Autocalibration for MEMS triaxial accelerometer based on a PID-based search algorithm

The errors can accumulate over time when microelectromechanical system (MEMS) accelerometers are in use, it is necessary to perform autocalibration to remove the systematic error effect. However, little research has been done on simultaneously considering the non-orthogonality and misalignment effect in MEMS triaxial accelerometer calibration. To enhance the calibration accuracy and extend the autocalibration methods, this paper proposed a new autocalibration method for MEMS triaxial accelerometers base on a PID-based search algorithm. Non-orthogonality and misalignment error factors were integrated into the error model and a PID-based search algorithm was developed to identify the optimal error factors, minimizing the difference between the actual accelerometer output and the local gravity. The proposed calibration method was tested through simulations, with results showing that the errors in scale factor, bias, non-orthogonality, and misalignment are within 1.5865×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup>, 2.0060×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup>, 5.0621×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup>, and 6.8104×10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-4</sup>, respectively. The proposed method was also compared with the existing calibration methods, with the maximum errors of the proposed method within 0.41% and those of the others exceeding 0.80%. Simulation and comparison results verified the effectiveness and improvement of the proposed method. The average time of the autocalibration is 13.22 s, offering practical value for MEMS triaxial accelerometers.