Analysis of factors affecting measurement accuracy and establishment of an optimal measurement strategy of a laser displacement sensor.

Laser triangulation method is widely used in online precision measurement owing to its advantages of being fast, accurate, and dynamic, and having large-scale measurement capability. To improve the accuracy of laser triangulation, the scan depth, inclination angle, rotation angle, and deflection angle are defined. Then, a spatial pose error model and an experimental model for laser measurement error are established. Next, error analysis experiments are conducted, and the influence of spatial pose parameters on the error is analyzed. Further, error proofreading experiments on the surface characteristics of the measured workpiece, including the material, surface roughness, and color, are completed, and their influences on the error are analyzed. Based on the experimental data, an error correction model based on support vector regression is established. Measurement strategies are formulated considering multi-factor constraints such as optical path interference, mechanical interference, scan depth of field, measurement angle, and measurement path. The tooth profile of a cycloid gear is taken as the measurement object, then the measurement path planning is performed, and the error correction model is used to correct the measured data. The accuracy of the results agrees well with the result of a fully automatic computer numerical control (CNC)-controlled P 65 precision measuring center.