Errors, failures and disasters

Abstract

In the scenario in Chapter 1, we described a future robot assembly cell that was capable of automatically building quite complex assemblies from a range of components. When the human supervisor asked for a report, the system was able to give both a diagnosis of any errors which had occurred and an account of any repair work that had been applied to rectify faulty assemblies. In robotic assembly any kind of failure, be it due to a faulty component or a workcell error, is a potentially serious problem and hence facilities for automatic recovery are extremely desirable. Such automatic methods should not only reduce the down-time (when maintenance staff work on the cell) but could also provide protection from serious damage during operation. In this chapter we will examine the problems of error recovery and review the requirements that are necessary for our scenario to become a reality.

To conceive a plan and to carry it through are two different things.

G. Polya

Every week, in happy little family homes, something falls off, bends, buckles, breaks, dissolves, crumbles, collapses, bursts into flame or explodes.

C. Parker