Modeling and on-line optimization of cone crushers
Sammanfattning: This licentiate thesis deals with the Modeling, Control, and On-line optimization of Cone Crushers. Cone crushers are used for size reduction of minerals and are considered as a central element in many mineral processing plants. It consists of a cone rotating eccentrically inside a larger bowl and the particles are crushed in the cavity between these. In spite of its simple construction, the cone crusher represents a complex system from a modeling point of view, as its operation comprises many physical actions that are combined together to give the overall behavior.The main purpose of the work is to have a dynamic model that can predict the ow and the size distribution of the crusher as a function of the main manipulated variables so that realistic simulation of closed loop control strategies can be achieved. The model is based on rst principles and includes many factors that are known to aect the operation of the crusher, e.g operation of the crusher with two dierent materials. For the control of the crusher, a number of dierent approaches were considered. First, a simple PI controller of the percentage of large material in the output produced was simulated. It is known and also predicted by the model that the cone crusher's total throughput depends on the Eccentric Speed, and exhibits a quasi-concave response with respect to this variable.On-line optimization of the throughput is suggested to be based on the concept of Extremum Seeking Control (ESC).Two dierent methods of ESC were applied. The classic Band Pass Filters based approach, and the Extended Kalman Filter Based approach. Both methods were modied in order to achieve improved performance. These modications can be applied on other plants as well. Simulations of the closed loop for the two methods have demonstrated the applicability of ESC for optimizing the crusher on-line. The optimum operating point was reached in all cases, leading to improvement of the performance of the crusher.
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