Accuracy Enhancement and Nonlinear Coefficients Determination of MEMS Accelerometer Using Centrifuge Test

In order to increase the accuracy of inertial navigation system, it is necessary to calibrate the inertial measurement unit (IMU). In some applications, the acceleration that is applied to the accelerometer is greater than its linear operation area. In such a case, the input-output relationship of the accelerometer is deviated from its linear form that is determined in the earth s gravitational field (1g). The main purpose of this paper is estimate the coefficients of these nonlinear terms so that the accuracy of measurement be improved. For produce the high level of accelerations (greater than 1g) and use of them as a reference in accelerometer calibration, it can be used a centrifuge. In this paper, the linear and nonlinear coefficients of an accelerometer(x axis) of a low cost MEMS triad accelerometer are estimated using continuous calibration method in the earth s gravitational field (1g) and centrifuge test for accelerations between 0 to about 16g respectively. The errors of linear and nonlinear models are compared by Mean Square Error (MSE) criterion. The results showed that the nonlinear model improved the accuracy of measurement about 11.7%.

کلیدواژه ها:

Accelerometer calibration ، nonlinear coefficients ، high-g acceleration ، least squares ، kalman filter