Helicopter flight control system transfer characteristic test method

Abstract

The invention belongs to the technical field of helicopter dynamic tests, and discloses a helicopter flight control system transmission characteristic test method. The method comprises the steps of respectively performing sweep frequency excitation on a rotor time domain total distance and a periodic variable pitch through a control system, operating an excitation signal through a hydraulic actuator cylinder, and measuring the rotor time domain total distance and the periodic variable pitch under excitation; and performing FFT on the time domain total distance and the periodic variable pitch of the hydraulic actuator cylinder and a paddle to obtain a control system total distance and periodic variable pitch frequency domain transfer function. The method can be used for providing data for establishing a helicopter flight control system mathematical model based on tests, and providing basic technical support for establishing a helicopter rotor and body coupling stability model considering a flight control system and stability comprehensive analysis. The method has a certain engineering reference value for design and analysis of ground resonance and air resonance of advanced helicopters in China, and has far-reaching significance for guaranteeing safe flight and stability improvement of modern advanced helicopters.

Description

technical field [0001] The invention belongs to the helicopter dynamics test technology, and relates to a test method for the transmission characteristics of a helicopter flight control system, which grasps the transmission relationship between the input of a hydraulic cylinder and the total pitch of the rotor, and the horizontal and vertical periodic pitch values, and considers the flight control system for the establishment of the test method. The helicopter rotor and body coupled stability model and comprehensive stability analysis provide basic technical support. Background technique [0002] While modern advanced helicopters usually use automatic flight control or stability augmentation systems to increase the stability of helicopter manipulation, advanced helicopters with automatic flight control systems or stabilization systems often encounter automatic Phenomenon in which the flight control system or stability augmentation system adversely affects the helicopter grou...

AI Technical Summary

Problems solved by technology

The change of the helicopter's flight attitude is a low-frequency change. The flight control system controls the rotor pitch in real time according to the flight attitude signal. The pitch also changes at a low frequency according to the feedback flight attitude, so that the blades move with the low-frequency movement of the helicopter to produce waving and shimmy motions. , however, because its frequency is very close to the rotor shimmy frequency, it causes continuous excitation to the rotor / body coupling system, and the input excitation frequency of the flight control system also just covers the frequency range of ground and air resonance, resulting in reduced ground / air Resonance Damping Margin in case of ground / air resonance hazard

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