The Development and Application of Kinematic Icon and Inactive-Joint Concepts in Automated Mechanism Sketching

An important step within the automated type synthesis process is the generation of graphical displays of proposed mechanisms which permit designers to visualize the candidates. In this paper, the concepts of kinematic icon and inactive joint have been developed and applied to the problem of automatically generating sketches of mechanisms, given only the kinematic structure. Each different link type is treated as a separate entity: an icon, with its own predefined graphical representation. Moving-link icons, (as opposed to icons of fixed links) have special properties defined according to the joint types on the adjacent links. The locations, sizes, and orientations of the icons depend on the locations of the joints whose coordintaes may be directly assigned (in simple cases) using joint placement procedures. However, because the icons are defined by assigning a specific graphical representation to groupings of joints, and not just single joint, not all joints can be directly assigned their coordinates and this other class of kinematic joint is defined as an inactive joint. The kinematic icon and inactive joint concepts make possible the sketching of mechanisms with more complicated joint types such as prismatics and gears, for the first time in a systematic manner.