Application Research On Fractional Controller In Five Degrees-of-freedom Air-bearing Spacecraft Simulation System

The fractional calculus theory applying in the field of control theory is arelatively new and popular subject and the advent of the fractional controller is animportant advance in the control area.In this paper,in which the fractional calculus theory is the theoretical basis,wefirstly introduce the three definitions of the fractional calculus and theircorresponding Laplace change,then analysize the feature of fractional differentialoperator in the frequency domain,and introduce several discrete methods of thefractional differential operator.Also,we state Nyquist stability criterion of fractionalcontrol system based on the open-loop transfer function,and prove the validation ofthe criterion by a example.we emphasize on the reaserch of the characteristics of thefractionalPI~λ D~μcontroller,and the difference between the fractionalPI~λ D~μcontroller and the traditional PID controller. We research the the fractionalPI~λ D~μcontroller in frequency domain in detail and package its simulation module. Bysimulation we know the impact of the five parameters of the fractionalPI~λ D~μcontroller. We compare the control performance of the traditional PID controller andthe fractionalPI~λ D~μcontroller by simulation. And we get the conclusion that thefractionalPI~λ D~μcontroller has much better control performance especially whenthe control objection is fractional.The paper combines the fractionalPI~λ D~μcontroller and the fuzzy controltheory and proposes a new-type controller, which is called adaptive fuzzy fractionalPID controller. We give the detailed structure and establish the simulation module ofthis new kind controller. By simulation we demonstrate the advantage of thenew-type controller comparing to the traditional PID controller and the fractionalPI~λ D~μcontroller. At last we use the adaptive fuzzy fractional PID controller in thefive degrees-of-freedom air bearing spacecraft simulator control system. This kindof new-type controller can satisfy the performance index of the fivedegrees-of-freedom air bearing spacecraft simulator control system, and can get thebetter performance than the traditional PID controller and the fractionalPI~λ D~μcontroller.