Research on straightness evaluation of the machine guideway based on the new generation geometrical product specifications

Most evaluation technology of the rail straightness at present is still built on the specifications based on the geometries. The principles of duality and consistency between specifications and verification stage proposed in the new generation of geometrical product specifications (GPS) have not been taken into consideration and resulted in the loss of control of the functional requirements. To solve this problem, this paper summarizes the research status of both the measurement and the functional requirements of the guideway straightness. We propose a new evaluating scheme based on duality principle of new GPS. In this scheme, B-spline method was adopted to meet the duality requirement and functional requirement in model establishment. In the measurement and certification process we adopt the same operations proposed in the new GPS both on specification surface model and verification surface model. Thus the duality principle between the specification stage and verification stage was implemented. To demonstrate the new method, an example was given in details following the steps above. Meanwhile, the results using minimum zone was given to verify the proposed method. The comparison showed that the new method can be able to meet the requirements of new GPS system, and can satisfy the design accuracy.