线振动硅微机械陀螺结构误差参数分离和辨识

Separation and identification for structure error parameter in vibratory silicon MEMS gyroscopes

推导了线振动微机械陀螺的三自由度误差力学方程,并详细分析了陀螺耦合误差的产生机理。分析结果表明,各种结构误差是导致陀螺耦合误差信号的主要原因。在此基础上,利用振动和模态理论给出了陀螺结构误差参数的分离和辨识的试验方法和结果。试验结果表明,同相耦合分量和正交耦合分量是微机械陀螺的两种主要误差信号,造成正交耦合的主要原因是驱动轴和检测轴之间的刚度耦合以及驱动轴和检测轴各自的刚度不对称,造成同相耦合的主要原因是驱动轴和检测轴之间的阻尼耦合以及检测轴刚度不对称和驱动力不对称。结构误差参数的分离和辨识试验方法将为下一步的陀螺结构优化、微加工工艺改进以及耦合误差抑制提供基础。

A three-freedom dynamics model of gyroscopes was developed, and the mechanism of generating cross-coupling error sources in MEMS gyroscopes were analyzed. The analysis demonstrates that the structure imperfections are the main cause that leads to the gyro coupling error. The experiment approach to separate and identify main structure error parameters was presented based on the vibrating and mode theories. The experiment results demonstrate that the quadrature component and the in-phase component are the main error sources of gyroscopes. The main reasons resulting in the quadrature component include the cross-coupling stiffness between the drive and the sense, and the stiffness asymmetry between drive beams and between sense beams. The cross-coupling dampness between the drive and the sense, and stiffness asymmetry between sense beams and drive force asymmetry mainly contribute to the in-phase component of the gyro bias. The identified structure parameters can provide basis for structure design, laser trimming, and coupling error reduction in gyroscope.