Sliding mode control design techniques

The objective of variable structure control (VSC) is to drive the state from some arbitrary initial conditions onto the intersection of the switching surfaces, and then to maintain it on, or in the neighbourhood of, this intersection subspace. The switching hyperplanes must be chosen so that the sliding mode on their intersection gives the desired dynamic performance of the reduced order equivalent system. The time response of the system is determined by its eigenstructure, and it is therefore important to select suitable hyperplanes for satisfactory performance