MODEL REFERENCE ADAPTIVE CONTROL BASED ON NONLINEAR COMPENSATION FOR TURBOFAN ENGINE

The design of a turbofan rotor speed control system, using model reference adaptive control（MRAC） method with input and output measurements, is discussed for the purpose of practical application. The nonlinear compensator based on functional link neural network is used to deal with the engine nonlinearity and the hardware-in-loop simulation is also developed. The results show that the nonlinear MRAC controller has the adequate performance of compensating and adapting nonlinearity arising from the change of engine state or working environment. Such feature demonstrates potential practical applications of MRAC for aeroengine control system.

Applicahon of a Simplified Model Reference Adaptive Algorithm

The application of a simplifed model reference adaptive control(SMRAC) on a typical Pump controlled motor electrohydraulic servo system is studied here. The algorithm of first-order scalar SMRAC ac second-order vector SMRAC are derived. Computer simulations of the algorithms are presented. Experimental results prove that the method of control adopted here perform satisfactorily over a wide range of operating conditions.

Design of a Kind of Model Reference Adaptive Missile Control System

Aim To present an adaptive missile control system adaped to the external disturbance and the mobility of target movement. Methods Model reference adaptive control (MRAC) was applied and modified in the light of the traits of the anti tank missile. Results Simulation results demonstrated this control system satisfied the requirement of anti tank missile of dive overhead attack. Conclusion It is successful to use MRAC in missile control system design, the quality is better than that designed by classical control theory.

MULTIVARIABLE MODEL REFERENCE ADAPTIVE CONTROL FOR A TURBOFAN ENGINE

A decentralized model reference adaptive control (MRAC) scheme is proposed and applied to design a multivariable control system of a dual-spool turbofan engine.Simulation studies show good static and dynamic performance of the system over the fullflight envelope. Simulation results also show the good effectiveness of reducing interactionin the multivariable system with significant coupling. The control system developed has awide frequency band to satisfy the strict engineering requirement and is practical for engineering applications.

Decentralized model reference adaptive sliding mode control based on fuzzy model

A new design scheme of decentralized model reference adaptive sliding mode controller for a class of MIMO nonlinear systems with the high-order interconnections is propcsed. The design is based on the universal approximation capability of the Takagi - Seguno （T-S） fuzzy systems. Motivated by the principle of certainty equivalenteontrol, a decentralized adaptive controller is designed to achieve the tracking objective without computafion of the T-S fuzz ymodel. The approach does not require the upper bound of the uncertainty term to be known through some adaptive estimation. By theoretical analysis, the closed-loop fuzzy control system is proven to be globally stable in the sense that all signalsinvolved are bounded, with tracking errors converging to zero. Simulation results demonstrate the effectiveness of the approach.

Robustness Analysis of Discrete-time Indirect Model Reference Adaptive Control with Normalized Adaptive Laws

For a class of discrete-time systems with unmodeled dynamics and bounded disturbance, the design and analysis of robust indirect model reference adaptive control （MRAC） with normalized adaptive law are investigated. The main work includes three parts. Firstly, it is shown that the constructed parameter estimation algorithm not only possesses the same properties as those of traditional estimation algorithms, but also avoids the possibility of division by zero. Secondly, by establishing a relationship between the plant parameter estimate and the controller parameter estimate, some similar properties of the latter are also established. Thirdly, by using the relationship between the normalizing signal and all the signals of the closed-loop system, and some important mathematical tools on discrete-time systems, as in the continuous-time case, a systematic stability and robustness analysis approach to the discrete indirect robust MRAC scheme is developed rigorously.

A Systematic Analysis Approach to Discrete-time Indirect Model Reference Adaptive Control

这份报纸论述间接模型引用的设计和分析有为分离时间的系统的一个类的规范的适应法律的适应控制(MRAC ) 。主要工作包括三部分。第一，构造工厂参数评价算法不仅拥有传统的评价算法的象那些的一样的性质而且在零避免分割的可能性。第二，由发现在工厂参数之间的关系，估计和控制器参数估计并且用工厂参数的性质估计，控制器参数估计的类似的性质也被建立。第三，基于关系，在使正常化之间的性质发信号并且在靠近环的系统并且在分离时间的系统上的一些重要数学工具上的所有信号作为在连续时间的盒子中，到分离间接 MRAC 计划的系统的稳定性和集中分析途径严厉地被开发。

Discrete-time Direct Model Reference Adaptive Control： A Systematic Approach

为直接模型引用的分离时间的系统，设计和分析的一个类，有规范的适应法律的适应控制(MRAC ) 被调查。我们责骂在输入和产量之间的 p 和 2 个关系性质上的分离时间的结论，和分离时间的交换词根 1 和 2。我们也建立分离时间的适应法律的性质，定义使正常化的信号，并且联系有在靠近环的系统的所有信号的信号。因此，分离时间的 MRAC 计划的稳定性和集中性质作为在连续时间的案例中以一种系统的方式严厉地被分析。

Model Reference Adaptive Control for Switched Systems with Closed-loop Reference Model Under Arbitrary Switching

This paper explores the model reference adaptive control problem for a class of switched linear systems under arbitrary switching with no need for the measurability of the system state.Based on the state of reference model and the measurable output error, adaptive laws and controllers are designed for switched systems.Each subsystem may have its individual reference model and controller, which increases the design flexibility.The introduction of the closed-loop reference model is to get a better transient performance of the whole switched systems.A numerical example is provided to verify the effectiveness of the main results.

