Three-degree-of-freedom helicopter robust output feedback control method based on time-varying observer

The invention discloses a three-degree-of-freedom helicopter robust output feedback control method based on a time-varying extended state observer, and belongs to the technical field of aircraft attitude control. The method comprises the following steps: firstly, establishing a mathematical model of a three-degree-of-freedom helicopter, and obtaining a disturbed double-integrator model by using a feedback linearization technology; a first-order derivative and a second-order derivative of an expected attitude angle are estimated by utilizing a third-order tracking differentiator, and meanwhile, in order to solve the influence of parameter values of an extended state observer on initial overshoot and steady-state errors, a time-varying extended state observer is arranged to ensure the stability of a closed-loop system and improve the transient response performance of the closed-loop system. Designing a controller based on proportion-integration-differentiation; and inputting the real attitude angle and the outp