Study On Mass Sensing Method Of Four-Coupled Cantilevers Based On Mode Localization

Nowadays,with the introduction of big data and Internet of Things,sensors have become an indispensable key node of modern technology,affecting the development of science and technology society and the improvement of human living standards.In recent years,resonant sensors using coupled beam arrays have been widely used in a variety of fields,such as ultra-high sensitive mass detection of biomolecules and chemical analytes,electrostatic coupling resistance,and detection of circuit changes in capacitive resonators.Sensor technology based on coupled cantilever arrays is used in many applications as mass detectors,such as biological,physical,chemical,medical diagnostics and environmental monitoring.The array has a well-symmetrical dynamic structure,exhibiting a structured modal spectrum,adding a tiny mass can change the spectral characteristics and then detect mass disturbances by measuring the amount of change.However,the sensitivity of quality detection needs to be improved.Therefore,this paper studies the four-coupling cantilever beam quality detection method based on modal localization,and proposed the method of determining the optimal coupling factor,optimized the structure of the coupled sensor,and realized more high sensitivity quality inspection.Based on the spring-mass model of the fourth-order vibration system,the influence of the external small mass disturbance on the vibration response characteristics of the coupled cantilever beam structure is analyzed.The sensitivity evaluation method based on frequency variation,modal change and amplitude ratio is analyzed and compared.The amplitude ratio is determined to be the sensitivity evaluation parameter.At this time,the sensitivity of the detection system is the largest.The theoretical analysis shows that the smaller the coupling factor is,the higher the sensitivity is.The state space expression of the fourth-order vibration system is established.The optimal coupling factor of the cantilever beam coupling part is obtained by using matlab.The relationship between the natural frequency and the size parameters of the coupled cantilever beam structure is analyzed.The dimensions of the cantilever beam resonator and the coupling structure are optimized and the weak coupling structure design is realized.A test experiment platform was built,and the resonance characteristics of the system with or without external mass disturbance were analyzed.The influence of coupling size on sensitivity was studied.The relationship between sensitivity analysis based on amplitude ratio and coupling size was analyzed under different coupling structures of cantilever beam.The influence of the four beams as additional mass disturbances on the sensitivity of the three-coupling beam is analyzed.In order to further improve the sensitivity of the existing research,a four-coupling cantilever beam mass sensor is proposed.The amplitude ratios of the double-coupling cantilever beam,the three-coupling beam and the four-coupling cantilever beam,which are widely studied,are compared,and the sensitivity under different mass disturbances is analyzed.After comparison,the optimized four-coupling cantilever beam structure proposed by the paper has greater sensitivity.Sensing scheme with high sensitivity is proposed.