28. A method as recited in claim 27 wherein said step of combining control output membership functions includes scaling the selected control output membership functions in response to the magnitudes of the sensed variable signals.
27. A method as recited in claim 26 wherein said selection of a control output linguistic variable and associated membership function additionally includes the steps of identifying a plurality of control output linguistic variables and associated control output membership functions from the control output membership function set in response to multiple logical rules and of combining said control output membership functions to produce the control output.