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Full-Text Articles in Applied Mechanics
Design And Implementation Of A Z-Axis Mems Gyroscope With A Symmetric Multiple-Mass Mechanical Structure, Yujie Zhang
Design And Implementation Of A Z-Axis Mems Gyroscope With A Symmetric Multiple-Mass Mechanical Structure, Yujie Zhang
Mechanical & Aerospace Engineering Theses & Dissertations
This thesis presents a z-axis MEMS gyroscope with a symmetric mechanical structure. The multiple-mass design prioritizes the sense-mode Quality Factor (Q) and thus improves its scale factor. The proposed mechanically coupled, dynamically balanced anti-phase sense-mode design minimizes energy dissipation through the substrate in order to maximize the Q. Numerical simulation is implemented in a finite element analysis software, COMSOL, to identify the two operation modes of the gyroscope: drive-mode and sense-mode. The multiple-mass gyroscope design is further fabricated using a one-mask process. Experimental characterization of frequency response in both drive-mode and sense-mode of the device are conducted, proving the design …
Integrated Control Of Thermally Distorted Large Space Antennas, Robert H. Tolson
Integrated Control Of Thermally Distorted Large Space Antennas, Robert H. Tolson
Mechanical & Aerospace Engineering Theses & Dissertations
Studies on controlling the thermal distortion of large space antennae have generally investigated a single orbital position and have optimized actuator locations based on minimizing the RMS surface deviation from the original parabolic shape. One study showed the benefits of directly using far zone electric field characteristics as the performance measure; but, this approach resulted in a nonlinear programming problem. The objective of the current study is to develop an approach to designing a control system that (1) recognizes the time dependence of the distortion and (2) controls variables that are directly related to far field performance in a quadratic …