Research On Natural Frequency Recognition Method Of Microchannel Cantilever Sensor Based On Phase-locked Loop Technology

In recent years,microchannel cantilever beam sensors usually detect physical properties such as mass,volume,density,and concentration of cells and biomolecules based on their natural frequency changes.Their quality factor can reach 10~3 to 10~5,and the quality detection resolution can reach 0.3 ag.It is widely used in chemical,biopharmaceutical and physical sensing fields.The natural frequency identification method of the microchannel cantilever beam is based on the phase-locked loop technology,and the natural frequency value of the cantilever beam is obtained by keeping the phase difference between the vibration signal and the excitation signal of the microchannel cantilever beam constant.In this paper,the microchannel cantilever beam is taken as the research object,and the natural frequency recognition system of the microchannel cantilever beam based on phase-locked loop technology is designed and developed.The main contents are as follows:First,the dynamic analysis and simulation of the micro-channel cantilever beam were carried out,which provided a basis for the subsequent design and verification of the phase-locked loop system parameters.The microchannel cantilever beam is modeled by Rayleigh method and Newton method,and the lateral natural frequency expression of the cantilever beam is solved.At the same time,the frequency shift of the cantilever beam with different additional mass size and position is analyzed using Ansys finite element software.Secondly,according to the dynamic analysis and simulation results of the microchannel cantilever beam,the main parameters of the PLL system are designed,and the vibration characteristics of the cantilever beam are simulated and verified.According to the natural frequency and frequency shift of the microchannel cantilever beam,the parameters of each module of the phase-locked loop system are designed.At the same time,the system-view software is used to perform the simulation and verification of the cantilever beam vibration characteristics captured by the designed phase-locked loop system parameters.The development platform completes the code implementation of the phase-locked loop system.Finally,on the FPGA hardware platform,the phase-locked loop system was used to test the vibration frequency shift bandwidth and frequency shift rate of the cantilever beam.Design and implement a digital signal synthesizer to simulate the microchannel cantilever beam vibration signal.According to the amount of frequency shift of the cantilever beam under different additional masses,the capture bandwidth and capture frequency shift rate performance of the phase-locked loop system are tested to achieve microchannel cantilever beam natural frequency identification function.