Direct model reference adaptive control using K_p = LDU factorization for multivariable discrete-time plants

For a large class of discrete-time multivariable plants with arbitrary relative degrees, the design and analysis of the direct model reference adaptive control scheme are investigated under less restrictive assumptions. The algorithm is based on a new parametrization derived from the high frequency gain matrix factorization Kp=LDU under the condition that the signs of the leading principal minors of/fp are known. By reproving the discrete-time Lp and L2σ norm relationship between inputs and outputs, establishing the properties of discrete-time adaptive law, defining the normalizing signal, and relating the signal with all signals in the closed-loop system, the stability and convergence of the discrete-time multivariable model reference adaptive control scheme are analyzed rigorously in a systematic fashion as in the continuous-time case.

System Design of a Reference Model Adaptive Control for Radial Plasma Position on HL-2A Tokamak

The design of the control system for radial plasma position on HL-2A based on model reference adaptive control (MRAC) principle is presented in this paper. The simulated results show that it can be used to improve the performance of the system greatly. Compared with the classical PID control system, it has obvious advantages in the better dynamic response, the smaller quantity of calculation and the better robustness.

New model reference adaptive control with input constraints

A new scheme of adaptive control is proposed for a class of linear time-invariant（ LTI） dynamical systems,especially in aerospace,with matched parametric uncertainties and input constraints. Based on a typical and conventional direct model reference adaptive control scheme,various modifications have been employed to achieve the goal. ＂C omposite model reference adaptive control＂of higher performance is seam-lessly combined with ＂positive μ-mod＂,which consequently results in a smooth tracking trajectory despite of the input constraints. In addition,bounded-gain forgetting is utilized to facilitate faster convergence of parameter estimates. The stability of the closed-loop systemcan be guaranteed by using Lyapunov theory.The merits and effectiveness of the proposed method are illustrated by a numerical example of the longitudinal dynamical systems of a fixed-wing airplane.

基于滑窗滤波器的改进MRAS转动惯量辨识

交流伺服电机在负载突变时,传统模型参考自适应(model reference adaptive system,MRAS)不能同时满足辨识精度和收敛速度两方面的需求,鉴于此,提出一种基于滑窗滤波器的改进MRAS转动惯量辨识策略。首先,利用曲率模型(curvature model,CM)对电机的负载扰动进行实时估测;其次,对传统MRAS法进行改进,基于滑窗滤波器原理设置变增益机制的判断依据,使负载突变时系统自动调整自适应率中的增益系数,确保转动惯量被快速、精准的辨识;最后,通过仿真和搭建实平台对所提方法进行验证,结果证明此方法不仅具备较高的辨识精度,同时收敛速度快,很好的克服了传统方法的不足,表现出优异的动态性能。

考虑边端效应及参数变化的直线感应电机MRAS速度观测方法

以轨道交通直线感应电机(Linear Induction Motor,LIM)牵引驱动系统速度观测器为研究对象,针对边端效应及电机参数变化导致辨识结果实时性、鲁棒性不足的问题,提出一种基于二阶超螺旋滑模的改进模型参考自适应系统(Model Reference Adaptive System,MRAS)速度观测方法。首先,以计及动态边端效应的初次级电压电流磁链方程为核心,设计直线感应电机标准MRAS速度观测器,降低边端效应对速度辨识性能的影响。然后,进一步分析初级集肤效应和初次级横向错位对标准MRAS速度观测器辨识性能的影响。在此基础上,基于二阶超螺旋算法对MRAS参考模型进行改进,利用主滑模面和辅助滑模面对次级磁链观测的干扰项进行补偿,同时抑制由于滑模算法引入的系统抖振,提高了速度观测器的鲁棒性和动态性能。最后,搭建仿真和硬件在环实验环境进行算法验证。实验结果表明:励磁互感及其他电机参数随边端效应修正因子变化,标准MRAS观测器在突加负载、引入测量误差和电机参数突变的工况下,速度辨识误差明显;改进的MRAS观测器能够实现直线感应电机速度的快速、准确辨识,基于该速度观测器的矢量控制策略,在突加负载、引入测量误差和电机参数突变的工况下,控制性能满足设计要求。研究结果能为轨道交通直线感应电机无速度传感器牵引驱动系统的研究提供一定借鉴。

