LAUSR

A robust incremental-quaternion-based algorithm is proposed in this paper to estimate the angle and the axis of a single-axis rotation whose rotation axis is invisible or inaccessible. We establish a model to estimate the rotation angle and axis according to the relationship between the incremental quaternion and the pair of rotating axis and angles. Moreover, the solutions for the model are detailedly described in this paper. This algorithm could achieve full range of rotation angle and all-attitude rotation axis measurements with high-computational efficiency. It has good performances in the rotation angle and axis estimation no matter whether the measured target is in dynamic or static movement, which solves the inaccurate rotating-axis attitude problem in other methods when the target is doing low-speed rotation. Using the designed measurement unit based on magnetic, angular rate, and gravity sensors, this algorithm eliminates the drift of measurement results caused by the integral error of the gyroscope. The effectiveness of this algorithm has been validated through a single-axis motion control platform by comparing with another two methods. Results show that the proposed algorithm provides a more accurate estimation of rotation angle and the axis of a single-axis rotation of high or low speed.