| Affected by atmospheric environment,aircraft structure corrosion is very serious,caused huge losses to the aviation industry.At present,China mainly uses the traditional detection method for the aircraft structure in the atmospheric environment corrosion detection and maintenance.However,this method is difficult to detect the corrosion of the aircraft structure in time,can’t be an effective monitoring and maintenance.This paper is based on the principle of electrochemical corrosion monitoring,sets up a relation model of corrosion monitoring signal and the sensor impedance,and completed the development of corrosion monitoring system prototype.For the measurement system,the main research content includes the following aspects:Firstly,the corrosion mechanism of aircraft structure is studied and analyzed,the monitoring parameters of the environmental corrosion monitoring system and the sensor surface humidity sensor,the environment corrosive sensor and the cadmium sulfide coating(CDS)sensor were determined as the tools for monitoring environmental parameters.And introduces the overall design of the corrosion monitoring system.Secondly,the characteristics and difficulties of environmental corrosion monitoring system for circuit design of sensor is analyzed.The sensor signal processing circuit and the main control circuit are designed.The sensor circuit mainly includes CDS coating sensor,surface humidity sensor and environmental corrosive sensor measurement circuit.As the current is very weak in the traditional CDS coating sensing measurement circuit,it is easy to be disturbed by the space noise current,which leads to the decrease of the signal to noise ratio and the error of the measurement results.Based on the establishment of the spatial current noise model,a simple high impedance symmetrical resistance measurement circuit is proposed,which overcomes the shortcomings of traditional electrochemical impedance measurement susceptible to spatial noise interference and greatly eliminates the interference of noise current,to achieve high-precision impedance measurement.Thirdly,corrosion monitoring system software design.The software design of the system mainly uses STM32F103RCT6 MCU to collect,process and store data,and control the measurement of the sensor and display the collected data in real time.In the algorithm of data processing.The quadratic semi-periodic difference algorithm and the least squares sine fitting algorithm are used to remove noise and restore the output signal.Finally,a functional verification of the corrosion environment monitoring system was carried out.Through the different environmental experiments,it is verified that the environmental corrosion sensor can distinguish the corrosivity of different environmental.The CDS coating sensor can reflect the failure threshold of different coatings and the surface humidity sensor can detect the dry and wet state of the environment.The experimental results show that the system can prevent the aircraft in the atmospheric environment corrosion,and corrosion has a predictive effect,to achieve low power consumption,long time monitoring. |
