Unstable motion analysis method based on bifurcation theory and degree-of-freedom release experiment

Abstract

The invention discloses an unstable motion analysis method based on a bifurcation theory and a degree-of-freedom release experiment. The method comprises the following steps: firstly, establishing a set of degree-of-freedom release experiment system in a wind tunnel; then, a bifurcation theory is introduced into a degree-of-freedom release experiment, a continuous algorithm based on control is established, and a branch balance point and a periodic closed orbit are searched; non-invasive control is adopted, a branch search process is converted into an optimization process with a feedback control quantity tending to zero, so that the feedback control keeps the position of a balance branch while changing the stability of the balance branch, stable and unstable balance solutions are continuously tracked in an experiment, the global stability characteristic of an aircraft is obtained, and the stability of the aircraft is improved. A brand-new experimental method is provided for dynamic characteristic research of the aircraft, and accurate prediction of the stall deviation characteristic of the aircraft can be achieved.

Description

Technical field [0001] The present invention involves the field of aviation aircraft ground test technology, especially an analysis method based on a break -based and freedom release experiment. Background technique [0002] In order to pursue high mobility, modern fighter planes often enter the large -scale welcoming area. The movement may show serious non -linearity under the corner, which is very prone to defect deviations, and even risk to enter the tail rotation. The research on this kind of disappointment problem is not only related to flight safety, but also the combat capabilities of modern high -performance aircraft. Due to the severe non -linearity of the dynamic and torque from the region, the cross -coupling of vertical and horizontal pneumatic, the impact of non -regular characteristics, and obvious pneumatic stagnation phenomenon have brought great difficulties and risks to the aircraft stalling prediction and test flight, which brings great difficulties and risks E...

AI Technical Summary

Problems solved by technology

Due to the severe nonlinearity of aerodynamic force and torque in the stall deviation region, vertical and horizontal aerodynamic cross-coupling, the influence of unsteady characteristics, and obvious aerodynamic hysteresis, it brings great difficulties and risks to the aircraft stall deviation prediction and flight test

[0003] Most of the current stall deviation research methods and stall deviation criteria are based on conventional wind tunnel experimental data, which have limitations in reflecting nonlinear aerodynamic characteristics, and when the nonlinear system is in the critical state of stall deviation, the analysis results will be consistent with the actual A non-negligible error occurs between the system responses

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