Automatic warning system and method of rotor vortex ring status based on aerodynamic noise monitoring

Abstract

The invention discloses a rotor vortex ring state automatic early warning method based on aerodynamic noise monitoring. The automatic warning method comprises the following steps of: acquiring aerodynamic noise signals of a fuselage during descent or landing flight collected by a microphone having a plurality of microphones arranged on a fuselage surface of a helicopter or a tilt rotor aircraft; The aerodynamic noise signal is analyzed by frequency spectrum, and the aerodynamic noise signal in frequency domain is obtained. The low frequency noise signal is filtered to obtain the noise signal of rotor and tail rotor in frequency domain and then separated. Dynamic analysis of rotor aerodynamic noise signals in frequency domain; When the noise pressure level corresponding to the rotor blade passing frequency of 6-40 times is increasing, an alarm command is sent to the rotor to alert that the rotor has entered into a dangerous vortex ring state. The invention can more conveniently realizetimely and automatic early warning when the rotor enters the vortex ring state, and ensure the safety of the helicopter and the tilt rotor aircraft when landing.

Description

technical field [0001] The invention relates to the technical field of rotorcraft, in particular to an automatic warning system and method for a rotor vortex ring state based on aerodynamic noise monitoring. Background technique [0002] Entering the Vortex Ring State (VRS) when the rotor descends vertically has a great impact on the safety of the helicopter. According to relevant statistics, from 1982 to 1997 alone, there were as many as 42 serious accidents caused by helicopters falling into a vortex ring state when landing. [0003] Severe vortex rings will also occur in tilting rotorcraft. In 2000, when a U.S. Marine Corps V-22 "Osprey" tilt-rotor aircraft landed, because one rotor was caught in a vortex ring, the fuselage rolled uncontrollably and fell rapidly, directly causing 19 occupants to die. tragedy. Therefore, it is of great practical significance to explore the early warning method of the vortex ring state to ensure the flight safety of the rotorcraft. [0...

AI Technical Summary

Problems solved by technology

[0006] 1) It is difficult to directly monitor the rotor tension and torque. The monitoring of the rotor tension and torque requires a large number of strain gauges on the blades, which is more complicated to implement and will affect the performance of the rotor

[0007] 2) Although the rotor gradually enters the vortex ring state, it will produce a certain degree of vibration, but due to the vibration interference caused by the engine operation, it is difficult for the pilot of the helicopter or tilt rotor to find out that the rotor has entered the vortex ring earlier according to the vibration level of the cockpit. ring state, when the pilot notices a significant increase in the vibration level of the cockpit, the rotor may have been trapped in a deep vortex ring state

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