Quadrature error compensation and its effects on the performance of fully decoupled mems gyroscopes

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Elektrik ve Elektronik Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2010

Öğrenci: ERDİNÇ TATAR

Danışman: TAYFUN AKIN

Özet:

This thesis, for the first time in the literature, presents the effect of quadrature error compensation on the performance of a fully decoupled MEMS gyroscope and provides experimental data on the sources of quadrature error. Dedicated quadrature error cancellation electrodes operating with only differential DC potentials are designed. Gyroscopes with intentionally placed imperfections are fabricated with SOG based SOI process which provides higher yield and uniformity compared to SOG process. Tests show that the fully closed loop system with quadrature cancellation operates as expected. Gyroscope performance is improved up to 7.8 times for bias instability, 10 times for angle random walk (ARW) and 800 times for output offset with quadrature cancellation. The actual improvement is higher since some sensors cannot be operated without quadrature cancellation and they are not included in improvement calculations. The best obtained performance is bias instability of 0.39⁰/hr and ARW of 0.014⁰/√hr with theoretical ARW limit of 0.012⁰/√hr. The minimum bandwidth is 70Hz but typically varies between 80Hz-100Hz. The gyroscopes have a measured range of ±100⁰/sec but at least ±150⁰/sec is possible. The measurements show that spring design is significant to reduce the quadrature error. Quadrature error is found to be the major error source of gyroscopes and in the path to sub degree per hour gyroscopes, it should absolutely be compensated.