Study On Sensing Mechanisms Of Liquid Viscosity And Density With Uncoupled Cantilevers

The viscosity and density of liquids are important basic parameters in physics that reflect the nature and state of liquids.Online detection of these parameters is of great significance to industrial production,healthcare,and petrochemical industries.In recent years,MEMS(micro-electromechanical systems)technology has emerged as a new and promising technology.Sensors based on MEMS technology are widely used in electronic communication,mobile devices,and wearable devices due to their advantages such as small size,light weight,high sensitivity,and low manufacturing cost.Liquid viscosity density sensors based on MEMS technology help solve the current limitations of liquid viscosity density sensors and have high research value and market potential.In this study,we propose a single-cantilever-beam-based liquid viscosity density sensing scheme that achieves high-precision sensing of liquid viscosity density.We first analyze the vibration response of the cantilever beam in air,showing that the resonant frequency and quality factor of the vibration of the cantilever beam are affected by different factors that can convey different information when applied to sensing applications.We then analyze the vibration response of the cantilever beam in liquid,and demonstrate that the resonant frequency and quality factor of the vibration of the cantilever beam in liquid can be used to decouple the liquid ambient viscosity and density.We carry out a theoretical derivation of the sensing scheme to construct the decoupling equations.To verify the feasibility of the sensing scheme,we construct numerical simulation models and carry out simulations for various sizes of cantilever beams in the range of = 6006)2)/8)～12006)2)/8), = 108)(6 ? ～1008)(6 ? .The results show that some sizes of cantilever beams can achieve good sensing effects in this liquid viscous density range,but due to the nature of the decoupling equation itself,it is prone to multiple solutions or no solutions.To address the problems exposed in the numerical simulation of the single cantilever beam sensing scheme,we further propose a uncoupled double-cantileverbeam-based viscosity density sensing scheme.We use the resonant frequencies of two cantilever beams of different sizes as the input quantity to decouple the viscosity density of the liquid.A numerical simulation model is constructed,and the simulation analysis shows that the scheme is suitable for more cantilever beam sizes than the single cantilever beam sensing scheme and is less likely to generate multiple solution problems or unsolved problems than the single cantilever beam sensing scheme.We propose two correction schemes to further reduce the relative errors in the sensing process and improve the sensing accuracy in response to the regular error distribution phenomenon.Finally,we perform experimental verification work.We design and build an experimental platform and configure experimental liquid samples with different viscous densities.We carry out experimental verification for cantilever beams of different sizes.We use the measured resonant frequencies to perform the viscosity and density decoupling calculation.The calculation results show that the viscosity and density sensing theory constructed in this study can achieve the sensing objectives with the relative errors of both viscosity and density within ±10%.In this study,we propose two different sensing schemes that achieve good sensing effects on the viscosity density of liquids and provide new ideas for the design of liquid viscosity density sensors.