Output feedback adaptive fault-tolerant compensation tracking control for linear systems based on the closed-loop reference model

This paper investigates the problem of output feedback adaptive compensation tracking control for linear systems subject to external disturbances and actuator failures including loss of effectiveness faults and bias faults. The impact of actuator faults on the transient performance of systems can be mitigated predicated on the closed-loop reference model with an additional degrees of design freedom. Using the estimation information provided by the adaptive mechanism, an output feedback adaptive fault-tolerant control strategy is developed to track closed-loop reference model systems. It is shown that all the signals of the resulting closed-loop system are bounded. Finally, simulation results are given to demonstrate the effectiveness of the proposed fault-tolerant tracking control method.     

Output feedback adaptive command following and disturbance rejection for nonminimum phase uncertain dynamical systems

In this paper, we develop an output feedback adaptive control framework for continuous‐time nonminimum phase multivariable systems for output stabilization, command following, and disturbance rejection. The approach is based on a nonminimal state space realization that generates an expanded set of states using the filtered inputs and filtered outputs and their derivatives of the original system. Specifically, a direct adaptive controller for the nonminimal state space model is constructed using the expanded states of the nonminimal realization and is shown to be effective for multi‐input, multi‐output nonminimum phase systems with unstable dynamics. The adaptive controller does not require any model information nor does it require information of the system poles and system zeros or estimation of the system Markov parameters. Several illustrative numerical examples are provided to demonstrate the efficacy of the proposed approach. Copyright © 2010 John Wiley & Sons, Ltd.     

永磁直线同步电机的改进线性自抗扰控制

在永磁直线同步电机（PMLSM）的运动控制系统中,提出一种位置环的改进线性自抗扰控制（ILADRC）方法。相对于传统的线性自抗扰控制（LADRC）,ILADRC仅利用线性扩张状态观测器输出的位置估计信号,通过PD控制器计算初始控制量,避免了引入速度估计信号的滞后影响。对PMLSM运行过程中受到的总扰动通过线性扩张状态观测器进行实时估计,并在控制律中进行动态补偿。利用李雅普诺夫函数方法证明了闭环误差系统的渐近稳定性。通过系统辨识得到了PMLSM平台的传递函数模型,在MATLAB中进行了仿真分析,并搭建了基于dSPACE控制器的实验系统。实验结果表明,相比于PID和LADRC,ILADRC能够有效减小跟踪误差,降低超调,且具有更好的扰动抑制能力。     

双重化PWM整流器自抗扰模型预测直接功率控制

针对车载双重化脉宽调制(pulse width modulation,PWM)整流器控制性能易受到模型不确定性和列车运行条件(输入电压、功率等级、电路参数等)变化影响的问题,提出一种基于自抗扰控制(active disturbance rejection control,ADRC)和模型预测直接功率控制(model predictive direct power control,MPDPC)的双闭环控制算法。其中,外环基于自抗扰控制理论,构建了基于误差驱动的ADRC(error-based ADRC,EADRC)控制器调节直流侧电压;内环结合基于内模原理的功率补偿方案使用两步MPDPC算法实现电流信号的控制。仿真和实验将所提自抗扰模型预测直接功率控制(ADRC-MPDPC)算法与传统基于比例积分的直接功率控制(proportional integral-based direct power control,PI-DPC)算法和PI-MPDPC方法进行对比,结果表明所提策略在系统启动、负载变化及工况切换等场景表现出更优的动态特性和鲁棒性能。     

基于自抗扰的感应电机无模型预测电流控制

针对采用传统比例积分(proportional integral, PI)控制算法的感应电机在面对复杂扰动时控制性能降低的问题,基于矢量控制系统,提出了感应电机的自抗扰(active disturbance rejection control, ADRC)无模型预测控制(model-free predictive control, MFPC)方法。首先,结合转速环和磁链环数学模型,设计了转速环和磁链环的ADRC控制器,对负载变化和内参摄动产生的内外扰动进行观测并补偿。其次,为避免内环控制器对电机参数的依赖,基于无模型控制原理,建立了dq电流环的超局部方程,将控制量之外的变量视为干扰量,并引入非线性扩张状态观测器估计干扰量。最后,结合预测控制思想设计了电流环控制器,得到开关状态作用于逆变器。仿真与实验结果表明提出的算法相对PI算法有更好的抗扰性和鲁棒性,可以有效提高感应电机的动态和稳态性能。     

微型燃气轮发电机系统的自抗扰控制方法研究

微型燃气轮机是一个复杂的热能动力系统,它的不确定性与非线性特性使得难以对其实现高精度控制,为了实现对微型燃气轮机的稳定控制,充分发挥微型燃气轮机在分布式发电中的优越性,引入自抗扰控制器,以转速为输入设计扩张观测器,利用前馈环节予以补偿,同时通过非线性组合抑制转速偏差,实现整个微型燃气轮机控制的优化.论文详细介绍了微型燃气轮机的模型及ADRC控制策略,通过负荷波动仿真及鲁棒性仿真来研究自抗扰控制器在提高微型燃气轮机系统稳定性上的优势.仿真结果表明,基于自抗扰控制器的微型燃气轮机表现出良好的动态性能,具有较强的鲁棒性能.     

