scholarly journals H∞ Controller Design for an Observer-Based Modified Repetitive-Control System

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Lan Zhou ◽  
Jinhua She ◽  
Shaowu Zhou ◽  
Qiwei Chen
Keyword(s):  
Control System ◽  
Controller Design ◽  
Linear Time ◽  
Repetitive Control ◽  
State Observer ◽  
Disturbance Attenuation ◽  
Linear Matrix ◽  
Design Algorithm ◽  
Linear Time Invariant ◽  
Value Decomposition

This paper presents a method of designing a state-observer based modified repetitive-control system that provides a given H∞ level of disturbance attenuation for a class of strictly proper linear plants. Since the time delay in a repetitive controller can be treated as a kind of disturbance, we convert the system design problem into a standard state-feedback H∞ control problem for a linear time-invariant system. The Lyapunov functional and the singular-value decomposition of the output matrix are used to derive a linear-matrix-inequality (LMI) based design algorithm for the parameters of the feedback controller and the state-observer. A numerical example demonstrates the validity of the method.

Nonfragile H∞ Output Feedback Controller Design for Linear Systems*

2003 ◽  
Vol 125 (1) ◽  
pp. 117-123 ◽  
Author(s):  
Guang-Hong Yang ◽  
Jian Liang Wang
Keyword(s):  
Output Feedback ◽  
Controller Design ◽  
Linear Time ◽  
Output Feedback Control ◽  
Disturbance Attenuation ◽  
Output Measurement ◽  
Linear Time Invariant ◽  
Measurement Feedback ◽  
Linear Time Invariant Systems ◽  
Time Invariant

This paper is concerned with the nonfragile H∞ controller design problem for linear time-invariant systems. The controller to be designed is assumed to have norm-bounded uncertainties. Design methods are presented for dynamic output (measurement) feedback. The designed controllers with uncertainty (i.e. nonfragile controllers) are such that the closed-loop system is quadratically stable and has an H∞ disturbance attenuation bound. Furthermore, these robust controllers degenerate to the standard H∞ output feedback control designs, when the controller uncertainties are set to zero.

scholarly journals Quadratic Stabilization of LPV System by an LTI Controller Based on ILMI Algorithm

2007 ◽  
Vol 2007 ◽  
pp. 1-9 ◽  
Author(s):  
Wei Xie
Keyword(s):  
Controller Design ◽  
Linear Time ◽  
Admissible Solution ◽  
Linear Matrix ◽  
Linear Parameter Varying ◽  
Linear Time Invariant ◽  
Lpv Control ◽  
Lpv System ◽  
Time Invariant ◽  
Iterative Linear Matrix Inequality

A linear time-invariant (LTI) output feedback controller is designed for a linear parameter-varying (LPV) control system to achieve quadratic stability. The LPV system includes immeasurable dependent parameters that are assumed to vary in a polytopic space. To solve this control problem, a heuristic algorithm is proposed in the form of an iterative linear matrix inequality (ILMI) formulation. Furthermore, an effective method of setting an initial value of the ILMI algorithm is also proposed to increase the probability of getting an admissible solution for the controller design problem.

Design of Repetitive-Control System With Input Dead Zone Based on Generalized Extended-State Observer

2017 ◽  
Vol 139 (7) ◽  
Author(s):  
Min Wu ◽  
Pan Yu ◽  
Xin Chen ◽  
Jinhua She
Keyword(s):  
Control System ◽  
Dead Zone ◽  
Repetitive Control ◽  
State Observer ◽  
Control Technique ◽  
Linear Matrix ◽  
Tuning Parameters ◽  
Assignment Method ◽  
Exogenous Disturbance ◽  
The Stability

This paper concerns a repetitive-control system with an input-dead-zone (IDZ) nonlinearity. First, the expression for the IDZ is decomposed into a linear term and a disturbance-like one that depends on the parameters of the dead zone. A function of the system-state error is used to approximate the combination of the disturbancelike term and an exogenous disturbance. The estimate is used to compensate for the overall effect of the IDZ and the exogenous disturbance. Next, the state-feedback gains are obtained from a linear matrix inequality that contains two tuning parameters for adjusting control performance; and the pole assignment method is employed to design the gain of a state observer. Then, two stability criteria are used to test the stability of the closed-loop system. The method is simple, employing neither an inverse model of the plant nor an adaptive control technique. It is also robust with regard to the different parameters of the IDZ, uncertainties in the plant, and the exogenous disturbance. Finally, two numerical examples demonstrate the effectiveness of this method and its advantages over others.

scholarly journals The road disturbance attenuation for quarter car active suspension system via a new static two-degree-of-freedom design

