基于神经网络的自适应控制研究综述

神经网络与自适应控制相结合的研究,已成为智能控制的一个新的分支。自适应具有强鲁棒性,神经网络则具有良好的自学习功能和良好的容错能力,神经网络自适应控制由于较好地融合了两者的优点而具有强大的优势。该文综述了近年来神经网络自适应控制的研究现状,阐述了神经网络模型参考自适应控制及神经网络自校正控制两种典型的控触方案,并对神经网络自适应控制的应用作了介绍。在此基础上,对神经网络自适应控制存在的主要问题,如稳定性、鲁棒性及收敛性等问题作了积极有益的探讨。最后,展望了神经网络自适应控制未来的发展趋势,并指出了其研究方向。     

Multivariable adaptive control: A survey

Adaptive control is a control methodology capable of dealing with uncertain systems to ensure desired control performance. This paper provides an overview of some fundamental theoretical aspects and technical issues of multivariable adaptive control, and a thorough presentation of various adaptive control schemes for multi-input–multi-output systems, literature reviews on adaptive control foundations and multivariable adaptive control methods, and related technical problems. It covers some basic concepts and issues such as certainty equivalence, stability, tracking, robustness, and parameter convergence. It discusses some of the most important topics of adaptive control: plant uncertainty parametrization, stable controller adaptation, and design conditions for different adaptive control schemes. The paper also presents a detailed study of well-developed multivariable model reference adaptive control theory and design techniques. It provides an introduction to multivariable adaptive pole placement and adaptive nonlinear control, and it concludes by identifying some open research problems.     

σ校正混合自适应控制律

本文提出了一种σ校正混合自适应控制律,并且证明在对象具有相加和相乘未建模动 态(unmodeled dynamics)的情况下,若采用文中所给出的混合自适应控制系统结构,这种σ 校正混合自适应控制律可保证闭环系统中的所有信号有界,并且对于任何有界初始条件,系 统具有小的均值残余跟踪误差.数学模拟结果表明,本文所提出的混合自适应控制律优于相 类似的全连续和全离散自适应控制律.     

连续时间混沌系统的参数自适应控制

研究了连续时间混沌系统的参数自适应控制,提出了关于多重参数混沌非线性系统 的参数自适应控制的新方法.考虑系统参数是线性形式的自适应控制,利用Lyapunov方法 证明了参数控制方程是全局渐近稳定的.研究结果表明该控制方法是分析混沌参数白适应控 制的一个十分有效的方法.     

连续时间混沌系统的参数自适应控制1)

研究了连续时间混沌系统的参数自适应控制,提出了关于多重参数混沌非线性系统的参数自适应控制的新方法.考虑系统参数是线性形式的自适应控制,利用Lyapunov方法证明了参数控制方程是全局渐近稳定的.研究结果表明该控制方法是分析混沌参数自适应控制的一个十分有效的方法.     

L1 adaptive control with sliding-mode based adaptive law

This paper presents an adaptive control scheme with an integration of sliding mode control into the $\mathcal{L}_1$ adaptive control architecture, which provides good tracking performance as well as robustness against matched uncertainties. Sliding mode control is used as an adaptive law in the $\mathcal{L}_1$ adaptive control architecture, which is considered as a virtual control of error dynamics between estimated states and real states. Low-pass filtering mechanism in the control law design prevents a discontinuous signal in the adaptive law from appearing in actual control signal while maintaining control accuracy. By using sliding mode control as a virtual control of error dynamics and introducing the low-pass filtered control signal, the chattering effect is eliminated. The performance bounds between the close-loop adaptive system and the closed-loop reference system are characterized in this paper. Numerical simulation is provided to demonstrate the performance of the presented adaptive control scheme.     

