High Dynamic Micro Vibrator with Integrated Optical Displacement Detector for In-Situ Self-Calibration of MEMS Inertial Sensors

Abstract

The scale factor drifts and other long-term instability drifts of Micro-Electro-Mechanical SystemMEMS) inertial sensors are the main contributors of the position and orientation errors in high dynamic environments. In this paper, a novel high dynamic micro vibrator, which could provide high acceleration and high angular rate rotation with integrated optical displacement detector, is proposed. Commercial MEMS inertial sensors, including 3-axis accelerometer and 6-axis inertial measurement unit which is about 3 mm * 3 mm * 1 mm with 19 mg, could be bonded on the vibration platform of the micro vibrator to perform in-situ during the self-calibration procedure. The high dynamic micro vibrator is fabricated by a fully-integrated MEMS process, including lead zirconate titanate (PZT) film deposition, PZT and electrodes patterning, and structural ion etching. The optical displacement detector, using vertical-cavity surface-emitting laser (VCSEL) and photoelectric diodes (PD), is integrated on the top of the package to measure the 6-DOF vibrating displacement with the detecting resolution of 150 nm in the range of 500 μm. The maximum out-of-plane acceleration of the z-axis vibrating platform loaded with commercial 3-axis accelerometer (H3LIS331DL) achieves above 16 g and the maximum angular velocity achieves above 720°/s when the driving voltage is ±6 V.

Impacts of Residual Stress on Micro Vibratory Platform Used for Inertial Sensor Calibration

“…Sensors 2020, 20, x FOR PEER REVIEW 2 of 14 the in-situ calibration of inertial MEMS devices [17]; it can provide 16 g acceleration and 720°/s angular rate for 19 mg payload (a commercial 3-axis accelerometer H3LIS331DL). However, due to the appearance of the residual stress of micro fabrication and the hysteresis effect [18,19] of piezoelectric material, the vibratory stage exhibited an initial displacement of 0~20 μm and an abnormal displacement response, which was obtained using an optical measurement system proposed in our previous work [20].…”

“…The additional optical metrology system can ensure the long-term stability of the vibratory platform at 10 ppm. In the same period, a team at the China Academy of Engineering Physics also reported a micro Sensors 2020, 20, 3959 2 of 13 vibratory platform with high dynamic for the in-situ calibration of inertial MEMS devices [17]; it can provide 16 g acceleration and 720 • /s angular rate for 19 mg payload (a commercial 3-axis accelerometer H3LIS331DL).…”