切换带厚度递减的离散变结构控制方案

对离散趋近律方法进行研究,针对利用该方法设计变结构控制时系统产生抖振的原因,提出一种准滑动模态带宽度单调减小的离散变结构控制方案.理论分析及仿真结果表明,该方案较好地克服了由离散趋近律引起的抖振问题,可以大大改善离散变结构控制系统的稳态性能.     

一种离散变结构控制趋近律

提出一种符合高氏6个特点的离散变结构控制的趋近律.应用该趋近律设计的变结构控制系统,可保证系统在有限步到达准滑模带,系统运动最终趋于原点,并有降低抖动及保持快速趋近的品质.仿真结果说明了该方法的可行性和有效性.     

离散时间系统变结构控制分段趋近律

对高为炳先生提出的离散时间系统变结构控制的趋近律进行改进,提出了系统状态在进入准滑动模态带内和带外分别采用不同趋近律的分段式趋近律,该趋近律符合高氏关于离散变结构控制到达条件的6个特点,采用该趋近律设计的系统运动最终趋近于原点,从而具有快速趋近和降低抖振的品质。仿真结果说明了该方法的有效性。     

基于趋近律方法的Delta算子滑模变结构控制系统

针对高速信号不确定滑模变结构控制系统的抖振问题,提出一种基于Delta算子离散化方法的不确定Delta算子系统的滑模变结构控制器。基于反正切函数给出了一种改进的Delta算子离散趋近律,将系统的不确定部分用其上、下确界代替,然后设计滑模变结构控制律。仿真结果表明了该方法的可行性和有效性,对内部参数摄动和外部干扰具有良好的完全鲁棒性。因此,基于该趋近律方法设计的滑模变结构控制系统既能在有限时间内快速趋近切换面,又最终稳定于平衡状态。     

不确定离散时间系统的变结构控制设计

讨论了利用离散趋近律设计不确定离散时间系统的变结构控制问题,分析了离散趋 近律系数造成系统颤振的原因,给出了改进的离散趋近律,并利用它设计了变结构控制律,对 不确定部分建立灰色估计模型,估计出参数值.仿真结果表明该方法是可行的,有效地防止了 系统的颤振和不确定因素的影响.     

一种不确定离散时间系统的变结构控制方法

针对离散时间系统变结构控制中存在的问题,利用指数趋近律的趋近特性,提出一种新的离散变结构控制方法.利用递推估计的方法设计变结构控制律,有效地抵消了线性系统中慢变不确定性的影响,实现了对慢变非线性系统的控制.该方法克服了以往控制方法中需已知扰动上界的限制,降低了抖振,加快了趋近速度.仿真结果证明了该方法的有效性.     

一种离散时间系统变结构控制的新方法

研究离散时间系统变结构控制问题,提出一种新的离散变结构趋近律.利用该趋近律设计的离散变结构控制器,不仅能大幅度削弱抖振,使系统运动最终趋干原点不存在稳态振荡,而且可使系统的准滑动模态保持步步穿越切换面的基本属性,有效地改善了控制品质,提高了系统的鲁棒性.仿真结果验证了该方法的有效性与合理性.     

新的离散时间系统变结构趋近律

针对离散时间系统变结构控制的设计问题进行了研究。为了改善离散指数趋近律的趋近过程,提出了一种新的趋近律,利用该趋近律设计的变结构控制器,不仅能够大幅度削弱抖振,使系统运动最终趋于原点不存在稳态振荡,而且能使系统的准滑动模态保持步步穿越切换面的基本属性,有效地改善了趋近过程,提高了控制品质。仿真分析验证了该方法的合理性与有效性。     

基于趋近律方法的离散时间系统变结构控制

对变结构控制设计中的离散趋近律方法进行深入研究,提出了"理想趋近律"与"鲁棒趋近律"的概念.基于这些概念可以将离散趋近律区分为两类.研究了采用不同类型趋近律求取变结构控制时的异同及鲁棒性保证机理.澄清了使用趋近律方法设计变结构控制时存在的混乱和误解.     

一种基于离散变结构控制理论的有功分配控制器

对离散变结构控制理论进行研究并提出一种新的趋近律形式：离散变速趋近律,其特点是可期待原点的稳定性,将离散趋近律方法应用于电力系统,设计了并联运行同步发电机组有功分配的离散变结构控制器,仿真结果表明,本文设计的控制器可以明显改善系统的动态性能。     

Decentralized variable-structure adaptive controller synthesis of large-scale systems subjected to bounded disturbances

The regulation control problem is considered for a large-scale system in the presence of interconnected terms, system parameter variations and external disturbances. Based on the technique of parameter estimations and the theory of variable-structure systems, this paper presents a new and feasible design algorithm for the synthesis of a decentralized variable-structure adaptive controller which can easily tackle the control problem of large-scale systems subjected to interconnected terms, system parameter variations and bounded disturbances. In contrast to previous results, the restrictive condition that the exact value of the parameter describing the input gain must be known can be relaxed. A series of computer simulations are also included to illustrate the proposed design algorithm.     

