A study of decoupling with skeleton matrix in two‐degree‐of‐freedom generalized minimum variance control

There are many multi‐input multi‐output (MIMO) systems in chemical plants, and they have multiple time delays of different length in each input and output pair. This paper explains a two‐degree‐of‐freedom (2DOF) control system based on generalized minimum variance control (GMVC) for MIMO systems. It can improve the tracking performance with respect to the reference signals and the response properties for the disturbance. The states between the sampling period can be expressed by using the modified z transform to take account of multiple time delays. Additionally, a tracking controller is designed to decouple the plant. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 176(1): 28–36, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21046     

Design of a robust PWM power amplifier using approximate two‐degree‐of‐freedom integral‐type control

A method is proposed for designing a robust controller for PWM power amplifiers, which are widely used as amplifiers and power supplies. The main technical requirements imposed on PWM power amplifiers are linearity in a wide frequency range and a well‐damped fast dynamic response in the presence of extensive load and DC power supply variations. Therefore, in order to satisfy the design specifications, namely, linearity in a wide frequency range and no overshoots during transients, an approximate two‐degree‐of‐freedom integral control structure is proposed and a design procedure for the robust controller is discussed. It is shown by some simulations and experiments that the designed controller shows especially good dynamic performance and effective disturbance rejection in the presence of external disturbances, that is, load and power‐supply variations. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(1): 68–77, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10102     

Two‐degree‐of‐freedom model matching control of shift‐by‐wire system with emergency mechanical link

A new shift‐by‐wire system having a standby mechanical link with backlash is proposed. The link directly connects the select lever and the manual lever of the automatic transmission in case of emergency. Thus, it is necessary to keep the backlash free during normal operations without generating a force. The angles of the manual lever driven by an actuator should follow the angles of the select lever exactly and quickly. A two‐degree‐of‐freedom model matching control is developed to meet this requirement. It is shown that the backlash is kept free during the range select operation. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(3): 45–52, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21049     

多变量系统的广义预测控制解耦设计

针对双输入双输出机炉协调控制系统,首先将系统分解为两个双输入单输出系统,并用广义预测控制原理设计控制器,通过求解二元一次矩阵方程组,实现了多频预测的解耦控制。进行了仿真研究,仿真结果证实了算法的有效性。     

An engine control systems design for low‐emission vehicles by generalized predictive control based on identified model

Conservation of the environment has become critical to the automotive industry. Recently, requirements for on‐board diagnostic and engine control systems have been strictly enforced. In the present paper, in order to meet the requirements for low‐emission vehicles, a novel method for construction of the air‐fuel ratio (A/F) control system is proposed. The method of construction of the system is divided into two steps. The first step is to design the A/F control system for the engine based on an open loop design. The second step is to design the A/F control system for the catalyst system. The design method is based on generalized predictive control in order to assure robustness to open loop control as well as model uncertainty. The effectiveness of the proposed A/F control system is verified through experiments using full‐scale products. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 169(3): 47–55, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20907     

A new decoupling design of self‐tuning multivariable generalized predictive control

A novel robust decoupling method with multivariable generalized predictive control (MGPC) for a class of nonlinear systems is presented in an adaptive version. The cross‐coupling action and the non‐linear actors of the system are identified on‐line by a neural network. A feedforward compensation based on generalized predictive control, is proposed for decoupling control. A modified recursive least‐squares (RLS) algorithm can be used to estimate the linear parameters for time‐varying systems. Simulations are carried out and the results show the effectiveness of the proposed algorithm. Copyright © 1999 John Wiley & Sons, Ltd.     

基于模糊控制的三自由度直升机系统仿真研究

针对三自由度直升机系统的多变量、强耦合等特点,首先从俯仰、横侧、旋转通道分别建立3个通道的数学模型.而后对俯仰通道设计常规的PD控制器,对耦合的横侧和旋转通道设计以横侧轴为内回路的PID控制器.考虑到系统被控对象参数不确定等因素,以及PID控制器不能很好适应参数时变的因素,在常规PID控制参数下,设计模糊控制器.经仿真实验得出该方法克服了常规PID的不足,控制效果较为理想.     

