| Micro-gyro is an inertial sensor for measuring angular rate or attitude angle,which is widely used in many fields such as automotive safety for driving stability and rollover detection,camera stabilization,consumer electronics such as virtual reality and computer mouse,robot control technology and navigation guidance,etc.It has many advantages such as small size,low cost and excellent performance.The contradictory problem between bandwidth and gain has been a bottleneck in micro-gyro performance enhancement,i.e.,single-degree-of-freedom(DOF)micro-gyros have high gain but narrow bandwidth,while multi-DOF micro-gyros have wider bandwidth at the expense of gain.To solve the contradiction between bandwidth and gain of multi-DOF micro-gyros,this paper investigates the effect of stiffness nonlinearity on the bandwidth and gain of micro-gyros for a class of three-DOF micro-gyros with a single-DOF drive system and a complete two-DOF sense system,and compares it with the linear case.Firstly,the structural design of the three-DOF micro-gyro is carried out by designing the drive beam as a straight beam,which is applied to provide non-linearity to enhance the bandwidth.Secondly,a lever structure is added to the micro-gyro to enhance the gain.The linearity of a linear micro-gyro without an anchored lever mechanism(ALM),a non-linear micro-gyro without an ALM,a linear micro-gyro with an ALM and a non-linear micro-gyro with an ALM were also compared.Finally,two arrays of micro-gyros were designed to achieve simultaneous gain and bandwidth improvements.The main research and findings are as follows:(i)Design of straight beams to provide non-linear characteristics for a three-DOF micro-gyro and separate designs for drive and sense resonant frequencies by decoupling mass blocks.The complete two-DOF sense system is designed to enable arbitrary adjustment of the peak spacing.Apply the multi-scale method for numerical analysis and apply the Runge-Kutta method for numerical verification.Investigate the effects of peak spacing,driving resonant frequency position,damping,non-linear coefficients,etc.on the bandwidth and gain of the micro-gyro and resolve the conflicting bandwidth and gain problems.(ii)A complete two-DOF system with an ALM is designed and applied to the sense structure of a three-DOF micro-gyro,and the lever amplification principle is applied to further improve the gain performance.The effects of frequency coupling parameters(FCP)and lever amplification coefficients(LAC)on the gain of linear and non-linear micro-gyro are investigated,and the gain of the micro-gyro is optimally improved through the reasonable selection of FCP and LAC.Finally,nonlinear differential equations considering the effect of angular velocity are established.The resonant frequency of the micro-gyro is investigated as affected by the input angular velocity,and the linearity problem of the linear and nonlinear micro-gyro before and after the addition of the lever is analyzed.(iii)Two array forms of the three-DOF micro-gyro have been designed.The first array gyro applies the same decoupling framework to each sense module,achieving an exponential increase in gain while the bandwidth of the micro-gyro remains unchanged.Based on the first array micro-gyro,decoupling masses are designed into the individual sense modules so that the sense modules are decoupled from each other.The sense module of the second type of array micro-gyro can be selected with different peak spacing to achieve both bandwidth and gain enhancement. |
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