A micro vibratory stage for on chip physical stimulation and calibration of MEMS gyroscopes

This paper presents the design and preliminary test results of a micro actuation and sensing platform to provide on chip physical stimulus for in situ calibration of long-term drifts in scale factor and offset of dual-axis MEMS gyroscopes. The platform consists of a 3-DOF micro vibratory stage that can provide piezoelectric actuation for X/Y-tilting reference stimuli, off-axis motion compensation, analog sensing of applied periodic stimulus, and electrostatic position lockdown for shock protection. Initial characterizations are performed with a commercial MEMS gyroscope (25 mg) mounted on top of the micro motion platform, while its electrical interconnects provided through microfabricated highly-flexible parylene cables. The piezoelectric stage is measured to provide up to 220 degree/sec angular AC excitation, while providing an analog sensing signal to determine the applied stimulus with a precision of 1.2 degree/sec. The estimated scale factor has < 0.8% deviation from rate-table values on the same-model gyroscope samples.