Compiling assembly plans into hard automation

摘要

For high-volume assembly, "hard automation" systems consisting of a pipelined series of simple operations are often preferred over multi-axis robots for reasons of cost, speed, and precision. Given a desired final assembly, designing an appropriate assembly system requires the intuition of experienced designers who require up to six months to produce a design and may overlook a better design or fail to find a design when one exists. Thus there is a need for CAD tools that can assist the designers of assembly hardware and to give rapid feedback to product designers to facilitate design for assembly. We introduce a class of vertical assembly (VA) plans such that any valid VA plan can be "compiled" into a hard automation assembly system. VA plans consist of vertical insertions alternated with rotations such that parts and subassemblies at each stage sit stably on conveyor belts without fixtures. For an assembly with n vertices, we can decide if a VA plan exists in time O(n/sup 4/). We describe a complete and implemented planning algorithm that takes as input a 2D slice of an assembly consisting of polygonal parts and returns all valid VA plans ranked by a quality metric.