A two-tier pattern matching scheme has been developed which presents a designer with a mechanism structure having a prescribed coupler curve pattern from a database of dimensionally-parameterized mechanisms. The database for the prototype system includes one hundred and eighty four-bar mechanisms, and sixty six-bar mechanisms. image. A digital video camera serves as the means for entering the image of a desired coupler curve, i.e., the 'target' curve, and also to expand the database. This target curve is compared with curves in the library of mechanisms using a two-tier pattern matching algorithm. In the first tier, the entire database is scanned for a match of the invariants of the moments of the coupler curves, and the system calculates numerical certainty factors which quantify the degree of matching. Second tier matching employs the Fourier and Mellin Transforms as a basis for a more refined comparison of the twenty best matching curves from tier one, and presents a list of candidate mechanism structures possessing coupler curves which approximate that of the target curve. This methodology represents an extension of our previous work, called pattern matching synthesis, for automating the process of creative mechanism synthesis using backward reasoning.
|Number of pages||11|
|State||Published - 1 Dec 1990|
|Event||21st Biennial Mechanism Conference - Chicago, IL, USA|
Duration: 16 Sep 1990 → 19 Sep 1990
|Conference||21st Biennial Mechanism Conference|
|City||Chicago, IL, USA|
|Period||16/09/90 → 19/09/90|