SAGE: A decision support system for the sequencing of operations within a robotic workcell

摘要

This paper describes a new approach to decision support based on logic programming. SAGE, Sequence Analysis by Graphical Evaluation, is a both a logic framework and a set of Prolog programs to express and then solve the problem of repetitive sequencing of operations within a robotics workcell. We create a Timed Petri Net from the user description consisting of the initial state of the workcell, plus the operations to be performed. Each operation is defined by (i) the command to be executed, (ii) a list of enabling conditions, (iii) a list of changes made to the state of the workcell by executing the command, and (iv) its relative integer duration. After some preliminary analysis, this net is used to generate the Task Space of all feasible time histories of workcell events. Repetitive sequences of all the workcell operations are then constructed from cycles in the Task space. From the feasible sequences thus identified, the time-optimal one is selected. SAGE clearly demonstrates both the power of symbolic expression, and the power of pattern matching as a basis for decision support systems.