Generalized Internal Model Control Research Articles

Uncertainty Analysis of Suspension System Caused by Horizontal Misalignment and Its Suppression Method

The suspension system of the maglev train is a complex system, which is difficult to model accurately. The horizontal misalignment between the suspension magnet and the rail is one of the common uncertainty factors in the suspension system, which will affect the suspension performance. This article focuses on this problem. Firstly, the formula of suspension force considering horizontal misalignment is derived and the results of the formula and the FEA (Finite Element Analysis) simulation is consistent. Secondly, a suspension system model considering the horizontal misalignment is established for the first time, which can effectively describe the impact of the horizontal misalignment on the suspension system. Thirdly, a controller for the suspension system is designed by using the GIMC (Generalized Internal Model Control) paradigm and how the controller can effectively suppress the uncertainty caused by the horizontal misalignment is proved theoretically for the first time. Finally, the simulation and physical experiment verify that the proposed algorithm shows excellent performance and robustness in the system.

Active Actuator Fault Tolerant Control Based on Generalized Internal Model Control and Performance Compensation

In this paper, two active fault-tolerant control (AFTC) structures are proposed for multiplicative and additive actuator faults respectively. Considering that the traditional generalized internal model control (GIMC) changes the dynamic input-output relationship of the original system, more exact fault information is employed to design the robustification controller of GIMC with the help of fault diagnosis observers. Further, a feedforward compensation unit and a feedback compensation unit are respectively designed for multiplicative and additive faults, striving to approximately recover the system performance to the normal one. Finally, an air handling unit (AHU) system is provided to verify the effectiveness and superiority of the proposed structures.

Two Active Fault-Tolerant Control Schemes of Induction-Motor Drive in EV or HEV

In this paper, two active fault-tolerant control (AFTC) schemes dedicated to induction-motor drives in electric or hybrid vehicle powertrains are presented and compared. Fault detection and mitigation are merged to propose a robust algorithm against speed-sensor faults (fault is modeled as significant additional noise or an exponential type emulating a bias) leading to uncertainties in the measurement. The first architecture is a hybrid fault tolerant-control (FTC) with proportional-integral and H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞</sub> controllers; the second architecture is the generalized internal model control (GIMC) with a natural reconfiguration. Both are built to ensure resilience while keeping good dynamic performances. For each architecture, the speed-sensor fault detection is based on an extended Kalman filter (EKF) that generates a residual vector. The correction method is calculated differently for the two schemes specifically in the switching transition phase between the nominal and robust controllers. A comparative study is carried out between the two FTC schemes.

Fault Diagnosis and Reconfigurable Control of Singularly Perturbed Systems using GIMC Structure

paper proposes the extension of generalized internal model control (GIMC) based diagnosis and fault tolerant control to singularly perturbed system. This control method consists of two parts: a controller which guaranties nominal performance and works in the fault free case and a robustness controller to compensate the fault when a sensor failure is detected. This work describes the way to design such controllers for singularly perturbed systems so that the performance with the nominal controller may be guaranteed in the case of sensor failure.

GIMC architecture for linear systems with a single I/O delay

A new feedback controller architecture is presented for linear systems with a single I/O delay in the generalized internal model control (GIMC) framework. According to the doubly coprime factorization of these systems, traditional GIMC strategy is extended to linear systems with a single I/O delay. The distinguished feature of the control system architecture is that high tracking performance and good external disturbance rejection could be done separately by a nominal Smith predictor part and a finite dimensional conditional controller. First, a nominal Smith predictor part could be designed to deal with command tracking performance. Second, according to the left coprime factorization of the nominal controller, a finite dimensional conditional controller could be considered for external disturbance rejection, when the controlled plant should be assumed to be a square one. Finally, a simple design example is illustrated the effectiveness of the presented method.Finally, a simple design example is illustrated the effectiveness of the presented method.

Model free control based on GIMC structure

Many control researches for complicated and uncertain system are model-dependent and therefore require some prior knowledge for the complex systems. To avoid this problem, a number of model-free controllers are proposed. However, it is difficult to determine the control performance as the controller is not designed according certain system model especially when there are uncertainties and/or nonlinear dynamics in the system. To get over this problem, the model free controller (MFC) based on generalized internal model control (GIMC) structure is proposed in this paper. The MFC is used to attenuate the disturbance or uncertainty, and the system performance is determined by the nominal model and the nominal model controller. The parameters of nominal-model controller can be easily changed for meeting the change of the desired requirements. Moreover, the robust controller in the original GIMC is disassembled and rearranged to make the proposed methods easier to use, and the proposed method makes the controller be more flexible and greatly improves the system performance. Finally, the experiment results show that the MFC can be used to control the nonlinear systems and get the expected performance. The statistical analysis of performance for servo and regulatory behaviors also shows that the proposed method can achieve a better control performance than just using model free controller.

