慢衰减抗振动MEMS半环谐振陀螺及其制造方法研究

In the current MEMS hemispherical resonator gyroscopes (HRG),the bias stability is limited due to short decay time of the shell structure. To solve the problem, with the improved 3D shell structure of resonator, a half-toroidal resonator gyroscope based on diamond MEMS is proposed in this project. Characteristics of slow decay and anti vibration are studied, and the micromachining technology is developed for the proposed gyroscope. The half-toroidal shell structure in the gyroscope has advantages of low resonate frequency, high quality factor and wide frequency gap between wineglass mode (n=2) and disturbance modes，which help improve decay time and vibration immunity. Dynamics of the 3D axisymmetric shell gyroscope is analyzed and modeling method including scale effect and multi-field couplings are presented. Mutual influence between frequency characteristics, quality factor, angle scale factor and modal distribution are studied. A 3D micromachining technology based on micro-EDM is developed to fabricate the half-toroidal molds with quantitative control of dimensions. A new integration process flow is established to develop the MEMS half-toroidal resonator gyroscope working in rate-integrating mode. The study of slow-decay and anti-vibration MEMS half-toroidal resonator gyroscope provides fundamental theory and technology support for the realization of inertial-grade high precision microscale gyroscope.

现有MEMS半球谐振陀螺的零偏置稳定性因壳体衰减时间短而受到限制。针对这一问题，本项目改进三维壳谐振子结构，提出一种基于金刚石MEMS的半环谐振陀螺设计，并对其慢衰减抗振动特性和微制造方法进行研究。陀螺半环壳结构有谐振频率低、品质因数高、四波腹振型和干扰振型的频率间隔宽等优点，有助于提高衰减时间和抗振动稳定性。建立三维轴对称半环壳谐振陀螺的动力学模型，分析半环谐振陀螺中包含微尺度效应的多场耦合建模方法，研究半环壳频率特性、品质因数、角度增益因子和振型分布特征之间的相互影响规律。提出基于微电火花加工的半环凹模三维曲面的结构定量控制微加工方法，建立三维轴对称陀螺的新集成工艺，开发基于金刚石MEMS的半环谐振陀螺样机，实现微型速率积分陀螺。慢衰减抗振动MEMS半环谐振陀螺的研究可为惯性级别高精度微型陀螺的制造提供理论基础和技术支持。

针对现有MEMS平面陀螺零偏置和角度随机游走等参数无法达到导航级别精度的问题，本项目研究了基于金刚石MEMS微半球谐振陀螺，改进三维壳谐振子结构，提出一种半环谐振陀螺设计，并对其慢衰减抗振动特性和微制造方法进行研究。陀螺半环壳结构有谐振频率低、品质因数高、四波腹振型和干扰振型的频率间隔宽等优点，有助于提高衰减时间和抗振动稳定性。研究了三维半环壳谐振陀螺的动力学模型和多场耦合建模方法，推导半环壳的等效质量和弹簧刚度，分析角度增益因子的影响因素和灵敏度温度系数，研究包含多场耦合问题的建模方法。建立三维硅微加工工艺，分析HNA硅各向同性腐蚀加工参数，优化该方法的三维加工特性，批量加工出高对称的光滑半环形凹模。采用CVD金刚石可提高半环壳的品质因数，表征CVD金刚石的材料属性，研究半环壳形成工艺和电极形成工艺。从材料和结构分析CVD金刚石在半球谐振陀螺应用中的品质因数的影响规律。根据设计建立陀螺新集成工艺，解决因半环结构而使传统的MEMS沉积和刻蚀由二维扩展至三维的工艺难题，实现高质量半球谐振子。基于金刚石MEMS的微半环谐振陀螺的研究为惯性级别高精度的MEMS陀螺的实现提供理论基础和技术。