Research On The Identification Method Of Mass Position Of Multiple Particles By Resonant Microstructures

MEMS,as a modern high-tech sensor technology,will become the key development trend of modern sensor technology.The development of sensors continues to extend human perception.People are more and more interested in using micro-nano resonators as biological and chemical sensors,mainly due to their small size,high sensitivity,relatively cheap and portable,suitable for integration into advanced analysis systems.Among the many structures,the micro cantilever is the most widely used in imaging and sensing applications.The working principle of the dynamic response of the micro cantilever sensor is that tiny particles are attached to the surface of the microbeam,and the mass of the entire microbeam changes,and the corresponding resonance frequency also changes.Integrating the frequency shift data,the quality and position of the tiny particles can be obtained in reverse.At the same time,the small-sized sensor load has higher frequency movement after adsorbing the particle load,so it has higher detection sensitivity.In the application of sensors,scholars generally set ideal conditions for the detection of particles,that is,ignore the influence of stress and stiffness on the sensor mode.At the same time,it is generally assumed that the mass of the particles to be measured is much smaller than the mass of the sensor,so it is considered that the sensor mode before and after the particles are adsorbed does not change.Based on previous studies,this paper has mainly completed the following work:(1)Taking the microcantilever beam structure as the research object,Rayleigh-Ritz theorem was used to analyze the accurate mode and closed expression of the resonant frequency of the sensor loaded with particles,and the relationship between the adsorbed mass and position and the frequency movement before and after the sensor adsorbed particles was obtained,and the sensor model for adsorbed multiple particles was established.(2)The sensor model is used to detect the information of multiple particles.A step-bystep method is proposed to detect the particles in real time.Using at least two frequencies,you can eventually get the mass and even the position of the particle.(3)The plate theory is used for dynamic analysis,and the inverse problem solving method of the two-dimensional model of the microcantilever plate sensor with multiple concentrated mass bodies attached on the surface is studied by Kirchhoff plate theory and Rayleigh-Ritz method.The relationship between the frequency shift of the microcantilever beam and the mass and position of multiple objects is established,and the optimal position and mass are obtained by fitting.The vibration mode of the sensor is simulated by COMSOL(5.4)software,and the corresponding resonance frequency and other data are extracted.The influence of the aspect ratio of the board,the mass and position of the adsorbed particles on the dynamic characteristics of the board is analyzed.(4)On the basis of solving the positive problem,the positions of different adsorbents along the length and width directions were detected step by step on the two-dimensional microcantilever sensor.Finally,the calculation results were compared with relevant literatures to verify the detection effect of the model established in this study.At the same time,relevant experimental tests were carried out at the macro level,and the results proved the correctness of the theoretical derivation.