Sv. Yallapragada et al., REACHING CONDITIONS FOR VARIABLE-STRUCTURE CONTROL WITH OUTPUT-FEEDBACK, Journal of guidance, control, and dynamics, 19(4), 1996, pp. 848-853
A design technique for satisfying the reaching condition when applying
variable structure control to a linear system with output feedback is
described. The control consists of a linear feedback term and a disco
ntinuous feedback term. By combining the linear term with the disconti
nuous term, very good disturbance rejection and robustness can be achi
eved with a lower control effort than would be required from either co
ntrol when used independently. The linear gain and the discontinuous g
ain are designed so that the sliding surface exists and is globally re
achable. Furthermore, the time spent in the reaching phase can be redu
ced by proper selection of a scalar parameter that is imbedded in the
linear-gain matrix. A specific algorithm is given along with a numeric
al example.