An anti‐windup strategy for a feedback control system based on youla parametrization

In this paper, the design strategy of anti‐windup controller (AWC) for feedback control system is proposed. The proposed method is based on Youla parametrization of linear controllers in the framework of left coprime factorization. Conventional anti‐windup controllers have difficulty in optimization of parameters. The suppression effect of windup phenomena can be adjusted easily with the proposed AWC. The effectiveness of proposed method is shown with some numerical and experimental results. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 139(4): 64–70, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10013     

Online trained support vector machines‐based generalized predictive control of non‐linear systems

In this work, an online support vector machines (SVM) training method (Neural Comput. 2003; 15 : 2683–2703), referred to as the accurate online support vector regression (AOSVR) algorithm, is embedded in the previously proposed support vector machines‐based generalized predictive control (SVM‐Based GPC) architecture (Support vector machines based generalized predictive control, under review), thereby obtaining a powerful scheme for controlling non‐linear systems adaptively. Starting with an initially empty SVM model of the unknown plant, the proposed online SVM‐based GPC method performs the modelling and control tasks simultaneously. At each iteration, if the SVM model is not accurate enough to represent the plant dynamics at the current operating point, it is updated with the training data formed by persistently exciting random input signal applied to the plant, otherwise, if the model is accepted as accurate, a generalized predictive control signal based on the obtained SVM model is applied to the plant. After a short transient time, the model can satisfactorily reflect the behaviour of the plant in the whole phase space or operation region. The incremental algorithm of AOSVR enables the SVM model to learn the new training data pair, while the decremental algorithm allows the SVM model to forget the oldest training point. Thus, the SVM model can adapt the changes in the plant and also in the operating conditions. The simulation results on non‐linear systems have revealed that the proposed method provides an excellent control quality. Furthermore, it maintains its performance when a measurement noise is added to the output of the underlying system. Copyright © 2006 John Wiley & Sons, Ltd.     

基于智能积分的多模协调控制交流伺服系统研究

为了满足交流伺服系统高精度、快响应的要求,结合模糊控制、比例控制和积分控制各自的优点,设计了一种基于智能积分的多模控制模糊控制器,并且分析了该控制策略的可行性,并将其应用于交流伺服系统.通过仿真和具体实验分别验证了上述分析和设计的合理性.试验结果表明:该控制方法不仅大大提高了交流伺服系统的稳态精度,缩短了过渡过程时间,加快了交流伺服系统的动态响应,而且对交流伺服系统有很好的抗干扰性能和较强的鲁棒性,使交流伺服系统具有较好的动、静态性能.     

基于阶梯式广义预测控制的锅炉主蒸汽温度控制系统

针对电厂锅炉主蒸汽温度难以投入自动控制的问题，在充分了解系统特征，综合考虑各项扰动因素后，有针对性地提出阶梯式广义预测控制策略，该算法引入10个影响因素，能解决大惯性、大时延及多扰动系统控制问题。算法应用于平圩电厂的2008t/h锅炉，成功解决了该厂主蒸汽温度难投自动的问题。并使控制指标优于疗颁标准。应用实践证明该技术具有很高的市场推广价值。     

锅炉水位控制系统的串级广义预测控制

针对火电厂锅炉汽包水位对象的复杂非线性动态特性,为提高水位系统控制的可靠性和安全性,设计串级广义预测控制(CGPC)结构。内回路采用PID控制可以快速消除给水流量的扰动,外回路采用具有滚动优化和反馈校正功能的CGPC控制结构,有效克服了蒸汽流量的扰动。仿真结果表明,应用该方法得到的CGPC-PID控制系统具有较高的预测精度和良好的抗扰动性,提高了系统的静态和动态性能指标,CGPC-PID串级控制系统控制性能优于常规PID-PID串级控制系统。     

一种基于改进广义积分控制的有源滤波器谐波补偿方法

针对传统广义积分控制存在的稳定性问题,提出一种基于改进广义积分控制的谐波补偿方法,以增强有源电力滤波器的补偿性能。通过在传统广义积分控制器中引入一阶微分环节,抵消被控对象极点并等效降低系统阶数,从而使得系统相位裕度提升。同时构建同步旋转坐标系下的多通道改进广义积分控制结构,使得改进广义积分控制器数量和需整定的控制器参数减半,降低了设计复杂度且有效避免滤波频段交叉问题。接着开展离散域下的控制器关键参数影响特性分析,得到不同积分系数下的系统稳定性演化趋势,校核结果表明了参数设计的合理性。最后,通过仿真验证了所提方法的可行性和有效性。     

A study of a two‐stage maximum power point tracking control of a photovoltaic system under partially shaded insolation conditions

