Control of a Production-Inventory System Using a PID and Demand Prediction Based Controller

TOSETTI SANTIAGO; PATIÑO DANIEL; CAPRARO FLAVIO; GAMBIER ADRIAN

Rio Gallegos

Congreso; XII Reunión de Trabajo en Procesamiento de la Información y Control; 2007

Universidad Nacional de la Patagonia Austral

The need of reducing inventory levels as much as possible without loosing sales opportunities is an important goal not only for small but also for mid-size and large companies, on account of the high costs associated with large inventory stocks. In general, the performance of inventory systems is also affected by the Bullwhip effect caused, among other factors, by non-zero lead times. This paper proposes an automatic pipeline feedback order-based production control system (APIOBPCS) considering a demand with cyclic and stochastic components. The dynamics and delays of the production process are modeled as a pure delay. The control system structure consists of a PID controller and demand prediction based on an Extended Kalman Filter (EKF) The main objective of the controller is to stabilize and regulate the inventory levels about a desired set-point. The extended Kalman filter estimates the parameters of a Volterra time-series model to predict future values of the demand. The control system is evaluated by imulations, showing a good performance and better results than those achieved by using traditional inventory control techniques.