Improving robust self-organizing fuzzy variable structure controller

The improvements were mainly in two respects: elimination of need for upper bounds on norms of system uncertainties and large reduction of control chatter. The key to the improvements was the selection of a equation that represented a virtual controller (virtual controller was a part of the fuzzy controller) and allowed mismatched uncertainties to be compensated for adaptively. Thus no upper bounds on norms of system uncertainties were needed. With mismatched uncertainties adaptively compensated for, k in the sliding-mode control law becomes very small according to Kosko's theory, small k signified that chatter was small. Simulation results show that steady-state chatter is very small.