共查询到20条相似文献,搜索用时 15 毫秒
1.
The paper considers the control of an unknown linear time-invariant plant using Direct and Indirect Model Reference Adaptive Control. Employing a specific controller structure and the concept of positive realness, adaptive laws are derived using Indirect Control which are identical to those obtained in the case of Direct Control. The stability questions that arise are also shown to be the same. Simulation results using the new scheme are presented for the control of both stable and unstable plants. 相似文献
2.
GANG FENG 《International journal of systems science》2013,44(11):1957-1963
A new variable structure model reference adaptive control scheme is proposed in this paper to achieve robustness to bounded disturbance. A key feature of this scheme is that the knowledge of neither the upper bound on the disturbance nor the upper bound on the norm of the matching controller parameters is required. Another advantage of the scheme is its zero output error tracking 相似文献
3.
Benjamin C. Gruenwald Daniel Wagner Jonathan A. Muse 《International journal of control》2016,89(12):2434-2452
Although model reference adaptive control theory has been used in numerous applications to achieve system performance without excessive reliance on dynamical system models, the presence of actuator dynamics can seriously limit the stability and the achievable performance of adaptive controllers. In this paper, a linear matrix inequalities-based hedging approach is developed and evaluated for model reference adaptive control of uncertain dynamical systems in the presence of actuator dynamics. The hedging method modifies the ideal reference model dynamics in order to allow correct adaptation that is not affected by the presence of actuator dynamics. Specifically, we first generalise the hedging approach to cover a variety of cases in which actuator output and the control effectiveness matrix of the uncertain dynamical system are known and unknown. We then show the stability of the closed-loop dynamical system using Lyapunov-based stability analysis tools and propose a linear matrix inequality-based framework for the computation of the minimum allowable actuator bandwidth limits such that the closed-loop dynamical system remains stable. Finally, an illustrative numerical example is provided to demonstrate the efficacy of the proposed approach. 相似文献
4.
This article proposes a new technique for the tuning of a discrete adaptive controller that is designed based on Lyapunov stability concepts. The tuning is based on the minimisation of a performance index that can be calculated from a generalised eigenvalue problem (GEVP) using LMI's (Linear Matrix Inequalities). The proposed technique results in an adaptive controller with time-varying tuning gains. The solution is based on an approximation of the optimal dual adaptive control problem. The tuning technique was used to perform on-line control of a first-order system and an isothermal and a non-isothermal CSTR. The results show that the proposed approach provides better performance than an adaptive algorithm with the same structure, but with constant adaptation gains. Also, the proposed algorithm is shown to be superior to an adaptive controller based on a Recursive Least Squares (RLS) estimator during sudden changes in model parameters. 相似文献
5.
Active queue management (AQM) can maintain smaller queuing delay and higher throughput by purposefully dropping packets at intermediate nodes. Most of the existing AQM schemes follow the probability dropping mechanism originating from random early detection (RED). This paper develops a novel packet dropping mechanism for AQM through designing an ONOFF controller applying the variable structure control theory. Because the binary ONOFF controller can considerably simplify the manipulation on the AQM router, it is helpful for implementing the high performance router. The design principles of ONOFF controller are discussed in detail. The guidelines towards parameter settings are presented. The performance is extensively evaluated and compared with other well-known controllers through simulations and theoretical analysis. The results demonstrate that the ONOFF controller is responsive and robust against external disturbances, and is insensitive to variances of the system parameters. Therefore, it is very suitable for the time- varying network system, and at the same time, it can also keep the instantaneous queue length at a desired level with rather small oscillations, which is conducive to achieving the technical objectives of AQM. 相似文献
6.
Kar-Keung Young 《Automatic Control, IEEE Transactions on》1977,22(2):279-281
The application of theory of variable structure systems (VSS) in the design of controllers for single input-single output model reference systems is considered. It is shown that the resulting controller has similar structure as those obtained using the second method of Lyapunov except that the states of the model are also used. The error trajectories move towards the switching surface for all values of the error and continues on it as sliding motions. The present approach clarifies the relationship between stability and nonminimum phase zeros of the plant. 相似文献
7.
