A Framework of Predicate-Based GPS Operations

Operation and operator technologies used in new generation Geometrical Product Specifications (GPS) provide the necessary knowledge basis for digitization and standardization in verification process of geometrical products. This paper presents a framework of predicate-based operations which obtain features or values of characteristics, their nominal values and their limits. The knowledge about operations, constraints, objective and result is represented using predicate calculus, and it forms the basis of formalizing operator. Conditions give an equality or inequality to be respected by the specified characteristic. With a simple example, the geometrical expression specifications for the functions, design, manufacture and verification of a product are illustrated. The case of perpendicularity tolerance indicates that the proposed method is efficient and feasible.