Two sufficient conditions for the fuzzy controller with constant output
模糊控制器输出值不变的两个充分条件

A fuzzy controller is usually composed of three parts: fuzzification, fuzzy inference and defuzzification. The fuzzy inference defines a fuzzy mapping from the input universe to the output universe. When the fuzzy mapping is a constant mapping, for any given fuzzification and defuzzification methods, the output of the fuzzy controller will never change with the input value. Two sufficient conditions are proposed under which the fuzzy mapping will remain constant. These conclusions are generalized from the single-input single-output fuzzy system to the multiple-input single-output one.