Performance of MEMS Vibratory Gyroscope under Harsh Environments

Microelectromechanical systems (MEMS) gyroscope is a sensor that measures the rate of change in an angular position of an object. MEMS vibratory gyroscopes are increasingly used in applications ranging from consumer electronics to aerospace and are now one of the most common MEMS products after accelerometers.With advances in fabrication technologies, the low-cost MEMS gyroscope has opened up a wide variety of applications with environmental conditions ranging from medium to harsh. Despite their widespread use, the performance of MEMS gyroscopes in harsh environments is still under question. While some studies have been conducted to understand the effects of high mechanical shock, high frequency vibration and high frequency acoustic environment on the MEMS gyroscopes,the effects of sustained exposure to temperature combined withother harsh environment stresseshave not been well researched.Thus, it is necessary to quantify MEMS vibratory gyroscope performance under such conditions.This research reviews current harsh environment studies anddemonstrates the effects of an elevated temperature and sustained exposure to temperature combined humidity on the MEMS vibratory gyroscope. In order to quantify such effects, several tests have been performed. A short-term temperature effect on MEMS gyroscope was examined through temperature characterization test forfive thermal cycles at wider temperature ranges. A long-term temperature effect on the MEMS gyroscope was inspected through 500 thermal cycles; while, combined effects of temperature and humidity was studied through temperature humidity bias(THB) test and highly accelerated stress test (HAST).