微型燃气轮发电机系统的自抗扰控制方法研究

微型燃气轮机是一个复杂的热能动力系统,它的不确定性与非线性特性使得难以对其实现高精度控制,为了实现对微型燃气轮机的稳定控制,充分发挥微型燃气轮机在分布式发电中的优越性,引入自抗扰控制器,以转速为输入设计扩张观测器,利用前馈环节予以补偿,同时通过非线性组合抑制转速偏差,实现整个微型燃气轮机控制的优化。论文详细介绍了微型燃气轮机的模型及ADRC控制策略,通过负荷波动仿真及鲁棒性仿真来研究自抗扰控制器在提高微型燃气轮机系统稳定性上的优势。仿真结果表明,基于自抗扰控制器的微型燃气轮机表现出良好的动态性能,具有较强的鲁棒性能。     

Discrete-time combined model reference adaptive control

The discrete-time version of continuous-time combined model reference adaptive control (CMRAC) is presented in this paper. A global stability proof of the overall adaptive scheme is given using arguments similar to those used in discrete-time direct model reference adaptive control (DMRAC) but properly modified to account for the different structure of CMRAC with respect to DMRAC. © 1997 by John Wiley & Sons, Ltd.     

基于微分几何理论和自抗扰控制技术的励磁控制器设计

针对仿射非线性系统,通过微分几何坐标变换将系统非线性因素转换到含有控制输入的状态方程中.由于微分几何方法坐标变换本身是精确无误的,所以转换后的系统中,线性部分是精确的;系统参数的不确定、模型的不精确最终反映到转换后的非线性部分.利用自抗扰技术中的扩张状态观测器观测该部分的非线性摄动,通过反馈将其线性化并消除扰动.推导了单机无穷大系统的非线性励磁控制规律,在PSASP上进行仿真试验.理论论证和仿真试验证明该方案提高了非线性励磁控制的鲁棒性.     

Lyapunov‐stable discrete‐time model reference adaptive control

Discrete‐time model reference adaptive control (MRAC) is considered with both least squares and projection algorithm parameter identification. For both cases complete Lyapunov proofs are given for stability and convergence. The results extend the approach of Johansson (Int. J. Control 1989; 50 (3):859–869) to include Lyapunov stability for MRAC when the normalized projection algorithm is used for parameter identification. Copyright © 2005 John Wiley & Sons, Ltd.     

大型风电机组自抗扰转速控制

大型风电机组通常具有较大的转动惯量,因此在风速变化时机组转速不能快速地跟踪最大功率点.为了提高风电机组在低风速下对风能的利用率,提出自抗扰转速控制策略.利用基于转速反馈的扩张状态观测器对系统的内外扰动进行观测,并采用扰动补偿的方法,将风电机组等效为一阶线性系统.基于自抗扰控制原理设计了系统的转速控制器.实时估计出机组捕获的机械功率并计算出转速给定值,采用转速控制器直接对转速进行控制.仿真结果表明,与采用传统的功率控制策略的机组相比,自抗扰转速控制策略在风速变化时对最大功率点的跟踪速度要快,机组对风能的捕获效率得到了提高,同时对风力机的参数依赖性小.     

On necessary assumptions in discrete-time model reference adaptive control

In this paper we investigate the discrete-time model reference adaptive control problem, ascertain the extent to which the classical assumptions are necessary and provide several suitably modified inviolable requirements. In particular, we show that under a closed-loop causality constraint the problem is solvable only if there is an upper bound on the plant relative degree and the plant zeros outside the open unit disc lie in a finite set. We also derive a bound on the achievable asymptotic performance in the event that these requirements are not met.     

Adaptive state‐feedback control with sensor failure compensation for asymptotic output tracking

This paper addresses a new adaptive output tracking problem in the presence of uncertain plant dynamics and uncertain sensor failures. A new unified nominal state‐feedback control law is developed to deal with various sensor failures, which is directly constructed by state sensor outputs. Such a new state‐feedback compensation control law is able to ensure the desired plant‐model matching properties under different failure patterns. Based on the nominal compensation control design, a new adaptive compensation control scheme is proposed, which guarantees closed‐loop signal boundedness and asymptotic output tracking. The new adaptive compensation scheme not only expands the sensor failures types that the system could tolerate but also avoids some signal processing procedures that the traditional fault‐tolerant control techniques are forced to encounter. A complete stability analysis and a representative simulation study are conducted to evaluate the effectiveness of the proposed adaptive compensation control scheme.     

