A robust flight control method for nonlinear non-minimum phase aircraft

Abstract

The invention provides a robust flight control method for a nonlinear non-minimum phase aircraft. It avoids the problem of non-minimum phase by assisting the design of the observer, and based on the compensation idea, the classical linear robust control method is well extended to nonlinear systems, and the flight control of nonlinear non-minimum phase aircraft is realized. The method is simple and effective, and has high flexibility and safety. The method has two steps: step 1, model transformation stage, decompose the original nonlinear system into two subsystems based on additive state decomposition theory; step 2, controller design stage, design controllers for the two subsystems respectively and combine auxiliary The observer gets the final robust flight controller.

Description

technical field [0001] The invention belongs to the technical field of flight control, in particular to a robust flight control method for a nonlinear non-minimum phase aircraft. Background technique [0002] A nonlinear system is non-minimum phase if its intrinsic or zero dynamics are unstable. Many aircraft can be modeled as nonlinear non-minimum phase systems, such as hypersonic vehicles, conventional fixed-wing aircraft, and vertical take-off and landing aircraft. For the aircraft, the non-minimum phase characteristics of the system are determined by its dynamic characteristics. [0003] For most aircraft, the track maneuver is based on the adjustment of the aircraft attitude angle. The deflection of the control surface not only produces a rotational moment that changes the attitude of the aircraft, but also produces a force that changes the trajectory of the aircraft, which is the parasitic force of the rotational moment. It is this coupling of forces and moments tha...

AI Technical Summary

Problems solved by technology

However, for nonlinear systems with unstable zero dynamics, the non-minimum phase property limits the direct application of these techniques

Also, zero dynamics are not changed by feedback, so non-minimum-phase systems are much more difficult to control than minimum-phase systems

Images