Master Thesis, Report UPTEC 95150E, December 1995.
Report, without figures, available in Postscript : compressed(gz) 254K , uncompressed 775K.
Model-based anti-windup compensation is here considered for both single-input single-output (SISO) and multiple-input multiple-output (MIMO) systems.
A modified controller structure is proposed, which leaves the nominal closed-loop dynamics unchanged, as long as none of the control signals saturate. The loop gain around the saturation can be adjusted by designing a special anti-windup compensation transfer-function matrix.
Two approaches for the design of MIMO anti-windup compensation are developed. One is based on a fully crosscoupled MIMO system, whereas the other approach is applicable for control systems which utilize decoupling. Both approaches are generalizations of the systematic anti-windup design procedure developed by Sternad and Rönnbäck for scalar systems.
The main idea behind the MIMO approaches in the present report, is to reduce MIMO design to a set of scalar designs, by diagonalizing the loop gain around the control signal saturation elements. As in the scalar case, the design equations will then consist of scalar spectral factorizations. The multivariable approach is completely general and since it is based on rational fractions, it will be applicable to continuous-time systems as well as discrete-time systems. A number of examples are investigated and diffenrent design choices are evaluated.