Design of a MEMS Gyroscope for Absolute Angle Measurement

MEMS陀螺仪通常被设计为测量旋转的角速率。 角度本身的测量在许多应用中是有用的，但是由于存在引起漂移的偏置误差，不能通过积分角速率来获得。 本项目开发了一种可直接测量角度和角速率的振动陀螺仪的创新设计。 所提出的设计是基于测量相对于陀螺仪的外壳的悬挂质量的自由振动的角度的原理。 该设计采用了非线性反馈控制系统，以解决两个关键的挑战。 首先，控制系统补偿耗散力，并保持质量块以恒定的能量水平振动。 第二，控制系统补偿由于悬挂弹簧的非理想性质而发生的旋转交叉耦合。 该控制系统经过精心设计，使其不会影响质量的自由振动性质，也不会改变在角速率测量中起重要作用的科里奥利力，该项目包括一个三阶段工作计划，用于设计和在明尼苏达大学微技术实验室（MTL）内部制造振动陀螺仪。该项目的意义在于，它通过将复杂的控制系统引入MEMS领域而开辟了新的领域。 使用先进的控制技术导致一种新的传感器，使测量一个新的变量（绝对角度）成为可能。 此外，该计划所发展的多项技术，可广泛应用于一般的振动传感器设计，并可改善加速度计、速率陀螺仪及微量天平的技术。该计划的教育目标包括发展课程、促进跨学科技能，以及发展网上教育的基准模型。

MEMS gyroscopes are typically designed to measure angular rate of rotation. A measurement of the angle itself is useful in many applications but cannot be obtained by integrating the angular rate due to the presence of bias errors which cause a drift. This project develops an innovative design for a vibrating gyroscope that can directly measure both angle and angular rate. The proposed design is based on the principle of measuring the angle of free vibration of a suspended mass with respect to the casing of the gyroscope. The design incorporates a nonlinear feedback control system in order to address two critical challenges. First, the control system compensates for dissipative forces and keeps the mass vibrating at a constant level of energy. Second, the control system compensates for the rotary cross-coupling that occurs due to the non-ideal nature of the suspending springs. The control system is carefully designed so that it does not affect the free vibration nature of the mass and does not alter the Coriolis forces which play an important role in the measurement of angular rate.The project includes a three-phase work plan for design and in-house fabrication of the vibratory gyroscope in the University of Minnesota's Microtechnology Laboratory (MTL). The significance of the project is that it breaks new ground by introducing sophisticated control systems into the MEMS domain. The use of advanced control techniques leads to a new sensor making the measurement of a new variable (absolute angle) possible. On a lesser note, several techniques developed in the project have wide applicability to vibratory sensor design in general and would lead to technical improvements in accelerometers, rate gyroscopes and microbalances.The educational objectives of the project include curriculum development, promotion of cross-disciplinary skills, and development of benchmark models for web-based education.