Abstract:For the characteristics of three degree of freedom helicopter, such as multivariable, strong coupling and so on, first the mathematical model of the system was established from three channels individually. These three channels were evaluation channel, traverse channel and rotation channel. Then for evaluation channel, PD controller was designed; while for coupling traverse channel and rotation channel, a kind of method was adopted which making traverse angle as inner loop, then PID controller was designed for inner loop and outer loop individually. Considering the factor about uncertain parameters in system, and common PID controller could not suit the factor about varying parameters, thus fuzzy controller was designed. It was shown by simulation that fuzzy PID could overcome the deficiencies in common PID, and got better control effect.