Measurement error caused by bearing runout in laser tracking system and the selection of bearings

Bearing runout is one of the main error sources of laser tracking system. This paper tried to analyze the relationship between the measurement errors and the bearing runouts through establishing an error model. According to the model, the error distribution diagram has been drawn. It is pointed out that the measurement errors change as the pitch angle changes, the maximum errors distribute on a plane whose pitch angle equals π/2. With regard to the measurement, it is better to avoid placing the measured points on this plane. The errors are irrelevant to the distance between the measured point and the tracking head. When bearings with P2 precision grade are used, the measurement error is as high as 9.8091μm. The error model can effectively guide bearing selection, shorten selection time and improve production efficiency.