Safety of Manufacturing Systems Controllers by Logical Constraints With Safety Filter

This brief presents an approach to safe controller synthesis for manufacturing systems controlled by programmable logic controllers (PLCs). In this brief, manufacturing systems are considered as discrete-event dynamic systems with logical inputs and outputs. The methodology is based on the use of safety constraints placed at the end of the PLC program. These constraints are checked offline by a formal approach and acted as a safety filter in order to be robust against control errors. The proposed approach separates the functional control part from the safety part and focuses on the latter. This brief presents the whole methodology and recent improvements on consistency checking of a set of Boolean expressions.