sliding surface to make whole subsystems move toward their sliding surface. A fuzzy controller is used to obtain a smooth boundary layer to the sliding surface. Finally, the fuzzy sliding mode controller presented is used to control an under-actuated nonlinear system, and confirms the validity of the proposed approach and its robustness to uncertainties.     

有限时间收敛的Terminal滑模控制设计

讨论了一类SISO非线性系统的滑模变结构控制有限时间收敛问题,提出一种新的Terminal滑动模态及相应控制的设计方法,可用于带有外部扰动的二阶非线性系统。研究结果表明,系统状态在滑模面上能以较快的速度达到平衡点,在滑模面上到达平衡点的时间均是有限的,并且与普通的Terminal滑模相比,在滑模面上能以更短的时间到达平衡点。仿真结果表明了所提方法的有效性。     

一类切换系统基于观测器的滑模降阶控制

针对一类状态不可测的切换系统, 研究了其基于观测器的滑模控制问题. 设计了一类降阶观测器, 并用观测到的状态设计了滑模面函数以及滑模控制器, 使得闭环系统的状态能够到达滑模面上, 产生滑动模态. 并应用Lyapunov函数的方法给出了切换系统的滑动模态可达条件以及确保闭环切换系统渐近稳定的离散切换律. 最后,数值仿真验证了本文所提方法的有效性.     

Adaptive fuzzy terminal sliding mode controller for linear systems with mismatched time-varying uncertainties

A new design approach of an adaptive fuzzy terminal sliding mode controller for linear systems with mismatched time-varying uncertainties is presented in this paper. A fuzzy terminal sliding mode controller is designed to retain the advantages of the terminal sliding mode controller and to reduce the chattering occurred with the terminal sliding mode controller. The sufficient condition is provided for the uncertain system to be invariant on the sliding surface. The parameters of the output fuzzy sets in the fuzzy mechanism are adapted on-line to improve the performance of the fuzzy sliding mode control system. The bounds of the uncertainties are not required to be known in advance for the presented adaptive fuzzy sliding mode controller. The stability of the fuzzy control system is also guaranteed. Moreover, the chattering around the sliding surface in the sliding mode control can be reduced by the proposed design approach. Simulation results are included to illustrate the effectiveness of the proposed adaptive fuzzy terminal sliding mode controller.     

Novel sliding mode control for multi‐input–multi‐output discrete‐time system with disturbance

This paper investigates sliding mode control for multi‐input–multi‐output discrete‐time system with disturbances. First of all, a novel nonlinear sliding surface, named as hyperbolic hybrid switching sliding surface, is proposed. Two different types of hyperbolic functions are introduced into the proposed sliding surface. Due to the changing of values of the hyperbolic functions, sliding surface switching occurs during the control process, which ensures that both settling time and overshoot can be decreased. The sliding mode controller is obtained based on a novel nonlinear reaching law. The nonlinear reaching law contains several parameters, and by properly designing these parameters, we can decrease the bounds of the sliding variables to small values. The stability analysis of the sliding motion is carried out from singular system viewpoint. Finally, simulation examples and comparison examples are presented to illustrate that the system performance is improved obviously by proposed novel sliding mode control, and the system is robust to the disturbances.     

Memory sliding mode control for semi‐Markov jump system with quantization via singular system strategy

This technical note is concerned with the memory sliding mode stabilization for semi‐Markov jump nonlinear systems with input subject to mismatch quantization. Firstly, a sliding mode surface is constructed such that the sliding motion is stochastic admission in terms of linear matrix inequalities by a singular system strategy. A sufficient condition for the existence of linear memory sliding surfaces is given. Then, the memory sliding‐mode quantized controller designing problem is considered by the designed sliding surface function. Finally, a numerical example illustrates the effectiveness of the proposed method.     

