多输出非线性系统神经网络变结构控制的算法及其实现

在变结构控制系统中，切换函数的实际值与理想值之差反映了模型与实际系统的差别，引入神经网络的目的是在线辨识出这种差别。方法实现了对输入多输出非线性系统轨迹踊跃的控制，且对摄动具有很强的鲁棒性，大大减小了系统在切换面上的抖动。     

一类非线性系统的变结构控制

给出了类似于单变量系统的多输入非线性系统的规范型，以及系统可化为这种形式的充分必要条件。针对化为规范型的非线性系统，讨论了对其实施变结构控制问题。     

非线性系统的模型到达变结构控制

本文对一般非线性控制系统,提出了一种模型到达控制的概念,作为模型跟踪控制的推广,为此,当模型与系统为同阶时,引入了动态补偿器,然后采用变结构控制(VSC)策略,来实现模型到达控制的目的,文中还研究了控制受限情况下的VSC,所提出的控制策略此时有很大的简化,最后讨论了滑动模态对摄动的自适应性,文中引用的趋近律为多输入情况提供简单的计算方法,也解决了VSC全过程的品质问题。     

具有不确定性的非线性系统的变结构控制

本文研究了具有不确定性非线性系统的鲁棒输出跟踪控制问题，考虑了对参数、建模不确定性及干扰的鲁棒性。这里的不确定性不需满足通常的匹配条件。通过构造一个Ｌｙａｐｕｎｏｖ函数，我们得到一个变结构控制器，并且证明了输出跟踪误差的收敛性。最后，给出了计算机仿真，结果表明本文提出的方法是有效的。     

非线性广义系统的变结构控制设计

从线性定常广义系统出发，研究非线性广义系统的变结构控制设计问题。其主要思想为：选取一具有指定性能的线性定常广义系统作为参考模型，根据所控系统与参考模型的误差方程设计变结构控制，使系统的状态（输出）向参考模型的状态（输出）逼近，由参考模型的性能即得所研究的非线性广义系统所希望的性能。仿真例子验证了所建立方法的有效性。     

非线性系统的变结构控制及其实现问题

本文研究一般的多变量非线性系统的变结构控制及其实现问题,给出了滑动模态存在的必要条件和充分条件,证明了当采用具有等速趋近律的变结构控制策略时,用状态观测器来实现变结构控制,对线性(一类非线性)系统,可以保证系统的状态全局(局部)无限趋近于滑动子空间(子流形)。     

一类非线性系统时变滑模变结构控制

针对参数不确定性非线系统,分析了在未知扰动下的输出调节问题,提出了基于李亚普诺夫稳定性理论意义下的时变滑模变结构控制律,该控制律能保证系统误差的快速收敛性及对外部扰动和参数不确定性的不敏感性,最后给出的仿真实例实证实了理论分析结果的正确性。     

非线性系统的变结构控制

本文研究了一般非线性系统的变结构控制.将系统变换为正则型,并引入趋近律这一新概念,保证动态过程品质,减弱抖振.对控制作用受限情况及系统受到摄动时的鲁棒性也进行了研究.仿真支持本文结果的有效性.     

广义非线性系统的变结构控制理论

利用几何方法,从广义非线性系统本身出发,研究了广义非线性控制的变化结构控制理论,给出了系统存在变结构控制的充分实际没动模式的近似定理。从所得结论可知,滑动条件仅能保证实际滑动模的慢变状态赵近于理想滑动模的慢变状态,而不能保证实际滑动模的状态趋近于理想滑动模的快变状态,研究正常非线性系统的方法已不能简单地被利用到广义非线性系统。     

滑模预测离散变结构控制

研究了不确定离散时间系统的变结构控制设计问题,提出了基于滑模预测思想的离散变结构控制系统设计新思路.该方法综合考虑抖振、鲁棒性以及控制量约束等指标要求,利用当前及过去时刻的滑模信息预测未来时刻的滑模动态,实现了滚动优化求解.仿真结果表明,该方法可有效消除抖振现象,并能够保证闭环系统的鲁棒稳定性.     

Adaptive variable structure control of MIMO nonlinear systems with time-varying delays and unknown dead-zones

In this paper, adaptive variable structure neural control is presented for a class of uncertain multi-input multi-output （MIMO） nonlinear systems with state time-varying delays and unknown nonlinear dead-zones. The unknown time-varying delay uncer- tainties are compensated for using appropriate Lyapunov-Krasovskii functionals in the design. The approach removes the assumption of linear function outside the deadband without necessarily constructing a dead-zone inverse as an added contribution. By utilizing the integral-type Lyapunov function and introducing an adaptive compensation term for the upper bound of the residual and optimal approximation error as well as the dead-zone disturbance, the closed-loop control system is proved to be semi-globally uniformly ultimately bounded. In addition, a modified adaptive control algorithm is given in order to avoid the high-frequency chattering phenomenon. Simulation results demonstrate the effectiveness of the approach.     

