Multi Fideld Coupled Dynamics Research Of Micro Resonant Chemical Gas Sensor

Micro resonant chemical sensor has broad application prospects with the advantagesof small size, high sensitivity, good reliability, easy to connect with the digital circuit. Themulti field coupled vibration characteristics of variable mass resonance beam of microresonator chemical gas sensor are studied. The design, manufacture and test of the sensorare completed as well.Firstly, the mechanical and chemical coupled model of micro cantilever beam isestablished, and the dynamics equation of free vibration is deduced. The second orderapproximate solution of the nonperiodic vibration equation of micro beam is calculated byMulti-scale method. Based on the Hilbert transformation, the expression of instantaneousfrequency is presented. The influence factors of instantaneous frequency and the sensorsensitivity are analyzed as well.Secondly, mechanical, electrical and chemical coupled dynamic model of microresonant beam system is established. Free vibration and forced vibration of the resonantbeams are analyzed. The expression of instantaneous frequency is deduced using themulti-scale method, and how the bias voltage and other main parameters influence theinstantaneous frequency is analyzed as well.Thirdly, mechanical, chemical and fluidal coupled dynamic model of micro resonantbeam system is established, and its dynamics equation is deduced. Then instantaneousfrequency expression is solved, and how the gas dynamic viscosity and other main systemparameters influence the displacement and instantaneous frequency is analyzed.The mechanical, electrical, chemical and fluidal coupled dynamic model of microresonant beam system is established with the consideration of electrostatic field force andair damping effect comprehensively. Then the nonlinear free vibration and nonlinearforced vibration analysis of micro resonant beam system is completed by using multi-scalemethod. The expressions of instantaneous frequency and the relation of amplitude andfrequency near resonance are deduced. How the factors influence the instantaneousfrequency and the amplitude frequency characteristics is discussed, and the sensitivity of the sensor is analyzed as well.Micro cantilever beam is designed and manufactured. Based on the principle ofelectrostatic excitation capacitance test, micro cantilever beam resonant frequencydetection experiment was carried out with the help of electrostatic driven micro resonantbeam dynamic testing system. Gas adsorption test experiment of resonant beam iscompleted with sensitive materials on its surface, proving that the theoretical analysis iscorrect.