Based On Multivariable Decoupling Of Direct Lift Control Application And Simulation

Direct Force Control(DFC) is one of main functions which Active Control Technique(ACT) must realize. It's main goal is realizing the part or complete decoupling between the movement parameters of the airplane, and directly producing aerodynamic force which can make the airplane to achieve desired flight path without changing flight attitudes. It is significant for the military and civil aircraft to realize DFC.Decoupling control is the kay technology in Direct Force Control. In the frequency domain and the time domain separately , this paper propose three methods to design the DFC controller, these are the Inverse Nyquist Array method based on the multivariables frequency domain theory, the state-feedback and input transformation method based on the state- space theory and the Eigenstructure Assignment method based on output feedback. Different results are gotten from deep analysis of DFC realization principle and the discussion of three kinds of basic patterns of DFC. These three methods have the similarities and differences. Through comparison to the structure of controllers, the Inverse Nyquist Array method and the Eigenstructure Assignment method had the better effect in the real project application and practice. In researching the Inverse Nyquist Array method, the graph judgement principles which combine the gershgorin band with step response curve of the system is used for analyze the system coupling response together, the possibility of decoupling on the condiction that the gershgorin band surrounds the zero point is dicussed.This method is effectively demonstrated by the examples.From the simulation results in the example,these three methods can realize the three kind of patterns of DFC and achieve the anticipated goal. By the comparison, on the condition that the responsing time and the control precision match the anticipation, the Inverse Nyquist Array mathod has lower request to the mathematical model, the structure of controller is simplest, and it has a stronger superiority and realization in DFC.As the application of DFC,a system of Gust Load Alleviation(GLA) is designed. DFC is used for suppressing the additional nomal load. The result of simulation shows that the Gust Load Alleviation control based on DFC plan is available..