A photovoltaic (PV) array shows relatively low output power density, and has a greatly drooping current–voltage (I–V) characteristic. Therefore, Maximum Power Point Tracking (MPPT) control is used to maximize the output power of the PV array. Many papers have been reported in relation to MPPT. However, the current–power (I–P) curve sometimes shows multi‐local maximum power points mode under nonuniform insolation conditions. The operating point of the PV system tends to converge to a local maximum output power point which is not the real maximal output point on the I–P curve. Some papers have tried to avoid this difficulty. However, most of those control systems become rather complicated. The two‐stage MPPT control method is proposed in this paper to realize a relatively simple control system which can track the real maximum power point even under nonuniform insolation conditions. The feasibility of this control concept is confirmed for steady insolation as well as for rapidly changing insolation by simulation study using software PSIM and LabVIEW. © 2005 Wiley Periodicals, Inc. Electr Eng Jpn, 153(4): 39–49, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20188     

Anti‐windup synthesis for a model predictive control system

In this paper, an anti‐windup design problem for a model predictive control system is studied. The plant is assumed to be stable. First, we propose the structure of an output feedback model predictive controller with an anti‐windup compensator. Then we show a design method of the anti‐windup compensator that guarantees closed‐loop stability and improves the transient response. The design problem of the anti‐windup compensator is reduced to a linear matrix inequality (LMI) optimization problem. Further, it is shown that there always exists an anti‐windup compensator that ensures global asymptotic stability. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

基于动态线性逼近的非线性系统预测控制

对于一类常见多重时滞非线性离散时间系统,提出了基于动态线性逼近的增量型简化递推预测模型,广义预测控制律、噪声估计器以及带有参数限定时域长度的参数自适应递推预报算法,实现了对存在较大滞后的时滞非线性系统的广义预测控制,通过仿真表明,该算法对于一类非线性系统实现预测控制是正确和有效的。     

Realization of precise force control using both 2‐DOF control and learning control

Recently, two degrees‐of‐freedom (2DOF) control has been widely recognized to be efficient. The major merit of 2DOF control is independence between tracking performance and the feedback performance. However, there is a limitation on tracking performance in the 2DOF control system. In this paper, we propose a new control system that consists of a conventional 2DOF controller and a learning controller. The role of the learning controller is to realize high tracking performance, which cannot be realized alone by the 2DOF controller. The learning controller can be designed by using only information specifying a 2DOF controller, and it does not need information about the controlled plant. We show some experimental results to verify the effectiveness of the proposed system. © 1999 Scripta Technica, Electr Eng Jpn, 128(4): 102–110, 1999     

Decentralized model predictive‐based load‐frequency control in an interconnected power system concerning wind turbines

This paper presents a load‐frequency control (LFC) design using the model predictive control (MPC) technique in a multi‐area power system in the presence of wind turbines (WTs). In the studied system, the controller of each local area is designed independently such that the stability of the overall closed‐loop system is guaranteed. A frequency response model of the multi‐area power system including WTs is introduced, and physical constraints of the governors and turbines are considered. The model was employed in the MPC structures. Digital simulations for a two‐area power system are provided to validate the effectiveness of the proposed scheme. The results show that with the proposed MPC technique the overall closed‐loop system performance shows robustness in the face of uncertainties due to governor and turbine parameter variation and load disturbances. A performance comparison between the proposed controller with WTs and MPC without WTs and a classical integral control scheme is carried out, confirming the superiority of the proposed MPC technique with WTs. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

A design method of strong stability self‐tuning controller based on on‐demand type feedback control

This paper proposes a design method of strong stability self‐tuning controller based on on‐demand type feedback control. For safety in industrial applications, although it is important to consider on‐demand type feedback control system, the previous papers about on‐demand type feedback control did not consider the influence of noise and fixed the design parameter to constant value. Therefore, this paper extends the design parameter of on‐demand type feedback control as stable rational function through the design method of strong stability system using coprime factorization. Moreover the self‐tuning controller of the proposed method is given and the control result with noise is shown by numerical example.     

直流伺服系统单值预估离散滑模控制

为了保证闭环系统的鲁棒稳定性,根据不确定系统的名义模型设计理想滑模面,并以名义模型作为预测模型,利用当前及过去时刻的滑模信息预测将来时刻的滑模动态,将预测控制理论中滚动优化、反馈校正的思想引入离散滑模控制系统的设计,提出了基于单值预估控制算法的离散滑模控制系统设计方法。仿真结果表明,该方法不仅完全消除了抖振现象,且能保证闭环系统的鲁棒稳定性。另外,由于采用了单值预估,使得控制算法非常简单。