基于有限时间的一类时滞非线性切换系统滑模控制

研究一类时滞非线性切换系统的有限时间滑模控制问题.针对所研究的系统模型,构造每个子系统对应的积分滑模面,基于滑模控制理论,设计带有状态时滞的滑模控制器使得每个子系统能在有限时间内到达相应的滑模面上,并对系统中存在的非线性项采用Lipschitz条件进行处理.根据多李亚普诺夫函数、平均驻留时间方法以及分割策略引理,给出滑模趋近段和滑模动态有限时间有界的充分条件,并通过对线性矩阵不等式的求解得到控制器增益.最后,通过一个数值仿真例子验证该设计方法的有效性.     

Second Order Sliding Mode Control for Robot Arms with Time Base Generators for Finite-Time Tracking

A novel chattering-free dynamic sliding mode controller for a class of uncertain mechanical systems is proposed in order to account globally for a time-varying sliding regime for all time and for any initial condition. The new sliding surface, parametrized by a time base generator, plays the role of moving, and rotating continuously the nominal sliding surface, while shifting is done through a known, state-independent, vanishing vector to eliminate the reaching phase for any initial condition, a weaker assumption in comparison to some moving sliding surface designs. In this way, the closed-loop system yields finite-time convergence of tracking errors, whose convergence time can be fixed independently of initial conditions, in contrast to terminal sliding mode wherein convergence time depends on initial conditions. To implement the controller, the upper bound of the derivative of the sliding surface is required, a weaker assumption in contrast to some dynamic sliding mode controllers. The performance of the closed-loop system is visualized through simulation.     

不确定时变时滞系统的自适应全局鲁棒滑模控制

针对一类存在时变状态时滞的不确定性系统, 基于全程滑模的思想, 引入一种带状态时滞项的积分型滑模面, 以消除趋近模态, 实现全程滑模控制; 基于一种新颖的自由权矩阵时滞转换模型, 采用线性矩阵不等式(LMI) 的方法给出并证明了滑动模态稳定的充分条件, 降低了保守性; 结合自适应控制思想设计出自适应滑模控制器, 克服了不确定性以及时变的时滞影响.

     

Adaptive sliding mode control with moving sliding surface

A continuous sliding mode control with moving sliding surface for nonlinear systems of arbitrary order is presented in this paper. The sliding surface is moved repetitively toward the target sliding surface in order to ensure that the system trajectory is close to the actual surface during the whole control process. The parameters of sliding mode control are tuned by a fuzzy logic. The proposed procedure reduces the time when the system operates in the approaching phase during which the control performance is deteriorated since the system is more susceptible to external disturbances and model uncertainties. The effectiveness of the presented approach is demonstrated on a control of a flexible robot manipulator arm.     

分数阶混沌系统的主动滑模同步

结合主动控制和滑模控制原理,提出了一个同步分数阶混沌系统的主动滑模控制方法.该方法首先用分数阶积分对所有维状态分量设计一个滑模面,分数阶混沌系统在该滑模面上稳定.然后采用极点配置的方法获得主动滑模控制器中的增益矩阵.应用Lyapunov稳定性理论、分数阶系统稳定理论对所提的控制器的存在性和稳定性分别进行了分析.对分数阶Lorenz系统进行数值仿真,仿真结果验证了该方法的有效性.     

不确定离散时间系统的滑模可靠控制

存在状态时滞的不确定离散时间系统的的滑模可靠控制问题,其中,被控系统执行器可能发生部分故障.通过构造一种拟积分型切换面,可以保证系统状态轨迹从开始时刻就位于切换面上.利用Lyapunov稳定性理论和线性矩阵不等式技术给出了滑模动态系统渐近稳定的充分条件.而且,所设计的滑模控制律可以保证在执行器故障影响下的滑动模态仍然是可达的.数值仿真验证了本文设计方法的有效性.     

