Rational approximate optimization method for unsteady aerodynamic load of aerodynamic servo elastic system

Abstract

The invention discloses a rational approximate optimization method for an unsteady aerodynamic load of an aerodynamic servo elastic system. Two types of original data of an analysis structure are obtained through existing commercial engineering numerical calculation software. On the basis, an unsteady aerodynamic force rational approximate expression form recognized by modern engineering analysisis applied, and a two-stage alternating double-iteration numerical optimization algorithm of two variables including a linear term coefficient and a nonlinear term coefficient is established. Two-stage double optimization iteration is performed until an optimal coefficient in a high-precision rational approximate fitting formula is obtained. The prediction precision of the unsteady aerodynamic load process in modeling analysis of the aerodynamic servo elastic system of the airplane selected structure is improved, rational approximate fitting errors are greatly reduced, and therefore high-precision load process numerical values are provided for dynamic response, dynamic stability and active elastic control of the airplane aerodynamic servo elastic system.

Description

technical field [0001] The invention relates to the field of aeroelasticity, in particular to a rational approximation optimization method for unsteady aerodynamic loads of an aeroservoelastic system. Background technique [0002] The aircraft deflects the control surface according to the control command, so that the aircraft changes the original flight trajectory, that is, various maneuvering actions of the aircraft are formed. The aerodynamic load history, also known as unsteady aerodynamic force, is formed on the lift surface of the aircraft during maneuvering flight. This changing load history will inevitably lead to elastic vibration of the structure; otherwise, the elastic vibration will affect the unsteady aerodynamic force. The most unfavorable situation of the coupling is that the amplitude of the lifting surface is self-excited and amplified. In the light case, the aircraft is difficult to control, and in the severe case, the structure is damaged. Therefore, in en...

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Problems solved by technology

Document 1 "Application of aeroservoelastic modeling using minimum-state unsteadyaerodynamic approximations [J]. Journal of guidance, control, and dynamics, 1991, 14(6): 1267-1276" proposed a minimum-state rational approximate fitting algorithm, but The constraints of this algorithm are too empirical, and the fitting effect is not ideal; Document 2 "Method for aerodynamic unsteady forces time calculations on an F/A-18 aircraft[J]. Aeronautical Journal, 2008, 112(1127): 27-32" In the calculation of the...

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