重力梯度仪加速度计控制回路分析与设计

Analysis and design on control loops of gravity gradiometer accelerometer

加速度计是旋转加速度计重力梯度仪的核心元件,梯度信号测量要求其加速度计具有高分辨率和低的噪声水平,这就需要对现有石英加速度计进行改进,通过表头抽真空,提高控制回路增益来抑制噪声,提高分辨率。抽真空后表头近似为无阻尼状态,其控制回路中需增加阻尼补偿的环节,避免系统在工作频段附近出现振荡;并且,对控制回路中的校正环节也进行了重新设计,加入积分环节,使系统对位置信号的稳态误差为零,大幅度提高工作频段的系统开环增益,从而有效地提高了系统的动态测量精度。

The key parts of rotating accelerometer gravity gradiometer （RAGG） are accelerometers, which must have high definition and low noise to measure gravity signal. Thus the optimization design of accelerometer is necessary. By evacuating the accelerometer, the gain of control loops was improved to reduce noise and increase definition. The improved accelerometers have no air damping, which must be compensated in order to avoid natural oscillation near the frequency bands of RAGt2 The novel control loops has integral units, which make steady-state error of the control system closing to zero, and the novel system increases the open-loop gain of the frequency bands of RAGG, so the precision of dynamic measurement is improved.