SCARA机器人模糊自适应滑模控制

为了提高SCARA机器人的轨迹跟踪控制性能,提出了一种基于非奇异终端滑模面和改进的快速趋近律的滑模控制策略。设计了一种非奇异的快速终端滑模面,可在任意初始状态下收敛到平衡点;改进滑模控制的趋近律,在保证快速趋近的同时可有效抑制抖振,并采用双曲正切函数代替传统的符号函数,有效地消除了高频抖振。采用模糊控制调节趋近律参数,改善初始状态误差过大时引起的力矩冲击问题;基于SCARA机器人模型仿真实验表明,实验结果跟踪性能良好,输出力矩平滑。     

一类非线性系统的Terminal滑模控制

首先结合Terminal滑模控制的基本思想,即突破以往的线性滑动面,将非线性项引入到滑动面设计中,使得系统处于滑动模态阶段时,状态变量能够在"有限时间内"收敛至平衡点,给出了适用于高阶非线性系统的Terminal滑动面设计方法,基于Lyapunov稳定性理论得出了相应的控制器.进一步考虑系统参数摄动和外界扰动等不确定性因素上界的未知性,用Lyapunov稳定性方法给出了一个带有未知性上界参数估计的自适应Terminal滑模控制器.     

模糊-滑模控制在着舰导引系统中的应用

舰尾气流扰动是影响舰载机着舰误差的主要因素之一,为提高着舰精度,消除舰尾气流扰动对着舰安全的影响,提出了运用模糊-滑模控制抑制舰尾气流的扰动。滑模控制系统在滑动模态时对系统的不确定性及外界干扰具有很强的鲁棒性,运用模糊控制理论建立了随系统状态变化的时变滑模面,所设计的模糊-滑模控制系统可以较早达到滑动模态,并最后进入预定滑模面,使其同时具有良好的动态特性和抗干扰能力。纵向自动着舰导引系统的仿真实例验证了其有效性。     

新型有限时间收敛滑模扩张状态观测器研究

针对一类具有量测噪声的非线性不确定系统,设计了基于新型滑模扩张状态观测器的Terminal滑模控制方案．首先对系统进行两次状态扩张,然后设计一种新型滑模扩张状态观测器,通过采用特殊的滑模面保证观测误差在有限时间内收敛到零．在此基础上,设计Terminal滑模控制器,使系统状态也能在有限时间内收敛到零．严格的理论证明和仿真结果均证明了所设计新型滑模观测器及闭环控制方案的有效性和快速性．     

非奇异终端滑模控制系统的设计方法

提出一种全局非奇异终端滑模控制器，可用于带有参数不确定和外部扰动的二阶非线性系统，证明了系统从任意初始状态到达滑模的时间和在滑模上到达平衡点的时间均为有限，分析了终端滑模控制用于不确定性系统的跟踪精度，推导了系统跟踪精度和用于消除抖振的饱和函数宽度之间的数学关系，根据给定的跟踪精度，可设计出合适的饱和函数，仿真结果证明了所提出方法的有效性。     

Passivity‐based sliding mode controller/observer for second‐order nonlinear systems

A passivity‐based sliding mode control for a class of second‐order nonlinear systems with matched disturbances is proposed in this paper. Firstly, a nonlinear sliding surface is designed using feedback passification, in which the passivity is employed to guarantee the closed‐loop system's stability. The passivity‐based controller comprising a discontinuous term guarantees globally asymptotical convergence to the sliding surface. A sliding mode‐based control law that satisfies the reaching and sliding condition is also developed. Moreover, the passivity‐based sliding mode observer is also developed to effectively estimate the system states. Compared with conventional sliding mode control, the proposed control scheme has a shorter reaching time; and hence, the system performance is less affected by disturbances, thus eliminating the need to increase the control input gain. Finally, simulation results demonstrate the validity of the proposed method.     

Robust passive control of uncertain switched time-delay systems: a sliding mode control design

In this paper, the problem of sliding mode control (SMC) with passivity for a class of uncertain switched time-delay systems is studied. By means of the multiple Lyapunov functions techniques, a delay-dependent sufficient condition for the existence of linear sliding surface of subsystem is deduced in which the solution to the switched sliding mode dynamics is robustly exponentially stable and passive under a state-based switching law. Moreover, the sliding mode controller is designed to drive the system trajectories onto the predefined sliding surface of subsystem in finite time. Finally, a numerical example is provided to illustrate the effectiveness of the proposed method.