You don't need an exact mathematical model of an object. In fact, fuzzy control is put forward to solve the problem that other control algorithms need accurate models, and sometimes the robustness to disturbances is poor after obtaining accurate models.

Fuzzy control is a control theory based on linguistic rules and fuzzy reasoning, and its foundation is fuzzy set theory in modern control theory. It is an important branch of intelligent control.

Compared with traditional control theory, fuzzy control has two incomparable advantages: first, fuzzy control can effectively and conveniently realize people's control strategy and experience in many applications, and it has been closely concerned by people since the birth of fuzzy control; Secondly, fuzzy control can achieve better control without the mathematical model of the controlled object, because the dynamic characteristics of the controlled object have been implied in the input-output fuzzy sets and fuzzy rules of the fuzzy controller. Therefore, fuzzy control is more and more used in various fields, especially in household appliances. The washing machine based on fuzzy control is a typical example.