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.

基于MPC-MRAC的用于子母式AUV投放的子AUV控制算法

针对水下搜救、水下集群作业等场合对负载能力、响应速度和多体协同的特殊要求,提出一种子母式自主水下航行器(AUV)概念。针对子母式AUV中的子AUV平台进行投放过程设计与分析,并对不同运动模式下的子AUV进行受力分析和建模。根据子AUV运动特性设计一套基于模型预测控制-模型参考自适应控制算法(MPC-MRAC)的子AUV控制算法,并进行仿真。结果显示:该算法具有较快的响应速度和控制稳定性,适用于子AUV投放后的自主运动控制;其响应速度比反演滑模控制算法快42.48%,比比例积分微分(PID)控制算法快87.05%;控制精度比反演滑模控制算法高77.54%,比PID控制算法高76.19%。针对该系统设计制作样机并开展湖上试验,结果表明,子AUV控制算法具有良好的可行性和可靠性,可顺利实现子AUV投放后运行的安全可靠。子AUV在出舱后经过短时间姿态变化,成功与母AUV分离并顺利进行定深任务,最终达到近似等距分布的效果。研究成果可为用于子母式AUV投放的子AUV提供控制算法基础。

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.

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.

ADAPTIVE CONTROLLER AND ITS APPLICATION IN FORCE SYSTEM OF ASYMMETRIC CYLINDER CONTROLLED BY SYMMETRIC VALVE

Partial pressure, system vibration and asymmetric system dynamic performance exit in asymmetric cylinder controller by symmetric valve hydraulic system. To solve this problem in the force control system, model reference adaptive controller is designed using equilibrium point stability theory and output error equation polynomial. The reference model is selected in such a way that it meets the system dynamic performance. Hardware configuration of asymmetric cylinder controlled by asymmetric valve hydraulic system is replaced by intelligent control algorithm, thus the cost is lowered and easy to application. Simulation results demonstrate that the proposed adaptive control sheme has good adaptive ability and well solves asymmetric dynamic performance problem. The designed adaptive controller is fairly robust to load disturbance and system parameter variation.

VARIABLE STRUCTURE MODEL－FOLLOWING ADAPTIVE CONTROL DESIGN FOR ROBOT MANIPULATORS

The increasing demand on robotic system performance leads to the use of advanced control strategies. A variable structure model-following adaptive control design is presented for the nonlinear robot manipulator systems, when subjected to fast and wide ranges of unknown-but-bounded parameter variations and disturbances. The design does not require any knowledge of a nonlinear robotic system. The system is robust and insensitive to the parameter variation, disturbances, as well as to the unmodeled dynamics. This insensitive property enables the elimination of interactions among the various joints of the robotic manipulator. In the closed loop, the robotic system asymptotically converges to the reference trajectory with a Prescribed transient resPOnse. The problem of chattering is discussed with the introduction of the special approaches: boundary layer, smoothing law, and nonlinear compensation.

基于模型参考自适应MRAC的双流传动调速控制

为使拖拉机作业过程中车速在受到作业阻力变化的影响下能迅速恢复稳定,文章设计一种双流传动(hydro-mechanical transmission, HMT)系统。通过实时调节发动机油门踏板的开度和改变电液伺服机构控制柱塞泵斜盘倾角的泵排量方式对车速进行调节;考虑到电液伺服机构存在强非线性、大时变参数以及外负载干扰等因素,将模型参考自适应控制(model reference adaptive control, MRAC)算法应用在液压泵排量调节的电液伺服执行机构中。结果表明:所设计的HMT系统在拖拉机遇到作业阻力变化引起车速变化时能有效地恢复稳定行驶状态;采用MRAC的电液伺服执行机构能够精确调节液压系统排量比来实现车速的改变,在简化变速操作的同时保证发动机工作在高效区,使拖拉机工作车速快速恢复到稳定区间。

Novel Lyapunov-based rapid and ripple-free MPPT using a robust model reference adaptive controller for solar PV system

The technological,economic,and environmental benefits of photovoltaic(PV)systems have led to their wide-spread adoption in recent years as a source of electricity generation.However,precisely identifying a PV system’s maximum power point(MPP)under normal and shaded weather conditions is crucial to conserving the maximum generated power.One of the biggest concerns with a PV system is the existence of partial shading,which produces multiple peaks in the P–V characteristic curve.In these circumstances,classical maximum power point tracking(MPPT)approaches are prone to getting stuck on local peaks and failing to follow the global maximum power point(GMPP).To overcome such obstacles,a new Lyapunov-based Robust Model Reference Adaptive Controller(LRMRAC)is designed and implemented to reach GMPP rapidly and ripple-free.The proposed controller also achieves MPP accurately under slow,abrupt and rapid changes in radiation,temperature and load profile.Simulation and OPAL-RT real-time simulators in various scenarios are performed to verify the superiority of the proposed approach over the other state-of-the-art methods,i.e.,ANFIS,INC,VSPO,and P&O.MPP and GMPP are accomplished in less than 3.8 ms and 10 ms,respectively.Based on the results presented,the LRMRAC controller appears to be a promising technique for MPPT in a PV system.

基于模型参考自适应的水肥一体化控制系统设计

针对水肥混合过程中水肥EC值精准控制的问题,设计一个基于模型参考自适应的水肥一体化决策和控制系统。建立母液动态调控模型,并通过该模型设计模型参考自适应控制器。仿真试验结果显示,模型参考自适应控制相较于模糊PID控制,在跟踪试验中超调量降低1.2%,调整时间减少12.6 s,阶跃试验中超调量降低14.4%,调整时间减少超过2 s,抗干扰能力优于模糊PID控制。通过3种方式进行田间试验,对比模糊PID控制和人工灌溉方式,采用模型参考自适应控制能够使番茄株高分别提高15.7%和35.6%,茎粗分别增长11.1%和18.6%,产量分别提升23.3%和48.1%,结果表明,模型参考自适应控制优于模糊PID控制和人工灌溉方式,从而验证模型参考自适应控制的有效性,为精准施肥灌溉提供技术支持。

一阶系统模型参考自适应辨识及位置控制

针对新建系统或负载变化导致的模型参数不确定问题,对交流伺服系统进行研究,提出模型参考自适应辨识(model reference adaptive identification,MRAI)算法,对一阶系统模型参数进行在线辨识。首先对一阶系统进行数学模型构建,然后根据李雅普诺夫(Lyapunov)稳定理论选择参考模型,并设计自适应控制律,在此基础上对一阶系统进行模型参数在线辨识。当参数收敛后,根据系统要求的自然频率和阻尼比,在线设计位置控制器参数,并进行跟踪定位控制。仿真和实验结果表明,模型参考自适应在线辨识算法能快速精准地辨识出系统模型参数,通过在线设计控制器参数实现了对参考信号的快速跟踪。