Structure Design And Optimization Of A Novel Biomimetic Hair Flow Sensor

Due to the rapid development of micro processing technology,integrated circuit technology,packaging technology and simulation technology,micro sensor technology can continuously move toward higher performance,smaller volume and lower power consumption.One of the main trends of micro sensors is to mimic the structure and principles of micro sensors in natural biological systems.In creatures of nature,there is some physiological structure with excellent sensor characteristics which can achieve a variety of functions such as balance maintaining,inertial sensing and gas detection.One of the typical,widely distributed and versatile structures is the hair structure.This paper gives the design simulation and performance optimization of a micro hair flow sensor.The performance test result of fabricated sensor was also given.This paper focuses on the following research point:(1)Research of the working mechanism and motion characteristics of micro hair flow sensor.The hair structure in nature and its motion state in air flow are introduced.The principle of the double-ended tuning forks and its electrostatic driving and sensing principle are also introduced.The working principle of the micro lever mechanism is introduced.(2)Structure design of micro hair flow sensorMicro hair flow sensor consists of a upper hair structure,a middle silicon micro sensor structure and a lower metal circuit.The structure of each part of the sensor was analyzed and optimized,including elastic beams of the asymmetric rotation center,swing reduction elastic beams,asymmetrical rotational force amplification mechanism.After that,the structure of the double-ended tuning forks and its electrostatic driving and sensing mechanism are presented(3)Finite element simulation of micro hair flow sensorThe rationality of the structure design of the hair micro flow sensor is simulated by the finite element simulation software,including the modal simulation,thermal stress simulation and transient impact simulation.After that,the performance of the sensor and the influence of different hair shape were simulated.(4)Fabrication and performance test of micro hair flow sensorThe DDSOG process is introduced,and the wiring and packaging steps of the silicon sensor part of the hair flow micro sensor are given.After completion of the package,the bonding of the hair structure is introduced.Then,the response sensitivity of the sensor structure to the external flow speed input is tested.The experimental results are as follows:the natural frequencies of the resonator are 17032.81Hz and 19362.99Hz,and the sensitivity to flow velocity from 1m/s to 10m/s is realized.From the experimental results,we can see that the design and optimization of hair micro flow sensor in this paper is successful and can realize the sensitivity of convection velocity.