Model Reference Adaptive Controller for Simultaneous Voltage and Frequency Restoration of Autonomous AC Microgrids

In an autonomous droop-based microgrid,the system voltage and frequency(VaF)are subject to deviations as load changes.Despite the existence of various control methods aimed at correcting system frequency deviations at the secondary control level without any communication network,the challenges associated with these methods and their abilities to simul-taneously restore microgrid VaF have not been fully investigated.In this paper,a multi-input multi-output(MIMO)model reference adaptive controller(MRAC)is proposed to achieve VaF restoration while accurate power sharing among distributed generators(DGs)is maintained.The proposed MRAC,without any communication network,is designed based on two methods:droop-based and inertia-based methods.For the microgrid,the suggested design procedure is started by defining a model reference in which the control objectives,such as the desired settling time,the maximum tolerable overshoot,and steady-state error,are considered.Then,a feedback-feedforward con-troller is established,of which the gains are adaptively tuned by some rules derived from the Lyapunov stability theory.Through some simulations in MATLAB/SimPowerSystem Tool-box,the proposed MRAC demonstrates satisfactory perfor-mance.

基于BP双层神经网络MRAS下PMSM的转速辨识研究

针对无速度传感器下传统模型参考自适应(MRAS)方法在低速区转速负载发生突变后速度估计准确度下降的问题,利用双层神经网络超强的在线估计以及自适应能力,提出一种基于误差反向传播(BP)双层人工神经网络(ANN)与MRAS相结合的转速辨识方法,实现了对低速范围下转速响应动态性能的改善。通过Matlab仿真以及PMSM驱动控制实物平台,对ANN-MRAS观测器与传统MRAS观测器进行对比分析,结果表明:在转速及负载转矩发生突变后,该方法仍能保持较好动态性能,具有较强的鲁棒性。

带负载扰动补偿的永磁同步电机改进MRAS观测器控制

针对传统模型参考自适应系统(MRAS)对转速和负载变化敏感及鲁棒性差等问题,提出一种基于快速超螺旋滑模自适应观测器的改进型控制算法。利用快速超螺旋滑模代替传统的PI自适应环节,提高了系统鲁棒性;考虑负载转矩对系统产生的影响,将负载转矩和转速作为状态变量,选取转速实际值与观测值误差作为滑模面,设计负载转矩滑模观测器,将实时辨识的负载转矩引入到电流环,对参考转矩进行前馈补偿,提高了系统的抗负载扰动能力。以表贴式永磁同步电机为控制对象进行仿真和实验。结果表明:相比传统的模型参考自适应控制,改进型快速超螺旋滑模观测器控制具有更好的动态性能和鲁棒性。

基于MRAS永磁同步电机无速度传感器的改进控制策略

为了优化永磁同步电机无速度传感器的控制策略,对模型参考自适应永磁同步电机控制算法进行了改进。设计了基于同步旋转坐标系下的定子磁链状态方程模型参考自适应的修正补偿,改善了可调模型的可控性,转速抖动小,收敛速度快;理论验证和仿真结果表明,改进后的控制策略对电机实际参数的依赖性低,适用于参数可发生变化的实际工况,提高了永磁同步电机矢量控制的鲁棒性以及系统稳定性。

基于同步坐标系MRAS的异步电机无速度传感器控制

为了提高三相异步电机控制的精准度,对传统无速度传感器的转速估算控制策略进行改良,研究并设计了以转子磁链定向的基于同步旋转坐标系的MRAS(Model Reference Adaptive System)模型参考自适应无速度传感器异步电机矢量控制的新型控制策略,以转子磁链电流模型作为参考模型,将转子磁链电压模型和转速反馈作为可调模型,运用同步旋转坐标系定子电流和转子磁链的算法理论设计了转子磁链、转速以及位置的估算方法,仿真和实验结果表明,该控制方法具有更准确的估算精度和更快的收敛速度,提高了异步电机矢量控制的估算精度以及鲁棒性。

一种参数自适应双滑模结构MRAS永磁同步电机矢量控制方法

针对模型参考自适应系统(MRAS)在永磁同步电机控制中存在的响应速度慢、控制精度低、对参数变化敏感等问题,提出了一种参数自适应双滑模结构的MRAS永磁同步电机矢量控制方法。将传统模型参考自适应系统中的PI速度环和PI自适应调节器用滑模结构替代,提高系统的抗干扰能力和控制精度。基于波波夫超稳定性理论设计电机参数自适应系统,对电机参数进行辨识,进而提高系统鲁棒性。为抑制抖振,引入饱和函数和随系统状态变量自适应变化的滑模增益。最后借助SIMULINK软件进行仿真实验,实验结果表明该方法提高了控制精度和响应速度,且鲁棒性强,具有一定的优越性。