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Propeller hub center non-linear dynamic characteristic modeling method

A modeling method and nonlinear technology, applied in special data processing applications, instruments, electrical and digital data processing, etc., can solve problems such as inability to obtain correct results, analysis of the dynamic characteristics of the hub center, and ground resonance analysis errors, etc. Accuracy and the effect of avoiding large errors

Inactive Publication Date: 2015-01-28
CHINA HELICOPTER RES & DEV INST
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Problems solved by technology

In the analysis of the dynamic characteristics of the helicopter hub center, engineering practice usually adopts a linear processing method based on small disturbances in the equilibrium position, assuming that the dynamic characteristics of the landing gear buffer and the wheel are linear, so that it is considered within a small amplitude range, From a microscopic point of view, when the actual amplitude does not exceed the range, the result is correct, but the correct conclusion cannot be drawn for the situation beyond the amplitude range
In fact, the stiffness and damping of the landing gear buffer and the wheel have highly nonlinear characteristics, and are sensitive to environmental changes, especially when the helicopter has a large motion amplitude when the road surface is rough, gusts, etc. when taking off and landing at sea or sliding. Linearization processing will bring great errors to the analysis of the dynamic characteristics of the center of the propeller hub and the analysis of ground resonance

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  • Propeller hub center non-linear dynamic characteristic modeling method
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Embodiment Construction

[0021] The method for modeling the nonlinear dynamic characteristics of the center of the hub involved in the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0022] Step 1: Establish a coordinate system describing the movement of the body on the landing gear, using a three-point and column-type landing gear layout. Other configurations can be similarly simplified to this type, see figure 1 . Define the origin of the body coordinate system at the center of gravity of the body; the X-axis is the heading, and the backward is positive; the Y-axis is lateral, and the right is positive; the Z-axis is vertical, and the upward is positive. The airframe has six degrees of freedom of motion at the center of gravity: heading, lateral, and vertical displacements, and roll, pitch, and yaw motions. (X G , Y G ,Z G ) is the displacement of the center of gravity of the whole machine; (φ x , φ y , φ z ) is the rotation angle o...

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Abstract

The invention discloses a propeller hub center non-linear dynamic characteristic modeling method, which belongs to helicopter theoretical modeling technology. The propeller hub center non-linear dynamic characteristic modeling method is characterized by comprising the following steps: establishing an engine body coordinate system, and describing the motion of an engine body and undercarriages; carrying out the balance computation of single undercarriage, and establishing force and position relationship between airplane wheels and a buffer; carrying out the balance computation of the engine body on the undercarriage; and determining the non-linear constraint force of an undercarriage system to the motion of the engine body in a time domain, and inertial load acted to the engine body, establishing an engine body motion equation on a fixed coordinate system by adopting a d'alembert's principle, and simultaneously establishing the balance equation of each undercarriage and the motion equations of the engine body on the undercarriage to obtain a propeller hub center non-linear dynamic characteristic equation of the engine body on the undercarriage. The invention can be applied to helicopter propeller hub center non-linear dynamic characteristic analysis and ground resonance modeling and analysis and can improve the accuracy of the propeller hub center non-linear dynamic characteristic analysis and the ground resonance stability analysis.

Description

technical field [0001] The invention belongs to the theoretical modeling technology of helicopters, and relates to a nonlinear dynamic characteristic modeling method of the hub center of a helicopter body on the landing gear for the analysis of the dynamic characteristics of the hub center of the helicopter body and the modeling and analysis of ground resonance. Background technique [0002] According to the requirements of the specification, before the ground resonance driving test of a helicopter with a new model or a major change in the landing gear system, the dynamic characteristic test and analysis of the center of the propeller hub must be carried out, so as to analyze the ground resonance and give a conclusion whether it can be driven. In the analysis of the dynamic characteristics of the helicopter hub center, engineering practice usually adopts a linear processing method based on small disturbances in the equilibrium position, assuming that the dynamic characteristi...

Claims

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Application Information

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IPC IPC(8): G06F17/50G06F19/00
Inventor 朱艳凌爱民
Owner CHINA HELICOPTER RES & DEV INST
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