Modeling and automatic calculation of restart states for an industrial windscreen mounting station

Paper in proceeding, 2015

The production in an automated manufacturing system will not always progress as intended. A wide variety of possible faults may cause errors that lead to an unsynchronization between the control system and the physical system that consequently lead to production stoppages. The common industrial practice to deal with such non-intended progress is to extend the control system with tailor-made solutions to account for errors. This extension is both time consuming and there is no guarantee that all relevant errors are handled. This paper models the control system to enable automatic derivation of restart states applied to an existing station for automatic mounting of windscreens onto car bodies. These restart states are states in the control system where it is correct to resynchronize the control and the physical systems so that the automated production can be resumed. This aids the preparation phase by letting the developer focus on modeling the nominal production and on specifying (un-)desired behavior during the restarted production, and then automatically retrieve the restart states for all control states. The online restart process is then reduced to a semi-automatic process where an operator can be supported with instructions for how to correctly resynchronize the control and the physical systems in a selected restart state.