A discrete event approach to the command sequence replanning and control in a teleprogramming system

A command sequence replanning and control method, which enables the slave s ystem to autonomously recover from error conditions, is proposed in a teler obot system. A task model described as a form of the controlled Petri net ( CPN) is used as a prior knowledge for the slave system to carry out the giv en task successfully without the operator's aid even in unexpected error co nditions. The CPN model incorporates the contact states and transitional mo tions between them that possibly exist in the task execution process. The m otion command is automatically generated from the master system and transmi tted to the slave whenever the contact state changes in the master model. R eferring to the CPN model and the given motion commands, the slave system d etects if the actual contact state is unexpected and then plans the recover y path from the unexpected state. The feasibility of the command sequence r eplanning and control algorithm is verified through an example to perform a simple part-mating task. (C) 2001 John Wiley & Sons, Inc.