力平衡加速度计的刚度耦合特性

Characteristics of stiffness coupling in force-balanced accelerometer

通过分析力平衡加速度计的工作原理,运用解析法推导出输入惯性力与质量块位移的关系,指出加速度计的工作过程包括刚度"刚化"与刚度"软化"2种状态,有别于开环加速度计仅涉及刚度"软化"状态。以质量块位移的静电刚度与机械刚度之比作为结构的刚度耦合值,分析表明:加速度计的"刚化"与"软化"的分界点是耦合值为零的位置,而"正"刚度与"负"刚度的分界点是耦合值为-1的位置。耦合曲线的尖锐程度反映了质量块的允许位移大小和耦合的非线性度,刚度耦合的幅值越大,耦合曲线越尖锐,非线性度越大,质量块允许位移反而越小。

By analyzing working principle of force-balanced accelerometer, and using analytical method, the relation of input inertial force and mass block＇s displacement is derived. Both the states of＂ stiffening＂ and＂ softening＂ are involved in the procedure of operation,which is different from the open-loop accelerometer which only involve the state of＂ softening＂. The stiffness coupling value is defined as the ratio of electrostatic stiffness and mechanical stiffness of block＇s displacement. Analysis indicates that the dividing point of＂ stiffening＂ and＂ softening＂ is where the coupling value equals to zero, and dividing point of＂ positive＂ and＂ negative＂ stiffness is where the coupling value equals to -1, the sharpness of coupling curve reflects the permitted displacement and coupling nonlinearity, the lager is the amplitude of stiffness coupling value, the more sharp is the curve, and the larger is the nonlinearity,the smaller is the displacement permitted by massblock.