A New Framework of Disturbance Observer with Vidyasagar's Structure

This paper proposes a novel two degree of
freedom (TDOF) control structure: a combination of
Vidyasagar’s structure (VS) and the doubly coprime
factorization based disturbance observer (DCFDOB).
The DCFDOB-VS framework is aimed at providing
a control structure and design procedure for a MIMO
system with good characteristics of disturbance
attenuation, tracking, and decoupling property. The
structure can deal with stable/unstable and minimum
phase/non-minimum phase plants. The advantage of
the method is that two parameters can be designed
for different purposes, independently. The parameter
H stabilizes the system and improves tracking
property. Once the parameter H has been
designed, then the Y Q can be implemented via a
parameter Q for rejecting disturbances and
improving the system robustness.