大冲击后力反馈微加速度计吸合失效与防止  

Analysis & prevention on pull-in failure of force feedback micro-accelerometer after heavy impact

作　　者：万蔡辛[1] 董景新[1] 刘云峰[1] 

机构地区：[1]清华大学精密仪器与机械学系,北京100084

出　　处：《中国惯性技术学报》2007年第5期615-619,共5页Journal of Chinese Inertial Technology

基　　金：国防科技重点预研项目(51309050809)

摘　　要：冲击载荷强迫微加速度计的敏感质量大大偏离平衡位置,使差动静电力发生器的非线性效应体现出来,其结果是使正常工作时敏感质量仅在平衡位置附近有微小位移的状况下成立的负反馈闭环系统模型不再适用,敏感质量的受控特性可能变为正反馈,从而使微加速度计失效。为提高微加速度计受外界大载荷冲击后的可靠性,分析了加速度计的敏感质量在不同限制的静电反馈力下的受控特性及对应的闭环系统特性,推导了在已知止挡机械参数下确定微加速度计相应电气参数从而避免此类失效的防吸合准则。多次的验证实验表明,按防吸合准则设计了系统参数的静电力反馈加速度计,在受到远超过其本身量程的载荷冲击后,可以100%地防止吸合现象的出现。An impact load causes the proof mass of a micro accelerometer greatly depart from the balance position, making the nonlinear effect of the differential electrostatic force generator show out. The consequence is that the negative feedback model is nolonger suitable, resulting in the failure of micro accelerometer. To improve its reliability, the paper analyzes the control characteristic of MEMS sensor in closed loop control system with the feedback electrostatic forces in various restrictions, and proposes an anti-pull-in criterion which shows how to determine the system parameters of micro accelerometers with known mechanical parameters of the stopper. The experiments verifie that the micro-accelerometers, designed by the anti-pull-in criterion, never suffer pull-in failure even the impact far exceeds the accelerometer＇s maximum measurement range.

关 键 词：微机电系统 加速度计 冲击 吸合失效 可靠性 

分 类 号：TH824.4[机械工程—仪器科学与技术]