Stability regions in the parameter space: D-decomposition revisited

The challenging problem in linear control theory is to describe the total set of parameters (controller coefficients or plant characteristics) which provide stability of a system. For the case of one complex or two real parameters and SISO system (with a characteristic polynomial depending linearly on these parameters) the problem can be solved graphically by use of so called D-decomposition. Our goal is to extend the technique and to link it with general M - framework. On this way we investigate the geometry of D-decomposition for polynomials and estimate the number of root invariant regions. Several examples verify that these estimates are tight. We also extend D-decomposition for the matrix case, i.e. for MIMO systems. For instance, we partition real axis or complex plane of the parameter k into regions with invariant number of stable eigenvalues of the matrix A + kB. Similar technique can be applied to double-input double-output systems with two parameters. Key words: Stability an...

• Type: Journal
• Year: 2006
• Where: AUTOMATICA
• Authors: Elena N. Gryazina, Boris T. Polyak
• Keywords: AUTOMATICA 2006, Linear Control Theory, Parameter, Root Invariant Regions