Position and orientation determination of a probe with use of the IMU MPU9250 and a ATmega328 microcontroller

Abstract

This paper gives an overview of the position and orientation determination system made in context of the final project of the bachelor Electrical Engineering at Delft University of Technology. By combining the measurements of the accelerometers, gyroscopes and magnetometer from the Intertial Measurement Unit MPU9250 in a complementary filter, the orientation of the MPU9250 was determined. The displacement of the MPU9250 was determined by using the trapezoidal integrating method to integrate the acceleration measured with the accelerometers. This displacement was combined with the orientation to determine the position of the MPU9250. With the knowledge of the relative orientation and distance between the MPU9250 and the probe-tip, the orientation and the position of the probe-tip was determined with use of quaternions. Pitch and Roll angles were determined with an accuracy of 2 degrees. The yaw angle determination was incorrect due to the inaccuracy of the magnetometers. The position determined did not drift, but was off due to imprecise filtering and integration. For better results a microcontroller with more programmable space is suggested.