Shafting error parameters identification and compensation of non-orthogonal laser theodolite without reference end on laser axis

Abstract

The research about non-orthogonal shafting laser theodolite (N-theodolite) is motivated by the growing demand for instrument. The reference pose of laser axis in motion state cannot be obtained due to the absence of reference end, and the error compensation of the N-theodolite is lack of basis. Therefore, the shafting error parameters identification and compensation method without reference end is proposed in this paper. Based on the derived kinematics model of the N-theodolite, the laser axis pose error in motion state can be described accurately. Then the aiming error is defined as the key reference parameters to construct the linear equations for effective identification and iterative compensation of shafting error. The experimental results have shown that the average aiming error of the compensated N-theodolite is less than 0.04 mm within 10 m. Compared with the existing calibration approaches, the shafting parameters adjustment performance of the proposed method is more prominent.