PID‐Augmented Adaptive Control of a Gyro Mirror Los System

In this paper, a composite control scheme using a synergy of PID and adaptive control is proposed. The adaptive control component provides an adaptive feedforward control signal, while the PID component provides feedback control for robustness against modeling errors in the feedforward control design. The PID control can be automatically tuned using a relay. The control scheme developed is relevant to a large class of nonlinear servo‐mechanical systems, although in this paper, it is specifically implemented and demonstrated on a gyro mirror line‐of‐sight (LOS) system.     

Stability overlay for adaptive control laws

This paper proposes an architecture referred to as Stability Overlay (SO) for adaptive control of a class of nonlinear time-varying plants. The SO can be implemented in parallel with a wide range of “performance-based” adaptive control laws, i.e., adaptive control laws that seek to improve closed-loop performance, but may be susceptible to instability in the presence of unaccounted model uncertainty. In this architecture, the performance-based adaptive control law designates candidate controllers based on performance considerations, while the SO supervises this selection based upon online robust stability considerations. A particular selection of a performance-based adaptive control law is not specified. Rather, this selection can be from a wide range of adaptive control schemes. This paper provides stability proofs for the SO architecture and presents a simulation that illustrates the applicability of the proposed method.     

液压釜温度自适应预测控制

详细介绍了液压釜温度系统自适应控制方案、误差分析及实际应用调试情况．应用全系数自适应控制理论及模型预测控制原理设计了一种新的自适应预测控制方案,并给出了控制算法的稳定性证明及闭环系统稳态误差和动态特性分析．实际应用表明,该方法对建模误差、系统延时及测量噪声具有较好的鲁棒性．     

一种新的时变系统极点配置自适应控制方法*

本文针对连续快时变系统，提出不要求系统参数未知部分上界的先验信息的自适应算法，得到间接自适应控制方案并且证明闭环系统稳定，仿真结果说明本文的方法有效．     

An approach to adaptive control of fuzzy dynamic systems

This paper discusses adaptive control for a class of fuzzy dynamic models. The adaptive control law is first designed in each local region and then constructed in the global domain. It is shown that the resulting fuzzy adaptive control system is globally stable. Robustness issues of the adaptive control system are also addressed. A simulation example is given for demonstration of the application of the approach     

液压釜温度自适应预测控制1)

This paper introduces the details of the adaptive control scheme,error analysis and field adjustment of a hydraulic cauldron control system.A kind of new adaptive predictive control scheme is designed based on the all-coefficient adaptive control theory and model predictive control theory.The stability of this control algorithm is proved,and the analysis of error in stable stage and analysis of dynamic performance in the closed loop system are given.The actual application shows that the method proposed in this paper has good robustness to model error,system delay and measure noise.     

On adaptive robust backstepping control schemes suitable for PM synchronous motors

This paper presents new adaptive robust control strategies suitable for permanent magnet (PM) synchronous motors. By using the backstepping approach, both the adaptive and robust controllers are appropriately designed to ensure global stability. Taking into account the variation ranges of system parameters, the adaptive robust methods are further developed to achieve better tracking performance. It is shown that the synthesized adaptive robust control schemes developed here can retain advantages of both adaptive and robust control schemes and overcome their shortcomings. To avoid discontinuous control laws which may cause problems in both theoretical and practical aspects, a continuous adaptive robust control method associated with a mu - modification scheme is also proposed to guarantee both the uniform boundedness of the system and suitably designated tracking precision. The paper includes simulation studies demonstrating the performance of the proposed control schemes.     

液压釜温度自适应预测控制

详细介绍了液压釜温度系统自适应控制方案、误差分析及实际应用调试情况.应用 全系数自适应控制理论及模型预测控制原理设计了一种新的自适应预测控制方案,并给出了 控制算法的稳定性证明及闭环系统稳态误差和动态特性分析.实际应用表明,该方法对建模 误差、系统延时及测量噪声具有较好的鲁棒性.     

