The least square circle model and parametric estimating method for the superprecision measurement of circle contour

While the cross section contour of the round workpiece is measured at super-accuracy, the most important problem that restricts accuracy is the establishment of a precise least square circle model. In superprecision measuring, if the approximate model and the estimating method are used improperly, it will lead to a series of problems such as contour distortion, eccentricity error, etc. The authors analyze the drawbacks of the approximate model and the parametric estimating model, and propose the precise parameter model of a least square circle, and an optimized estimating method which can be used to solve the parameters of a least square circle