Accelerometer for mobile robot positioning

Abstract

An evaluation of a low-cost small-sized solid-state accelerometer is described in this paper. The sensor is intended for positioning of a mobile robot or platform. The acceleration signal output by the sensor is doubly integrated with time, which yields the traveled distance. Bias offset drift exhibited in the acceleration signal is accumulative and the accuracy of the distance measurement deteriorates with time due to the integration. This problem can be fixed by periodic recalibration by the use of external measurements on position, velocity, and attitude which can be compared with the corresponding quantities calculated by the inertial system. A Kalman filter could use the differences between those values to provide an optimum estimate of the system error. The random bias drift of the accelerometer was found experimentally to be 2.5 mg. The accelerometer was moved back and forth three times for a distance of 40 cm with an acceleration of 8 m/s2. The final distance error accumulated was -1.08 cm. The bias drift rate due to temperature was 0.108 μg/s when the accelerometer was placed at room temperature. The results show that the accelerometer could be a viable solution as a short-duration distance-measuring device for a mobile robot or platform.