A duality principle for state estimation with partially noise-corrupted measurements. Volume 37, number 5, pp. 1039–1056

This paper deals with the design and evaluation of a variable-structure stabilizer (VSS) for a synchronous machine using variable-structure systems theory. The stabilizer design is based on a recently proposed geometric approach for finding out the switching hyperplanes for discontinuous control. The transient response of the variable-structure stabilizer is compared with those obtained using a power system stabilizer (PSS) based on a speed signal. The computer simulation results show that the VSS is more effective in improving system damping, transient stability and post-fault recovery of the terminal voltage. It is also shown that by operating the control system in a sliding mode, the performance of the controlled synchronous machine can be made insensitive to changes in the system parameters.     

Controller design for a class of nonlinear systems with input saturation using convex optimization

In this paper, we propose a new design strategy for nonlinear systems with input saturation. The resulting nonlinear controllers are locally asymptotically stabilizing the origin. The proposed methodology is based on exact feedback linearization which is used to reformulate the nonlinear system as a linear system having state-dependent input saturation. Linear saturating state feedback controllers and soft variable-structure controllers are developed based on this system formulation. The resulting convex optimization problems can be written in terms of linear matrix inequalities and sum of squares conditions for which efficient solvers exist. Polynomial approximation based on Legendre polynomials is used to extend the methodology to a more general class of nonlinear systems. To demonstrate the benefit of this design method, a stabilizing controller for a single link manipulator with flexible joint is developed.     

Output transient trajectory shaping control for a class of nonlinear systems

This paper presents a transient trajectory shaping (TTS) control method for the SISO strict feedback nonlinear systems. The TTS control refers to explicitly constraining the system output tracking error transient trajectories within predesigned time‐varying boundaries while they are converging to equilibrium. By this method, the boundaries of system output transient trajectories can be designed a priori according to the system transient control performance requirements in both symmetric and asymmetric ways. With a class of time‐varying boundary functions, control laws can be devised by utilizing the enhanced differential unbounded function techniques. Such control laws can ascertain that the system output tracking errors travel within their respectively predesigned time‐varying boundaries while converging to origin. To handle the control input exaggeration issue in TTS, input constraint control techniques are proposed to effectively reduce the required control input magnitude for second‐order systems. A numerical example is utilized to show the effectiveness of the proposed TTS control methods. Copyright © 2013 John Wiley & Sons, Ltd.     

Decentralized dynamic output feedback controllers for interconnected systems with mismatched uncertainties using new sliding mode control

This paper presents a method for the design of decentralized output feedback controllers for an interconnected systems with mismatched uncertainties using a variable-structure control approach. A new reaching condition of the sliding mode is derived such that the reduced-order system is invariant to the mismatched uncertainties. In every subsystem, a new idea for a sliding mode that consists of two sets of switching surfaces is introduced, and a scheme of decentralized dynamic control using only output states is also proposed. This scheme can guarantee closed-loop stability of a sliding manifold of the composite system. Finally, a numerical example is given to illustrate the controller design method.     

基于DSP的电线加塑恒张力模糊变结构控制系统的设计

针对电线加塑生产过程中张力系统中存在的加塑不均匀、铜芯易被拉断或堆挤等问题,提出利用数字信号处理器(DSP)对张力进行控制的方案。硬件设计以美国TI公司生产的TMS320LF2407A DSP芯片为主控单元,软件设计是利用DSP集成开发环境CCS 2.2,采用C语言和汇编语言混合编译的方法进行控制程序的开发,在控制策略上采用模糊变结构控制。     

Optimal fast-response sliding-mode control for flexible-substrate measurement

In order to control bending radii of flexible substrates in displays, this paper presents an optimal fast-response sliding-mode control method. Maximum driving voltages are utilized in sliding-mode control based on a linear quadratic estimator. An optimal design for the threshold value and the reaching-law parameter are obtained by using a procedure of the fast-response regulation. Implementing the proposed method, this study measures electrical resistances for different widths of line patterns on polyethylene terephthalate/indium tin oxide substrates up to 11,000 bending times.     

Variable-structure PID controller for level process

A variable-structure (VS) PID controller for the level process is proposed. A methodology of analysis of its stability and performance is given. It is proposed that stability of the VS system can be approximately analyzed via the describing function method. The describing function of the VS PID controller is derived. It is shown that the system with the VS PID controller is quasi-linear. Tuning rules for the VS PI controller for the level process are given. It is shown via the theory and simulations presented that, if properly tuned, the VS PI controller has higher performance than the conventional PI controller for the process considered.     

统一潮流控制器逆系统方法控制策略

统一潮流控制器在同步旋转dq坐标系下的数学模型, 反映出统一潮流控制器是一个强耦合的、非线性的系统. 为解决对这个强耦合、非线性系统直接设计控制器的困难, 采用逆系统方法, 将原系统线性化且解耦, 构造出一个伪线性系统. 然后, 运用变结构控制, 针对构造出的这个伪线性系统, 设计该系统的控制策略以实现对统一潮流控制器综合控制. 最后, 通过建立仿真试验模型进行仿真, 仿真的结果验证了文中提出的这种控制策略的可行性和有效性.