Spatial Coordinates Measurement For Hidden Parts Based On Non-diffracting Beam

In large-scale space coordinate measurement, because of large measuring space of equipment and complicated field environment, there are always some key hidden points that must be measured but are difficult to be measured caused by factors such as spatial barrier, self-occlusion of components or mutual occlusion and concaved points of interest, etc. To solve the problem of hidden points of large equipment under intervisibility blocking conditions, this dissertation studies a new combined measuring method which combines space attitude measurement and laser ranging. By virtue of fundamental instruments such as total station and on the condition that coordinate datum is not changed, this method realizes large-scale non-contact obstacle detouring survey under single-coordinate datum through turning of measuring directions. The main contents and creative points are as follows:The basic characteristics of non-diffracting beams are analyzed. And based on angle measurement theory of non-diffracting beams and through theoretical calculation, the constrained parameters the optical system which satisfies the non-diffracting attitude angle sensor are optimized; then the mathematical model of spatial attitude angle measurement is established and the attitude angle measurement system based on non-diffracting beams is established.A reconfigurable coordinate measurement system comprising attitude angle sensor, laser rangefinder, and total station is proposed. The structure, basic measurement principle and calibration method of the combined measurement system are described. The mathematical model of the measurement system is built up. The calibration target is designed and this measurement system is calibrated.A rotatable mobile probe comprising attitude angle sensor, angle encoder and laser rangefinder is proposed, and the probe together with the total station constitutes a large-scale non-contact coordinate measurement system. Focusing on the unequal distribution of the calibration points in practical application settings, a weighted least squares calibration method in which weights are determined for the angular distribution density is adopted. Simulation results by the Monte Carlo method and experimental results show that the measurement system could expand the scale and achieve reliable precision during combined measurement and the measurement error of the weighted least squares method is less than that of the ordinary least square method, which verifies feasibility of this calibration method.Experimental verification and uncertainty analysis of the measurement accuracy of the reconfigurable and the rotatable combined measurement system are performed. The software platform of the measurement system is compiled. Based on analysis of errors of the total station, the attitude angle sensor, the angle encoder and the laser rangefinder, according to mathematical model, the measurement uncertainty of spatial coordinates is discussed.