In the past three decades. a lot of Petri net-based methods have been proposed for deadlock prevention/liveness enforcing in flexible manufacturing systems (FMSs). Firstly. a plant Petri net model of an FMS is obtained and then the liveness enforcing supervisor (LES) or the controller is computed as a Petri net. https://chefesquipmenters.shop/product-category/butter-rollers/