Authors: H. Ko, S. Park, B-D Choi, Y. Park, T. Song, G. Lim, K. Yoo, S. Lee, S.C. Lww, A. Lee, S.C. Lee and D-I Cho
Affilation: Seoul National University, Korea
Pages: 431 - 434
Keywords: intelligent sensor, IMU, SBM
This paper presents the intelligent digital 3-axis IMU (inertial measurement unit) system. The MEMS accelerometer and gyroscope sensing cores are fabricated by using the SBM (Sacrificial Bulk Micromachining) process. The fabricated sensing cores accomplish the high performance, high yield and high reliability by the inherent high-aspect-ratio, footing-free advantages of the SBM process. To protect the sensing cores from environmental attacks, the wafer-level packaging is performed by using glass-silicon anodic bonding. Gettering is used for the vacuum required in gyroscopes. The analog acceleration and angular rate signal from sensing cores are converted into the digital signals using 24 bit delta-sigma A/D converter, then the digital filtering is performed to reduce the noise and drift. The network connection to the host platform is established using the RS232C serial interface. The accelerometer channel of the system has the input range of ±10 g, nonlinearity of 0.37 %FSO, resolution of 50 _g, and 4-hr bias stability of 1.5 mg. The gyroscope channel of the system has the input range of ±60 deg/s, nonlinearity of 0.65 %FSO, resolution of 0.00014 deg/s, and 4-hr bias stability of 1.5 deg/hr. This system will provide more cost effective, highly reliable and easy-to-use IMU solution with high network connectivity.