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Alireza Karimi

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Related publications (165)

Model-Free Precompensator Tuning Based on the Correlation Approach

Roland Longchamp, Alireza Karimi, Mark Edward John Butcher

High performance output tracking can be achieved by precompensator or feedforward controllers based on the inverse of either the closed-loop system or the plant model, respectively. However, it has been shown that these inverse controllers can adversely af ...

2008

A Statistical Analysis of Certain Iterative Learning Control Algorithms

Roland Longchamp, Alireza Karimi, Mark Edward John Butcher

Iterative Learning Control (ILC) is a technique used to improve the tracking performance of systems carrying out repetitive tasks, which are affected by deterministic disturbances. The achievable performance is greatly degraded, however, when non-repeating ...

2008

Data-Driven Estimation of the Infinity Norm of a Dynamical System

Dominique Bonvin, Alireza Karimi, Klaske van Heusden

The estimation of a system’s infinity norm using one set of measured input and output data is investigated. It is known that, if the data set is noise free, this problem can be solved using convex optimization. In the presence of noise, convergence of this ...

2007

Robust PID controller tuning with specifications on the infinity-norm of sensitivity functions

Roland Longchamp, Daniel Garcia, Alireza Karimi

An overview of the recent works on proportional integral derivative (PID) controller tuning methods based on specifications on the infinity-norm of the sensitivity functions is presented. The presented approach is very flexible relative to the controller s ...

2007

Correlation-Based Tuning of Decoupling Multivariable Controllers

Dominique Bonvin, Ljubisa Miskovic, Alireza Karimi

The iterative data-driven method labelled Correlation-based Tuning (CbT) is considered in this paper for the tuning of linear time-invariant multivariable controllers. The approach allows one to tune some elements of the controller transfer function matrix ...

2007

Robust Control of Polytopic Systems by Convex Optimization

Roland Longchamp, Alireza Karimi, Hamid Khatibi

Robust control synthesis of linear time-invariant SISO polytopic systems is investigated using the polynomial approach. A convex set of all stabilizing controllers for a polytopic system is given over an infinite-dimensional space. A finite-dimensional app ...

2007

Robust Loop Shaping Controller Design for Spectral Models by Quadratic Programming

Roland Longchamp, Alireza Karimi, Gorka Galdos Sanz de Galdeano

A quadratic programming approach is proposed to tune fixed-order linearly parameterized controllers for stable LTI plants represented by spectral models. The method is based on the shaping of the open-loop or closed-loop frequency functions in the Nyquist ...

2007

Robust Controller Design by Linear Programming with Application to a Double-Axis Positioning System

Roland Longchamp, Marc Kunze, Alireza Karimi

A linear programming approach is proposed to tune fixed-order linearly parameterized controllers for stable LTI plants. The method is based on the shaping of the open-loop transfer function in the Nyquist diagram. A lower bound on the crossover frequency a ...

2007

Robust Pole Placement of Systems with Polytopic Uncertainty Via Convex Optimization

Roland Longchamp, Alireza Karimi, Hamid Khatibi

Convex parameterization of fixed-order robust stabilizing controllers for systems with polytopic uncertainty is represented as an LMI using KYP Lemma. This parameterization is a convex inner-approximation of the whole non-convex set of stabilizing controll ...

2007

Gain-Scheduled Controller Design by Linear Programming

Roland Longchamp, Marc Kunze, Alireza Karimi

A linear programming approach is proposed to tune fixed-order linearly parameterized gain-scheduled controllers for stable SISO linear parameter varying (LPV) plants. The method is based on the shaping of the open-loop transfer functions in the Nyquist dia ...

2007

Noniterative Data-driven Controller Tuning Using the Correlation Approach

Dominique Bonvin, Alireza Karimi, Klaske van Heusden

Data-driven controller tuning for model reference control problem is investigated. A new controller tuning scheme for linear time-invariant single- input single-output systems is proposed. The method, which is based on the correlation approach, uses a sing ...

2007

Robust Control of Polytopic Systems by Convex Optimization

Roland Longchamp, Alireza Karimi, Hamid Khatibi

2007

Robust PID Controller Design by Linear Programming

Roland Longchamp, Marc Kunze, Alireza Karimi

2006

Direct Closed-Loop Identification of Multi-Input Systems: Variance Analysis

Dominique Bonvin, Ljubisa Miskovic, Alireza Karimi

An analysis of the variance of the parameters of a multi-input plant estimated in closed-loop operation is performed. More specifically, the effect of the simultaneous excitation of an additional input on the variance of the estimated parameters is investi ...

2006

Identification of multi-input systems: variance analysis and input design issues

Dominique Bonvin, Ljubisa Miskovic, Alireza Karimi

This paper examines the identification of multi-input systems. Motivated by an experiment design problem (should one excite the various inputs simultaneously or separately), we examine the effect of an additional input on the variance of the estimated coef ...

2006

Friction Modeling of a High-Precision Positioning System

Alain Curnier, Roland Longchamp, Marc Kunze, Alireza Karimi, Sébastien Thiery

Friction modeling of a high-precision positioning system using linear permanent magnet synchronous motors is investigated. The friction force is measured precisely by some specific experiments to eliminate the parasitic ripple force. The experimental data ...

2006

Data-Driven Controller Tuning Using Frequency Domain Specifications

Roland Longchamp, Daniel Garcia, Alireza Karimi

A model-free PID controller tuning approach is presented in this paper. The method can handle different stability and performance indicators in the frequency domain. The phase margin, gain margin, crossover frequency and more advanced indicators which are ...

2006

On the Input Design for Data-Driven Correlation-Based Tuning of Multivariable Controllers

Dominique Bonvin, Ljubisa Miskovic, Alireza Karimi

An iterative data-driven correlation-based method has been proposed recently to tune multivariable linear time-invariant controllers in closed-loop operation. In this contribution, the preferred way of exciting a 2 × 2 system is investigated via the accura ...

2006

A Comparison of Iterative Learning Control Algorithms with application to a Linear Motor System

Roland Longchamp, Alireza Karimi, Mark Edward John Butcher

2006

PID controller design with constraints on sensitivity functions using loop slope adjustment

Roland Longchamp, Daniel Garcia, Alireza Karimi

This paper presents a PID controller design method for stable minimum- phase systems. The approach is similar to the one proposed in the so-called modified Ziegler- Nichols method, where only one point on the frequency response of the plant is measured and ...

2006

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