Stability analysis of continuous time indirect pole placement adaptive control with input constraint is presented in this paper. It is shown that the closed loop system for a class of stable type-1 plants is globally stable in the sense that all the signals in the loop remain bounded, and that certain degree of robustness with respect to modelling uncertainties and disturbances can be achieved by implementing a simple fixed dead zone in the parameter estimator. It is also shown that if the plant is free from modelling uncertainties and disturbances, and the control input is not saturated for a finite period of time, then the closed loop system will asymptotically be characterized by the desired closed loop poles within this time period. 相似文献
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9.
Design of large-scale time-delayed systems with dead-zone input via variable structure control 总被引:1,自引:0,他引:1
Kuo-Kai Shyu Author Vitae Wen-Jeng Liu Author Vitae Kou-Cheng Hsu Author Vitae 《Automatica》2005,41(7):1239-1246
To deal with time delay in the interconnection and dead-zone nonlinearity in the input, a new decentralized variable structure control (DVSC) law is proposed for a class of uncertain large-scale system (LSS) in this paper. The developed DVSC for the interconnected systems is realized independently through the delay terms. The applied control effort of the DVSC law is always out of the dead-band to eliminate the effects arisen from the dead-zone nonlinearity in the input function. In the sliding mode, it can be seen that the invariance condition also holds. It is worth noting that the traditional large-scale time-delayed system is only a special case in this work. Illustrative examples are given to verify the validity of the developed controller. 相似文献
10.
K. Merve Dogan Benjamin C. Gruenwald Jonathan A. Muse 《International journal of control》2018,91(8):1774-1784
It is known that a closed-loop dynamical system subject to an adaptive controller remains stable either if there does not exist significant unmodelled dynamics or the effect of system uncertainties is negligible. This implies that these controllers cannot tolerate large system uncertainties even when the unmodelled dynamics satisfy a set of conditions. In this paper, we present an adaptive control architecture such that the proposed adaptive controller is augmented with an adaptive robustifying term. Unlike standard adaptive controllers, the proposed architecture allows the closed-loop dynamical system to remain stable in the presence of large system uncertainties when the unmodelled system dynamics satisfy a set of conditions. A numerical example is provided to demonstrate the efficacy of the proposed approach. 相似文献
11.
B. Erik Ydstie 《Systems & Control Letters》1989,13(5):429-438
We demonstrate that the model reference adaptive controller is robust with respect to small model/plant mismatch. The sign and a lower bound on the high frequency gain are known and the control parameters are constrained to belong to a compact set which contains the parameters of a stabilizing controller. Data normalization and deadzones do not play a role in the analysis. A constructive proof is used to develop bounds for the allowable gain of the model mismatch. When the algorithm state is far from equilibrium the signals are measured by a decaying exponential. The rate of convergence is estimated. An expression which can be used to calculate the size of an overbounding set is developed. Its size scales uniformly with respect to the external disturbances, the inverse of the adaptive gain and the reference. The ideal case is obtained as these tend to zero. This result holds true even when there is a model mismatch. 相似文献
12.
A model reference adaptive control algorithm is shown not to be exponentially convergent when the high frequency gain of the plant is unknown. The implication is that such an algorithm will be lacking in some way in robustness. 相似文献
13.
介绍了荷兰Twente大学控制工程系研发的先进控制实验平台的基本组成、功能和基于机电一体化设计软件20-sim。以先进控制演示仪为研究对象,在20-sim环境下建立了系统的图标化数学模型,并从理论上对模型作了降阶分析。根据系统辨识的模型参考自适应控制(MRAC)原理,编制了模型参考自适应和Lyapunov求解模块。采用线性二次型调节器为控制模块,构成了完整的先进控制演示仪的MRAC控制系统。该系统仿真结果显示所建立的模型针对性强,可用于各种先进控制策略的仿真研究。 相似文献
14.
In this paper, the problem of robust adaptive tracking control of uncertain systems with time-varying input delays is studied. Under some mild assumptions, a robust adaptive controller is designed by using adaptive backstepping technique such that the system is globally stable and the system output can track a given reference signal. At the same time, a root mean square type of bound is obtained for the tracking error as a function of design parameters and thus can be adjusted. Finally, one numerical example is given to show the effectiveness of the proposed scheme. 相似文献
15.