A GIMC Architecture for Time-delay Systems

摘要: 为了克服传统反馈控制中标称性能和鲁棒性能之间的矛盾, Zhou提出一般化内模控制方法(Generalized internal model control, GIMC). 然而在实际工业生产中, 控制对象一般都含有时滞环节. 本文针对含有时滞环节的真有理传递函数矩阵对象, 在时滞系统既约分解的基础上, 提出一种针对时滞系统的一般化内模控制方法, 使得一般化内模控制方法能够应用于时滞控制对象. 最后, 为了验证该方法的有效性, 将该控制结构应用于直流电机中, 取得了良好的控制效果. 关键词: 标称性能 / 鲁棒性能 / 一般化内模控制 / Youla参数化结构 / 时滞系统

Direct design from input/output data of a fault‐tolerant control system based on GIMC structure

AbstractThis paper deals with a method for the design of a fault‐tolerant control system based on the Generalized Internal Model Control (GIMC) structure, consisting of a standard outer loop feedback controller and an extra inner loop controller. The distinguishing feature of the GIMC structure is that controller design for performance and robustness may be performed separately. The outer loop controller is designed for nominal performance using some controller synthesis to meet the (nominal) control specification, while the inner loop controller is designed to make a trade‐off between robustness and performance. This feature is suitable for fault‐tolerant control. The outer loop controller is designed for the fault‐free case, and the inner loop controller for the fault‐time case. In the conventional methods, the inner loop controller is designed to maximize the robust stability margin without fault information. Therefore, the performance in the fault‐time case tends to become conservative. In this paper, the inner loop controller is directly designed from experimental data collected from the faulty system. Since the collected data contains information on the fault, conservativeness in the conventional methods is decreased. The inner loop controller is designed by Virtual Reference Feedback Timing (VRFT). VRFT is a method of direct design from input‐output data without identifying any models. Since the complexity of the controller can be specified by the designer, no complexity reduction is necessarily required, which is advantageous in implementation. The effectiveness of the proposed design method is confirmed by an experiment. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 171(4): 53–62, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20929

Fault Tolerant Control: Application of GIMC structure to a PLL Identi-fier Module

In this paper, we present a study dealing with stabilizing and robust controllers synthesis, precisely the Fault Tolerant Control (FTC). The case where these controllers are calculated by GIMC (Generalized Internal Model Control) structure will be developed and applied to a Phase-locked Loop (PLL) Identifier Module. In each case, we will focus on the control and the system output evolutions in the defects event. We will show the control quality and the advantages offered by GIMC structure in the transitory mode and the permanent one.

Compensation of performance degradation caused by fault based on GIMC structure: Application to a redundant sensor fault of flexible arm

AbstractIn recent years, control system reliability has received much attention with an increase of situations where computer‐controlled systems such as robot control systems are used. In order to improve reliability, control systems need to have abilities to detect a fault (fault detection) and maintain the stability and the control performance (fault tolerance). This paper deals with the strain gauge sensor fault of a flexible arm robot. In order to achieve a fault‐tolerant control system, the effect of the fault is identified as dual Youla parameter by regarding the estimation error of the faulty sensor signal as the faulty plant output. Moreover, Youla parameter is designed so as to suppress the effect of dual Youla parameter. Youla parameter is implemented in GIMC (Generalized Internal Model Control) structure proposed by Zhou. Since GIMC structure includes a conditional feedback, it is suitable for achieving a fault‐tolerant control system. The effectiveness of the proposed fault‐tolerant control system is confirmed by experiments. © 2009 Wiley Periodicals, Inc. Electr Eng Jpn, 168(3): 48–58, 2009; Published online in Wiley InterScience (www. interscience.wiley.com). DOI 10.1002/eej.20830

Generalized internal model architecture for gain-scheduled control

A two-degree-of-freedom controller architecture and its design strategy for linear parameter-varying (LPV) systems, where the dependent parameters are assumed to be measurable, are proposed in the generalized internal model control (GIMC) framework. First, coprime factorization and Youla parameterization for LPV systems are introduced based on a parameter-dependent Lyapunov function. Then, the GIMC architecture for linear time-invariant systems is extended to LPV systems with these descriptions. Based on this architecture, good tracking performance and good robustness (disturbance rejection) are compatibly achieved by a nominal controller and a conditional controller, respectively. Furthermore, each controller design problem is formulated in terms of linear matrix inequalities related to each L2-gain performance. Finally, a simple design example is illustrated.

