Evaluation of a low-cost MEMS accelerometer for distance measurement

This paper gives an evaluation of a low-cost MEMS accelerometer. The accelerometer is intended for the distance measurement of a mobile robot or platform in short duration. The distance traveled is obtained by double integration of the sensor signal with time. Bias offset drift exhibited in the acceleration signal is accumulative and the accuracy of the distance measurement can deteriorate with time due to the integration. This problem can be fixed by periodic recalibration with the help of external measurements on position, velocity and attitude. These external signals can be calculated by an inertial system. A Kalman filter can use the differences between these values to provide an optimum estimate of the system error. The random bias drift of the accelerometer was found by experiment to be 2.5 mg. The bias drift rate due to temperature was 0.108 mug/s when the accelerometer was placed at room temperature. With proper compensation on gravitation, the accelerometer can be a viable solution as a short duration distance-measuring device for a mobile robot.