Published

2010-09-01

Sum of squares decomposition: theory and applications in control

Descomposición en suma de cuadrados: teoría y aplicaciones en control

DOI:

https://doi.org/10.15446/ing.investig.v30n3.18178

Keywords:

sum of squares (SOS), stability analysis, nonlinear systems, switched systems (en)
suma de cuadrados, SOS, análisis de estabalidad, sistemas no lineales, sistemas conmutados (es)

Authors

  • Andrés Pantoja niversidad de los Andes
  • Eduardo Mojica Nava Universidad Católica
  • Nicanor Quijano Universidad de los Andes

The sum of squares (SOS) decomposition technique allows numerical methods such as semidefinite programming to be used for proving the positivity of multivariable polynomial functions. It is well known that it is not an easy task to find Lyapunov functions for stability analysis of nonlinear systems. An algorithmic tool is used in this work for solving this problem. This approach is presented as SOS programming and solutions were obtained with a Matlab toolbox. Simple examples of SOS concepts, stability analysis for nonlinear polynomial and rational systems with uncertainties in parameters are presented to show the use of this tool. Besides these approaches, an alternative stability analysis for switched systems using a polynomial approach is also presented.

Las técnicas de descomposición en sumas de cuadrados (SOS) permiten emplear métodos numéricos para probar la positividad de funciones polinómicas multivariables resolviendo problemas de programación en semidefinida. Teniendo en cuenta que generalmente es difícil encontrar funciones de Lyapunov para realizar análisis de estabilidad en sistemas no lineales, con el uso de técnicas SOS se utiliza una herramienta computacional para resolver este problema, planteando las condiciones de estabilidad como un problema SOS y obteniendo la solución con un toolbox de Matlab. Para mostrar el uso de esta herramienta se presentan ejemplos simples de los conceptos de SOS, análisis de estabilidad para sistemas no lineales polinomios, racionales, con incertidumbre en los parámetros y de sistemas conmutados con una aproximación en polinomio. Con dicha aproximación se encuentran funciones adecuadas para demostrar estabilidad asintótica para estos sistemas.

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