2017 ◽  
Vol 7 (2) ◽  
pp. 142-148
Author(s):  
Yusuf Altun
Keyword(s):  
Linear Time ◽  
Active Suspension ◽  
Suspension System ◽  
Disturbance Attenuation ◽  
Linear Matrix ◽  
Static Structure ◽  
The Road ◽  
Linear Time Invariant ◽  
Road Disturbance ◽  
Quarter Car

The main aim of this paper is to attenuate the effects of the road disturbance on the quarter-car active suspension system (ASS) for the passenger comfort by using design. Therefore, a new static disturbance compensator is proposed by using linear matrix inequality method such that the disturbance compensator and feedback controller are simultaneously designed for the disturbances in the linear time-invariant systems, which are measurable or predictable. They have static structure, and the disturbance compensator is designed on the feedforward path. The design is applied against the road disturbance affecting the quarter car ASS. The effectiveness of the design is demonstrated with the simulations.

scholarly journals Event–Based Feedforward Control of Linear Systems with input Time–Delay

2019 ◽  
Vol 29 (3) ◽  
pp. 541-553
Author(s):  
Carlos Rodríguez ◽  
Ernesto Aranda-Escolástico ◽  
María Guinaldo ◽  
José Luis Guzmán ◽  
Sebastián Dormido
Keyword(s):  
Disturbance Rejection ◽  
Feedforward Control ◽  
Linear Time ◽  
Disturbance Attenuation ◽  
Linear Matrix ◽  
Linear Time Invariant ◽  
Linear Time Invariant Systems ◽  
Control Of Linear Systems ◽  
Event Based ◽  
Performance Conditions

Abstract This paper proposes a new method for the analysis of continuous and periodic event-based state-feedback plus static feed-forward controllers that regulate linear time invariant systems with time delays. Measurable disturbances are used in both the control law and triggering condition to provide better disturbance attenuation. Asymptotic stability and L2-gain disturbance rejection problems are addressed by means of Lyapunov–Krasovskii functionals, leading to performance conditions that are expressed in terms of linear matrix inequalities. The proposed controller offers better disturbance rejection and a reduction in the number of transmissions with respect to other robust event-triggered controllers in the literature.

Decentralized time-delay controller design for systems described by delay differential-algebraic equations

2021 ◽  
pp. 014233122110159
Author(s):  
H. Ersin Erol ◽  
Altuğ İftar
Keyword(s):  
Time Delay ◽  
Time Delays ◽  
Controller Design ◽  
Linear Time ◽  
Differential Algebraic Equations ◽  
Algebraic Equations ◽  
Design Algorithm ◽  
Linear Time Invariant ◽  
Delay Differential ◽  
Time Invariant

This paper presents a complete approach for designing stabilizing linear time-invariant decentralized finite-dimensional or retarded time-delay output feedback controllers for linear time-invariant systems of delay differential-algebraic equations. The proposed approach is based on the sequential design of the local controllers by using a centralized controller design algorithm. In this sequential design approach, the local controller to be designed at each step is determined depending on the mobility of the rightmost modes with respect to the controllers that have not yet been designed and closed with the system. Since no predefined sequence is followed, a sequence that can target the least effort and dimension for each agent can be aimed. Also, in the proposed approach, a base controller effort can be targeted for each control agent, so that the effort required to stabilize the system can be distributed among the local controllers. In the centralized controller design algorithm used for the design of each local controller, the parameters of the controllers are changed stepwise in a quasi-continuous way to shift the targeted rightmost modes towards the stable area. For a time-delay controller, the desired mode placement can be achieved by applying small changes stepwise to the elements of the matrices and the time-delays of the controller while time-delays remain always non-negative. The effect of small perturbations on the time-delays in the open-loop system or to be added by the controller to be designed is taken into account to ensure some degree of robustness against all possible perturbations on the delays. The effectiveness of the proposed design approach is demonstrated by a numerical example.

