Helicopter rotor and fuselage coupling stability modeling method

Abstract

The invention discloses a helicopter rotor and fuselage coupling stability modeling method, and belongs to the helicopter dynamics modeling and analysis technology. The method includes: adopting a modal synthesis technology to perform comprehensive modeling on a rotor and fuselage dynamics coupling system, describing the motion of a fuselage and rotors in different coordinates, establishing structural dynamics finite element method models of isolated rotor blades and an airframe structure respectively, adopting an aerodynamic model to model aerodynamic force, and deducing a rotor / airframe coupling system kinetic equation by applying the Hamilton principle; establishing an automatic flight control system control model, and deriving an aerodynamic load matrix related to the pitch variable, thereby establishing a rotor wing and aircraft body coupling aeroelastic stability analysis model considering the flight control system; and finally, solving a characteristic value through a characteristic value method, and judging the stability of the coupling system through a characteristic value solution. The model can be used for calculating and analyzing the'ground resonance 'and'air resonance' stability of all advanced helicopters, and key technical support is provided for model design and development.

Description

technical field [0001] The invention belongs to the modeling and analysis technology of helicopter dynamics, and relates to a modeling method for coupling stability of a helicopter rotor and a fuselage. Background technique [0002] Modern advanced helicopters usually use Automatic Flight Control System (AFCS) or Stability Augmentation System (SAS) to increase the stability of helicopter handling. Although AFCS can achieve increased handling stability, if the design does not consider its impact on the helicopter's "ground resonance" and "air resonance", the completion may deteriorate the "ground resonance" and "air resonance", especially the "air resonance". [0003] The automatic flight control system uses the state of the helicopter's flight attitude as the feedback variable, and increases the flight stability of the helicopter through pitch control. Helicopter flight attitude changes at low frequency. The flight control system controls the rotor pitch in real time accord...

AI Technical Summary

Problems solved by technology

However, because the rotor shimmy frequency in the frequency domain is very close, it causes continuous excitation to the rotor / body coupling system, and the input excitation frequency of the flight control system just covers the frequency range of "ground resonance" and "air resonance", resulting in Reduced "Ground / Air Resonance" damping margin, dangerous "Ground / Air Resonance" situations

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