Bao Jiading

The Parallelism error evaluation of line to plane based on new GPS

Based on metrology, Geometrical Product Specifications (GPS) standard system proposes higher specification requirements for position tolerance evaluation. Based on analyzing of the definition of the axis of the plane and the measurement method, the least square method of parallel evaluation model is used for the model coordinate system transformation, so it can unify the elements of the tested elements and reference elements to simplify the assessment mode. The examples show that the method not only accords Geometrical Product Specifications (GPS) standards, but also can evaluate the error of space on the plane parallel to the axis correctly and effectively.

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.

Specification design of planar feature based on the new generation geometrical product specification and verification

In accordance with the new generation geometrical product specification and verification (GPS), the specification design process and the measurement and verification process must satisfy with duality principle so as to avoid the ambiguous problems during the verification process. To solve the problems how to generate the specification surface model of planar feature and design and apply the corresponding specification operators. This paper firstly presents a method to generate the specification surface model of planar feature. The tolerance mathematic model of the planar factors should be established in first step. Then the influences of processing technology on the specification surface model need to be considered. The simulation points under the normal distribution are generated in the tolerance zone. By using the fitting approach of the least-squares B spline, the specification surface model is generated. Secondly, this paper makes a corresponding analysis and design on specification operators of plane feature with flatness requirement. Lastly takes the worktable of M7140 grinding machine as an example, builds its specification surface model and the specification design results by operations on specification surface model are given.