高精度石英挠性加速度计闭环系统的设计与分析  

Design and analysis of closed-loop system of high resolution flexure pendulum accelerometer

作　　者：刘润[1,2,3] 蔡体菁[1,2] 丁昊[1,2] 

机构地区：[1]东南大学微惯性仪表与先进导航技术教育部重点实验室,南京210096 [2]东南大学仪器科学与工程学院,南京210096 [3]南京航空航天大学工程训练中心,南京210016

出　　处：《东南大学学报（自然科学版）》2010年第2期311-315,共5页Journal of Southeast University：Natural Science Edition

基　　金：国家高技术研究发展计划(863计划)资助项目(2006AA12Z302)

摘　　要：探讨了石英挠性加速度计的分辨率影响因素,提出了一种对现有石英挠性加速度计的改进设计.根据重力梯度测量对加速度计分辨率的要求,推导出摆片的固有频率,然后使用有限元方法重新设计加速度计的摆片结构.另外,为了降低加速度计的机械热噪声,对表头抽真空,通过加入比例-微分环节对加速度计的控制回路进行阻尼补偿.计算出系统的开环传递函数,并对其进行动态性能仿真分析.分析结果表明:加速度计系统通过在系统前向通道添加比例微分环节能够补偿系统的阻尼,消除加速度计在固有频率处的振荡,使加速度计闭环后处于临界阻尼状态并保持系统的稳定性.改进后加速度计的系统带宽为515Hz,响应时间为3.7m s,分辨率达到10-10g,能够满足高精度测量的需要.The influential factors on the resolution of quartz-flexure accelerometer are analyzed.Modification design of the accelerometer is brought forward.The resonant frequency of pendulum is obtained according to the demand of accelerometer resolution in gravity gradient measurement.Then the structure of pendulum is redesigned by the finite element method.The mechanical Brownian noise is reduced greatly by evacuating the accelerometer.The damping of the accelerometer is increased by adding a damping compensator in the control loop.The open-loop transfer function is deduced and the dynamic performance is simulated.The analysis results show that differential factor can be put in series to compensate air damping which makes the accelerometer in a critical-damping state.Oscillation at resonant frequency of pendulum can be eliminated and the control system can keep stabilization.All these make the accelerometer optimized,the bandwidth and response time being 515Hz and 3.7ms,respectively.The resolution can reach 10^-10g,which can meet the requirements of high resolution measurement.

关 键 词：石英挠性加速度计 分辨率 重力梯度 

分 类 号：V411[航空宇航科学与技术—航空宇航推进理论与工程] U666.1[交通运输工程—船舶及航道工程]