A generic run-time environment for a robotic workcell /

Abstract

The complexity of modern robotic workcells, consisting of many cooperating elements (eg. robots, sensing systems) makes programming applications enormously difficult. Programming such a complex robotic system is a complicated task that requires thorough understanding of each of its elements. Thus far, little has been done in the way of developing a robotic workcell programming environment: this dissertation addresses this very problem. A hierarchical framework is proposed that decomposes the problem into three sub-problems, (i) the Planning sub-problem, addressed by the Strategy level, which determines what has to be done in terms of 'steps' that have to be performed, decides which active element will perform each of those 'steps' and determines the layout of the workcell, (ii) the Coordination sub-problem, addressed by the Tactics level which determines when a 'step' can be executed, and (iii) the Command sub-problem, addressed by the Virtual Device level, which determines how each of the 'steps' is executed. In particular, we will focus on the Coordination and Command sub-problems addressed by the run-time control environment. We will define a state formalism and based on it we will build a model of the intended workcell behavior. A prototype implementation of the proposed run-time control and programming environment, called WRAP (Workcell ReAl-time Programming) is described. An idealized assembly task was programmed to evaluate the approach and an evaluation of these experimental results is presented.