Task Level Programming And Robot Autonomy

Abstract

We consider the class of intervention mobile robots that huve to perform tasks in ill-known environments which are often remote or of difflicult or dangerous access. An outstanding example of this would be a Mars Rover designed to carry out planet exploration, scientific measurements and experiments, according lo the requeslis of Earth based scientists over a long period of time, e.g. one Martian year. The lack of structure in the environment of this class of intervention robots, as well as the nonrepetitive nature of the tasks, clearly require eficient task programming and constant adaptation to the environment by the robot. We contend that this class of problems demands a specific decisional architecture which couples “intelligence” at the programming level with “intelligence” at the level of the physical machine. This second requirement implies that the machine exhibits the attributes of an autonomous intelligent robot. In this paper we develop the concepts of a generic architecture aimed to achieve task control of a remote intervention robot. The robot is fully autonomous at task level. It receives tasks assignements that it transforms into sequences of actions using ats own interpretation and planning capacities, and executes these actions while being ,reactive to asynchronous events and environment conditions. We have developed the approach presented here in the context of several domain-oriented projects, and fully implemented a first version of the concepts in our newest mobile robot, HILARE II. The framework of the french Mars Rover project VAP is used as an illustration of some crucial aspects discussed in the paper.