No abstract

In this paper we study Computer Aided Geometric Design (CAGD) and Manufacturing (CAM) of developable surfaces. We develop a direct representation of developable surfaces in terms of plane geometry. It uses control planes to determine a surface which is a Bezier or a B-spline interpolation of the control planes. In the Bezier case, a de Casteljau type construction method is presented for geometric design of developable Bezier surfaces. In the B-spline case, de Boor type construction for the geometric design of the developable surface and Boehm type knot insertion algorithm are presented. In the area of manufacturing or fabrication of developable surfaces, we present simple methods for both development of a surface into a plane and bending of a flat plane into a desired developable surface. The approach presented uses plane and line geometries and eliminates the need for solving differential equations of Riccatti type used in previous methods. The results are illustrated using an example generated by a CAD/CAM system implemented based on the theory presented.

This paper presents an approach to the finite position synthesis of spherical four-bar linkages that unites traditional precision theory with recent results in approximate position synthesis. This approach maps the desired positions to points in an image space, and the motion of the coupler of a spherical four-bar to a curve. The synthesis problem then becomes one of finding the image curve that passes through the given positions (precision position synthesis) or as close as possible (approximate position synthesis), the solution of which is obtained by minimizing the normal distance error. Nonbranching constraints are incorporated into the minimization problem to give the designer control over the type of the linkage synthesized. Numerical examples are presented for five, six, and ten positions.

No abstract

Open Access Original Article