20. The fuzzy logic controller of claim 15 wherein said defuzzifier means comprises means for selecting a clearness distribution from said knowledge-base corresponding to each of said control action fuzzy patterns, and means for utilizing each said control action fuzzy pattern clearness distribution to map said representation of a control action clearness degree to a value for one of said process control signals.
21. The fuzzy logic controller of claim 20 wherein each clearness distribution has an x-axis representing the range of control action values for the fuzzy pattern which is associated with the control action and which corresponds with said each clearness distribution and a y-axis representing clearness degrees and wherein said means for utilizing each said control action fuzzy pattern clearness distribution to map said representation of a control action clearness degree to a value for one of said control signals comprises means for locating said control action clearness degree on the y-axis of said control action fuzzy pattern clearness distribution and for projecting said control action clearness degree onto the x-axis of said control action fuzzy pattern clearness distribution.