Adaptive controllers with a vector variable forgetting factor

This paper addresses the blow-up problem associated with the estimation part of an adaptive controller. A partial solution of the problem has been deviced by introduction of a variable forgetting factor. It does, however, not eliminate the blow-up possibility. This is shown by simultation experiments on two different models. Two new methods based on a vector variable forgetting factor are presented. One of these methods completely solves the blow-up problem, whereas the other reduces the possibility of blow-up tendencies. Simulation experiments using both methods are compared with the single variable forgetting factor case.