Adaptive Robust Sliding Mode Control

The conventional sliding mode control is well known for its robust property to nonlinear uncertainty. However the assumption that the upper-bound of the uncertainty must be known and the excessive switching gain which is determined by the upper-bound always limit its application. For this, Slotine(2) proposed adaptive sliding mode control which partitiones the uncertainty into two parts: one is known structurally but unknown with unknown parameters, the other one is structurally unknown but its upper-bound is known. The first part is identified and compensated, so that switching gain can be decreased. However the upper-bound must be known as usual. For this, in this paper, we improve it making use of the idea of adaptive robust control law in which the upper-bound is estimated.