PID and Predictive PID Control Design for Crushing And Screening

Crushing and screening processes are often regulated using relay-based on/off controls or, when controlled by PID controllers, the control design is limited to a single crusher and its proximity. The design does not necessarily consider process interactions, load disturbances and, in a wider perspective, does not treat a crushing and screening plant as an entity from feeding to product piles. This paper outlines a plant-wide process control design with guidelines for crushing and screening processes. To allow usage of conventional PID controllers, effort is placed on designing controls that aim to decouple interactions and provide a good load disturbance rejection. Sensors and actuators play a significant role in any process control and, therefore, they are also considered in this paper. The paper also introduces a new controller type, Predictive PID, and justifies its usage for regulating dead-time dominant integrating crushing processes.