Indirect model reference adaptive control with dynamic adjustment of parameters

The paper discusses in detail a new method for indirect model reference adaptive control (MRAC) of linear time-invariant continuous-time plants with unknown parameters. The method involves not only dynamic adjustment of plant parameter estimates but also those of the controller parameters. Hence the overall system can be described by a set of non-linear differential equations as in the case of direct control. Many of the difficulties encountered in the conventional indirect approach, where an algebraic equation is solved to determine the control parameters, are consequently bypassed in this method. The proof of stability of the equilibrium state of the overall system is found to be different from that used in direct control. Using Lyapunov's theory, it is first shown that the parameter errors between the parameter estimates of the identifier and the true parameters of the plant, as well as those between the actual parameters of the controller and their desired values, are bounded. Following this, using growth rates of signals in the adaptive loop as well as order arguments, it is shown that the error equations are globally uniformly stable and that the tracking (control) error tends to zero asymptotically. This in turn establishes the fact that both direct and indirect model reference adaptive schemes require the same amount of prior information to achieve stable adaptive control.     

Transients in output feedback adaptive systems with observer‐like reference models

This note presents analysis and quantification of transient dynamics in Model Reference Adaptive Control (MRAC) with output feedback and observer‐like reference models. A practical design methodology for this class of systems was first introduced in 1 , 2 , where an output error feedback was added to the reference model dynamics. Here, this design is complemented with an analysis of the corresponding transients. Specifically, it is shown that employing observer‐like reference models in MRAC leads to a trade‐off between achieving fast transient dynamics and using large error feedback gains in the modified reference model. For clarity sake, only systems with matched uncertainties are analyzed, yet the reported results can be extended to a broader class of uncertainties by utilizing MRAC modifications for robustness 3 , 4 . The note ends with a summary of the derived results and a discussion on practical design guidelines for adaptive output feedback controllers with observer‐like reference models. Copyright © 2015 John Wiley & Sons, Ltd.     

锅炉过热蒸汽温度系统的串级自抗扰控制

针对过热蒸汽温度系统是一个非线性、时滞系统,而且它本身又有大惯性、大延迟的特点,提出了串级自抗扰控制的方法.在过热蒸汽导前区的内环控制中,应用扩张状态观测器、状态误差的非线性反馈、扰动估计补偿相结合的控制方法;在惰性区的外环控制中,应用高阶自抗扰控制对其进行控制.仿真实例表明,此控制方法具有很好的抗干扰能力,能对过热蒸...     

A new model reference adaptive control for linear time‐varying systems

Recent results on the adaptive control of linear time‐varying systems have considered mostly the case in which the range or rate of parameter variations is small. In this paper, a new state feed‐back model reference adaptive control is developed for systems with bounded arbitrary parameter variations. The important feature of the proposed adaptive control is an uncertainty estimation algorithm, which guarantees almost zero tracking error. Note that the conventional parameter estimation algorithm in the adaptive control guarantees only bounded tracking error. Copyright © 2000 John Wiley & Sons, Ltd.     

Neural adaptive robust output feedback control of wheeled mobile robots with saturating actuators

This paper addresses the output feedback tracking control problem of electrically driven wheeled mobile robots subjected to actuator constraints. The main drawback of previously proposed controllers is the actuator saturation problem, which degrades the transient performance of the closed‐loop control system. In order to alleviate this problem, a saturated tracking controller has been proposed using the hyperbolic tangent function. A new nonlinear observer is introduced in order to leave out the velocity sensors in the robot system to decrease the cost and weight of the system for practical applications. A dynamic surface control strategy is effectively used to reduce the design complexity when considering actuator dynamics. In addition, neural network approximation capabilities and adaptive robust techniques are also adopted to improve the tracking performance in the presence of uncertain nonlinearities and unknown parameters. Semi‐global stability of the closed‐loop system is presented using direct Lyapunov method. Simulation results are provided to illustrate the effectiveness of the proposed control system for a differential drive mobile robot in practice. Copyright © 2014 John Wiley & Sons, Ltd.     

Load frequency control in deregulated environments via active disturbance rejection

Linear active disturbance rejection control (LADRC) method is investigated for the load frequency control (LFC) of power systems in deregulated environments. The connections between one area and the rest of the system and the effects of possible contracts are treated as a set of new disturbances besides the system load. LADRC uses an extended state observer (ESO) to estimate the disturbances and compensates them quickly. Thus it can achieve good disturbance rejection performance and is a good candidate for LFC design. The proposed method is tested on two power systems. Simulation results show that the LADRC is simple to tune for load frequency control systems, and good performance can be achieved.