Electrical Stimulus Based Calibration of MEMS Accelerometer

Micro Electro-Mechanical Systems (MEMS) accelerometers are utilized in safety-critical applications, including airbags, aircraft, medical devices, as well as various consumer electronic applications. Despite providing highly accurate results, they require calibration during production and periodic recalibration due to potential degradation over time. The National Institutes of Standards and Technology (NIST) stipulates that the accuracy of motion sensors used in safety-critical applications must be maintained within a 1% error margin. In our research, we propose an electrical stimulus-based calibration method for sensors during production and in-field use. In-field electrical stimulation and calibration can facilitate prolonged sensor operation without the need to remove the sensor from its environment. Although electrical stimulation has been suggested as a replacement for physical stimulation to reduce testing costs for sensors, it has not yet demonstrated the ability to meet the 1% error requirement mandated by NIST safety standards. We propose an incremental sensor-based model that can correlate sensor sensitivity degradation and process variation to its electrical response for in-field monitoring. Simulations demonstrate that the model can forecast sensitivity changes within a 1% error margin. Additionally, we have developed a cost-effective rotating test platform for calibrating and measuring accelerometer sensitivity. This method utilizes wireless technology to transmit accelerometer data to a computer, eliminating the necessity for lengthy cables. The rotating platform can produce various accelerations at different distances along the radius by spinning at different RPMs, leveraging centripetal force to apply a fixed acceleration at a set RPM.