Publications by Roland Longchamp

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

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 ...

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

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 ...

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 ...

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 ...

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 ...

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 ...

This paper describes how an undergraduate control course is enhanced with Sysquake interactive applications. Basic concepts in control theory, different ways to assess performance and robustness of a controlled system, and limits of closed-loop systems are illustrated with graphics which can be manipulated directly with the mouse, letting the student acquire a deeper and broader understanding of the theory. The applications, implemented with Sysquake as stand-alone programs, offer a simple user interface wh

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 ...

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 ...

A new method for PID controller tuning based on Bode's integrals is proposed. It is shown that the derivatives of amplitude and phase of a plant model with respect to frequency can be approximated by Bode's integrals without any model of the plant. This information can be used to design a PID controller for slope adjustment of the Nyquist diagram and improve the closed-loop performance. Besides, the derivatives can be also employed to estimate the gradient and the Hessian of a frequency criterion in an iter

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 ...

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 ...

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 ...

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 ...

In this paper, it is shown that dynamic optimization problems of first-order systems can be transformed into a static paramertic programming problem, where the state plays the role of the parameter. Thus, an optimal feedback law is obtained. This concept is applied to the die-sinking Electrical Discharge Machining, a highly time varying industrial process which necessitates adapation of machining settings during operation. It is shown that the minimum-time operation of this process is equivalent to choosing

A method to design decentralized PID controllers for MIMO systems is presented in this paper. Each loop is designed separately, but the Gershgorin bands are considered to take interactions into account. The method uses different design parameters: The infi ...

A controller design method using a frequency criterion is proposed in this paper. The frequency criterion is defined as the weighted sum of squared errors between the specified and computed values of the design parameters. These are the infinity-norm of th ...

Roland Longchamp

Chat with Graph Search

Frequency Domain Controller Design by Linear Programming Guaranteeing Quadratic Stability

Model-Free Precompensator and Feedforward Tuning Based on the Correlation Approach

Robust Loop Shaping Controller Design for Spectral Models by Quadratic Programming

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

Interactive applications to explore the parametric space of multivariable controllers

Gain-Scheduled Controller Design by Linear Programming

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

Use of Sysquake applications in an undergraduate control course

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

Robust Control of Polytopic Systems by Convex Optimization

PID Controller Tuning Using Bode's Integrals

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

Model-Free Precompensator Tuning Based on the Correlation Approach

A Statistical Analysis of Certain Iterative Learning Control Algorithms

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

Robust Control of Polytopic Systems by Convex Optimization

Dynamic Optimization of First-Order Systems via Static Parametric Programming: Application to Electrical Discharge Machining

PID Controller Design for Multivariable Systems Using Gershgorin Bands

Robust Pole Placement of Systems with Polytopic Uncertainty Via Convex Optimization

PID Controller Design with Specifications on the Infinity-Norm of Sensitivity Functions