Scheduling of a multi-robot assembly cell

One of the key problems in robotics is to make full use of the flexibility provided by the robots. This flexibility can be used to assemble variants of the same product or even different products in the same cell. In a multi-robot assembly cell, flexibility may also mean that some operations can be performed by different robots. This choice of robots leads to a new problem: how to distribute the assembly operations among the robots to minimize global assembly time. The paper presents different approaches to this problem: the synchronous approach, which enables on-line scheduling, and the asynchronous approach, which requires offline scheduling, but enables better assembly times. These different approaches have been tested on real assembly cases (e.g. an electrical signalling relay) and simulated on a robotics CAD system (ROBCAD). Results are presented and discussed.