Yiheng Wei Zhenyuan Sun Yangsheng Hu 《International journal of systems science》2016,47(11):2521-2531
This paper presents a novel composite model reference adaptive control approach for a class of fractional order linear systems with unknown constant parameters. The method is extended from the model reference adaptive control. The parameter estimation error of our method depends on both the tracking error and the prediction error, whereas the existing method only depends on the tracking error, which makes our method has better transient performance in the sense of generating smooth system output. By the aid of the continuous frequency distributed model, stability of the proposed approach is established in the Lyapunov sense. Furthermore, the convergence property of the model parameters estimation is presented, on the premise that the closed-loop control system is stable. Finally, numerical simulation examples are given to demonstrate the effectiveness of the proposed schemes. 相似文献
16.
非参数模型控制在液位控制系统中的应用研究 总被引:1,自引:0,他引:1
针对工业控制过程中液位系统的时变和明显的滞后特征,研究了非参数模型控制方法在液位控制系统中的设计方案,讨论了控制算法中引入的伪偏导数的在线估计问题,实现了通过液位系统的输入输出信息并利用递归最小二乘法对伪偏导数进行在线估计的过程,仿真实验验证了非参数模型算法对液位控制的鲁棒性、快速性及抗干扰性,通过仿真比较,展示了该算法性能优于PID算法和模糊控制的结果. 相似文献
17.
Nowadays, high-precision motion controls are needed in modern manufacturing industry. A data-driven nonparametric model adaptive control (NMAC) method is proposed in this paper to control the position of a linear servo system. The controller design requires no information about the structure of linear servo system, and it is based on the estimation and forecasting of the pseudo-partial derivatives (PPD) which are estimated according to the voltage input and position output of the linear motor. The characteristics and operational mechanism of the permanent magnet synchronous linear motor (PMSLM) are introduced, and the proposed nonparametric model control strategy has been compared with the classic proportional-integral-derivative (PID) control algorithm. Several real-time experiments on the motion control system incorporating a permanent magnet synchronous linear motor showed that the nonparametric model adaptive control method improved the system’s response to disturbances and its position-tracking precision, even for a nonlinear system with incompletely known dynamic characteristics. 相似文献
18.
19.
Zhihua Qu 《国际强度与非线性控制杂志
》1997,7(11):951-974
》1997,7(11):951-974
In this paper, a recently proposed control design technique, model reference robust control (MRRC), is generalized to provide input–output robust control for a much wider class of SISO systems. A system under consideration may contain not only parametric uncertainties, disturbances, uncertain high-order nonlinearities associated with system output (including stable unmodelled dynamics of the output), but also multiplicative unmodelled dynamics of the input of the system. Input unmodelled dynamics may be unstable and of infinite dimension. Common assumptions such as the order of the system, or bounds on system parameters, or coefficients in size-bounding functions on uncertainties and unmodelled dynamics are not needed in this paper. The a priori information required to apply the proposed design procedure includes the relative degree of the overall system, closed-form expressions of bounding functions, and, for arbitrarily small error in tracking the output of any given reference model, the minimum phase condition. Under the proposed control, the output tracking error can be made arbitrarily small to achieve any specified tracking accuracy. The distinct feature of MRRC is that neither uncertainties nor unmodelled dynamics are required to be small. © 1997 by John Wiley & Sons, Ltd. 相似文献
20.
A variable structure model reference robust control without a prior knowledge of high frequency gain sign 总被引:1,自引:0,他引:1
Lin Yan Author Vitae Liu Hsu Author Vitae Author Vitae Fernando Lizarralde Author Vitae 《Automatica》2008,44(4):1036-1044
The design of a variable structure model reference robust control without a prior knowledge of high frequency gain sign is presented. Based on an appropriate monitoring function, a switching scheme for some control signals is proposed. It is shown that after a finite number of switching, the tracking error converges to zero at least exponentially for plants with relative degree one or converges exponentially to a small residual set for plants with higher relative degree, and the input disturbance can be completely rejected without affecting the tracking performance. 相似文献