| With the development of global information technology,the navigation system is an essential part with increasingly demand of inertial navigation market,and micro-machined gyroscope is the core device in the micro-inertial system.With the market demand for the higher detection accuracy of micro-gyroscope,the core technology in the development of high-precision micro-gyroscope is the detection of weak displacement.The conventional detection method of micro-gyroscope is capacitance-based detection,the comb voltage is susceptible to break down and fails to pull-in when it’s impacted laterally,since limited resolution of interface circuit,making it difficult to achieve detection of weak displacement.Therefore,it is urgently needed to explore the high-precision micro-gyroscope based on new effect/structure to achieve technical breakthrough.Tunneling magneto-resistance effect（TMR）is a kind of spin-dependent tunneling effect,it causes considerable resistance change with weak variation of the magnetic field,which has the advantages of high sensitivity,high resolution,low power consumption and small volume,effectively solving the existing issue of low detection accuracy of gyroscope.In this paper,we proposed a kind of centrifugal micro-gyroscope based on TMR.Firstly,we established the mechanical model of the micro-gyroscope,researched the dynamic characteristics and analyzed the damping type of micro-gyroscope,obtaining the structural sensitivity of 1.69nm/°/s.Secondly,we discussed the magnetic field detection technology with high rate of variation,and designed the magnetic field detection scheme with folded current coils,the change rate of magnetic field can reach to 9×10-44 Oe/nm;Thirdly,we studied the TMR technology and adopted four-bridge TMR detection scheme,the external magnetic field interference can be effectively suppressed and the magneto-resistance sensitivity can reach to7 mV/Oe.Finally,we calculated and analyzed the sensitivity and noise level of centrifugal TMR micro-gyroscope,with total sensitivity of 10.65 mV/°/s and noise level of 2.36×10-4°/s/√Hz.Combined with the structural characteristics of the gyroscope and the domestic processing level,we studied the processing technology of the centrifugal TMR micro-gyroscope,and designed the specific processing flow and the corresponding mask layout of the micro-gyroscope.In this paper,we preliminarily completed the fabrication of the folded current coils,built the magneto-resistance effect test platform,and tested the magneto-resistance effect of the centrifugal TMR micro-gyroscope,which laid a good experimental foundation for the subsequent performance test of the centrifugal micro-gyroscope. |