Self-tuning type variable structure control method for a class of nonlinear systems

In this paper we propose a new self-tuning type Variable Structure Control (VSC) method for a class of nonlinear dynamical systems with parametric uncertainties. The controller is designed to satisfy the sliding mode condition; mean-while the on-line parameter identification is incorporated in the control system. Necessary modifications are made for the parameter identification to avoid the control singularity problem. By virtue of the sliding mode, the proposed identification algorithm can be applied to those nonlinear systems which may not be linear in parametric space but are linear while in the sliding mode. A model-based strategy is further introduced to estimate the uncertainty bound. The new approach attains the gain scheduling property by tuning the switching gain in accordance with the estimated system uncertainties, that is, the switching gain decreases asymptotically while the sliding mode condition is still maintained. © 1998 John Wiley & Sons, Ltd.     

一类非线性系统的积分变结构模糊自适应跟踪控制

针对一类具有未知常数控制增益的不确定非线性系统,基于变结构控制原理,并利用具有非线性可调参数的模糊系统逼近等价控制,提出一种具有监督控制器的积分变结构模糊自适应跟踪控制策略.该策略通过监督控制器保证闭环系统所有信号有界.进一步,通过引入最优逼近误差的自适应补偿项来消除建模误差的影响.理论分析证明了跟踪误差能够收敛到零.仿真结果表明了该方法的有效性.     

Output tracking control of nonlinear switched cascade systems using a variable structure control method

This article is concerned with the output tracking control problem for a class of nonlinear switched cascade systems under some average dwell-time-based switching laws. Firstly, stabilisation problem of this class of switched systems is considered. Then, the result is extended to the output tracking control problem. Based on the variable structure control technique and the characteristic of the system, the variable structure controllers and the average dwell-time are designed. The effectiveness of the proposed design approach is illustrated with simulation results.     

An adaptive variable structure control for a class of nonlinear systems

Motivated by the recent advance in adaptive output-feedback control for a class of nonlinear systems which can be transformed into the so-called output-feedback form [7,10,11], an adaptive structure controller is proposed in this paper to solve the nonlinear model reference adaptive control problem. It is shown that an asymptotic output tracking performance can be achieved for this class of nonlinear system even if some nonlinearity is not available or some unknown parameters are fast time-varying.     

输出非对称死区的非严格反馈非线性系统控制

本文研究了具有输出非对称死区和状态含未知控制方向的非严格反馈非线性系统, 设计了稳定的自适应 神经网络控制器. 首先, 针对输出非对称死区的问题, 本文采用死区逆的方法, 构造光滑模型逼近原死区模型. 其 次, 在控制器设计过程中, 基于障碍Lyapunov函数的构造, 动态面控制和反步法, 设计出自适应控制信号, 虚拟控制 信号和实际控制信号. 通过稳定性分析, 证明所设计的神经网络控制器可以保证闭环系统内所有信号是半全局一致 最终有界. 最后, 通过MATLAB数值仿真, 说明所设计控制器的有效性.     

Necessary and sufficient conditions for robust perfect tracking under variable structure control

The tracking control of linear MIMO systems with structured uncertainty is considered. A necessary and sufficient condition for robust asymptotic tracking employing variable structure techniques in the presence of multiplicative uncertainty is derived. The constructive proof of the theorem provides an explicit formula for controller synthesis. Copyright © 2002 John Wiley & Sons, Ltd.     

An approach to polynomial NARX/NARMAX systems identification in a closed-loop with variable structure control

Many physical processes have nonlinear behavior which can be well represented by a polynomial NARX or NARMAX model. The identification of such models has been widely explored in literature. The majority of these approaches are for the open-loop identification. However, for reasons such as safety and production restrictions, open-loop identification cannot always be done. In such cases, closed-loop identification is necessary. This paper presents a two-step approach to closed-loop identification of the polynomial NARX/NARMAX systems with variable structure control （VSC）. First, a genetic algorithm （GA） is used to maximize the similarity of VSC signal to white noise by tuning the switching function parameters. Second, the system is simulated again and its parameters are estimated by an algorithm of the least square （LS） family. Finally, simulation examples are given to show the validity of the proposed approach.     

不确定非线性系统的鲁棒自适应输出反馈控制

基于自适应非线性阻尼,提出一种鲁棒自适应输出反馈控制方法。该方法适用于带有未建模动态、未知非线性、有界扰动、未知非线性参数和不确定控制系数的多输入多输出非线性系统。理论证明,在一定的假设条件下,该方法能保证闭环系统所有动态信号有界;不论有多少不确定非线性参数、多高阶的非线性系统,只需要一个自适应控制参数和观察参数;而且通过选择适当的控制器和观测器参数,能使控制误差和估计误差达到任意小。仿真结果表明了所提出方法的有效性。