Publications de Roland Longchamp

RST Controller Design by Convex Optimization Using Frequency-Domain Data

Alireza Karimi, Roland Longchamp, Gorka Galdos Sanz de Galdeano

A new robust fixed-order RST controller design approach by convex optimization is proposed in this paper. Only frequency-domain data are considered in the approach for linear time-invariant single-input single-output systems. It is shown that performance s ...

2011

Interactive applications to explore the parametric space of multivariable controllers

Roland Longchamp, Yves Henri Philippe Piguet

This paper describes interactive applications used to illustrate an advanced course on multivariable control. The direct manipulation of features in graphics, such as eigenvectors in the phase plane or observer eigenvalues in the complex plane, gives the s ...

2011

Robust Controller Design by Convex Optimization based on Finite Frequency Samples of Spectral Models

Alireza Karimi, Roland Longchamp, Gorka Galdos Sanz de Galdeano

Some frequency-domain controller design problems are solved using a finite number of frequency samples. Consequently, the performance and stability conditions are not guaranteed for the frequencies between the frequency samples. In this paper, all possible ...

Ieee Service Center, 445 Hoes Lane, Po Box 1331, Piscataway, Nj 08855-1331 Usa2010

H∞ Controller Design for Spectral MIMO Models by Convex Optimization

Alireza Karimi, Roland Longchamp, Gorka Galdos Sanz de Galdeano

A new method for robust ﬁxed-order H∞ controller design by convex optimization for multivariable systems is investigated. Linear Time-Invariant Multi-Input Multi- Output (LTI-MIMO) systems represented by a set of complex values in the frequency domain are ...

Elsevier2010

H-infinity Controller Design for Spectral MIMO Models by Convex Optimization

Alireza Karimi, Roland Longchamp, Gorka Galdos Sanz de Galdeano

A recent method for robust fixed-order H-infinty controller design by convex optimization proposed in [1] is investigated in this paper for the tuning of multivariable controllers. Linear Time-Invariant Multi-Input Multi-Output (LTI-MIMO) systems represent ...

2009

Modeling and Control of a Magnetically Levitated Planar Motor

Alireza Karimi, Roland Longchamp, Marc Kunze, Vincent Reymond

This paper deals with the modeling and control of a magnetically levitated planar motor. The actuator considered has moving coils and stationary magnets. The principal objective is to develop a model which can be implemented in simulation. Therefore, the d ...

2009

Iterative Learning Control based on Stochastic Approximation

Alireza Karimi, Roland Longchamp, Mark Edward John Butcher

In this paper stochastic approximation theory is used to produce Iterative Learning Control algorithms which are less sensitive to stochastic disturbances, a typical problem for the learning process of standard ILC algorithms. Two algorithms are developed, ...

2008

Frequency Domain Controller Design by Linear Programming Guaranteeing Quadratic Stability

Alireza Karimi, Roland Longchamp, Marc Kunze

In a recent work, a frequency method based on linear programming is proposed to design fixed-order linearly parameterized controllers for stable linear multi- model SISO systems. The method is based on the shaping of the open-loop transfer functions in the ...

IEEE2008

Fixed-Order Controller Design for Systems with Polytopic Uncertainty Using LMIs

Alireza Karimi, Roland Longchamp, 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 control ...

2008

Robust fixed-order H infinity Controller Design for Spectral Models by Convex Optimization

Alireza Karimi, Roland Longchamp, Gorka Galdos Sanz de Galdeano

A new approach for robust fixed-order

H_\infty

controller design by convex optimization is proposed. Linear time-invariant single-input single-output systems represented by a finite set of complex values in the frequency domain are considered. It is show ...

IEEE2008