Closed‐loop control for self‐calibration of accelerometer achieved through integrated sensor and actuator system

Abstract

In-situ self-calibration can fundamentally solve the problem of long-term stability of the accelerometer. The implementation of external integrated micro structure to provide physical excitation has become an effective method to compensate for the long-term drift error of the accelerometer. A closed-loop self-calibration system for accelerometers by integrating sensors and actuators is presented. The piezoelectric MEMS microvibrator acts as an acceleration source, providing a standard acceleration for the accelerometer integrated on it. An optical displacement sensing system consisting of vertical cavity surface emitting laser (VCSEL) and photodiodes (PDs) detects the motion state of the microvibrator to achieve the accurate output by closed-loop control. The self-calibration process of the accelerometer is performed by establishing an error model of the accelerometer and a vibration model of the integrated micro-vibrator. The drift error of the accelerometer is compensated by obtaining the error coefficient and the compensation coefficient. It has been verified that the error of the self-calibrated accelerometer when performing 15 g acceleration output is less than 1.5%.