Model-Reference Fuzzy Adaptive Control as a Framework for Nonlinear System Control

The paper presents a general methodology of adaptive control based on fuzzy model to deal with unknown plants. The problem of parameter estimation is solved using a direct approach, i.e. the controller parameters are adapted without explicitly estimating plant parameters. Thus, very simple adaptive and control laws are obtained using Lyapunov stability criterion. The generality of the approach is substantiated by Stone-Weierstrass theorem, which indicates that any continuous function can be approximated by fuzzy basis function expansion. In the sense of adaptive control, this implies the adaptive law with fuzzified adaptive control parameters. The proposed control algorithm may be viewed as an extension of classical adaptive control for linear plants, but compared to the latter it provides higher adaptation ability and consequently better performance if the plant is nonlinear. The global stability of the control system is assured and the tracking error converges to the residual set that depends on fuzzification properties. The main advantage of the approach is simplicity that suits control engineers since wide range of industrial processes can be controlled by the proposed method. In the paper, the control of heat exchanger is performed.     

An architecture for adaptive fuzzy control in industrial environments

The paper presents an architecture for adaptive fuzzy control of industrial systems. Both conventional and adaptive fuzzy control can be designed. The control methodology can integrate a priori knowledge about the control and/or about the plant, with on-line control adaptation mechanisms to cope with time-varying and/or uncertain plant parameters. The paper presents the fuzzy control software architecture that can be integrated in industrial processing and communication structures. It includes four distinct modules: a mathematical fuzzy library, a graphical user interface (GUI), fuzzy controller, and industrial communication. Three types of adaptive fuzzy control methods have been studied, and compared: (1) direct adaptive, (2) indirect adaptive, and (3) combined direct/indirect adaptive. An experimental benchmark composed of two mechanically coupled electrical DC motors has been employed to study the performance of the presented control architectures. The first motor acts as an actuator, while the second motor is used to generate nonlinearities and/or time-varying load. Results indicate that all tested controllers have good performance in overcoming changes of DC motor load.     

基于参数估计误差的鲁棒自适应律设计及验证

针对传统自适应控制系统设计的自适应律参数收敛慢进而影响控制系统瞬态性能的问题,研究一类新的基于参数估计误差修正的鲁棒自适应律设计.首先引入滤波操作给出参数估计误差的提取方法,构建出含参数估计误差修正项的自适应律,进而将该自适应律用于控制器设计和分析中,可同时实现控制误差和参数估计误差指数收敛.对比分析了几类传统自适应律和所提出自适应律的收敛性和鲁棒性,并给出了保证参数收敛所需持续激励条件的一种直观、简便的在线判别方法.数值仿真及基于自制三自由度直升机系统俯仰轴实验结果表明,基于参数误差修正的自适应律及控制器可得到优于传统自适应方法的跟踪控制和参数估计性能.     

Comments on ‘ Asymptotic behaviour of root-loci of linear multivariable systems ’

In the first part of this paper, a continuous time adaptive identification algorithm via newly developed adaptive laws is presented. The principle of the algorithm is very simple, nevertheless the convergence property is quite excellent. In the second half part, two continuous time adaptive control algorithms via adaptive laws, as were used for adaptive identification, are presented. A new canonical form for adaptive control is first developed for this purpose. The design procedure for adaptive control systems requires neither positive realness nor augmented error signals and can be applied irrespective of the relative degree of the plant transfer function.     

自适应控制技术的应用和发展*

本文首先介绍了自适应控制应用的发展过程,接着详细介绍了自适应控制在我国的实际应用情况。本文的重点是在自适应控制应用中的问题和体会。文章最后阐述了自适应控制技术的发展前景。     

液压机器人自适应控制系统的研究

本文针对液压机器人在随机干扰和随机特征参数作用下的自适应控制系统设计研究的基础上,加入饱和非线性控制,从而改善了被控对象的控制输入,为机器人在线实时自适应控制提供了理论依据.通过仿真研究说明,文中采用的自适应控制方案具有很强的自适应能力.