ＧＩＭＣ構造による故障検出とその磁気浮上システムへの応用

This paper deals with a fault detection for a magnetic suspension system by using Generalized Internal Model Control (GIMC) structure. To design a robust fault detection filter, fault detection design problems are formulated as multiple objective optimization problems by minimizing the effects of disturbances and keeping the fault sensitivity involving an LTI system with disturbance and fault signals. The designed fault detection filters by solving each optimization problems are implemented with the magnetic suspension system to verify its validity. In experimental results, the sensor fault is detected by the designed filter. Moreover, the disturbance affection is more reduced than the detection system using the conventional detection filter.

GIMC-based Fault Detection and Its Application to Magnetic Suspension System

Abstract This paper deals with a fault detection for a magnetic suspension system by using Generalized Internal Model Control (GIMC) structure. To design robust fault detection filters, two fault detection design problems are formulated as multiple objective optimization problems by minimizing the effects of disturbances and maximizing the fault sensitivity involving an LTI system with disturbance and fault signals. The fault detection filters designed by solving each optimization problems are implemented with the magnetic suspension system to verify its validity. A filter designed via the problem 1 has good transient performance, but the output signal of the filter is affected by the disturbance signals. Another filter which is designed via the problem 2, however, has good robustness for disturbance signals. Moreover, experimental results show that both filters have enough fault detection properties compared with a conventional detection filter.

2212 磁気浮上システムに対するGIMC構造に基づく故障検出(磁気浮上・磁気軸受の制御(2))

This paper deals with a fault detection for a magnetic suspention system by using a switching control based on Generalized Internal Model Control (GIMC) structure. To design robust fault detection filters, two fault detection design problems are formulated as multiple objective optimization problems by minimizing the effects of disturbances and maximizing the fault sensitivity involving a LTI system with disturbance and fault signals. The designed fault detection filters by solving each optimization problems are implemented with the magnetic suspention system to verify its validity. A filter designed by the problem I has good transient performance, but the output signal of the filter is affected by the disturbance signals. Another filter which is designed via the problem 2, however, has good robustness for disturbance signals. Moreover, experimental results show that both filters have enough fault detection properties compared with a conventional detection filter.

GIMC構造に基づいた故障による性能劣化の補償

In recent years, control system reliability has received much attention with increase of situations where computer-controlled systems such as robot control systems are used. In order to improve reliability, control systems need to have abilities to detect a fault (fault detection) and maintain the stability and the control performance (fault tolerance). This paper deals with the strain gauge sensor fault of a flexible arm robot. In order to achieve a fault-tolerant control system, the effect of the fault is identified as dual Youla parameter by regarding the estimation error of the faulty sensor signal as the faulty plant output. Moreover, Youla parameter is designed so as to suppress the effect of dual Youla parameter. Youla parameter is implemented in GIMC (Generalized Internal Model Control) structure proposed by Zhou. Since GIMC structure includes a conditional feedback, it is suitable for achieving a fault-tolerant control system. The effectiveness of the proposed fault-tolerant control system is confirmed by some experiments.

Design and Development of Speed Controller for Wheeled Walking Frames (Application of Internal Model Control and LQ Control with Servo Compensation)

The work presents the wheeled walking frames that are supporting equipments, to be used by elderly people or handicapped in rehabilitation. Mostly, standard frames have weakness in walking on upward/downward slope. People often need power assistance on upward, and need secure walking support without falling on downward. The purpose of this paper is to develop a speed control assisting unit for wheeled walking frames by using the generalized internal model control (GIMC) with LQ control. By selecting appropriate parameter, the control method has various type of control scheme. Effectiveness of the assisting unit is confirmed by comparative experiments on upward and downward slopes. The result shows that the proposed method is effective on speed control for the assisting unit of wheeled walking frames.