Modeling and control of continuous tumble mixing of granular materials.

摘要

An approach to automatic control of a continuous tumble mixer of powders is presented. The control system is based on an ideal model that describes the mixer dynamics where the controlled variables are the outlet flow from the mixer and the variance of mixing, while the manipulated variables are the inlet flow of material to mix, with a predetermined ratio of compounds A and B, and the rotational velocity of the mixer. The system illustrates a Multi Input Multi Output (MIMO) control problem, where each manipulated variable affect both controlled variables. A strategy of two feedback PI controllers was successfully implemented, and it was compared to an MPC strategy: The simulations results provided an excellent tool to compare and study stability, effects of overshoots on set-point tracking, performance, robustness and the capacity to reject the effect of load disturbances.