Design and implementation of decoupled periodic control scheme for a laboratory-based quadruple-tank process

2021 ◽  
pp. 095965182110228
Author(s):  
Jatin K Pradhan ◽  
Arun Ghosh
Keyword(s):  
Real Time ◽  
High Frequency ◽  
Linear Time ◽  
Disturbance Attenuation ◽  
Minimum Phase ◽  
Periodic Control ◽  
Linear Time Invariant ◽  
Control Scheme ◽  
Gain Margin ◽  
Time Invariant

It is well known that linear time-invariant controllers fail to provide desired robustness margins (e.g. gain margin, phase margin) for plants with non-minimum phase zeros. Attempts have been made in literature to alleviate this problem using high-frequency periodic controllers. But because of high frequency in nature, real-time implementation of these controllers is very challenging. In fact, no practical applications of such controllers for multivariable plants have been reported in literature till date. This article considers a laboratory-based, two-input–two-output, quadruple-tank process with a non-minimum phase zero for real-time implementation of the above periodic controller. To design the controller, first, a minimal pre-compensator is used to decouple the plant in open loop. Then the resulting single-input–single-output units are compensated using periodic controllers. It is shown through simulations and real-time experiments that owing to arbitrary loop-zero placement capability of periodic controllers, the above decoupled periodic control scheme provides much improved robustness against multi-channel output gain variations as compared to its linear time-invariant counterpart. It is also shown that in spite of this improved robustness, the nominal performances such as tracking and disturbance attenuation remain almost the same. A comparison with [Formula: see text]-linear time-invariant controllers is also carried out to show superiority of the proposed scheme.

Parameter Uncertainty Modeling Using the Multidimensional Principal Curves

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
M. Sepasi ◽  
F. Sassani ◽  
R. Nagamune
Keyword(s):  
Transfer Functions ◽  
Linear Time ◽  
Optimization Technique ◽  
Parametric Uncertainty ◽  
Uncertainty Modeling ◽  
Principal Component ◽  
Linear Matrix ◽  
Linear Time Invariant ◽  
Uncertain Variables ◽  
Uncertainty Model

This paper proposes a technique to model uncertainties associated with linear time-invariant systems. It is assumed that the uncertainties are only due to parametric variations caused by independent uncertain variables. By assuming that a set of a finite number of rational transfer functions of a fixed order is given, as well as the number of independent uncertain variables that affect the parametric uncertainties, the proposed technique seeks an optimal parametric uncertainty model as a function of uncertain variables that explains the set of transfer functions. Finding such an optimal parametric uncertainty model is formulated as a noncovex optimization problem, which is then solved by a combination of a linear matrix inequality and a nonlinear optimization technique. To find an initial condition for solving this nonconvex problem, the nonlinear principal component analysis based on the multidimensional principal curve is employed. The effectiveness of the proposed technique is verified through both illustrative and practical examples.

Discrete Speed Controller Design of a Marine Diesel Engine Including Sampling Effects due to Fuel Injection

2002 ◽  
Vol 8 (5) ◽  
pp. 659-671 ◽  
Author(s):  
Mosaad Mosleh ◽  
Amier Al-Ali
Keyword(s):  
Diesel Engine ◽  
Fuel Injection ◽  
Controller Design ◽  
Linear Time ◽  
Marine Diesel Engine ◽  
Linear Time Invariant ◽  
Speed Controller ◽  
Injection Process ◽  
Loop Transfer Function ◽  
Marine Diesel

A linear time invariant (LTI) model of a marine diesel engine is presented. The effect of the discontinuity of the fuel injection into the cylinders and the injection period is considered. The proposed discrete model consists of a sampler and zero-order-hold mechanism, representing the fuel injection process. The design of the discrete controller is based on the pole assignment of the characteristic polynomial of the closed-loop transfer function with the goal of achieving zero steady-state error, and satisfying other design specifications. A numerical example illustrating the characteristic performance of a two stroke marine diesel engine is presented.

scholarly journals Design of Reduced-Order Multiple Observers for Uncertain Systems with Unknown Inputs

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Mihai Lungu
Keyword(s):  
Linear Time ◽  
Design Procedure ◽  
Lyapunov Theory ◽  
Design Algorithm ◽  
Reduced Order ◽  
Unknown Inputs ◽  
Linear Time Invariant ◽  
Reduced Order Observer ◽  
Multiple Observer ◽  
Takagi Sugeno

The paper presents the design of a new reduced-order multiple observer for the estimation of the state associated with Takagi-Sugeno systems with unknown inputs, this being only the second reduced-order multiple observer ever designed. The design of reduced-order multiple observers which can achieve the finite-time state reconstruction for nonlinear systems described by multiple models is a niche area problem; the author of this paper continuing his work started with the introduction of the reduced-order multiple observer concept. The new multiple observer is a combination of a typical reduced-order observer for linear-time invariant multivariable systems and a full-order multiple observer for Takagi-Sugeno systems. The sufficient stability conditions of the observer are derived via the Lyapunov theory and its robustness is improved by means of a novel and efficient method which cancels the negative effect of the uncertainties appearing in the system. To validate the suggested design algorithm, the steps of the design procedure have been summarized and software implemented for the concrete case of a light aircraft lateral-directional motion.

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