| Due to its unique advantages,helicopters are becoming more and more widely used in military and civilian applications.In order to improve the safety and stability of helicopters and reduce the occurrence of accidents,the rapid fault diagnosis and management of the key parts of helicopters is one of the key technologies in the design of modern helicopters.At present,the main method of helicopter fault diagnosis is to detect the vibration signal,that has become a mature HUMS system used in military helicopters at home and abroad.In order to further improve the sensitivity of fatigue crack initiation and propagation in helicopter moving parts,acoustic emission(AE)technology has been widely used in the detection of helicopter metal component cracks in recent years.As an important part of the helicopter,the centerpiece of the rotor helicopter hub is one of the key components of fault monitoring due to its complex force,large and continuous strength.In order to effectively study the application of acoustic emission technology in the crack detection of the rotor helicopter hub centerpiece,it is an important foundation of the entire research work that rotor helicopter hub component acoustic emission signal sampling,wireless transmission research and development.This paper proposes a wireless WIFI-based acoustic emission signal synchronization data acquisition,based on the analysis of the principle of acoustic emission technology in detecting the initiation and propagation of cracks in stressed parts.Taking into account that the rotor helicopter hub central part is in a rotating state during operation.This paper analyzes the requirements of the whole acoustic emission signal data acquisition and transmission device,proposes the overall design and structure of hardware design and software design.On this basis,the hard and software design process and implementation of the device are elaborated.System hardware circuit consists of acoustic emission signal conditioning circuit,high-precision and high-speed A/D conversion circuit,STM32 embedded microprocessor system and peripheral circuit,data storage circuit,wireless WIFI communication circuit,GPS synchronization circuit,and power supply circuit.Among them,the design of band-pass filter to filter the signal,ADS8422 analog-to-digital conversion device achieves a sampling rate of up to 2MSPS,LAN8720 and HF-A11 to achieve datawireless WIFI transmission,GPS synchronization receiver for multi-channel signal acquisition system to provide clock synchronization.The software system design mainly includes 16-bit high-accuracy A/D sampling rate control,data exchange between two microcontrollers,LWIP protocol migration and network card chip driver control,wireless module initialization configuration and UDP communication program design,receiving software design of PC server data and so on.The system debugging part passed the test of the overall circuit performance of the hardware and the software configuration and the optimized test,which realized the stable acquisition of the acoustic emission signal and the wireless transmission of the data.Finally,through joint testing of hardware and software and acquisition of live acoustic emission signals,the system can achieve high-speed sampling rate of 2MSPS,data acquisition synchronization accuracy is 1us,and the sound emission data is uploaded to the PC server in real time through WIFI technology.The preservation and waveform display realize the acquisition of the acoustic emission signal of the central part of the helicopter hub,which provides a possibility to further diagnose the initiation and expansion of cracks. |
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