【作者】 李孟委；

【导师】 刘俊；

【作者基本信息】 中北大学 ， 精密仪器及机械， 2010， 博士

【摘要】 陀螺是惯性导航和制导的核心器件之一,决定着武器的精确打击能力,而高灵敏度陀螺是国外禁运技术,因此发展陀螺技术是国防建设的需要。微机械陀螺以体积小、成本低、搞过载能力强等优势,成为世界各国研究的热点。本文就此提出了一种压阻系数比硅高的新型介观压阻效应微机械陀螺,对其敏感机理、结构设计、制造工艺、性能测试等方面开展了研究。介观压阻效应的敏感机理是：在力学信号作用下,多层纳米膜结构中的应变发生变化；一定条件下应变可引起结构内建电场的产生；内建电场将导致纳米带结构中量子能级发生变化；量子能级变化会引起共振隧穿电流变化。简言之,在能发生共振隧穿效应的条件下,通过上述四个物理过程,可将一个微弱力学信号转化为一个较强的电学信号。本文所研究的微机械陀螺采用电磁驱动的方式,驱动力易控,幅值稳定,驱动模态设计为滑膜阻尼,检测模态设计为压膜阻尼,当质量块运动间隙为15μm时,驱动模态品质因子为4591,检测模态品质因子为167。仿真分析了驱动模态和检测模态的固有频率分别为3530Hz和3671Hz,微机械陀螺工作带宽为76 Hz,驱动X方向抗冲击能力为24579g,检测Z方向抗冲击能力为7974g。结构位移灵敏度设计为5.21×10-8m/°/s,结构应力灵敏度为2.52×10-2Mpa/°/s,量程为±288°/s,热噪声为0.3665°/h/(?)。研究了纳米膜压敏结构与微机械陀螺结构制造耦合工艺,利用开发的空气桥、欧姆接触、控制孔、腐蚀自停止等关键工艺在内的MEMS加工工艺,实现了MEMS制造工艺与多层纳米薄膜制作工艺的结合,成功制作了介观压阻效应微机械陀螺。研究了介观压阻效应微机械陀螺电磁驱动电路和Goriolis力微弱信号检测电路关键技术,设计了开环驱动电路,驱动反馈检测电路、介观压阻电桥检测电路、可调稳压电源电路、解调电路、滤波电路等,实现了微机械陀螺的驱动和微弱信号的检测。搭建了实验测试系统,对微机械陀螺的性能进行了测试。在大气压下,微机械陀螺的驱动模态谐振频率为4060Hz,品质因子为815,驱动模态谐振频率为4040Hz,品质因子为175。理论计算微机械陀螺负阻区灵敏度为19.8mV/°/s,正阻区灵敏度为52.8μV/°/s,实验测试结果显示检测灵敏度为9.35gV/°/s,微机械陀螺工作在正阻区而非所期望的负阻区,输入角速度在[-500°/s,+500°/s]范围内,线性系数为0.99。分析和测试结果表明,微机械陀螺因偏压漂移而工作在正阻区,灵敏度较低,但原理上实现了角速度的检测；证明了电磁驱动方法、介观压阻效应检测方法、工艺制造方法和实验测试方法可行,为进一步研究介观压阻效应微机械陀螺奠定了一定的理论基础和实验基础。更多还原

【Abstract】 Gyroscope is the core device in inertial navigation and guidance, which determines the precision strike capability of weapons. The high sensitivity gyroscope is an embargo technology to foreign, so it is the needs of developing the gyroscope technology in national defense. With the advantages of small size, low cost, greater overload performance, the gyroscope becomes the research hotspot around the world. A novelty meso-piezoresistance effect gyroscope with the higher piezoresistive coefficient than silicon is proposed in the paper. And the main research works will focus on the aspects of sensitive mechanism, structure design, fabrication process, performance measurement of this gyroscope.The operating principle of meso-piezoresistance effect is:if a mechanical signal is acted in a related mechanical nano-structure, the corresponding strain distribution will be produced in the structure. The strain distribution can generate built-in electric fields, and then change the electronic energy state which will influence on the value of the tunneling current. In short, a weak mechanical signal can be converted into a strong tunneling current signal.The gyroscope studied in this paper using the electromagnetic driven approach which with the advantages of controllable driven force and stable amplitude. The driven modal and detection modal is designed as slide film damping, squeeze film damping, respectively. As the movement gap between the proof mass and the base plate is 15μm, the quality factors of driven modal and detection modal are 4591,167, respectively. The natural frequencies of driven and detection modal are 3530Hz and 3671Hz according to simulation analysis. The performance bandwidth of micromechanical gyroscope is 76Hz; the anti-impact ability in driven X direction and detection Z direction are 24579g,7974g, respectively. The displacement sensitivity of the structural is 5.21×10-8 m/°/s, the stress sensitivity is 2.52×10-2Mpa/°/s, the measurement range is±288°/s, and the thermal noise is 0.3665°/h/(?). The coupling process between the nano-film pressure-sensitive structure and micromechanical gyroscope structure is studied. It is achieved the combination of MEMS manufacturing process and multi-layer nano film fabrication process by using some key MEMS processes technology, including the air bridge, ohmic contact, control holes, self-stop etch. And micromechanical gyroscope with the meso-piezoresistance effect is fabricated successfully.The key technology of magnetic driven circuit and weak signal detection circuit of meso-piezoresistance effect micromechanical gyroscope are also researched. The open-loop driven circuit, driven feedback detection circuit, meso-piezoresistance bridge detection circuit, adjustable regulated power supply circuit, demodulation circuit, filter circuit are designed, which achieve the driven and weak signal detection of micromechanical gyroscope.The performance of MEMS gyroscope is tested by the building measurement system. In the atmospheric pressure, the resonant frequency of driven modal is 4060Hz; and the quality factor of micromechanical gyroscope is 815. The sensitivity of micromechanical gyroscope in negative resistance area and positive resistance area is 19.8mV/°/s and 52.8μV/°/s by theoretical calculation. According to the experimental results, it is show that the detection sensitivity is 9.35μV/°/s as the gyroscope working in positive resistance area not the desired negative resistance area. The linearity coefficient is 0.99 when the angular velocity in the range of [-500°/s,+500°/s].The analysis and testing results show that the gyroscope works in the positive resistance area due to the drift of bias voltage, therefore the sensitivity is low, but the angular velocity detection is achieved in principle. The electromagnetic driven-meso-piezoresistance effect detection approaches, manufacturing process method and experimental measurement method is verified feasible, which provide theoretical foundation and experimental foundation for further study of meso-piezoresistance effect micromechanical gyroscope.更多还原