Digital Inspection for External Projections of Passenger Cars Based on Free Rolling Contact Constraints

To protect human from sharp edges of passenger cars, the fillet radius of external projections on car surface should conform the national standard. To inspect underlying problems of the external projections on the design stage, a sphere should roll freely on the car surface in the design platform, which is difficult to achieve in the existing CAD software. Hence, a novel approach to establish the free rolling contact constraints is presented in this paper. The car surface is modelled by triangular facets, and the rolling of the sphere on car surface is converted to the motion on the facets. The rolling contact constraints for both single facet and double facets are established, and are switched through understanding the manipulation purpose of the designer. The tool of digital inspection for external projections is developed based on NX secondary development, which notably improves the inspection efficiency on the car design stage.