RELIABILITY AND FLEXIBILITY - A MUTUALLY EXCLUSIVE PROBLEM FOR ROBOTIC ASSEMBLY

One problem often encountered when performing assembly using robots is how to deal with variation and uncertainty in the workcell. Either th e workcell becomes tightly constrained, thus losing the flexibility of the system, or errors occur, which reduces the reliability of the sys tem. This paper attempts to address this problem using a hybrid archit ecture. A planning system produces a high-level ordering of the assemb ly in terms of part motions, which are translated into robot motions b y an adaptive run-time execution system. The execution system contains a flexible hierarchy of competent modular units which combine to perf orm the assembly reliably, The work in this paper attempts to reduce t he complexity found in assembly planning and to provide a reactive run -time system which can deal with uncertainty and variation without ref erence to a computationally expensive global-world model. The backgrou nd to this work is presented, along with an experimental system design ed to test out the ideas, Conclusions about the usefulness of the syst em are drawn at the end of the paper.