Design And Implementation Of MEMS Vector High-resolution Marine Turbulence Sensor

Since the beginning of the 21 st century,China's efforts to explore and develop the oceans have been unprecedentedly strengthened and China has successively proposed national maritime development strategies such as " Marine Potestatem","21st-Century Maritime Silk Road",and "Two Oceans and One Sea".Among them,marine environmental monitoring,as an important way to understand the ocean,is the prerequisite and foundation of all ocean projects.As one of the elements of marine environmental monitoring,turbulence mixing is the driving force of transport for material and energy in the ocean,which is crucial to understand the oceanic various scale phenomena and energy cascade.In addition,studies have shown that turbulence has an important impact on marine ecosystems and global climate change.However,the turbulence is still covered by a mysterious veil.The mechanism of its formation,mixing and dissipation are not clear yet.Nobel Laureate in Physics Feynman called it the last major unsolved problem in classical physics.Therefore,turbulence research has become a significant application basic subject that the country urgently needs to solve.It is widely believed that turbulence sensors are essential for the ocean turbulence observation.Since the 1960 s,platinum hot-wire probe and piezoelectric ceramic probe have been developed to observe ocean turbulence.However,these sensors are all one-dimensional scalar sensors with low detection spatial resolution.The lack of the ability to observe the fine vector turbulence characteristics directly impede the succedent research process of turbulence formation and dissipation.Herein,it is intended to develop creatively a vector high-resolution marine turbulence sensor based on MEMS technology and bionic principles.(1)A bionic MEMS vector high-resolution marine turbulence sensor is proposed.The core sensitive unit of the sensor adopts the cilium-cross beam microstructure.The cilium is used to sense the external turbulence force,and turbulence force is orthogonally decomposed onto mutually perpendicular cross beams.By extracting the change in the resistance of the piezoresistors on the beam,the vector turbulence characteristics in two orthogonal directions in the horizontal plane are solved.(2)Finite element analysis of MEMS vector high-resolution marine turbulence sensor.Through simulation analysis,the effects of parameters of cilium,beam,and square ciliary base on sensor performance were obtained.Considering the simulation results and the actual processing difficulty,the final size parameters of the sensitive structure were determined.Based on the designed sensor,simulation analysis of static,modal,transient response and crosssensitivity were carried out to verify the feasibility of the designed structure for turbulence observation.(3)System integration of MEMS vector high-resolution marine turbulence sensor.The production of bionic cilia and the processing technology of the cross beams chip were introduced.The secondary integration of cilium and cross beam was completed.The sensor's marine environment adaptable packaging structure and signal preprocessing circuit were designed.(4)Performance test of MEMS vector high-resolution marine turbulence sensor.After completing the design and production of the sensor,the sensor was calibrated and tested.The calibration results showed that the sensitivity of the ciliary turbulence sensor was about 50 times that of the current commercial PNS shear probe;the series of tests on the sensor's marine environment adaptability showed that the feasibility of the sensor used in the marine environment;the vector test experiment verified that the sensor has the advantages of singlepoint vector and high-point resolution in turbulence detection.