Three-phase approach to interference detection for reconfigurable workholding techniques

In general, the reconfigurable workholding approach employs a number of fixture modules which are set-up, adjusted and changed automatically by a manipulator. The fixture design, analysis, and verification are performed using a dedicated software program. These software tools are integrated with a dedicated modeling system, or a commercially available computer-aided design (CAD) package, to provide a user-friendly platform for modeling and display purposes. The manipulator program for setting up, adjusting, and dismantling the designed fixture is generated automatically. Interference between fixture modules during the fixture construction may arise due to incorrect selection of the fixture contact points at the design stage. The objective of the work described here is to develop a hierarchical approach for calculation of interference between fixture modules appropriate to reconfigurable workholding (i.e. fixturing) approach. The formulation for the interference detection employs geometrical constraints as the basis. These formulations are embedded in a three-phase interference detection technique. At each level, a number of possible interference conditions are eliminated, thus narrowing the range for other constraints. The approach does not require detailed simulation of the fixture construction for interference detection.