Research On Temperature Compensation Method Of Surface Acoustic Wave Micro Force Sensor

The vigorous development of science and technology has greatly improved the productivity of society.In this information age,the influence of science and technology is everywhere.With the rapid improvement of industrial automation level,people are increasingly demanding the measurement of physical parameters in nature.As a common physical quantity,the accuracy of pressure measurement directly affects the performance of the whole pressure detection system.Pressure sensor is a tool to detect pressure.The detection accuracy is the key index to measure its performance.It is a very important research topic to design and produce high-precision pressure sensor.Surface acoustic wave is a kind of wave propagating along the surface of elastomer.It has a history of more than 100 years.With the development of science and technology,SAW technology has gradually matured,and various types of SAW devices have emerged as the times require.SAW micro-force sensor based on SAW technology can carry out passive wireless communication in special environment such as slit and micro-gap.At the same time,its preparation process is simple,the instrument is small,and the production cost is low.It has a good application prospect in the field of modern pressure detection.As a high-precision intelligent equipment,the sensor will be affected by external conditions when it is used,and there will be measurement errors.This paper takes SAW micro-force sensor as the research object,and studies the temperature compensation method for the main error source,so as to improve the measurement accuracy.Firstly,based on SAW micro-force sensor,the piezoelectric properties of materials,the design theory of interdigital transducer and the working principle of the sensor are analyzed.The mechanism of temperature on the structure of the sensor is mainly studied,includingpiezoelectric materials,cantilever beams,resonators and oscillating circuits.From the above analysis,we can see that temperature is the main source of measurement error of SAW micro-force sensor.In order to ensure high-precision performance,it is necessary to compensate the temperature of the sensor.Secondly,on the basis of traditional hardware temperature compensation method,this paper designs a system of hardware circuit temperature compensation,which consists of SAW oscillator,temperature sensor,external counter and main controller.The mathematical relationship between temperature change and oscillation frequency offset caused by temperature is deduced,and the temperature compensation of sensor is realized by combining multi-sensor data fusion technology.Through theoretical deduction and experimental verification,this method can effectively reduce the influence of temperature on SAW micro-force sensor.Finally,in view of the relative error of the above temperature compensation circuit,two kinds of temperature compensation neural network models are proposed: BP neural network model based on improved simulated annealing algorithm and RBF neural network model based on factor analysis.The output of the sensor is optimized by software algorithm.The simulation results show that the two models can effectively improve the temperature stability of SAW micro-force sensor,and the temperature compensation effect is good.The difference is that the BP neural network model can jump out of the local scope and find the optimal solution in the global.RBF neural network model can realize the classification of training samples,and the learning speed of the neural network is greatly improved,and the compensation efficiency is improved.In practical application,suitable temperature compensation model can be selected according to different requirements.