高Q值闭环电容式MEMS加速度计高精度数字化读出技术研究

项目名称： 高Q值闭环电容式MEMS加速度计高精度数字化读出技术研究

项目编号： No.61473007

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 自动化技术、计算机技术

项目作者： 陈中建

作者单位： 北京大学

项目金额： 86万元

中文摘要： 惯性导航系统广泛应用于航天、航空、航海等领域，高精度加速度计是其核心部件。目前零偏稳定性和噪声问题是制约电容式MEMS加速度计在惯性导航系统中应用的主要瓶颈，采用高Q值二次量化型ΣΔ闭环结构实现该加速度计是解决该问题的最可行方案之一。本项目围绕该结构，研究高Q值闭环电容式MEMS加速度计高精度数字化读出技术，重点探索如下亟待解决的科学问题：1）建立高Q值二次量化型ΣΔ闭环加速度计微系统的集总参数模型，探索质量块冗余运动的作用机理，分析冗余运动噪声与系统各参数之间的关系；2）分析多位ADC特性对系统整体性能的影响，研究最佳的量化区间分布以降低量化噪声；3）研究针对该微系统的零漂自补偿的实现原理，探索同时实现低噪声和低零漂的方法。瞄准惯性导航应用要求，基于上述研究成果实现高精度数字化读出的微加速度计样品，验证理论分析的正确性和相关技术的有效性。本研究对我国高精度惯性测量单元研制有重要意义。

中文关键词： 传感器；微弱信号检测；微机电系统；温度补偿

英文摘要： High precision accelerometer is one of the key components of inertial navigation system (INS) which is widely used in aerospace and navigation field. However, bias stability and noise problems currently become the main bottleneck of the inertial navigation application of the capacitive MEMS accelerometer. The capacitive MEMS accelerometer embedded in high-Q twice-quantization sigma-delta loop is one of the most feasible schemes in solving these problems. With regard to this architecture, high precision digitalized readout techniques for high-Q closed-loop capacitive MEMS accelerometer will be researched and three critical scientific problems as following will be explored. 1) A lumped-parameter model of the high-Q twice-quantization sigma-delta closed-loop MEMS accelerometer system will be built, the mechanism of the mass residual motion will be explored, and the relationship between the noise resulting from the residual motion and parameters of the system will be analyzed. 2) The influence of the multibit ADC's characteristics on the system performance will be analyzed and the optimal quantization interval design will be researched in order to reject the in-band quantization noise. 3) The self-compensation principle of the bias drift caused by parasitic capacitances in a high-Q twice-quantization sigma-delta loop will be researched and the method of implementing both low noise and low bias drift will be explored. Aimed at the requirements of the inertial navigation application, MEMS accelerometer prototypes with high-precision digitalized readout are implemented and the validity of the theoretical analyses and related techniques will be verified. Our work is of great importance to the development of the inertial measurement unit (IMU) in our country.

英文关键词： sensor;weak signal detection;MEMS;temperature compensation