LFRT version 2.0 for Scilab: introduction

• Introduction
  • Short presentation
  • Definitions
• Basic functions
• Realization
• Order reduction and approximation
• Modelling a missile

Short presentation

With this toolbox, LFR-objects (see below for a definition) are created:

• By combination of 1-by-1 LFR-objects (object oriented realization)
• By direct realization of symbolic objects
• From numerical data by interpolation

This toolbox proposes order reduction and approximation tools for use after realization.

It is also possible to consider nonlinear systems, for example the continuum of linearized models can be modelled as an LFR-object. This problem is addressed considering a simplified missile model.

LFR-objects can be used in particular for µ-analysis.

Definitions

LFT: Linear Fractional Transformation
LFR: Linear Fractional Representation

State-space representation = realization of a transfer function matrix G(s)

Linear fractional representation = realization of a symbolic expression G(s,δ1,δ2,...)