Model Predictive Control of an Automated Storage/Retrieval System

Discrete-event systems occur often in the manufacturing field, but due to the characteristics of these systems Model Predictive Control (MPC) is not frequently used for them. This paper approaches MPC of an Automated Storage/Retrieval System (AS/RS) by using Mixed Logical Dynamical (MLD) modelling. Propositional calculus is used to transform the non-linear dynamic model equations and constraints of the AS/RS into the MLD form. We consider a performance index that makes sure that customer demand is satisfied as soon and as efficiently as possible. The MLD model and performance index are reformulated as an integer linear programming problem. A case study is performed on a laboratory stacker crane, and the simulations results illustrate the good performance of the control algorithm.