Robust Disturbance Decoupling in Linear Multivariable

The method of unmodelled disturbance decoupling compensator (DDC) design for multivariable systems is proposed using the unknown-input observer (UIO) technique. The DDC equations were founded in explicit form; at that disturbance estimation may be eliminated from the control law if established system structure non-singularity condition takes place. For the case when such a condition is violated the realizable form of the DDC with internal small time constant dynamic filter is proposed. It has been shown that the slow motion in obtained closed-loop two-time-scale system coincides with the processes in the system with ideal compensator if the fast motion is stable. As a result the DDC design is reduced to robust stabilization problem of singularly perturbed system. Copyright © 2005 IFAC