Research On Rainfall Measurement Method Based On Piezoelectric Technology

Rainfall observation is an important work of our meteorological department,and its observation data has a positive guiding significance for China's industrial and agricultural production.With the continuous development of information technology,automation technology has been widely used in rainfall observation of automatic weather stations.However,we should clearly recognize that the difference between automatic weather stations and artificial rainfall observation in data acquisition methods,data observation time and other aspects seriously affects the validity of rainfall observation data in China.In order to solve the problem of synchronous monitoring of rainfall and its micro-characteristics,a piezoelectric sensing method based on piezoelectric effect is proposed,and a piezoelectric rain sensor with low cost and low power consumption is designed,which realizes the measurement of rainfall and its micro-characteristics by using the principle of dynamic mechanics.Firstly,the advantages and disadvantages of various measurement methods of rainfall and raindrop size are compared,proposes a measurement scheme based on piezoelectric effect principle,and designs the overall scheme of software and hardware measurement platform.Then,the mechanical structure,hardware circuit,data acquisition program and user interface of the piezoelectric rain sensor are designed,and the existing measurement methods are optimized,including eliminating the boundary effect of the sensor by using array piezoelectric transducer,accurately measuring the momentum of raindrop falling,and parallel processing and analysis of two signals with different amplification multiples.Enough range and resolution to take into account the measurement of large and small raindrops;and a method of signal peak recognition based on voltage true effective value signal is proposed,which can effectively reduce the sampling resolution of signal processing and obtain rainfall amount and intensity by accumulating the volume of raindrops.Secondly,the input-output relationship and sensor resolution of piezoelectric precipitation sensor under the excitation of a single raindrop are initially calibrated by the method of equal momentum.Then,the output signal of the tipping bucket rain gauge collected synchronously is treated as the reference rainfall,and the calibration of the relationship between sensor output and raindrop size in simulated rainfall is realized by the method of model-based adaptive training and optimization.Rainfall volume and intensity can be obtained by accumulating the volume of raindrops.Rainfall spectrum can be calculated by synthesizing the size and quantity of raindrops,thus completing the measurement of rainfall and distribution of raindrops spectrum.The measurement schemes and sensor functions are verified by the measurement experiments in simulated and actual rainfall respectively.The experiments show that the scheme can automatically and continuously measure and record the amount of raindrops,particle size,rainfall amount and real-time rainfell intensity,and can ensure high measurement accuracy for heavy rain,light rain and micro-characteristics of rainfall.