Control Strategy of Ball Mill Based on Disturbance Observer and a Virtual Analyzer of Overload

Purpose of research.. Increasing the ore productivity of the grinding mill under the influence of external disturbances, preventing overloading of the mill in operating conditions close to overloading.

Methods. To achieve this goal, it is proposed a new automatic control system (ACS) for ore volumetric filling of grate-discharge ball mill in a closed grinding cycle using model predictive control and active disturbance observer (MPC-DOB). And in addition, virtual analyzer (VA) of the ore weight in the mill based on the developed model of the grinding process is proposed for mill overload control. The ACS was tested on a laboratory installation with the mill PC-model in Simulink and the PLC based implementation of control algorithms. 

Results. MPC-DOB was compared with other ACS based on PID, MPC controllers for various test scenarios and show high performance under the influence of sinusoidal and step disturbances by reducing relative standard deviation (RSD) by 4-7 %. The combined using of MPC-DOB and VA made it possible to increase the grinding process ore productivity by 1 % and improve the quality of mill vibration stabilization in the mode of functional instability.  Conclusion. The developed ACS can be used in the process control system for grinding in a ball mill with a grate to increase the productivity and stability of the technological process and reduce the energy consumption of the mill drive.

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